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  • 1.
    Abedan Kondori, Farid
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Bring Your Body into Action: Body Gesture Detection, Tracking, and Analysis for Natural Interaction2014Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Due to the large influx of computers in our daily lives, human-computer interaction has become crucially important. For a long time, focusing on what users need has been critical for designing interaction methods. However, new perspective tends to extend this attitude to encompass how human desires, interests, and ambitions can be met and supported. This implies that the way we interact with computers should be revisited. Centralizing human values rather than user needs is of the utmost importance for providing new interaction techniques. These values drive our decisions and actions, and are essential to what makes us human. This motivated us to introduce new interaction methods that will support human values, particularly human well-being.

    The aim of this thesis is to design new interaction methods that will empower human to have a healthy, intuitive, and pleasurable interaction with tomorrow’s digital world. In order to achieve this aim, this research is concerned with developing theories and techniques for exploring interaction methods beyond keyboard and mouse, utilizing human body. Therefore, this thesis addresses a very fundamental problem, human motion analysis.

    Technical contributions of this thesis introduce computer vision-based, marker-less systems to estimate and analyze body motion. The main focus of this research work is on head and hand motion analysis due to the fact that they are the most frequently used body parts for interacting with computers. This thesis gives an insight into the technical challenges and provides new perspectives and robust techniques for solving the problem.

  • 2.
    Abedan Kondori, Farid
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Yousefi, Shahrouz
    KTH Royal Institute of Technology, Department of Media Technology and Interaction Design.
    Kouma, Jean-Paul
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Liu, Li
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Li, Haibo
    KTH Royal Institute of Technology, Department of Media Technology and Interaction Design.
    Direct hand pose estimation for immersive gestural interaction2015In: Pattern Recognition Letters, ISSN 0167-8655, E-ISSN 1872-7344, Vol. 66, p. 91-99Article in journal (Refereed)
    Abstract [en]

    This paper presents a novel approach for performing intuitive gesture based interaction using depth data acquired by Kinect. The main challenge to enable immersive gestural interaction is dynamic gesture recognition. This problem can be formulated as a combination of two tasks; gesture recognition and gesture pose estimation. Incorporation of fast and robust pose estimation method would lessen the burden to a great extent. In this paper we propose a direct method for real-time hand pose estimation. Based on the range images, a new version of optical flow constraint equation is derived, which can be utilized to directly estimate 3D hand motion without any need of imposing other constraints. Extensive experiments illustrate that the proposed approach performs properly in real-time with high accuracy. As a proof of concept, we demonstrate the system performance in 3D object manipulation On two different setups; desktop computing, and mobile platform. This reveals the system capability to accommodate different interaction procedures. In addition, a user study is conducted to evaluate learnability, user experience and interaction quality in 3D gestural interaction in comparison to 2D touchscreen interaction.

  • 3.
    Abedan Kondori, Farid
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Yousefi, Shahrouz
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Li, Haibo
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Direct three-dimensional head pose estimation from Kinect-type sensors2014In: Electronics Letters, ISSN 0013-5194, E-ISSN 1350-911X, Vol. 50, no 4, p. 268-270Article in journal (Refereed)
    Abstract [en]

    A direct method for recovering three-dimensional (3D) head motion parameters from a sequence of range images acquired by Kinect sensors is presented. Based on the range images, a new version of the optical flow constraint equation is derived, which can be used to directly estimate 3D motion parameters without any need of imposing other constraints. Since all calculations with the new constraint equation are based on the range images, Z(xyt), the existing techniques and experiences developed and accumulated on the topic of motion from optical flow can be directly applied simply by treating the range images as normal intensity images I(xyt). In this reported work, it is demonstrated how to employ the new optical flow constraint equation to recover the 3D motion of a moving head from the sequences of range images, and furthermore, how to use an old trick to handle the case when the optical flow is large. It is shown, in the end, that the performance of the proposed approach is comparable with that of some of the state-of-the-art approaches that use range data to recover 3D motion parameters.

  • 4.
    Abedan Kondori, Farid
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Yousefi, Shahrouz
    KTH Royal Institute of Technology, Department of Media Technology and Interaction Design.
    Liu, Li
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Li, Haibo
    KTH Royal Institute of Technology, Department of Media Technology and Interaction Design.
    Head operated electric wheelchair2014In: IEEE Southwest Symposium on Image Analysis and Interpretation (SSIAI 2014), IEEE , 2014, p. 53-56Conference paper (Refereed)
    Abstract [en]

    Currently, the most common way to control an electric wheelchair is to use joystick. However, there are some individuals unable to operate joystick-driven electric wheelchairs due to sever physical disabilities, like quadriplegia patients. This paper proposes a novel head pose estimation method to assist such patients. Head motion parameters are employed to control and drive an electric wheelchair. We introduce a direct method for estimating user head motion, based on a sequence of range images captured by Kinect. In this work, we derive new version of the optical flow constraint equation for range images. We show how the new equation can be used to estimate head motion directly. Experimental results reveal that the proposed system works with high accuracy in real-time. We also show simulation results for navigating the electric wheelchair by recovering user head motion.

  • 5.
    Abu-Hamam, Anas
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Li, Haibo
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Georgakis, Apostolos
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Understanding Web Users Behaviour From A Web Video Camera2003Report (Other academic)
    Abstract [en]

    To develop a Real-Time system, which can capture and track the web user’s head motion. Based on the head motion information, the system should be able to identify whether the user is interested in the current homepage or not. A future system property would be to find out in which area of the homepage the user’s interest is moving.

  • 6.
    Algers, Björn
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Stereo Camera Calibration Accuracy in Real-time Car Angles Estimation for Vision Driver Assistance and Autonomous Driving2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The automotive safety company Veoneer are producers of high end driver visual assistance systems, but the knowledge about the absolute accuracy of their dynamic calibration algorithms that estimate the vehicle’s orientation is limited.

    In this thesis, a novel measurement system is proposed to be used in gathering reference data of a vehicle’s orientation as it is in motion, more specifically the pitch and roll angle of the vehicle. Focus has been to estimate how the uncertainty of the measurement system is affected by errors introduced during its construction, and to evaluate its potential in being a viable tool in gathering reference data for algorithm performance evaluation.

    The system consisted of three laser distance sensors mounted on the body of the vehicle, and a range of data acquisition sequences with different perturbations were performed by driving along a stretch of road in Linköping with weights loaded in the vehicle. The reference data were compared to camera system data where the bias of the calculated angles were estimated, along with the dynamic behaviour of the camera system algorithms. The experimental results showed that the accuracy of the system exceeded 0.1 degrees for both pitch and roll, but no conclusions about the bias of the algorithms could be drawn as there were systematic errors present in the measurements.

