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During 2020, the COVID-19 crisis expanded the use of digital tools in public health and social care. The aim of this qualitative, single-case study was to scrutinize how homecare professionals experienced meaningfulness in their work in the midst of a crisis and with the utilization of the videophone in long-term homecare service provision. The empirical data consisted of 20 thematic interviews carried out among homecare professionals and their managers in the city of Tampere, Finland. The results indicated that the videophone can generate significance, self-realization and broader purposes among homecare professionals, thus providing meaningfulness for work in the midst of a crisis and continuous work-related changes. In addition, a crisis may support change in the meaningfulness of e-welfare in work-related tasks and aid in overcoming reluctance amongst public-sector social care (homecare) professionals towards an e-welfare initiative: the videophone (VideoVisit). publishedVersion

[Aims]We conducted an intervention study to clarify how effectively a telemedicine system using a multi-functional videophone could be used in lifestyle guidance, with special focus on diet for diabetic patients cared for at home. [Methods]Patients were assigned to a 3-month intervention group or to a usual care group. In the intervention group, patients and a medical professional communicated bi-directionally through a videophone-based communication system for 30 min, once a week. The participants were encouraged to send pictures of each meal online, through the videophone system, in real time. [Results]In intra-subjective comparison, the 3-month intervention program resulted in a significant decrease in body weight (BW) (p < 0.0005) and average HbA1C level (p < 0.005) compared with before the intervention program. Three months after the conclusion of the intervention program, average HbA1C levels returned to almost the same levels as before intervention (p < 0.05). In the usual care group, average HbA1C level did not change significantly for 6 months. [Conclusions]3-month intensive communication using the multimodal videophone system led to a significant decrease in BW and average HbA1C level. This novel bi-directional communication is useful for improving conditions such as diabetes, BW, and hyperglycemia for homecare diabetes patients, thus, reducing cardiovascular risk.

With the big evolution in the quantity of video data issued from an increased number of video applications over networks such as the videophone, the videoconferencing, and multimedia devices such as the personal digital assistants and the high-definition cameras, it has become crucial to reduce the quantity of video data which will be stored or transmitted. In fact, since the capacity of the storage Medias has become high and sufficient, the data storage problem was resolved but the transmission of the data remains an important problem especially with the limited channel bandwidth.

The aim of this study is to evaluate the use of a videophone by people with an intellectual handicap and their relatives at a healthcare organisation in the Netherlands. A triangulation of methods is used. The first method was a questionnaire (pre-study) were 195 clients and 439 client representatives participated in a satisfaction survey from the healthcare organisation. Out of this satisfaction survey, approximately 30% (N = 116 out of N = 374 reactions) identified concerns related to communication. Secondly, a literature study was carried out using Pubmed database. Eleven publications were selected. Finally, based on the pre-study and the literature an experiment was performed in which the videophone was evaluated. Two clients and two relatives used the videophone for approximately two months. The data supported the use of the videophone with intellectual handicapped and their relatives to improve communication. The addition of visual non-verbal cues and the fixed place of the videophone enhanced social presence, the concentration, the duration and the quality of the conversation. In general, the videophone was easy to use, but the sound and screen quality of the videophone could be improved to support communication.

This is the post-print version of the final published article that is available from the link below. Copyright @ Intellect Ltd 2011. The aim of the author's media art research has been to uncover any new understandings of the sensations of liveness and presence that may emerge in participatory networked performance, using mobile phones and physiological wearable devices. To practically investigate these concepts, a mobile media performance series was created, called MINDtouch. The MINDtouch project proposed that the mobile videophone become a new way to communicate non-verbally, visually and sensually across space. It explored notions of ephemeral transference, distance collaboration and participant as performer to study presence and liveness emerging from the use of wireless mobile technologies within real-time, mobile performance contexts. Through participation by in-person and remote interactors, creating mobile video-streamed mixes, the project interweaves and embodies a daisy chain of technologies through the network space. As part of a practice-based Ph.D. research conducted at the SMARTlab Digital Media Institute at the University of East London, MINDtouch has been under the direction of Professor Lizbeth Goodman and sponsored by BBC R&D. The aim of this article is to discuss the project research, conducted and recently completed for submission, in terms of the technical and aesthetic developments from 2008 to present, as well as the final phase of staging the events from July 2009 to February 2010. This piece builds on the article (Baker 2008) which focused on the outcomes of phase 1 of the research project and initial developments in phase 2. The outcomes from phase 2 and 3 of the project are discussed in this article.

