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Tesi sul tema "Video processing"
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1
Aggoun, Amar. "DPCM video signal/image processing". Thesis, University of Nottingham, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335792.
Testo completo
2
Zhao, Jin. "Video/Image Processing on FPGA". Digital WPI, 2015. https://digitalcommons.wpi.edu/etd-theses/503.
Testo completoAbstract (sommario):
Video/Image processing is a fundamental issue in computer science. It is widely used for a broad range of applications, such as weather prediction, computerized tomography (CT), artificial intelligence (AI), and etc. Video-based advanced driver assistance system (ADAS) attracts great attention in recent years, which aims at helping drivers to become more concentrated when driving and giving proper warnings if any danger is insight. Typical ADAS includes lane departure warning, traffic sign detection, pedestrian detection, and etc. Both basic and advanced video/image processing technologies are deployed in video-based driver assistance system. The key requirements of driver assistance system are rapid processing time and low power consumption. We consider Field Programmable Gate Array (FPGA) as the most appropriate embedded platform for ADAS. Owing to the parallel architecture, an FPGA is able to perform high-speed video processing such that it could issue warnings timely and provide drivers longer time to response. Besides, the cost and power consumption of modern FPGAs, particular small size FPGAs, are considerably efficient. Compared to the CPU implementation, the FPGA video/image processing achieves about tens of times speedup for video-based driver assistance system and other applications.
3
Isaieva, O. A., e О. Г. Аврунін. "Image processing for video dermatoscopy". Thesis, Osaka, Japan, 2019. http://openarchive.nure.ua/handle/document/10347.
Testo completo
4
Chen, Juan. "Content-based Digital Video Processing. Digital Videos Segmentation, Retrieval and Interpretation". Thesis, University of Bradford, 2009. http://hdl.handle.net/10454/4256.
Testo completoAbstract (sommario):
Recent research approaches in semantics based video content analysis require shot boundary detection as the first step to divide video sequences into sections. Furthermore, with the advances in networking and computing capability, efficient retrieval of multimedia data has become an important issue. Content-based retrieval technologies have been widely implemented to protect intellectual property rights (IPR). In addition, automatic recognition of highlights from videos is a fundamental and challenging problem for content-based indexing and retrieval applications. In this thesis, a paradigm is proposed to segment, retrieve and interpret digital videos. Five algorithms are presented to solve the video segmentation task. Firstly, a simple shot cut detection algorithm is designed for real-time implementation. Secondly, a systematic method is proposed for shot detection using content-based rules and FSM (finite state machine). Thirdly, the shot detection is implemented using local and global indicators. Fourthly, a context awareness approach is proposed to detect shot boundaries. Fifthly, a fuzzy logic method is implemented for shot detection. Furthermore, a novel analysis approach is presented for the detection of video copies. It is robust to complicated distortions and capable of locating the copy of segments inside original videos. Then, iv objects and events are extracted from MPEG Sequences for Video Highlights Indexing and Retrieval. Finally, a human fighting detection algorithm is proposed for movie annotation.
5
Haynes, Simon Dominic. "Reconfigurable architectures for video image processing". Thesis, Imperial College London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322797.
Testo completo
6
Fernando, Warnakulasuriya Anil Chandana. "Video processing in the compressed domain". Thesis, University of Bristol, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326724.
Testo completo
7
Leonce, Andrew. "HDR video enhancement, processing and coding". Thesis, Loughborough University, 2015. https://dspace.lboro.ac.uk/2134/19639.
Testo completoAbstract (sommario):
Advances in digital camera technology have led to the development of image sensors that are capable of capturing High Dynamic Range (HDR) images. Although this has enabled the capture of greater depths of colour and illumination, there remain problems with regards to transmitting and displaying the HDR image data. Current consumer level displays are designed to only show images with a depth of 8-bits per pixel per channel. Typical HDR images can be 10-bits per pixel per channel and upwards, leading to the first problem, how to display HDR images on Standard Dynamic Range (SDR) displays. This is linked to a further problem, that of transmitting the HDR data to the SDR devices, due to the fact that most state-of-the-art image and video coding standards deal with only SDR data. Further, as with most technologies of this kind, current HDR displays are extremely expensive. Furthermore, media broadcast organisations have invested significant sums of money into their current architecture and are unwilling to completely change their systems at further cost.
8
Wu, Hao-Yu M. Eng Massachusetts Institute of Technology. "Eulerian Video Processing and medical applications". Thesis, Massachusetts Institute of Technology, 2012. http://hdl.handle.net/1721.1/77452.
Testo completoAbstract (sommario):
Thesis (M. Eng. and S.B.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2012.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 68-69).
Our goal is to reveal subtle yet informative signals in videos that are difficult or impossible to see with the naked eye. We can either display them in an indicative manner, or analyse them to extract important measurements, such as vital signs. Our method, which we call Eulerian Video Processing, takes a standard video sequence as input, and applies spatial decomposition, followed by temporal filtering to the frames. The resulting signals can be visually amplified to reveal hidden information, the process we called Eulerian Video Magnification. Using Eulerian Video Magnification, we are able to visualize the flow of blood as it fills the face and to amplify and reveal small motions. Our technique can be run in real time to instantly show phenomena occurring at the temporal frequencies selected by the user. Those signals can also be used to extract vital signs contactlessly. We presented a heart rate extraction system that is able to estimate heart rate of newborns from videos recorded in the real nursery environment. Our system can produce heart rate measurement that has clinical accuracy when newborns only have mild motions, and when the videos are acquired in brightly lit environments.
by Hao-Yu Wu.
M.Eng.and S.B.
9
Tsoligkas, Nick A. "Video/Image Processing Algorithms for Video Compression and Image Stabilization Applications". Thesis, Teesside University, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.517469.