  • 7.
    Augustian, Midhumol
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    ur Réhman, Shafiq
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Sandvig, Axel
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience. Norwegian University of Science and Technology (NTNU), Norway.
    Kotikawatte, Thivra
    Umeå University, Faculty of Medicine, Department of Pharmacology and Clinical Neuroscience.
    Yongcui, Mi
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Evensmoen, Hallvard Røe
    Norwegian University of Science and Technology (NTNU), Norway.
    EEG Analysis from Motor Imagery to Control a Forestry Crane2018In: Intelligent Human Systems Integration (IHSI 2018) / [ed] Karwowski, Waldemar, Ahram, Tareq, 2018, Vol. 722, p. 281-286Conference paper (Refereed)
    Abstract [en]

    Brain-computer interface (BCI) systems can provide people with ability to communicate and control real world systems using neural activities. Therefore, it makes sense to develop an assistive framework for command and control of a future robotic system which can assist the human robot collaboration. In this paper, we have employed electroencephalographic (EEG) signals recorded by electrodes placed over the scalp. The human-hand movement based motor imagery mentalization is used to collect brain signals over the motor cortex area. The collected µ-wave (8–13 Hz) EEG signals were analyzed with event-related desynchronization/synchronization (ERD/ERS) quantification to extract a threshold between hand grip and release movement and this information can be used to control forestry crane grasping and release functionality. The experiment was performed with four healthy persons to demonstrate the proof-of concept BCI system. From this study, it is demonstrated that the proposed method has potential to assist the manual operation of crane operators performing advanced task with heavy cognitive work load.

  • 8.
    Cedervall, Roger
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Development of a new wheel independent speed sensor for trains2017Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A ballasted railway track consists primarily of two rails discretely supported by sleepers. When a train passes over a sleeper a small vertical force arises due to the dynamic stiffness of the track. This force can be detected by an accelerometer mounted on the train. By analyzing the frequency content of the accelerometer data, it is possible to determine at what frequency the train is passing the sleepers. The train speed is obtained by multiplying this frequency with the distance between the sleepers. This work focuses on the development of an algorithm which identifies and tracks the measured vertical accelerations corresponding to the sleeper crossings, to produce an estimate of the train speed.

    The frequency content of the measured vertical accelerations are analyzed by performing a Fourier transform. A Blackman-Harris window is used to ensure periodicity of the signal and the signal is zero-padded to increase frequency resolution. The search for the sleeper crossing frequency is constrained using knowledge of the previous speed estimate when available and the maximum vehicle acceleration. The peak in the frequency spectrum which corresponds to the sleeper crossings has been observed to be the largest peak within the region of interest, especially at higher speeds. The root mean square value of the vertical accelerations were used as a criterion for standstill as this was observed to be a good indicator of movement.

    Two mounting locations for the accelerometer have been investigated; the axle-box and the car-body. The axle-box is the preferred mounting location due to the higher amplitude of the vertical accelerations which makes it possible identify sleeper crossings at lower speeds. It has also been found that the usage of combing two accelerometers improved the overall result.

    Measurements have been received from the tracks at Stockholm metro and the high-speed train Zefiro on the Velim test track, Czech Republic. Using the Zefiro measurements, the algorithm shows very promising results and can continuously track the sleeper passing peak with an error estimate of ±  m/s. The Stockholm metro measurements posed a more difficult case since there were many start and stops at low speeds, but the algorithm follows the sleeper passing peak except for a few cases where the estimate becomes temporarily erroneous.

  • 9.
    Claesson, Kenji
    Umeå University, Faculty of Science and Technology, Physics.
    Implementation and Validation of Independent Vector Analysis2010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This Master’s Thesis was part of the project called Multimodalanalysis at the Depart-ment of Biomedical Engineering and Informatics at the Ume˚ University Hospital inUme˚ Sweden. The aim of the project is to develop multivariate measurement anda,analysis methods of the skeletal muscle physiology. One of the methods used to scanthe muscle is functional ultrasound. In a study performed by the project group datawas aquired, where test subjects were instructed to follow a certain exercise scheme,which was measured. Since there currently is no superior method to analyze the result-ing data (in form of ultrasound video sequences) several methods are being looked at.One considered method is called Independent Vector Analysis (IVA). IVA is a statisticalmethod to find independent components in a mix of components. This Master’s Thesisis about segmenting and analyzing the ultrasound images with help of IVA, to validateif it is a suitable method for this kind of tasks.First the algorithm was tested on generated mixed data to find out how well itperformed. The results were very accurate, considering that the method only usesapproximations. Some expected variation from the true value occured though.When the algorithm was considered performing to satisfactory, it was tested on thedata gathered by the study and the result can very well reflect an approximation of truesolution, since the resulting segmented signals seem to move in a possible way. But themethod has weak sides (which have been tried to be minimized) and all error analysishas been done by human eye, which definitly is a week point. But for the time being itis more important to analyze trends in the signals, rather than analyze exact numbers.So as long as the signals behave in a realistic way the result can not be said to becompletley wrong. So the overall results of the method were deemed adequate for the application at hand.

  • 10.
    Darvish, Ali Mohammad
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Asymmetrical Principal Component Analysis Video Coding in the Frequency Domain2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The past few years have seen a rapid development in the area of image and video compression. With wide use of computers and consequently need for large scale storing and transmission of data therefore, efficient methods for storing and transmission of data have become an important issue of nowadays. Video compression is minimizing the number of bytes for each frame without degrading the quality of the frame. The reduction in frame size allows more frames to be transmitted through the internet and it also reduces the time required for frames to be sent over the network. Asymmetrical principal component analysis (aPCA) [1] and discrete wavelet transform [2] are two important techniques used for video compression in our implementation.In this thesis, we used aPCA for compression of facial video sequence. The idea behind aPCA is to use a part of the frame for encoding while using the entire frame for decoding. It can efficiently be used to reduce the complexity of encoding and decoding with only a slight decrease in reconstruction quality.Discrete wavelet transform decomposes the frames into subband images in different frequency domains where most of the information is stored in the low frequency subband (it is called LL). The stored information in low subband can be used for encoding in aPCA algorithm. Due to the very low amount of information which is used for encoding, the high reduction of complexity for encoding is achieved.

  • 11.
    Ehatisham-ul-Haq, Muhammad
    et al.
    Faculty of Telecom and Information Engineering, University of Engineering and Technology, Taxila, Punjab, Pakistan.
    Awais Azam, Muhammad
    Faculty of Telecom and Information Engineering, University of Engineering and Technology, Taxila, Punjab, Pakistan.
    Naeem, Usman
    School of Architecture, Computing and Engineering, University of East London, United Kingdom.
    Ur Rèhman, Shafiq
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Khaild, Asra
    Department of Computer Science, COMSATS Institute of Information Technology, Wah Campus, Pakistan.
    Identifying smartphone users based on their activity patterns via mobile sensing2017In: Procedia Computer Science, ISSN 1877-0509, E-ISSN 1877-0509, Vol. 113, p. 202-209Article in journal (Refereed)
    Abstract [en]

    Smartphones are ubiquitous devices that enable users to perform many of their routine tasks anytime and anywhere. With the advancement in information technology, smartphones are now equipped with sensing and networking capabilities that provide context-awareness for a wide range of applications. Due to ease of use and access, many users are using smartphones to store their private data, such as personal identifiers and bank account details. This type of sensitive data can be vulnerable if the device gets lost or stolen. The existing methods for securing mobile devices, including passwords, PINs and pattern locks are susceptible to many bouts such as smudge attacks. This paper proposes a novel framework to protect sensitive data on smartphones by identifying smartphone users based on their behavioral traits using smartphone embedded sensors. A series of experiments have been conducted for validating the proposed framework, which demonstrate its effectiveness.