This article discusses a pilot study testing a videophone intervention enabling hospice patients and caregivers to remotely participate in interdisciplinary team meetings, with the goal of improving pain management. The aim of this study was to test potential outcome measures and combine the data with qualitative observations to assess the overall feasibility and promise of the intervention. The outcomes evaluated included hospice patient quality of life, caregiver perceptions of pain medications, caregiver quality of life, and caregiver anxiety related to team participation. The pilot study showed that caregiver participation in the care planning process is feasible and may change caregiver perceptions of pain medication, potentially improving pain management for hospice patients.

In Alzheimer association’s clinique practice, there was a need to communicate with people with mild dementia. Videophone is considered as one of the best assistive communication tool for these people since video communication is not only a tool to break an isolation caused by the disease, but also a powerful way to help people demonstrate their ideas and understand what is said in a conversation with pictures, signs and body language. Therefore, an easy-to-use videophone for people with mild dementia is needed. The goal of this master thesis is to design a graphical user interface (GUI) of an easy-to-use videophone for people with mild dementia according to their characteristics and difficulties of using everyday technology. User centered design (UCD) was used in the design. To get familiar with the user, literature research was conducted before design. Low-fidelity prototype was created. With the help of Karolinska institute’ research group on people with dementia, the prototype was refined twice. Based on the refined low-fidelity prototype, an interactive prototype with navigation, sound and animation effect was created. A usability testing was conducted on older adults with this interactive prototype. In addition to the GUI of functions for people with mild dementia, GUI of functions for other care givers was also created and presented in this master thesis.

In this paper, we characterize the achievable performance of a wavelet encoding-based videophone system, which further compresses and protects the wavelet-based video codec's bit-stream with the aid of reversible variable-length (RVLC) codes. More specifically, the video codec uses RVLC codes for compressing and protecting the video frame header. By contrast irregular convolutional codes (IRCCs) are used for unequal error protection of the video bitstream generated from the wavelet-subbands, when communicating over intersymbol interference (ISI) contaminated channels. At the receiver, the turbo-equalizer, the IRCC decoder and the RVLC decoder all employ the maximum a-posteriori (MAP) algorithm and their operations are performed in an iterative turbo-detection style. The proposed system was designed for maintaining a near-unimpaired video reconstruction quality for channel signal-to-noise ratios (SNR) in excess of about 5 dB, when communicating over a five-path dispersive AWGN channel.

Most multimedia source signals are capable of tolerating lossy, rather than lossless delivery to the human eye, ear and other human sensors. The corresponding lossy and preferably low-delay multimedia source codecs however exhibit unequal error sensitivity, which is not the case for Shannon’s ideal entropy codec. This paper proposes a jointly optimised turbo transceiver design capable of providing unequal error protection for MPEG-4 coding aided wireless video telephony. The transceiver investigated consists of space-time trellis coding (STTC) invoked for the sake of mitigating the effects of fading, in addition to bandwidth efficient trellis coded modulation or bit-interleaved coded modulation, combined with a multi-level coding scheme employing either two different-rate non-systematic convolutional codes (NSCs) or two recursive systematic convolutional codes for yielding a twin-class unequal-protection. A single-class protection based benchmark scheme combining STTC and NSC is used for comparison with the unequal-protection scheme advocated. The video performance of the various schemes is evaluated when communicating over uncorrelated Rayleigh fading channels. It was found that the proposed scheme requires about 2.8 dBs lower transmit power than the benchmark scheme in the context of the MPEG-4 videophone transceiver at a similar decoding complexity.