Testo completoAbstract (sommario):
As the use of video becomes increasingly popular and wide spread in the areas of broadcast services, internet, entertainment and security-related applications, providing means for fast. automated, and effective techniques to represent video based on its content, such as objects and meanings, is important topic of research. In many applications.. removing the hand shaking effect and making video images stable and clear or decomposing (and then transmitting) the video content into a collection of meaningful objects is a necessity. Therefore automatic techniques for video stabilization, extraction of objects from video data as well as transmitting their shapes, motion and texture at very low bit rates over error networks, are desired. In this thesis the design of a new low bit rate codec is presented. Furthermore a method about video stabilization is introduced. The main technical contributions resulted from this work are as follows. Firstly, an adaptive change detection algorithm identifies the objects from the background. The luminance difference between framer~ in the first stage, is modelled so as to separate contributions caused by noise and illumination variations from those caused by meaningful moving objects. In the second stage the segmentation tool based on image blocks, histograms and clustering algorithms segments the difference image into areas corresponding to objects. In the third stage morphological edge detection, contour analysis, and object labelling are the main tasks of the proposed segmentation algorithm. Secondly, a new low bit rate codec is designed and analyzed based on the proposed segmentation tool. The estimated motion vectors inside the change detection mask, the comer points of the shapes as well as the residual information inside the motion failure regions are transmitted to the decoder using different coding techniques, thus achieving efficient compression. Thirdly, a novel approach of estimating and removing unwanted video motion, which does not require accelerators or gyros, is presented. The algorithm estimates the camera motion from the incoming video stream and compensates for unwanted translation and rotation. A synchronization unit supervises and generates the stabilized video sequence. The reliability of all the proposed algorithms is demonstrated by extensive experimentation on various video shots.
10
Tsoi, Yau Chat. "Video cosmetics : digital removal of blemishes from video /". View Abstract or Full-Text, 2003. http://library.ust.hk/cgi/db/thesis.pl?COMP%202003%20TSOI.
Testo completoAbstract (sommario):
Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2003.Includes bibliographical references (leaves 83-86). Also available in electronic version. Access restricted to campus users.
11
Korpinen, K. P. (Kalle-Pekka). "Projektinhallinan video yliopisto-opetuksessa". Master's thesis, University of Oulu, 2014. http://urn.fi/URN:NBN:fi:oulu-201405241497.
Testo completoAbstract (sommario):
Tutkielman tavoitteena oli selvittää millainen video auttaa yliopisto-opiskelijaa ymmärtämään projektinhallinnan keskeisten osa-alueiden tärkeyden? Tämä tutkielma toteutettiin kyselytutkimuksena, jota täydennettiin teemahaastatteluilla.
Lähtökohtana kyselylle oli projektiryhmän tuotos syksyn 2012 Projekti II kurssilla. Projektiryhmä tuotti projektityöskentelyä kuvaavan videon Big Things Have Small Beginnings, joka otettiin käyttöön osaksi kyseisen kurssin opiskelumateriaalia. Tämän myötä tuli esille halu selvittää kuinka opiskelijat kokevat kyseisen videotuotoksen opiskelumateriaalina: kuinka projektinhallinnan video on auttanut ymmärtämään eri projektihallinnan osa-alueita?
Tässä tutkimuksessa kyselytutkimuksella evaluoitiin projektinhallinnan videota, joka on osa Oulun yliopiston Tietojenkäsittelytieteidenlaitoksen Projekti II kurssin opetusmateriaalia. Videon ymmärrettävyyttä testattiin tutkimuksessa suoritetuilla kyselyillä. Vastaajat kyselyissä olivat Tietojenkäsittelytieteidenlaitoksen Projekti II kurssin opiskelijoita. Vastausten perusteella voidaan arvioida, että videon avulla opiskelijat olivat ymmärtäneet eri projektinhallintaa osa-alueet pääosin todella positiivisesti. Voidaan myös arvioida, että videota pidettiin opettavaisena ja sitä oli pidetty hyvänä lisänä aloitusluennolle. Tutkimuksen merkittävyydestä voidaan todeta, että opiskelijoiden tuotos on otettu osaksi yliopisto-opetuksen opetusmateriaalia. Hyvä palaute videosta opetusmateriaalina voi edesauttaa opiskelijavetoisten materiaalien tuottamista yliopisto-opetuksessa jatkossakin.
Haasteena tässä tutkielmassa on ollut löytää vastaavia tutkimuksia, kuin tämä tutkielma on. Näin ollen tässä tutkielmassa on keskitytty yleisimmin multimediamateriaaleihin ja keskittyen lisäksi erityisesti videomateriaaleihin. Myös huumori on tuotu esille johtuen tuotetun videon humoristisesta luonteesta.
12
Raihani, Nilgoun. "Respiration Pattern Using Amplified Video". Case Western Reserve University School of Graduate Studies / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=case151272961173245.
Testo completo
13
Lazcano, Vanel. "Some problems in depth enhanced video processing". Doctoral thesis, Universitat Pompeu Fabra, 2016. http://hdl.handle.net/10803/373917.
Testo completoAbstract (sommario):
In this thesis we tackle two problems, namely, the data interpolation prob-
lem in the context of depth computation both for images and for videos, and
the problem of the estimation of the apparent movement of objects in image
sequences. The rst problem deals with completion of depth data in a region
of an image or video where data are missing due to occlusions, unreliable data,
damage or lost of data during acquisition. In this thesis we tackle it in two ways.
First, we propose a non-local gradient-based energy which is able to complete
planes locally. We consider this model as an extension of the bilateral lter to
the gradient domain. We have successfully evaluated our model to complete
synthetic depth images and also incomplete depth maps provided by a Kinect
sensor.