  • 12.
    Ekström, Evelina
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Evaluation and optimization of PolyCor - a single-use Coriolis flowmeter2018Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    In the pharmaceutical industry it has become common to use single-use components in the production line to save time and money. Therefore, a team at General Electric started to develop a single-use Coriolis flowmeter, PolyCor M13, targeted at liquid chromatography systems. A Coriolis flowmeter in this embodiment is simply a tube put into vibration at its natural frequency. When there is a flow through the vibrating tube the Coriolis force arises, causing a phase shift of the pickup signals on each side of the actuator. This phase shift is linearly proportional to the mass flow through the tube.

     The approach of PolyCor M13 is a separate oscillator and flow path. The oscillator is a metal skeleton holding the flow path, a silicone tube. The initial requirement flow range was 0.16-7.8 kg/min with an error less than 2%. Initial tests indicated that the prototype fulfilled these requirements at ambient temperature. This thesis is a further evaluation of the performance of M13. The main goal was to establish the pressure and temperature dependence and find an model to compensate for these. Investigation if M13 can manage flows up to 10 kg/min was also a part of this scope.

     Control measurements showed that flows less than 2 kg/min could give large errors, over 5%. Flows higher than 2 kg/min up to 10 kg/min had errors less than 5%. The error was determined using a reference mass flow. By increasing the pressure in the system, from 0 to 4 bar, the error increased substantially. For the two lowest flows tested, 0.5 and 1 kg/min, the computed mass flows gave errors over 100%. The error for 2 kg/min was around 70% and the error successively decreased for higher flows and at 6-10 kg/min the error was around 20%. A compensation model was established by fitting a polynomial to the data. The best compensation model managed to reduce the error on new test data to 5-10% for flows between 2-10 kg/min. For smaller flows the error was still high but less than 100%.

     Significant deviation from the temperature at which the proportionality was determined caused large errors. Errors for low flows, 0.5 and 1 kg/min, gave errors mainly up to around 50% but some errors were over 100%. For higher flows, 2-10 kg/min the error is up to 30% with some occasional errors up to 60%. The procedure to establish a compensation model for temperature was similar to that for the pressure compensation model. The best model for temperature compensation managed to reduce the error to 5-10% for flows between 2-10 kg/min. For lower flows the error was still high but slightly better, some error was still over 100%.

     In conclusion, M13 is not as reliable as initial tests showed. The error limit is exceeded, especially for flows less than 2 kg/min. A more suitable range would be 2-10 kg/min. The pressure and temperature effects have an enormous impact but can be compensated to some extent. Since the accuracy of M13 is not perfect, errors less than 5% can be difficult to obtain in the current state of M13.

  • 13.
    Ekström, Mattias
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Acoustic feedback suppression in audio mixer for PA applications2017Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    When a speaker is addressing an audience, a PA system consisting of a microphone and a loudspeaker is often used. If the microphone picks up too much of the loudspeaker energy, acoustic feedback in the form of an unwanted characteristic howling can occur. Limes Audio is a software company that specializes in improving sound quality in digital communications, mainly conference telephony, and has developed a reference product, the Magneto mixer, to demonstrate the capability of their software TrueVoice. The company now wishes to expand the field of usage for the Magneto mixer to enable it to work as a microphone mixer in PA scenarios, and for this, a feedback suppression feature is needed. This master’s thesis aims at surveying the market and the literature in the field and specifying the requirements for a feedback suppression feature. Three methods for suppressing howling feedback are evaluated through simulations and compared in terms of maximum stable gain (MSG) and subjective listening experience. The method that performed the best based on these criteria was acoustic feedback cancellation with a 5 Hz frequency shift on the loudspeaker signal. This method makes use of an adaptive filter to model the acoustic feedback path and to remove the feedback component from the microphone signal. In the simulations, the method was able to increase the stable gain by approximately 10 dB while maintaining a good sound quality.

  • 14.
    Forsgren, Fredrik
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Active Noise Control in Forest Machines2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Achieving a low noise level is of great interest to the forest machine industry. Traditionally this is obtained by using passive noise reduction, i.e. by using materials for sound isolation and sound absorption. Especially designs to attenuate low frequency noise tend to be bulky and impractical from an installation point of view. An alternative solution to the problem is to use active noise control (ANC). The basic principle of ANC is to generate an anti-noise signal designed to destructively interfere with the unwanted noise.

    In this thesis two algorithms (Feedback FxLMS and Feedforward FxLMS) are implemented and evaluated for use in the ANC-system. The ANC-system is tuned to the specific environment in the driver’s cabin of a Komatsu forest machine. The algorithms are first tested in a simulated environment and then in real-time inside a forest machine.

    Simulations are made both in Matlab and in C using both generated signals and recorded signals. The C code is implemented on the Analog Devices Blackfin DSP card BF526.

    The result showed a significantly reduction of the sound pressure level (SPL) in the driver’s cabin. The noise attenuation obtained using the Feedback FxLMS was approximately 14 dB for a tonal 100 Hz signal and 11 dB using recorded engine noise from a forest machine at 850 rpm.

  • 15.
    Forsman, Mona
    et al.
    Department of Forest Resource Management, Swedish University of Agricultural Sciences.
    Börlin, Niclas
    Umeå University, Faculty of Science and Technology, Department of Computing Science.
    Holmgren, Johan
    Department of Forest Resource Management, Swedish University of Agricultural Sciences.
    Estimation of tree stem attributes using terrestrial photogrammetry2012In: International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Copernicus Gesellschaft , 2012, p. B5-261-B5-265Conference paper (Other academic)
    Abstract [en]

    The objective of this work was to create a method to measure stem attributes of standing trees on field plots in the forest using terrestrial photogrammetry. The primary attributes of interest are the position and the diameter at breast height (DBH).

    The developed method creates point clouds from image from three or more calibrated cameras attached to a calibrated rig. SIFT features in multiple images in combination with epipolar line filtering are used to make high quality matching in images with large amounts of similar features and many occlusions. After projection of the point cloud to a simulated ground plane, RANSAC filtering is applied, followed by circle fitting to the remaining points.

    To evaluate the algorithm, a camera rig of five Canon digital system cameras with a baseline of 123 cm and up to 40 cm offset in height was constructed. The rig was used in a field campaign at the Remningstorp forest test area in southern Sweden. Ground truth was collected manually by surveying and manual measurements.

    Initial results show estimated tree stem diameters within 10% of the ground truth. This suggest that terrestrial photogrammetry is a viable method to measure tree stem diameters on circular field plots.