The performance of turbo-equalized Global System of Mobile Communications/General Packet Radio Service (GSM/GPRS)-like videophone transceivers is studied over dispersive fading channels as a function of the number of turbo equalization iterations. Iteration gains up to 6 dB were attained. The operating channel signal-to-noise ratio (SNR) required for maintaining a peak SNR loss of less than 1 dB was reduced by 3.2dB for the one-slot system and by 4.1 dB for the four-slot system. The proposed system is capable of providing low-resolution videophone services over GSM/GPRS. Index Terms—GSM, GPRS, turbo equalization, wireless video telephone.

In order to efficiently use available computation power for producing a high performance videophone system, a new design methodology, which employs multithreading and data driven mechanism, is proposed in this paper. The method involves data independency exploitation, thread partitioning and scheduling to decrease processing latency. Fixed channel bit-rate is achieved by proposing computational adaptive rate control. Implementation results confirmed the proposed method can optimally use available computational power while maintaining constant bit-rate.

öz ÇOKLU İŞLEMCİLİ SAYISAL SİNYAL İŞLEMCİ MİMARİSİ ÜZERİNDE GERÇEK ZAMANLI BİR VİDEO KODLAYICISI VE KODÇÖZÜCÜSÜNÜN GERÇEKLENMESİ İnce, Serdar Yüksek Lisans, Elektrik ve Elektronik Mühendisliği Bölümü Tez Yöneticisi: Doç. Dr-. Gözde Bozdağı Akar Haziran 2002, 90 sayfa Gerçek zamanlı sesli ve görüntülü iletişim günümüz yaşamının önemli bir parçasıdır. Ancak video bilgisi yüksek bant genişliğine ihtiyaç duyduğundan sayısal videonun iletimi ancak sıkıştırma işleminden sonra mümkün olur. Sayısal Sinyal işlemciler (SSİ) hem gerçek zamanlı video sıkıştırma için gereken işlem gücünü hem de taşınabilme özelliğini bir arada sunarlar. Bu özel mimarilerden biri de çoklu işlemcili bir SSİ olan TMS320C80'dir. Texas Instruments'in bir ürünü olan TMS320C80 bir ana ve dört paralel işlemciden oluşur. Bu SSİ'nin işlemsel gücünü görüntü yakalama/gösterme gibi özelliklerle birleştirebilmek için SSİ, Precision MX Video Engine Kartı ile entegre edilmiştir. Önerilen sistemde video kodlayısının ana görevleri SSİ'nin paralel mimarisi kullanılarak işlemcilere paylaştırılmıştır. Hareket kestirimi, Ayrık Kosinüs Dönüşümü/Nicemleme/Entropi Kodlaması ve kodçözücügörevleri üç paralel işlemciye paylaştırılmıştır. Ana işlemci ise sistemin kontrolünden ve video çerçevelerinin gösterilmesinden/yakalanmasından sorumludur. Hareket kestirimi için bir miktar değiştirildikten sonra `Yoğun Kümelenmiş Düzgün-P Arama` algoritması kullanılmıştır. Ayrıca performansı artırmak amacıyla tüm işlemciler makina dili ile programlanmış ve paralel işlemcilerin aynı anda birden fazla işlem yapabilme özelliği kullanılmıştır. Hazırlanan sistemin sonuçları hem donanım hem de yazılım tabanlı sistemlerle karşılaştırılmıştır. Anahtar Kelimeler: Görüntülü Telefon, Video Sıkıştırma, Gerçek Zamanlı, Sayısal Sinyal İşlemci, Hareket Kestirimi, H.263 ABSTRACT IMPLEMENTATION OF A REAL-TIME VIDEO CODEC ON A MUL-TI PROCESSOR DSP ARCHITECTURE İnce, Serdar M.Sc, Department of Electrical and Electronics Engineering Supervisor: Assoc. Prof. Dr. Gözde Bozdağı Akar June 2002, 90 pages Real time audiovisual communication is an essential part of today's life. However, since uncompressed video data requires high bandwidth, transmission of digital video is possible after compression. Digital Signal Processors (DSPs) offer the required computational power for real time video compression along with portability. One of these special architectures is TMS320C80 which is a multi processor DSP. TMS320C80, a product of Texas Instruments, consists of one master processor and four parallel processors. This DSP is integrated to Precision MX Video Engine Card to combine the computational power of the chip with video capture and display properties. In the proposed system the video encoder's main tasks are divided between the parallel processors by exploiting the parallel architecture of DSP. Motion Estimation, Discrete Cosine Transform/Quantization/Entropy Coding and decoder tasks are divided between three parallel processors and master processor is responsible for the overall control of the codec anddisplay/capture of video frames. A fast search algorithm named `Densely Centered Uniform-P Search` is used for motion estimation after slight modifications. Moreover, in order to achieve the highest performance, all processors are programmed in assembly language and parallel instruction capability of parallel processors are exploited to optimize the system. The results are compared with both commercially available hardware and software based systems. Keywords: Videophone, Video Compression, Real-time, Digital Signal Processor, Motion Estimation, H.263 90