The second approach to tackle the problem is an experimental study of the
Biased Absolutely Minimizing Lipschitz Extension (biased AMLE in short) for
anisotropic interpolation of depth data to big empty regions without informa-
tion. The AMLE operator is a cone interpolator, but the biased AMLE is an
exponential cone interpolator which makes it more addapted to depth maps of
real scenes that usually present soft convex or concave surfaces. Moreover, the
biased AMLE operator is able to expand depth data to huge regions. By con-
sidering the image domain endowed with an anisotropic metric, the proposed
method is able to take into account the underlying geometric information in
order not to interpolate across the boundary of objects at di erent depths. We
have proposed a numerical model to compute the solution of the biased AMLE
which is based on the eikonal operators. Additionally, we have extended the
proposed numerical model to video sequences.
The second problem deals with the motion estimation of the objects in a
video sequence. This problem is known as the optical
ow computation. The
Optical
ow problem is one of the most challenging problems in computer vision.
Traditional models to estimate it fail in presence of occlusions and non-uniform
illumination. To tackle these problems we proposed a variational model to
jointly estimate optical
ow and occlusion. Moreover, the proposed model is
able to deal with the usual drawback of variational methods in dealing with
fast displacements of objects in the scene which are larger than the object it-
self. The addition of a term that balance gradient and intensities increases the
robustness to illumination changes of the proposed model. The inclusions of a
supplementary matches given by exhaustive search in speci cs locations helps
to follow large displacements.En esta tesis se abordan dos problemas: interpolación de datos en el contexto del cálculo de disparidades tanto para imágenes como para video, y el problema de la estimación del movimiento aparente de objetos en una secuencia de imágenes. El primer problema trata de la completación de datos de profundidad en una región de la imagen o video dónde los datos se han perdido debido a oclusiones, datos no confiables, datos dañados o pérdida de datos durante la adquisición. En esta tesis estos problemas se abordan de dos maneras. Primero, se propone una energía basada en gradientes no-locales, energía que puede (localmente) completar planos. Se considera este modelo como una extensión del filtro bilateral al dominio del gradiente. Se ha evaluado en forma exitosa el modelo para completar datos sintéticos y también mapas de profundidad incompletos de un sensor Kinect. El segundo enfoque, para abordar el problema, es un estudio experimental del biased AMLE (Biased Absolutely Minimizing Lipschitz Extension) para interpolación anisotrópica de datos de profundidad en grandes regiones sin información. El operador AMLE es un interpolador de conos, pero el operador biased AMLE es un interpolador de conos exponenciales lo que lo hace estar más adaptado a mapas de profundidad de escenas reales (las que comunmente presentan superficies convexas, concavas y suaves). Además, el operador biased AMLE puede expandir datos de profundidad a regiones grandes. Considerando al dominio de la imagen dotado de una métrica anisotrópica, el método propuesto puede tomar en cuenta información geométrica subyacente para no interpolar a través de los límites de los objetos a diferentes profundidades. Se ha propuesto un modelo numérico, basado en el operador eikonal, para calcular la solución del biased AMLE. Adicionalmente, se ha extendido el modelo numérico a sequencias de video. El cálculo del flujo óptico es uno de los problemas más desafiantes para la visión por computador. Los modelos tradicionales fallan al estimar el flujo óptico en presencia de oclusiones o iluminación no uniforme. Para abordar este problema se propone un modelo variacional para conjuntamente estimar flujo óptico y oclusiones. Además, el modelo propuesto puede tolerar, una limitación tradicional de los métodos variacionales, desplazamientos rápidos de objetos que son más grandes que el tamaño objeto en la escena. La adición de un término para el balance de gradientes e intensidades aumenta la robustez del modelo propuesto ante cambios de iluminación. La inclusión de correspondencias adicionales (obtenidas usando búsqueda exhaustiva en ubicaciones específicas) ayuda a estimar grandes desplazamientos.
14
Toivonen, T. (Tuukka). "Efficient methods for video coding and processing". Doctoral thesis, University of Oulu, 2008. http://urn.fi/urn:isbn:9789514286957.
Testo completoAbstract (sommario):
Abstract
This thesis presents several novel improvements to video coding algorithms, including block-based motion estimation, quantization selection, and video filtering. Most of the presented improvements are fully compatible with the standards in general use, including MPEG-1, MPEG-2, MPEG-4, H.261, H.263, and H.264.
For quantization selection, new methods are developed based on the rate-distortion theory. The first method obtains locally optimal frame-level quantization parameter considering frame-wise dependencies. The method is applicable to generic optimization problems, including also motion estimation. The second method, aimed at real-time performance, heuristically modulates the quantization parameter in sequential frames improving significantly the rate-distortion performance. It also utilizes multiple reference frames when available, as in H.264. Finally, coding efficiency is improved by introducing a new matching criterion for motion estimation which can estimate the bit rate after transform coding more accurately, leading to better motion vectors.
For fast motion estimation, several improvements on prior methods are proposed. First, fast matching, based on filtering and subsampling, is combined with a state-of-the-art search strategy to create a very quick and high-quality motion estimation method. The successive elimination algorithm (SEA) is also applied to the method and its performance is improved by deriving a new tighter lower bound and increasing it with a small constant, which eliminates a larger part of the candidate motion vectors, degrading quality only insignificantly. As an alternative, the multilevel SEA (MSEA) is applied to the H.264-compatible motion estimation utilizing efficiently the various available block sizes in the standard.
Then, a new method is developed for refining the motion vector obtained from any fast and suboptimal motion estimation method. The resulting algorithm can be easily adjusted to have the desired tradeoff between computational complexity and rate-distortion performance. For refining integer motion vectors into half-pixel resolution, a new very quick but accurate method is developed based on the mathematical properties of bilinear interpolation.