  • 16.
    Georgakis, Apostolos
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Li, Haibo
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Document distances using the Zipf distribution and a novel metric2003Report (Other academic)
    Abstract [en]

    A novel metric is proposed in the present report for the evaluation of the goodness-of-fit criterion between the distribution functions of two samples. We extend the usage of the proposed criterion for the case of the generalized Zipf distribution. Detailed mathematical analysis of the proposed metric, which is embodied in a hypothesis testing, is also provided.

  • 17.
    Georgakis, Apostolos
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Li, Haibo
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Web prefetching through automatic categorization2004Report (Other academic)
    Abstract [en]

    The present report provides a novel transparent and speculative algorithm for content based web page prefetching. The proposed algorithm relies on a user profile that is dynamically generated when the user is browsing the Internet and is updated over time. The objective is to reduce the user perceived latency by anticipating future actions. In doing so the adaboost algorithm is used in order to automatically annotate the outbound links of a page to a predefined set of “labels”. Afterwards, the links that correspond to labels relevant to the user’s preferences are pre-fetched in an effort to reduce the perceived latency when the user is surfing the Internet. A comparison between the proposed algorithm against two other pre-fetching algorithms yield improved cache-hit rates given a moderate bandwidth overhead.

  • 18.
    Halawani, Alaa
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. Computer Engineering Department, Palestine Polytechnic University, Hebron, Palestine.
    Li, Haibo
    KTH.
    100 lines of code for shape-based object localization2016In: Pattern Recognition, ISSN 0031-3203, E-ISSN 1873-5142, Vol. 60, p. 458-472Article in journal (Refereed)
    Abstract [en]

    We introduce a simple and effective concept for localizing objects in densely cluttered edge images based on shape information. The shape information is characterized by a binary template of the object's contour, provided to search for object instances in the image. We adopt a segment-based search strategy, in which the template is divided into a set of segments. In this work, we propose our own segment representation that we callone-pixel segment (OPS), in which each pixel in the template is treated as a separate segment. This is done to achieve high flexibility that is required to account for intra-class variations. OPS representation can also handle scale changes effectively. A dynamic programming algorithm uses the OPS representation to realize the search process, enabling a detailed localization of the object boundaries in the image. The concept's simplicity is reflected in the ease of implementation, as the paper's title suggests. The algorithm works directly with very noisy edge images extracted using the Canny edge detector, without the need for any preprocessing or learning steps. We present our experiments and show that our results outperform those of very powerful, state-of-the-art algorithms.

  • 19.
    Halawani, Alaa
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Li, Haibo
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Anani, Adi
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Building eye contact in e-learning through head-eye coordination2011In: International Journal of Social Robotics, ISSN 1875-4791, Vol. 3, no 1, p. 95-106Article in journal (Refereed)
    Abstract [en]

    Video conferencing is a very effective tool to use for e-learning. Most of the available video conferencing systems suffer a main drawback represented by the lack of eye contact between participants. In this paper we present a new scheme for building eye contact in e-learning sessions. The scheme assumes a video conferencing session with “one teacher many students” arrangement. In our system, eye contact is achieved without the need for any gaze estimation technique. Instead, we “generate the gaze” by allowing the user communicate his visual attention to the system through head-eye coordination. To enable real time and precise headeye coordination, a head motion tracking technique is required. Unlike traditional head tracking systems, our procedure suggests mounting the camera on the user’s head rather than in front of it. This configuration achieves much better resolution and thus leads to better tracking results. Promising results obtained from both demo and real time experiments demonstrate the effectiveness and efficiency of the proposed scheme. Although this paper concentrates on elearning, the proposed concept can be easily extended to the world of interaction with social robotics, in which introducing eye contact between humans and robots would be of great advantage.

  • 20.
    Johansson, Daniel
    Umeå University, Faculty of Science and Technology, Department of Physics.
    Automatic microphone mixing for a daisy chain connected multi-microphone speakerphone setup2016Independent thesis Advanced level (degree of Master (Two Years)), 300 HE creditsStudent thesis
    Abstract [en]

    Speakerphones are an essential part of making remote meetings with groups of people possible. An important ingredient to achieve a satisfying teleconferencing experience is good audio pickup quality of the speakerphone.

    Limes Audio supports a multi-microphone speakerphone reference design with daisy chain connectivity. This implies a structure where several microphone signals need to be mixed down to one output channel for transmission.This thesis is focused on the challenges of automatically mixing down these multiple microphone signals to one output with minimum amount of reverberation and extraneous noise.

    In this thesis, I thoroughly analyze the automatic microphone mixing problem and the existing implementation from Limes Audio. I review a selection of alternative mixing methods, propose a new method, and compare the performance of them using objective speech quality and intelligibility measures.

    One significant part of the process has been to define a suitable test protocol for assessing the performance of different mixer implementations, and the project has resulted in a test procedure which could be used for evaluating the automaticmixing performance of competing products in the future.

    The results from my evaluation show that the best quality is achieved by using a single microphone per speaker. The current method tries to do this and achieves relatively good performance compared to the alternatives. The proposed method with somewhat different characteristics performs worse in some scenarios, but better in others.

  • 21.
    Kadkhodaee, Amir
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Analysis of the short-term interactions between cardiovascular signals during the Deep Breathing test2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Analysis of the so called Heart Rate Variability (HRV) is a method for non-invasive assessment of autonomic function disturbances. HRV is based on the analysis of the beat-to-beat fluctuations in heart rate which are considered as a reflection of cardiac autonomic modulation. Reduced HRV is commonly found in patients with the disease Familial

    Amyloidotic Polyneuropathy (FAP), where autonomic deregulation is a common problem.

    In this study the focus was on the autonomic function test Deep Breathing, where the study group consisted of FAP patients with both regular and irregular HRV patterns, as well as healthy control subjects. In addition to traditional univariate HRV analysis, the influence of respiration was included by coherence and transfer function analysis. The system modeling was performed by two different methods: Fourier-Based (FB) and Parametric Modeling (PM). In the PM method coherence was estimated based on bivariate autoregressive modeling, whereas transfer function analysis was performed based on the State Space (SS) model of the relation between respiration (input) and HRV (output).

    To evaluate the performance of the different methods that were used in this study, the analysis was first performed using synthesized signals. The synthesized signals were generated based on the assumption that the HRV and respiration signals often are nearly

    sinusoida1. The results of this analysis, where the true gain of the transfer function was known, could be compared with the FB method and PM method and it showed that in most sets of synthesized data, the most accurate results were obtained by the FB method.

    However, for some sets of data, a better result was obtained in the estimated transfer function by using the SS model, i.e., the PM method.

    The main problem with the PM method is the selection of an appropriate model order. The results for both synthesized data and real data showed that increasing the number of order is not necessarily a good choice to have a more accurate result in PM method. Although the automatically determined "best" model order often appeared to give acceptable results, a fixed model order in the range 5-8 also might be a good compromise.