In this paper we improve the rate-distortion performance of a previously proposed video coder based on frame replenishment and adaptive mean-removed vector quantization. This is realized by determining for each block of a given frame the optimal encoding mode in the rate-distortion sense. The algorithm is a new contribution to very low bit rate video coding with adaptive vector quantization suitable for videophone applications. Experimental results comparing the two coders for several test sequences at different bit rates are provided.

International audience; A coding method for videophone communications over wireless, varying bit-rate, channels, is proposed. This method is based on defining one or more areas of interest and breaking them into a number of arbitrarily shaped regions which are homogeneous in their motion. The interest areas in the current implementation are human faces. They are detected with the help of a 2D scene model which is a-priori constructed and is based on knowledge of the application context. A mixed intra/inter-frame coding method is used for the description of the shape and topology of the regions where each polygonal vertex is encoded in a costless manner, either with regards to its predecessor in the same frame, or to the corresponding vertex in the previous frame. This coding is based on rate/distortion optimization constrained by the instantaneously available bit-rate. The error coding is also performed in an adaptive prioritized manner and is restricted within the detected areas of interest.

ÖZET ÇOK DÜŞÜK VERİ HIZLARINDA VİDEO KODLAYICI ÇÖZÜCÜ Hakkı Tunç Bostancı Elektrik ve Elektronik Mühendisliği Yüksek Lisans Tez Yöneticisi: Prof. Dr. Levent Onural Ocak 1997 Görüntülü telefon gibi gerçek zamanda çok düşük veri hızlarında çalışması gereken uygulamalarda kullanılabilecek bir hareketli görüntü kodlayıcı - çözücü sunulmuştur. MPEG-1, MPEG-2, H.261 ve en son H.263 var olan hareketli görüntü sıkıştırma standartlarıdır. MPEG-4 ve MPEG-7 standartları da geliştirilme aşamasındadır. Sunulan kodlama metodu zamanda öngörü ile başlayıp, iki boyutlu uzayda öngörü ile devam etmekte ve son basamakta entropi kodlamayı içermektedir. Bütün işlemler paletize edilmiş renk uzayında yapılmaktadır. Zamanda öngörü hatalarını gösteren fark görüntüsünü oluşturmak için desen özelliklerini kullanan yeni bir metod geliştirilmiştir. Farklı büyüklük ve şekilde alanları, seçeneğe göre kayıplı veya kayıpsız kodlamak için yeni bir iki boyutlu uzayda öngörü metodu kullanılmıştır. C++ dilinde nesneye yönelik program lama tekniklerini kullanarak bir simulasyon programı geliştirilmiştir. Bu program resmi MPEG-4 test görüntü dizilerinde denenmiş ve nümerik ölçümler açısından kötü olsa da görsel açıdan aynı veri hızlarında H.263 kodlaması ile benzer sonuçlar elde edilmiştir. Anahtar Kelimeler: Çok düşük veri hızlarında hareketli görüntü kodlama, hareketli görüntü sıkıştırma, veri sıkıştırma, görüntülü telefon. ABSTRACT A VERY LOW BIT RATE VIDEO CODER DECODER Hakkı Tunç Bostancı M.S. in Electrical and Electronics Engineering Supervisor: Prof. Dr. Levent Onural January 1997 A very low bit rate video coding decoding algorithm (codec) that can be used in real-time applications such as videotelephony is proposed. There are established video coding standards (MPEG-1, MPEG-2, H.261, H.263) and standards under development (MPEG-4 and MPEG-7). The