Finally, novel number theoretic transforms are developed which are best suited for two-dimensional image filtering, including image restoration and enhancement, but methods are developed with a view to the use of the transforms also for very reliable motion estimation.
15
Gause, Jõrn. "Reconfigurable computing for shape-adaptive video processing". Thesis, Imperial College London, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.397539.
Testo completo
16
Javadi, Seyed Mahdi Sadreddinhajseyed. "Research into illumination variance in video processing". Thesis, Brunel University, 2018. http://bura.brunel.ac.uk/handle/2438/17027.
Testo completoAbstract (sommario):
Inthisthesiswefocusontheimpactofilluminationchangesinvideoand we discuss how we can minimize the impact of illumination variance in video processing systems. Identifyingandremovingshadowsautomaticallyisaverywellestablished and an important topic in image and video processing. Having shadowless image data would benefit many other systems such as video surveillance, tracking and object recognition algorithms. Anovelapproachtoautomaticallydetectandremoveshadowsispresented in this paper. This new method is based on the observation that, owing to the relative movement of the sun, the length and position of a shadow changes linearly over a relatively long period of time in outdoor environments,wecanconvenientlydistinguishashadowfromotherdark regions in an input video. Then we can identify the Reference Shadow as the one with the highest confidence of the mentioned linear changes. Once one shadow is detected, the rest of the shadow can also be identifiedandremoved. Wehaveprovidedmanyexperimentsandourmethod is fully capable of detecting and removing the shadows of stationary and moving objects. Additionally we have explained how reference shadows can be used to detect textures that reflect the light and shiny materials such as metal, glass and water. ...
17
Blount, Alan Wayne. "Display manager for a video processing system". Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/12951.
Testo completoAbstract (sommario):
Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1991.Includes bibliographical references (leaves 44-45).
by Alan Wayne Blount.
B.S.
18
Lazcano, Vanel. "Some problems in depth enjanced video processing". Doctoral thesis, Universitat Pompeu Fabra, 2016. http://hdl.handle.net/10803/373917.
Testo completoAbstract (sommario):
In this thesis we tackle two problems, namely, the data interpolation prob-
lem in the context of depth computation both for images and for videos, and
the problem of the estimation of the apparent movement of objects in image
sequences. The rst problem deals with completion of depth data in a region
of an image or video where data are missing due to occlusions, unreliable data,
damage or lost of data during acquisition. In this thesis we tackle it in two ways.
First, we propose a non-local gradient-based energy which is able to complete
planes locally. We consider this model as an extension of the bilateral lter to
the gradient domain. We have successfully evaluated our model to complete
synthetic depth images and also incomplete depth maps provided by a Kinect
sensor.
The second approach to tackle the problem is an experimental study of the
Biased Absolutely Minimizing Lipschitz Extension (biased AMLE in short) for
anisotropic interpolation of depth data to big empty regions without informa-
tion. The AMLE operator is a cone interpolator, but the biased AMLE is an
exponential cone interpolator which makes it more addapted to depth maps of
real scenes that usually present soft convex or concave surfaces. Moreover, the
biased AMLE operator is able to expand depth data to huge regions. By con-
sidering the image domain endowed with an anisotropic metric, the proposed
method is able to take into account the underlying geometric information in
order not to interpolate across the boundary of objects at di erent depths. We
have proposed a numerical model to compute the solution of the biased AMLE
which is based on the eikonal operators. Additionally, we have extended the
proposed numerical model to video sequences.
The second problem deals with the motion estimation of the objects in a
video sequence. This problem is known as the optical
ow computation. The
Optical
ow problem is one of the most challenging problems in computer vision.
Traditional models to estimate it fail in presence of occlusions and non-uniform
illumination. To tackle these problems we proposed a variational model to
jointly estimate optical
ow and occlusion. Moreover, the proposed model is
able to deal with the usual drawback of variational methods in dealing with
fast displacements of objects in the scene which are larger than the object it-
self. The addition of a term that balance gradient and intensities increases the
robustness to illumination changes of the proposed model. The inclusions of a
supplementary matches given by exhaustive search in speci cs locations helps
to follow large displacements.En esta tesis se abordan dos problemas: interpolación de datos en el contexto del cálculo de disparidades tanto para imágenes como para video, y el problema de la estimación del movimiento aparente de objetos en una secuencia de imágenes. El primer problema trata de la completación de datos de profundidad en una región de la imagen o video dónde los datos se han perdido debido a oclusiones, datos no confiables, datos dañados o pérdida de datos durante la adquisición. En esta tesis estos problemas se abordan de dos maneras. Primero, se propone una energía basada en gradientes no-locales, energía que puede (localmente) completar planos. Se considera este modelo como una extensión del filtro bilateral al dominio del gradiente. Se ha evaluado en forma exitosa el modelo para completar datos sintéticos y también mapas de profundidad incompletos de un sensor Kinect. El segundo enfoque, para abordar el problema, es un estudio experimental del biased AMLE (Biased Absolutely Minimizing Lipschitz Extension) para interpolación anisotrópica de datos de profundidad en grandes regiones sin información. El operador AMLE es un interpolador de conos, pero el operador biased AMLE es un interpolador de conos exponenciales lo que lo hace estar más adaptado a mapas de profundidad de escenas reales (las que comunmente presentan superficies convexas, concavas y suaves). Además, el operador biased AMLE puede expandir datos de profundidad a regiones grandes. Considerando al dominio de la imagen dotado de una métrica anisotrópica, el método propuesto puede tomar en cuenta información geométrica subyacente para no interpolar a través de los límites de los objetos a diferentes profundidades. Se ha propuesto un modelo numérico, basado en el operador eikonal, para calcular la solución del biased AMLE. Adicionalmente, se ha extendido el modelo numérico a sequencias de video. El cálculo del flujo óptico es uno de los problemas más desafiantes para la visión por computador. Los modelos tradicionales fallan al estimar el flujo óptico en presencia de oclusiones o iluminación no uniforme. Para abordar este problema se propone un modelo variacional para conjuntamente estimar flujo óptico y oclusiones. Además, el modelo propuesto puede tolerar, una limitación tradicional de los métodos variacionales, desplazamientos rápidos de objetos que son más grandes que el tamaño objeto en la escena. La adición de un término para el balance de gradientes e intensidades aumenta la robustez del modelo propuesto ante cambios de iluminación. La inclusión de correspondencias adicionales (obtenidas usando búsqueda exhaustiva en ubicaciones específicas) ayuda a estimar grandes desplazamientos.