  • 22.
    Karlsson, Johannes
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Low-Complexity Encoding in Block-Based Hybrid Video Codecs by Moving Motion Estimation to Decoder Side2014In: International Journal of Adaptive, Resilient and Autonomic Systems, ISSN 1947-9220, E-ISSN 1947-9239, Vol. 5, no 1, p. 19-29Article in journal (Refereed)
    Abstract [en]

    In this paper the authors present an approach to provide efficient low-complexity encoding for the block-based video coding scheme. The authors present a method based on removing the most time-consuming task, that is motion estimation, from the encoder. Instead the decoder will perform motion prediction based on the available decoded frame and send the predicted motion vectors to the encoder. The results presented are based on a modified H.264 implementation. The results show that this approach can provide rather good coding efficiency even for relatively high network delays.

  • 23.
    Khan, Muhammad Sikandar Lal
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Presence through actions: theories, concepts, and implementations2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    During face-to-face meetings, humans use multimodal information, including verbal information, visual information, body language, facial expressions, and other non-verbal gestures. In contrast, during computer-mediated-communication (CMC), humans rely either on mono-modal information such as text-only, voice-only, or video-only or on bi-modal information by using audiovisual modalities such as video teleconferencing. Psychologically, the difference between the two lies in the level of the subjective experience of presence, where people perceive a reduced feeling of presence in the case of CMC. Despite the current advancements in CMC, it is still far from face-to-face communication, especially in terms of the experience of presence.

    This thesis aims to introduce new concepts, theories, and technologies for presence design where the core is actions for creating presence. Thus, the contribution of the thesis can be divided into a technical contribution and a knowledge contribution. Technically, this thesis details novel technologies for improving presence experience during mediated communication (video teleconferencing). The proposed technologies include action robots (including a telepresence mechatronic robot (TEBoT) and a face robot), embodied control techniques (head orientation modeling and virtual reality headset based collaboration), and face reconstruction/retrieval algorithms. The introduced technologies enable action possibilities and embodied interactions that improve the presence experience between the distantly located participants. The novel setups were put into real experimental scenarios, and the well-known social, spatial, and gaze related problems were analyzed.

    The developed technologies and the results of the experiments led to the knowledge contribution of this thesis. In terms of knowledge contribution, this thesis presents a more general theoretical conceptual framework for mediated communication technologies. This conceptual framework can guide telepresence researchers toward the development of appropriate technologies for mediated communication applications. Furthermore, this thesis also presents a novel strong concept – presence through actions - that brings in philosophical understandings for developing presence- related technologies. The strong concept - presence through actions is an intermediate-level knowledge that proposes a new way of creating and developing future 'presence artifacts'. Presence- through actions is an action-oriented phenomenological approach to presence that differs from traditional immersive presence approaches that are based (implicitly) on rationalist, internalist views.

  • 24.
    Khan, Muhammad Sikandar Lal
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    ur Réhman, Shafiq
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Li, Haibo
    Action Augmented Real Virtuality Design for Presence2017In: Article in journal (Refereed)
    Abstract [en]

    This article addresses an important question of howto design a video teleconferencing setup to increase the experienceof spatial and social presence. The traditional video teleconferencingsetups are abortive in presenting nonverbal behaviors ashumans express in face to face communication, which results inlack of presence. In order to address this issue, in this article,we first present a conceptual framework of presence for videoteleconferencing.We introduce a modern presence concept namedreal virtuality and propose a new way of achieving real virtuality.Our new way is based on bodily or artifact actions to increase thepresence and we named this concept presence through actions.Using this new concept, we present a design of a novel actionaugmentedreal virtuality prototype which consider the challengesrelated to design of an action prototype, action embodimentand face representation. Our action prototype is telepresencemechatronic robot (TEBoT) and action embodiment is done byhead mounted display (HMD). The face representation solvesthe problem of face occlusion introduced by HMD. The novelcombination of HMD, TEBoT and face representation algorithmis put into real video teleconferencing scenario to see howsuccessful is such a system in solving challenges related to spatialand social presence. We have performed a user study where theinvited participants were requested to experience our novel setupand compare it with the traditional video teleconferencing setup.The results show that the action capabilities not only increasethe spatial presence but also increase the social presence of aremote person among local collaborators.

  • 25.
    Khan, Muhammad Sikandar Lal
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    ur Réhman, Shafiq
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Embodied head gesture and distance education2015In: 6th International Conference on Applied Human Factors and Ergonomics (AHFE 2015) and the Affiliated Conferences, 2015, Vol. 3, p. 2034-2041Conference paper (Refereed)
    Abstract [en]

    Traditional distance education settings are usually based on video teleconferencing scenarios where human emotions and social presence are only expressed by the facial and vocal expressions which are not enough for complete presence; our bodily gestures and actions play a vital role in understanding exact meaning of communication patterns; especially in teaching-learning scenarios. The bodily gestures especially head movements offer cues to understand contextual knowledge during conversational dialogue. In this work, we have considered the tutor’s head gesture embodiment for educational assistive robot and compared the results with the standard audio-video tele-conferencing scenarios used in online education. We have used Embodied Telepresence System (ETS) to investigate the distance communication for online education setting. Our ETS emulates the head gestures of the human tutor for distance education scenario. Our experimental study includes ten able-bodied subjects (5 male and 5 female) from various countries. These participants were asked to participate in online education scenario through i) a traditional video conferencing tool, i.e. Skype and ii) an extended setup based on ETS. The statistical analysis is done on the results which indicates the effectiveness of our novel embodied head gesture based approach in distance education setting. Our experimental studies show that the proposed design of embodied head gesture based ETS is able to improve the user engagement in distance education.

  • 26.
    Khan, Muhammad Sikandar Lal
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    ur Réhman, Shafiq
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Lu, Zhihan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Li, Haibo
    Royal Institute of Technology (KTH), Stockholm, Sweden.
    Head Orientation Modeling: Geometric Head Pose Estimation using Monocular Camera2013In: Proceedings of the 1st IEEE/IIAE International Conference on Intelligent Systems and Image Processing 2013, 2013, p. 149-153Conference paper (Refereed)
    Abstract [en]

    In this paper we propose a simple and novel method for head pose estimation using 3D geometric modeling. Our algorithm initially employs Haar-like features to detect face and facial features area (more precisely eyes). For robust tracking of these regions; it also uses Tracking- Learning- Detection(TLD) frame work in a given video sequence. Based on two human eye-areas, we model a pivot point using distance measure devised by anthropometric statistic and MPEG-4 coding scheme. This simple geometrical approach relies on human facial feature structure on the camera-view plane to estimate yaw, pitch and roll of the human head. The accuracy and effectiveness of our proposed method is reported on live video sequence considering head mounted inertial measurement unit (IMU).

  • 27.
    Khan, Muhammad Sikandar Lal
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    ur Réhman, Shafiq
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Mi, Yongcui
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Li, Haibo
    Moveable facial features in a Social Mediator2017Conference paper (Refereed)
    Abstract [en]

    A brief display of facial features based behavior has a majorimpact on personality perception in human-human communications.Creating such personality traits and representations in a social robot isa challenging task. In this paper, we propose an approach for a roboticface presentation based on moveable 2D facial features and present acomparative study when a synthesized face is projected using three setups;1) 3D mask, 2) 2D screen, and 3) our 2D moveable facial featurebased visualization. We found that robot’s personality and character ishighly influenced by the projected face quality as well as the motion offacial features.