proposed cod ing method is based on temporal prediction, followed by spatial prediction and finally entropy coding. The operations are performed in a color-palletized space. A new method based on parameterizing texture features is used for de termining the difference image, which shows the temporal prediction errors. A new hierarchical 2D spatial prediction scheme is proposed for lossy or lossless predictive coding of arbitrary shaped regions. A simulation of the codec is implemented in object oriented C++ language using template based program ming techniques. The codec is tested using official MPEG-4 test sequences. Its performance is compared to H.263 coding at the same bit rate and although numerically inferior, visually similar results are obtained. Keywords: Very low bit rate video coding, video compression, data compres sion, videotelephony. IV 85

A variety of adaptively re-configurable wireless videophone transceivers are proposed and their video quality, bit rate, robustness and complexity issues are analysed. A suite of fixed but arbitrarily programmable low-rate, perceptually weighted vector quantised (VQ) codecs with and without run-length compression (RLC) are contrived for quarter common intermediate format (QCIF) videophone sequences. The 11.36 kbps Codec 1 is BCH(127,71,9) coded to a rate of 20.32 kbps and this arrangement is comparatively studied along with the 8 kbps Codec 2 and BCH(127,50,13) scheme, which has the same 20.32 kbps overall rate. The source-sensitivity matched Systems 1-6 characterised in Table 3 were contrived to comparatively study the range of system design options. For example, using Codec 1 in System 1 and coherent pilot symbol assisted 16-level quadrature amplitude modulation (16-PSQAM), an overall signalling rate of 9kBd was yielded. Over lower quality channels the 4QAM mode of operation had to be invoked, which required twice as many time slots to accommodate the resulting 18kBd stream. The robustness of Systems 2,3,4 and 6 was increased using Automatic Repeat Requests (ARQ), inevitably reducing the number of users supported, which was between 6 and 16. In a band-width of 200kHz, similarly to the Pan European GSM mobile radio systems's speech channel, using Systems 1, 3, 4 or 5 for example, 16 and 8 videophone users can be supported in the 16QAM and 4QAM modes, respectively. The basic system characteristics are highlighted in Table 3.

An H.263-based video transceiver is contrived, which maintains a near-constant bitrate and due to the proposed packetisation and packet dropping regime it provides near-unimpaired video quality for frame error rates up to 5%. The target frame error rate is maintained by invoking a novel power-control technique.

The cellular channel capacity of conventional cells is shown to vary dramatically as a function of the distance from the base station. An intelligent 7.3 kBaus adaptive videophone transceiver is contrived, in order to exploit the higher channel capacity of uninterfered cell areas and to satisfy the prevalent system optimisation criteria. The system employed an enhanced H.263-compatible video codec and it was capable of operating over a wide range of operating conditions. The proposed technique has the potential to support videotelephony over existing and future wireless systems using the H.263 video codec. The main system features are summarised in Table 1.