19
Kourennyi, Dmitri Dmitrievich. "Customer Tracking Through Security Camera Video Processing". Case Western Reserve University School of Graduate Studies / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=case1290122439.
Testo completo
20
Wedge, Daniel John. "Video sequence synchronization". University of Western Australia. School of Computer Science and Software Engineering, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0084.
Testo completoAbstract (sommario):
[Truncated abstract] Video sequence synchronization is necessary for any computer vision application that integrates data from multiple simultaneously recorded video sequences. With the increased availability of video cameras as either dedicated devices, or as components within digital cameras or mobile phones, a large volume of video data is available as input for a growing range of computer vision applications that process multiple video sequences. To ensure that the output of these applications is correct, accurate video sequence synchronization is essential. Whilst hardware synchronization methods can embed timestamps into each sequence on-the-fly, they require specialized hardware and it is necessary to set up the camera network in advance. On the other hand, computer vision-based software synchronization algorithms can be used to post-process video sequences recorded by cameras that are not networked, such as common consumer hand-held video cameras or cameras embedded in mobile phones, or to synchronize historical videos for which hardware synchronization was not possible. The current state-of-the-art software algorithms vary in their input and output requirements and camera configuration assumptions. ... Next, I describe an approach that synchronizes two video sequences where an object exhibits ballistic motions. Given the epipolar geometry relating the two cameras and the imaged ballistic trajectory of an object, the algorithm uses a novel iterative approach that exploits object motion to rapidly determine pairs of temporally corresponding frames. This algorithm accurately synchronizes videos recorded at different frame rates and takes few iterations to converge to sub-frame accuracy. Whereas the method presented by the first algorithm integrates tracking data from all frames to synchronize the sequences as a whole, this algorithm recovers the synchronization by locating pairs of temporally corresponding frames in each sequence. Finally, I introduce an algorithm for synchronizing two video sequences recorded by stationary cameras with unknown epipolar geometry. This approach is unique in that it recovers both the frame rate ratio and the frame offset of the two sequences by finding matching space-time interest points that represent events in each sequence; the algorithm does not require object tracking. RANSAC-based approaches that take a set of putatively matching interest points and recover either a homography or a fundamental matrix relating a pair of still images are well known. This algorithm extends these techniques using space-time interest points in place of spatial features, and uses nested instances of RANSAC to also recover the frame rate ratio and frame offset of a pair of video sequences. In this thesis, it is demonstrated that each of the above algorithms can accurately recover the frame rate ratio and frame offset of a range of real video sequences. Each algorithm makes a contribution to the body of video sequence synchronization literature, and it is shown that the synchronization problem can be solved using a range of approaches.
21
蔡固庭 e Koo-ting Choi. "Improved processing techniques for picture sequence coding". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1998. http://hub.hku.hk/bib/B31220642.
Testo completo
22
Choi, Koo-ting. "Improved processing techniques for picture sequence coding /". Hong Kong : University of Hong Kong, 1998. http://sunzi.lib.hku.hk/hkuto/record.jsp?B20565550.
Testo completo
23
Kang, Jung Won. "Effective temporal video segmentation and content-based audio-visual video clustering". Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/13731.
Testo completo
24
Jiang, Xiaofeng. "Multipoint digital video communications". Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239548.
Testo completo
25
So, Wai-ki, e 蘇慧琪. "Shadow identification in traffic video sequences". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2005. http://hub.hku.hk/bib/B32045967.
Testo completo
26
Biswas, Mainak. "Content adaptive video processing algorithms for digital TV /". Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2005. http://wwwlib.umi.com/cr/ucsd/fullcit?p3189792.
Testo completo
27
Haro, Antonio. "Example Based Processing For Image And Video Synthesis". Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/5283.
Testo completoAbstract (sommario):
The example based processing problem can be expressed as: "Given an example of an image or video before and after processing, apply a similar processing to a new image or video".
Our thesis is that there are some problems where a single general algorithm can be used to create varieties of outputs, solely by presenting examples of what is desired to the algorithm. This is valuable if the algorithm to produce the output is non-obvious, e.g. an algorithm to emulate an example painting's style. We limit
our investigations to example based processing of images, video, and 3D models as these data types are easy to acquire and experiment with.
We represent this problem first as a texture synthesis influenced sampling problem, where the idea is to form feature vectors representative of the data and then sample them coherently to
synthesize a plausible output for the new image or video. Grounding the problem in this manner is useful as both problems involve learning the structure of training data under some assumptions to sample it properly. We then reduce the problem to a labeling problem to perform example based processing in a more generalized and principled manner than earlier techniques. This allows us to perform a different estimation of what the output
should be by approximating the optimal (and possibly not known) solution through a different approach.