  • 28.
    Khan, Muhammad Sikandar Lal
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    ur Réhman, Shafiq
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Söderström, Ulrik
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Halawani, Alaa
    Li, Haibo
    Face-off: a Face ReconstructionTechnique for Virtual Reality(VR) Scenarios2016In: The 1st Int. Workshop on Egocentric, perception, interaction andcomputing,, 2016Conference paper (Refereed)
    Abstract [en]

    Virtual Reality (VR) headsets occlude a significant portionof human face. The real human face is required in many VR applications,for example, video teleconferencing. This paper proposes a wearable camerasetup-based solution to reconstruct the real face of a person wearingVR headset. Our solution lies in the core of asymmetrical principal componentanalysis (aPCA). A user-specific training model is built usingaPCA with full face, lips and eye region information. During testingphase, lower face region and partial eye information is used to reconstructthe wearer face. Online testing session consists of two phases, i)calibration phase and ii) reconstruction phase. In former, a small calibrationstep is performed to align test information with training data,while the later uses half face information to reconstruct the full face usingaPCA-based trained-data. The proposed approach is validated withqualitative and quantitative analysis.

  • 29. Kleyko, Denis
    et al.
    Hostettler, Roland
    Lyamin, Nikita
    Birk, Wolfgang
    Wiklund, Urban
    Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF).
    Osipov, Evgeny
    Vehicle Classification using Road Side Sensors and Feature-free Data Smashing Approach2016In: 2016 IEEE 19TH INTERNATIONAL CONFERENCE ON INTELLIGENT TRANSPORTATION SYSTEMS (ITSC), IEEE, 2016, p. 1988-1993Conference paper (Refereed)
    Abstract [en]

    The main contribution of this paper is a study of the applicability of data smashing - a recently proposed data mining method - for vehicle classification according to the "Nordic system for intelligent classification of vehicles" standard, using measurements of road surface vibrations and magnetic field disturbances caused by passing vehicles. The main advantage of the studied classification approach is that it, in contrast to the most of traditional machine learning algorithms, does not require the extraction of features from raw signals. The proposed classification approach was evaluated on a large dataset consisting of signals from 3074 vehicles. Hence, a good estimate of the actual classification rate was obtained. The performance was compared to the previously reported results on the same problem for logistic regression. Our results show the potential trade-off between classification accuracy and classification method's development efforts could be achieved.

  • 30.
    Kondori, Farid Abedan
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Liu, Li
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Li, Haibo
    KTH Royal Institue of Technology, Department of Media Technology and Interaction Design, School of Computer Science and Communication.
    Telelife: An immersive media experience for rehabilitation2014In: Proceedings of the 2014 Asia-Pacific Signal and Information Processing Association Annual Summit and Conference (APSIPA 2014), IEEE, 2014Conference paper (Refereed)
    Abstract [en]

    In recent years, emergence of telerehabilitation systems for home-based therapy has altered healthcare systems. Telerehabilitation enables therapists to observe patients status via Internet, thus a patient does not have to visit rehabilitation facilities for every rehabilitation session. Despite the fact that telerehabilitation provides great opportunities, there are two major issues that affect effectiveness of telerehabilitation: relegation of the patient at home, and loss of direct supervision of the therapist. Since patients have no actual interaction with other persons during the rehabilitation period, they will become isolated and gradually lose their social skills. Moreover, without direct supervision of therapists, rehabilitation exercises can be performed with bad compensation strategies that lead to a poor quality recovery. To resolve these issues, we propose telelife, a new concept for future rehabilitation systems. The idea is to use media technology to create a totally new immersive media experience for rehabilitation. In telerehabilitation patients locally execute exercises, and therapists remotely monitor patients' status. In telelife patients, however, remotely perform exercises and therapists locally monitor. Thus, not only telelife enables rehabilitation at distance, but also improves the patients' social competences, and provides direct supervision of therapists. In this paper we introduce telelife to enhance telerehabilitation, and investigate technical challenges and possible methods to achieve telelife.

  • 31.
    Li, Bo
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Jevtic, Aleksandar
    Robosoft,France.
    Söderström, Ulrik
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Ur Réhman, Shafiq
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Li, Haibo
    KTH.
    Fast edge detection by center of mass2013In: The 1st IEEE/IIAE International Conference on Intelligent Systems and Image Processing 2013 (ICISIP2013), Kitakyushu, Japan, 2013, p. 103-110Conference paper (Refereed)
    Abstract [en]

    In this paper, a novel edge detection method that computes image gradient using the concept of Center of Mass (COM) is presented. The algorithm runs with a constant number of operations per pixel independently from its scale by using integral image. Compared with the conventional convolutional edge detector such as Sobel edge detector, the proposed method performs faster when region size is larger than 9×9. The proposed method can be used as framework for multi-scale edge detectors when the goal is to achieve fast performance. Experimental results show that edge detection by COM is competent with Canny edge detection.

  • 32.
    Li, Bo
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Söderström, Ulrik
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Ur Réhman, Shafiq
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Li, Haibo
    KTH.
    Restricted Hysteresis Reduce Redundancy in Edge Detection2013In: Journal of Signal and Information Processing, ISSN 2159-4465, E-ISSN 2159-4481, Vol. 4, no 3B, p. 158-163Article in journal (Refereed)
    Abstract [en]

    In edge detection algorithms, there is a common redundancy problem, especially when the gradient direction is close to -135°, -45°, 45°, and 135°. Double edge effect appears on the edges around these directions. This is caused by the discrete calculation of non-maximum suppression. Many algorithms use edge points as feature for further task such as line extraction, curve detection, matching and recognition. Redundancy is a very important factor of algorithm speed and accuracy. We find that most edge detection algorithms have redundancy of 50% in the worst case and 0% in the best case depending on the edge direction distribution. The common redundancy rate on natural images is approximately between 15% and 20%. Based on Canny’s framework, we propose a restriction in the hysteresis step. Our experiment shows that proposed restricted hysteresis reduce the redundancy successfully.

  • 33.
    Li, Bo
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Ur Réhman, Shafiq
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Söderström, Ulrik
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Li, Haibo
    KTH.
    Independent Thresholds on Multi-scale Gradient Images2013In: The 1st IEEE/IIAE International Conference on Intelligent Systems and Image Processing 2013 (ICISIP2013), Kitakyushu, Japan, 2013, p. 124-131Conference paper (Refereed)
    Abstract [en]

    In this paper we propose a multi-scale edge detection algorithm based on proportional scale summing. Our analysis shows that proportional scale summing successfully improves edge detection rate by applying independent thresholds on multi-scale gradient images. The proposed method improves edge detection and localization by summing gradient images with a proportional parameter cn (c < 1); which ensures that the detected edges are as close as possible to the fine scale. We employ non-maxima suppression and thinning step similar to Canny edge detection framework on the summed gradient images. The proposed method can detect edges successfully and experimental results show that it leads to better edge detection performance than Canny edge detector and scale multiplication edge detector.