A comparative study of arbitrarily programmable, but fixed-rate videophone codecs using quarter common intermediate format (QCIF) video sequences scanned at 10 frames/s is offered. These codecs were designed to allow direct replacement of mobile radio voice codecs in second generation wireless systems, such as the Pan-European GSM, the American IS-54 and IS-95 as well as the Japanese systems, operating at 13, 8, 9.6 and 6.7 kbps, respectively.

The mismatch between dynamic ranges of intensities in nonuniformly illuminated portrait scenes and of intensities reproducible on common display devices is addressed. In particular, such mismatches appear quite often in videophone and videoconferencing situations. Displayed portrait images with no details visible in some facial regions result from them, and lead in turn to a reduced impression of telepresence. A novel image processing approach for dynamic range compression of portrait images is presented in this paper. Unlike conventional methods, it provides compressed images with a most natural appearance. The basic idea is to simulate a more uniform scene illumination in the video signals of portrait images. This requires knowledge about the scene's reflectance function. Based on scale-space filtering, an edge discrimination technique is developed that distinguishes intensity edges caused by reflectance from edges caused by illumination at smoothly curved surfaces. This facilitates an estimation of the reflectance component from the intensity distribution of portrait images using an extension of the classical lightness computation approach.

International audience; The increasing usage of application-specific instruction set processors (ASIPs) in audio and video telecommunications has made strong demands on the rapid availability of dedicated compilers. A rule-driven approach to code generation may have benefits over model-based approaches as the user is not confined to the capabilities supported by the model. However, the sole use of transformation rules may or may not be sufficient in optimization abilities depending on the target architecture. This paper outlines experiences with a rule-driven code generation approach for two applications in audio and video processing. The first is a controller for the VideoPhone codec at SGS-Thomson Microelectronics. The second is a VLIW (very large instruction word) processor for high-fidelity and MPEG audio at Thomson Consumer Electronic Components. The experience has shown that a rule-driven approach to compilation is applicable to both the controller and VLIW architectures; however, is limited in optimization abilities for the latter.

The design and performance of a range of wireless videophone transceivers are presented. Highly bandwidth efficient, fixed but arbitrarily programmable rate, perceptually weighted Discrete Cosine Transform (DCT) based video codecs are proposed for quarter common intermediate format (QCIF) videophone sequences. Perceptually weighted cost/gain controlled motion compensation and quad-class DCT-based compression is applied with and without run-length coding. Specifically, we propose video codecs having transmission rates in the range of 5-11.36 kbps and preselected the 11.36 kbps Codec 1, the 8.52 kbps Codec and the 8 kbps Codec 2a, for which we designed the intelligent reconfigurable Systems 1-5. After sensitivity-matched binary Bose-Chaudhuri-Hocquenghem (BCH) forward error correction (FEC) coding the data rate associated with Codec 1 and Codec 2a became 20.32 kbps, while that of Codec 2 was 15.24 kbps. Throughout these systems a partial forced update (PM) technique was invoked in order to keep transmitter and receiver aligned amongst hostile channel conditions. When using Codec 1 in System 1 anHcoherent pilot symbol assisted 16-level quadrature amplitude modulation (16-PSAQAM), an overall signalling rate of 9 kBd was yielded. Over lower quality channels the 4QAM mode of operation had to be invoked, which required twice as many time slots to accommodate the resulting 18 kBd stream. The system's robustness was increased using Automatic Repeat Requests (ARQ), Inevitably reducing the number of users supported, which was between 6 and 19 for the various systems. In a bandwidth of 200 kHz, similarly to the Pan-European GSM mobile radio system's speech channel, using System 1 for example 16 and 8 videophone users can be supported in the l6QAM and 4QAM modes, respectively. All system features are summarized In Table Ill.