28
Li, Min. "Markov Random field edge-centric image/video processing". Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2007. http://wwwlib.umi.com/cr/ucsd/fullcit?p3274746.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--University of California, San Diego, 2007.Title from first page of PDF file (viewed October 8, 2007). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 117-125).
29
Coimbra, Miguel Tavares. "Compressed domain video processing with applications to surveillance". Thesis, Queen Mary, University of London, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.413780.
Testo completo
30
Hamosfakidis, Anastasios. "MPEG-4 software video encoding using parallel processing". Thesis, Queen Mary, University of London, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.436200.
Testo completo
31
Hu, Yongtao, e 胡永涛. "Multimodal speaker localization and identification for video processing". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/212633.
Testo completo
32
Sims, Oliver. "Efficient implementation of video processing algorithms on FPGA". Thesis, University of Glasgow, 2007. http://theses.gla.ac.uk/4119/.
Testo completoAbstract (sommario):
The work contained in this portfolio thesis was carried out as part of an Engineering Doctorate (Eng.D) programme from the Institute for System Level Integration. The work was sponsored by Thales Optronics, and focuses on issues surrounding the implementation of video processing algorithms on field programmable gate arrays (FPGA). A description is given of FPGA technology and the currently dominant methods of designing and verifying firmware. The problems of translating a description of behaviour into one of structure are discussed, and some of the latest methodologies for tackling this problem are introduced. A number of algorithms are then looked at, including methods of contrast enhancement, deconvolution, and image fusion. Algorithms are characterised according to the nature of their execution flow, and this is used as justification for some of the design choices that are made. An efficient method of performing large two-dimensional convolutions is also described. The portfolio also contains a discussion of an FPGA implementation of a PID control algorithm, an overview of FPGA dynamic reconfigurability, and the development of a demonstration platform for rapid deployment of video processing algorithms in FPGA hardware.
33
Chen, Jiawen (Jiawen Kevin). "Efficient data structures for piecewise-smooth video processing". Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/66003.
Testo completoAbstract (sommario):
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 95-102).
A number of useful image and video processing techniques, ranging from low level operations such as denoising and detail enhancement to higher level methods such as object manipulation and special effects, rely on piecewise-smooth functions computed from the input data. In this thesis, we present two computationally efficient data structures for representing piecewise-smooth visual information and demonstrate how they can dramatically simplify and accelerate a variety of video processing algorithms. We start by introducing the bilateral grid, an image representation that explicitly accounts for intensity edges. By interpreting brightness values as Euclidean coordinates, the bilateral grid enables simple expressions for edge-aware filters. Smooth functions defined on the bilateral grid are piecewise-smooth in image space. Within this framework, we derive efficient reinterpretations of a number of edge-aware filters commonly used in computational photography as operations on the bilateral grid, including the bilateral filter, edgeaware scattered data interpolation, and local histogram equalization. We also show how these techniques can be easily parallelized onto modern graphics hardware for real-time processing of high definition video. The second data structure we introduce is the video mesh, designed as a flexible central data structure for general-purpose video editing. It represents objects in a video sequence as 2.5D "paper cutouts" and allows interactive editing of moving objects and modeling of depth, which enables 3D effects and post-exposure camera control. In our representation, we assume that motion and depth are piecewise-smooth, and encode them sparsely as a set of points tracked over time. The video mesh is a triangulation over this point set and per-pixel information is obtained by interpolation. To handle occlusions and detailed object boundaries, we rely on the user to rotoscope the scene at a sparse set of frames using spline curves. We introduce an algorithm to robustly and automatically cut the mesh into local layers with proper occlusion topology, and propagate the splines to the remaining frames. Object boundaries are refined with per-pixel alpha mattes. At its core, the video mesh is a collection of texture-mapped triangles, which we can edit and render interactively using graphics hardware. We demonstrate the effectiveness of our representation with special effects such as 3D viewpoint changes, object insertion, depthof- field manipulation, and 2D to 3D video conversion.
by Jiawen Chen.
Ph.D.
34
Grundmann, Matthias. "Computational video: post-processing methods for stabilization, retargeting and segmentation". Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/47596.
Testo completoAbstract (sommario):
In this thesis, we address a variety of challenges for analysis and enhancement of Computational Video. We present novel post-processing methods to bridge the difference between professional and casually shot videos mostly seen on online sites. Our research presents solutions to three well-defined problems: (1) Video stabilization and rolling shutter removal in casually-shot, uncalibrated videos; (2) Content-aware video retargeting; and (3) spatio-temporal video segmentation to enable efficient video annotation. We showcase several real-world applications building on these techniques.
We start by proposing a novel algorithm for video stabilization that generates stabilized videos by employing L1-optimal camera paths to remove undesirable motions. We compute camera paths that are optimally partitioned into constant, linear and parabolic segments mimicking the camera motions employed by professional cinematographers. To achieve this, we propose a linear programming framework to minimize the first, second, and third derivatives of the resulting camera path. Our method allows for video stabilization beyond conventional filtering, that only suppresses high frequency jitter. An additional challenge in videos shot from mobile phones are rolling shutter distortions. Modern CMOS cameras capture the frame one scanline at a time, which results in non-rigid image distortions such as shear and wobble. We propose a solution based on a novel mixture model of homographies parametrized by scanline blocks to correct these rolling shutter distortions. Our method does not rely on a-priori knowledge of the readout time nor requires prior camera calibration. Our novel video stabilization and calibration free rolling shutter removal have been deployed on YouTube where they have successfully stabilized millions of videos. We also discuss several extensions to the stabilization algorithm and present technical details behind the widely used YouTube Video Stabilizer.