  • 34.
    Li, Liu
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    ur Réhman, Shafiq
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Lindahl, Olof
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Li, Haibo
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Vibrotactile chair: A social interface for blind2006In: Proceedings SSBA 2006: Symposium on image analysis, Umeå, March 16-17, 2006 / [ed] Fredrik Georgsson, 1971-, Niclas Börlin, 1968-, Umeå: Umeå universitet. Institutionen för datavetenskap , 2006, p. 117-120Conference paper (Other academic)
    Abstract [en]

    In this paper we present our vibrotactile chair, a social interface for the blind. With this chair the blind can get on-line emotion information from the person he / she is heading to. This greatly enhances communication ability and improve the quality of social life of the blind. In the paper we are discussing technical challenges and design principles behind the chair, and introduce the experimental platform: tactile facial expression appearance recognition system (TEARS)TM".

  • 35.
    Lu, Zhihan
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Sikandar Lal Khan, Muhammad
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    ur Réhman, shafiq
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Hand and Foot Gesture Interaction for Handheld Devices2013In: MM '13 Proceedings of the 21st ACM international conference on Multimedia, New York, NY, USA: ACM , 2013, p. 621-624Conference paper (Refereed)
    Abstract [en]

    In this paper we present hand and foot based immersive multimodal interaction approach for handheld devices. A smart phone based immersive football game is designed as a proof of concept. Our proposed method combines input modalities (i.e. hand & foot) and provides a coordinated output to both modalities along with audio and video. In this work, human foot gesture is detected and tracked using template matching method and Tracking-Learning-Detection (TLD) framework. We evaluated our system's usability through a user study in which we asked participants to evaluate proposed interaction method. Our preliminary evaluation demonstrates the efficiency and ease of use of proposed multimodal interaction approach.

  • 36.
    Löthgren, Pia
    et al.
    Biostokastikum, SLU.
    Yu, Jun
    Biostokastikum, SLU.
    Maximum likelihood estimation of the distributional parameters of the magnitude and phase in magnetic resonance spectroscopy signals2012Conference paper (Refereed)
  • 37.
    Löthgren, Pia
    et al.
    Biostokastikum, SLU.
    Yu, Jun
    Biostokastikum, SLU.
    Maximum likelihood estimation of the parameters of a modified Rice distribution2010Conference paper (Refereed)
  • 38.
    Mejtoft, Thomas
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Bahtiri, Blerand
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Cripps, Helen
    Edith Cowan University.
    Söderström, Ulrik
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Use of Image Recognition of Social Media2017In: ANZMAC 2017: Marketing for Impact: Conference Proceedings / [ed] Linda Robinson, Linda Brennan, Mike Reid, Melbourne, 2017, p. 271-278Conference paper (Refereed)
    Abstract [en]

    Images are central to firms in their use of social media platforms as part of their marketing strategy. Images are a powerful online marketing tool as they allow for engagement and personalisation of marketing content for individual customers. However, images can be a double edge sword in the web 2.0 world, where consumers are able to post content to branded social media sites. This study evaluates the benefits of integrating image recognition into social media from the users perspective. The pilot study undertaken found the majority of the participants thought the possibilities presented for image recognition technology are useful, however they showed concern in relation to their privacy if this technology were to be in social media networks. The results also showed that prior familiarity with this technology does not have any significant impact in how social media users feel about having this technology in social media.

  • 39.
    Olofsson, Peter
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Simulation model of Synchronous Detection in a UV Monitor2015Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    A UV monitor is a part of a modular device that performs separation of protein solutions, for scientific use. It utilizes UV-light absorption to detect the type of proteins passing through it. Noise in the measurement signal affects the accuracy in the detection. For this project, a simulation model was produced in Matlab/Simulink to examine if synchronous detection could be implemented on a current hardware design, and if it could possibly improve the noise performance. Besides answering these questions, filters were designed to be used in a real-world test environment.

  • 40.
    Pizzamiglio, Sara
    et al.
    School of Architecture, Computing and Engineering, University of East London, United Kingdom.
    Naeem, Usman
    School of Architecture, Computing and Engineering, University of East London, United Kingdom.
    Ur Réhman, Shafiq
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics. School of Architecture, Computing and Engineering, University of East London, United Kingdom.
    Sharif, Muhammad Saeed
    School of Architecture, Computing and Engineering, University of East London, United Kingdom.
    Abdalla, Hassan
    School of Architecture, Computing and Engineering, University of East London, United Kingdom.
    Turner, Duncan L.
    Neurorehabilitation Unit, School of Health, Sport and Bioscience, University of East London, United Kingdom.
    A multimodal approach to measure the distraction levels of pedestrians using mobile sensing2017In: Procedia Computer Science, ISSN 1877-0509, E-ISSN 1877-0509, Vol. 113, p. 89-96Article in journal (Refereed)
    Abstract [en]

    The emergence of smart phones has had a positive impact on society as the range of features and automation has allowed people to become more productive while they are on the move. On the contrary, the use of these devices has also become a distraction and hindrance, especially for pedestrians who use their phones whilst walking on the streets. This is reinforced by the fact that pedestrian injuries due to the use of mobile phones has now exceeded mobile phone related driver injuries. This paper describes an approach that measures the different levels of distraction encountered by pedestrians whilst they are walking. To distinguish between the distractions within the brain the proposed work analyses data collected from mobile sensors (accelerometers for movement, mobile EEG for electroencephalogram signals from the brain). The long-term motivation of the proposed work is to provide pedestrians with notifications as they approach potential hazards while they walk on the street conducting multiple tasks such as using a smart phone.

  • 41.
    Ren, Keni
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Karlsson, Johannes
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Li, Haibo
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Interaction Design for Digital Zoo2011In: 2011 IEEE International Conferences on Internet of Things and Cyber, Physical and Social Computing / [ed] Feng Xia, Zhikui Chen, Gang Pan, Laurence T. Yang, and Jianhua Ma, Los Alamitos: IEEE Computer Society, 2011, p. 744-747Conference paper (Refereed)
    Abstract [en]

    This paper proposes a consumer-oriented design of Interaction System applied in a digital zoo. In order to introduce a new experience of visiting zoos, a series of interaction interfaces and applications is designed based on the web surfing. The applications can be located anywhere has Internet connection, used by visitors both in and out of the zoo. In the meantime, zoo staffs can use the system implement to manage the zoo more efficiently on both computer and smart phone. The digital zoo, as the showcase of the interaction system, employed the technology that combine radio frequency identification (RFID), wireless camera sensor network and computer vision system for collecting and processing information in a reality zoo. The Interaction System for digital zoo enhances effective interaction behavior between human-animals, human-human, and management over animals. The design is based on the Digital Djurpark Porject with current deployment a multimedia sensor network for human animal machine interaction. We have evaluated the effect of interaction model in field experiments.