A highly bandwidth efficient, fixed but arbitrarily programmable rate, perceptually weighted Discrete Cosine Transfor (DCT) based video communicator for quarter common intermediate format (QCIF) videophone sequences is presented. Perceptually weighted cost/gain controlled motion compensation and quad-class DCT-based compression is applied without variable rate compression techniques and without adaptive buffering in order to maintain a fixed transmission rate, which can be adjusted to any required value. in this treatise we opted for a source coded rate of 11.36 kbps and the sensitivity-matched forward error correction (FEC) coded rate became 20.32 kbps. A partial forced update technique was invoked in order to keep transmitter and receiver aligned amongst hostile channel conditions. When using coherent pilot symbol assisted 16-level quadrature amplitude modulation (16-PSAQAM), an overall signalling rate of 9 kBd was yielded. OVer lower quality channels 4QAM had to be invoked, which required twice as many time slots to accommodate the resulting 18 kBd stream. Over the best Gaussian and worst Rayleigh channels signal-to-noise ratio (SNR) values in the range of 7 to 20 dB were needed for these modems in order to maintain near-unimpaired image quality. In a bandwidth of 200 kHz, similarly to the GSM speech channel, 16 and 8 videophone users can be supported, when using the 16QAM and 4QAM systems, respectively.

Özet GORUNTU DİZİSİ KODLAMADA YÜZE AİT UÇ BOYUTLU HAREKET VE YAPI KESTİRİMİ Gözde Bozdağı Elektrik ve Elektronik Mühendisliği Doktora Tez Yöneticisi: Doç. Dr. Levent Onural 21 Ocak 1994 Tipik bir konuşmacı için geliştirilmiş bir tel çerçeve modeline dayalı üç boyutlu hareket kestirimi ve yüzdeki derinlik bilgisinin eldeki konuşmacıya uyarlanımı için yeni bir metod önerilmiştir. Kullanılan algoritma optik akı metoduna dayanmakta ve harekete bağlı fotometrik etkileri de kullanmaktadır. Kullanılan tel çerçeve modeli birbirine bağlı üçgenlerden oluşmakta ve bu üçgenlerin konumları normal vektörleri ile gösterilmektedir. Üçgenlerin birbirine bağlı olma özelliği algoritmada kullanılan bağımsız değişken sayısını azaltmaktadır. Bilinmeyen hareket ve yapı bilgilerinin bulunması için bir olasılıklı gevşeme metodu, başlangıç noktasının bulunması için de bir nokta eşleştirilme metodu gerçekleştirilmiştir. Hem gerçek hem de benzetilmiş yüz görüntü dizileri kullanılarak elde edilen sonuçlar sunulmuştur. Anahtar Görüntü dizisi kodlama, cisim modeline dayalı kodlama, 3-boyutlu Sözcükler: hareket ve yapı kestirimi, olasılıklı gevşeme, görüntülü telefon, çok düşük hızlarda iletim için kodlama, nesne şekli analizi, nesne hareketi analizi. Abstract THREE-DIMENSIONAL FACIAL MOTION AND STRUCTURE ESTIMATION IN VIDEO CODING Gözde Bozdağı Ph. D. in Electrical and Electronics Engineering Supervisor: Assoc. Prof. Dr.Levent Onural 21 January 1994 We propose a novel formulation where 3-D global and local motion estimation and the adaptation of a generic wire-frame model to a particular speaker are considered simultaneously within an optical flow based framework including the photometric eiFects of the motion. We use a flexible wire-frame model whose local structure is characterized by the normal vectors of the patches which are related to the coordinates of the nodes. Geometric constraints that describe the propagation of the movement of the nodes are introduced, which are then efficiently utilized to reduce the number of independent structure parameters. A stochastic relaxation algorithm has been used to determine optimum global motion estimates and the parameters describing the structure of the wire-frame model. For the initialization of the motion and structure parameters, a modified feature based algorithm is used whose performance has also been compared with the existing methods. Results with both simulated and real facial image sequences are provided. Keywords: Image sequence coding, object-based coding methods, 3-D motion and structure estimation, stochastic relaxation, videophone, very low bit rate coding, object shape analysis, object motion analysis. 89