We address the challenge of changing the aspect ratio of videos, by proposing algorithms that retarget videos to fit the form factor of a given device without stretching or letter-boxing. Our approaches use all of the screen's pixels, while striving to deliver as much video-content of the original as possible. First, we introduce a new algorithm that uses discontinuous seam-carving in both space and time for resizing videos. Our algorithm relies on a novel appearance-based temporal coherence formulation that allows for frame-by-frame processing and results in temporally discontinuous seams, as opposed to geometrically smooth and continuous seams. Second, we present a technique, that builds on the above mentioned video stabilization approach. We effectively automate classical pan and scan techniques by smoothly guiding a virtual crop window via saliency constraints.
Finally, we introduce an efficient and scalable technique for spatio-temporal segmentation of long video sequences using a hierarchical graph-based algorithm. We begin by over-segmenting a volumetric video graph into space-time regions grouped by appearance. We then construct a "region graph" over the obtained segmentation and iteratively repeat this process over multiple levels to create a tree of spatio-temporal segmentations. This hierarchical approach generates high quality segmentations, and allows subsequent applications to choose from varying levels of granularity. We demonstrate the use of spatio-temporal segmentation as users interact with the video, enabling efficient annotation of objects within the video.
35
Bailey, Kira Marie. "Individual differences in video game experience cognitive control, affective processing, and visuospatial processing /". [Ames, Iowa : Iowa State University], 2009. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1473177.
Testo completo
36
Gu, Lifang. "Video analysis in MPEG compressed domain". University of Western Australia. School of Computer Science and Software Engineering, 2003. http://theses.library.uwa.edu.au/adt-WU2003.0016.
Testo completoAbstract (sommario):
The amount of digital video has been increasing dramatically due to the technology advances in video capturing, storage, and compression. The usefulness of vast repositories of digital information is limited by the effectiveness of the access methods, as shown by the Web explosion. The key issues in addressing the access methods are those of content description and of information space navigation. While textual documents in digital form are somewhat self-describing (i.e., they provide explicit indices, such as words and sentences that can be directly used to categorise and access them), digital video does not provide such an explicit content description. In order to access video material in an effective way, without looking at the material in its entirety, it is therefore necessary to analyse and annotate video sequences, and provide an explicit content description targeted to the user needs. Digital video is a very rich medium, and the characteristics in which users may be interested are quite diverse, ranging from the structure of the video to the identity of the people who appear in it, their movements and dialogues and the accompanying music and audio effects. Indexing digital video, based on its content, can be carried out at several levels of abstraction, beginning with indices like the video program name and name of subject, to much lower level aspects of video like the location of edits and motion properties of video. Manual video indexing requires the sequential examination of the entire video clip. This is a time-consuming, subjective, and expensive process. As a result, there is an urgent need for tools to automate the indexing process. In response to such needs, various video analysis techniques from the research fields of image processing and computer vision have been proposed to parse, index and annotate the massive amount of digital video data. However, most of these video analysis techniques have been developed for uncompressed video. Since most video data are stored in compressed formats for efficiency of storage and transmission, it is necessary to perform decompression on compressed video before such analysis techniques can be applied. Two consequences of having to first decompress before processing are incurring computation time for decompression and requiring extra auxiliary storage.To save on the computational cost of decompression and lower the overall size of the data which must be processed, this study attempts to make use of features available in compressed video data and proposes several video processing techniques operating directly on compressed video data. Specifically, techniques of processing MPEG-1 and MPEG-2 compressed data have been developed to help automate the video indexing process. This includes the tasks of video segmentation (shot boundary detection), camera motion characterisation, and highlights extraction (detection of skin-colour regions, text regions, moving objects and replays) in MPEG compressed video sequences. The approach of performing analysis on the compressed data has the advantages of dealing with a much reduced data size and is therefore suitable for computationally-intensive low-level operations. Experimental results show that most analysis tasks for video indexing can be carried out efficiently in the compressed domain. Once intermediate results, which are dramatically reduced in size, are obtained from the compressed domain analysis, partial decompression can be applied to enable high resolution processing to extract high level semantic information.
37
Monaco, Joseph W. "Generalized motion models for video applications". Diss., Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/14926.
Testo completo
38
Pao, I.-Ming. "Improved standard-conforming video coding techniques /". Thesis, Connect to this title online; UW restricted, 1999. http://hdl.handle.net/1773/5936.
Testo completo
39
Huang, Jianzhong. "Motion estimation and compensation for video image sequences". Diss., Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/14950.
Testo completo
40
Saari, M. (Marko). "How usability is visible in video games". Bachelor's thesis, University of Oulu, 2017. http://urn.fi/URN:NBN:fi:oulu-201702231258.
Testo completoAbstract (sommario):
As video games have become have become more popular and as popular as music and movies, the need for more video game developers have increased also. But even though there are more people developing video games, there still exists usability issues in video games like also in general computer software. The purpose of the thesis is to find out how usability issues can be seen in video games.
To find out the answer for this research question, research was done as literature review. There already existed a fair amount of literature relating to usability issues of video games. Also the usability issues of computer software were discussed a little bit as video games are similar to computer software. The research on existing literature provided usability issues to be discussed and to find out the answer.
41
Dworaczyk, Wiltshire Austin Aaron. "CUDA ENHANCED FILTERING IN A PIPELINED VIDEO PROCESSING FRAMEWORK". DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/1072.
Testo completoAbstract (sommario):
The processing of digital video has long been a significant computational task for modern x86 processors. With every video frame composed of one to three planes, each consisting of a two-dimensional array of pixel data, and a video clip comprising of thousands of such frames, the sheer volume of data is significant. With the introduction of new high definition video formats such as 4K or stereoscopic 3D, the volume of uncompressed frame data is growing ever larger.