  • 42.
    Shafiq, ur Réhman
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Li, Haibo
    Royal Institute of Technology (KTH), Sweden..
    Using Vibrotactile Language for Multimodal Human Animals Communication and Interaction2014In: Proceedings of the 2014 Workshops on Advances in Computer Entertainment Conference, ACE '14, Association for Computing Machinery (ACM), 2014, p. 1:1-1:5Conference paper (Refereed)
    Abstract [en]

    In this work we aim to facilitate computer mediated multimodal communication and interaction between human and animal based on vibrotactile stimuli. To study and influence the behavior of animals, usually researchers use 2D/3D visual stimuli. However we use vibrotactile pattern based language which provides the opportunity to communicate and interact with animals. We have performed experiment with a vibrotactile based human-animal multimodal communication system to study the effectiveness of vibratory stimuli applied to the animal skin along with audio and visual stimuli. The preliminary results are encouraging and indicate that low-resolution tactual displays are effective in transmitting information.

  • 43.
    Skoog, Siri
    Umeå University, Faculty of Science and Technology, Umeå Institute of Design.
    OCK - Trygghet på offentliga platser2013Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Upplevelsen av att vistas på offentliga platser i större städer är olika. De plats er som upplevs obehagliga och med oro för att utsättas för brott är inte alltid de platser där det statistiskt sätt sker flest brott. Stockholm är en av de städer som jag har tittat på och på vilka platser i storstaden som upplevs på vilket sätt.

    Risken för att utsättas för brott på offentliga platser har ökat och våldsbrott på offentliga platser står för 18 % av antalet anmälda brott och där ingår även misshandel och sexualbrott. Jag har titta närmare på hur man upplever sin trygghet i vardagen och på vilket sätt man kan hindra eller förändra de utsattas beteenden och beslut.

    Mitt arbete har lett fram till en produkt som är personbunden och har som uppgift att visa anhöriga vart man befinner sig och hur man mår för att snabbt kunna ta kontakt med någon om otryggheten ökar och förstärka upplevelsen av kontroll och trygghet. Det resulterade i ett armbandskoncept som har en tjänst kopplat i sig i form av en applikation.

  • 44.
    Sonning, Samuel
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Lindström, Fredrik
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Mejtoft, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    VoxLog: Experiences from practical use of a voice data collection system2013Conference paper (Refereed)
  • 45.
    Sonning, Samuel
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Mejtoft, Thomas
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Ternström, Sten
    KTH.
    Lyberg Åhlander, Viveka
    Lunds universitet.
    Reliability of voice SPL estimations with an air-coupled microphone fastened to the neck2014Conference paper (Refereed)
  • 46.
    Söderström, Ulrik
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Personal Internet-driven maps based on time distances2011In: 2011 IEEE International Conferences on Internet of Things, and Cyber, Physical and Social Computing, Los Alamitos: IEEE Computer Society, 2011, p. 683-686Conference paper (Refereed)
    Abstract [en]

    New ways for map creation are presented. Instead of using the physical distance between locations the distance is measured in time, cost, environmental effect or as a weighted version between the different parameters. The maps will be personal and changed based on the user preferences so the map appearance will be different for different users. In closed-up version the standard map with physical distance should still be used since it is very important that the map resembles the actual surrounding when you are using a map in a local environment. As devices are connected to the Internet the calculation of distance can be made on-line and follow train/flight departures and delays.

  • 47.
    Söderström, Ulrik
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Li, Haibo
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Anonymous video processing for live street view2011In: 2011 IEEE International Conferences on Internet of Things, and Cyber, Physical and Social Computing, Los Alamitos: IEEE Computer Society, 2011, p. 109-113Conference paper (Refereed)
    Abstract [en]

    We propose a method for hiding the identity of persons and objects in video sequences. This type of video sequence will be used in applications where the scene is important but the identity of persons should be unrecognizable, e.g., street view applications. Other parts, such as company logos, names on house doors or license plates on parked cars should not be recognizable as well. This is today solved in street view by blurring out parts of images that are compressed with standard encoding techniques. We propose a method that automatically will blur out parts that are moving but still show the motion. Our technique requires very low bitrates for video transmission; almost as low as for a still image. The low bitrate and the low computational complexity will enable video views of streets at the same costs as for still images.

  • 48.
    Söderström, Ulrik
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Li, Haibo
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Customizing Lip Video into Animation for Wireless Emotional Communication2004Report (Other academic)
    Abstract [en]

    Universal Multimedia Access (UMA) engines are used to adapt the media content to suite different environments.

    The adaptation decision for content used over wireless networks is heavily dependent on the bandwidth needs since the transmission cost over wireless networks is high. We customize lip video into lip animations and through tests we challenge the assumption that the quality is reduced when the transmission cost is reduced. We show that animations are comparable with video when considering human emotion understanding and comparable with audio only when considering transmission cost. We argue that it is important to consider human cognitive and perceptive factors in the decision stage of a UMA engine. This can both improve the user’s perceived quality and lower the transmission cost.

  • 49.
    Söderström, Ulrik
    et al.
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Li, Haibo
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics.
    Emotion recognition and estimation from tracked lip features2004Report (Other academic)
    Abstract [en]

    Humans transmit and display information through the visual image of our lips; information about our speech and our emotions and expressions. By being able to track the movement of the lips, computers can make use of the visual part of the information. This information can be used for multiple purposes. Other research has mainly been focused on using lip tracking for speechreading, but here we focus on how to make use of tracked lip features for emotions. We have found that people are better at interpreting basic emotions displayed through an animation of lips than interpreting the same emotions displayed through a real video sequence that shows the lower part of the face. We have successfully transferred three basic emotions from visual information into information from another modality; touch.

  • 50. Tan, Wei
    et al.
    Qiu, Xiaodong
    Zhao, Gang
    Jia, Mengyuan
    Ma, Weiguang
    Umeå University, Faculty of Science and Technology, Department of Physics. Institute of Laser Spectroscopy, State Key Laboratory of Quantum Optics and Quantum Optics Devices, Shanxi University, Taiyuan 030006, China; Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, China.
    Yan, Xiaojuan
    Dong, Lei
    Zhang, Lei
    Tong, Zhaomin
    Yin, Wangbao
    Feng, Xiaoxia
    Xiao, Liantuan
    Axner, Ove
    Jia, Suotang
    High-efficiency frequency upconversion of 1.5 mu m laser based on a doubly resonant external ring cavity with a low finesse for signal field2017In: Applied physics. B, Lasers and optics (Print), ISSN 0946-2171, E-ISSN 1432-0649, Vol. 123, no 2, article id 52Article in journal (Refereed)
    Abstract [en]

    A doubly resonant external ring cavity with a low finesse for the signal field is used to improve the frequency upconversion efficiency of a weak 1583 nm signal laser to 636 nm by mixing with a resonance power enhanced 1064 nm pump laser in a 25 mm periodically poled lithium niobate crystal. The process of frequency upconversion is described and optimized by the doubly resonant cavity-enhanced sum frequency generation theory under the condition of undepleted pump approximation. By selecting the suitable reflectivity of the signal input mirror and the incident pump power, a cavity-enhanced frequency conversion efficiency of 94.6% was obtained for signal powers up to 25 mW with an input pump power of 780 mW.

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