Modern CPUs offer performance enhancements for processing digital video through SIMD instructions such as SSE2 or AVX. However, even with these instruction sets, CPUs are limited by their inherently sequential design, and can only operate on a handful of bytes in parallel. Even processors with a multitude of cores only execute on an elementary level of parallelism.
GPUs provide an alternative, massively parallel architecture. GPUs differ from CPUs by providing thousands of throughput-oriented cores, instead of a maximum of tens of generalized “good enough at everything” x86 cores. The GPU’s throughput-oriented cores are far more adept at handling large arrays of pixel data, as many video filtering operations can be performed independently. This computational independence allows for pixel processing to scale across hun- dreds or even thousands of device cores.
This thesis explores the utilization of GPUs for video processing, and evaluates the advantages and caveats of porting the modern video filtering framework, Vapoursynth, over to running entirely on the GPU. Compute heavy GPU-enabled video processing results in up to a 108% speedup over an SSE2-optimized, multithreaded CPU implementation.
42
Grundmann, Matthias. "Real-time content aware resizing of video". Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/26622.
Testo completoAbstract (sommario):
Thesis (M. S.)--Computing, Georgia Institute of Technology, 2009.Committee Chair: Essa, Irfan; Committee Member: Dellaert, Frank; Committee Member: Turk, Greg. Part of the SMARTech Electronic Thesis and Dissertation Collection.
43
Jiang, Min. "Hardware architectures for high-performance image and video processing". Thesis, Queen's University Belfast, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.492001.
Testo completoAbstract (sommario):
This PhD work has resulted in the development of a set of novel architectures and algorithms for high-performance image and video processing applications. The main architecture contributions are: 1) A range of area-efficient novel 3D median filter architectures for real time 3D noise removal. The proposed 3D median filter can be applied for both video and 3D medical images. Separately, one of the filter implementations on an FPGA was applied to processing the output from a low-light digital video camera (by Andor Technologies), as a demonstration of a typical scenario where this form of real time filtering is particularly applicable. 2) An area-efficient real time 3D wavelet transform processor architecture. The synthesis results show that the proposed 5-stage bit-parallel OA architecture can perform the 3D Wavelet transform on typical fMRI data at several volumes per second on a single FPGA. Implementation on a larger, more recent FPGA would provide real time performance. 3) A novel Full Search Block Matching (FSBM) architecture which maps the partial distortion elimination algorithm (POE) into a parallel systolic array processor with an Early-Jump-Out (EJO) / Early-Tum-Off (ETO) control unit. RTL simulation indicates that the proposed low power architecture could in some cases save about 50% of the power consumption for this part of motion estimation in MPEG-2/4 and H.264 video compression. 4) A generic image feature matching hardware engine on FPGAs for fast feature-based image retrieval, illustrated by an architecture with an Earlier-Jump-Out (EJO) control unit for fingerprint matching at potentially 1.23 million fingerprints per second. This architectural framework could be adapted for feature matching-based retrieval using other features and distance measures. 5) A novel low power, high radix multiplication architecture. Performance tests based on the number of bit reversals indicate that the power consumption estimated by this measure can be reduced by around 50% in comparison with the conventional multiplier. Although these application-specific circuit architectures are disparate with different characteristics and techniques, there are several reusable techniques which we have developed in the process which can be used for other hardware architectures: 1) The Early-Jump-Out (or Early-Tum-Off) approach applied in motion estimation and fingerprint matching can be generalized for many other multimedia search and image database retrieval applications. The primary purpose of the ETO form is to save power when certain elements of a regUlar array computation can be terminated early. The more standard EJO form can be used to speed up a more asynchronous (serial) search process. 2) The Proposed low-power high-radix BSO multiplication architecture, as a basic module for digital circuit design, can be applied in a wide range of circuit applications; The project also developed a novel facet-based Bayesian approach for video object motion tracking, which has been tested with a number of video clips. This approach can be also applied for high-level video retrieval as well as the basis of further hardware-based VO tracking. Based on the above work, 5 journal papers and 4 conference papers have been pUblished, and other 3 papers are under review. A patent for the BSO Multiplier has been applied for.
44
Friedland, Gerald. "Adaptive audio and video processing for electronic chalkboard lectures". [S.l.] : [s.n.], 2006. http://www.diss.fu-berlin.de/2006/514/index.html.
Testo completo
45
Altilar, Deniz Turgay. "Data partitioning and scheduling for parallel digital video processing". Thesis, Queen Mary, University of London, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.399730.
Testo completo
46
Case, David Robert. "Real-time signal processing of multi-path video signals". Thesis, University of Salford, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334170.
Testo completo
47
Dickinson, Keith William. "Traffic data capture and analysis using video image processing". Thesis, University of Sheffield, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306374.
Testo completo
48
Parimala, Anusha. "Video Enhancement: Video Stabilization". Thesis, 2018. http://ethesis.nitrkl.ac.in/9977/1/2018_MT_216EC6252_AParimala_Video.pdf.
Testo completoAbstract (sommario):
Video stabilization is required in digital video cameras as most of them are hand held or mounted on moving platforms (e.g. cars) undergo atmospheric vibrations and also the videos taken by the camera with CMOS sensors undergo rapid vibrations because of rolling shutter which scans an image horizontally or vertically instead of recording the whole image of the scene at same instant. And also the moving cameras cause geometric distortion of the objects in the video because of parallax. A method which handles parallax and rolling shutter effects along with removing the unwanted motion of frames caused by the movement of camera is proposed by modelling the camera motion with bundle of camera paths using bundled camera paths.
Bundled camera paths motion model involves dividing the video frames into mesh grid cells, extracting matched features for every two consecutive frames. Having these matched features and grid cell vertices, new vertices are obtained using Bilinear interpolation resulting in image warping of each frame in accordance with the camera motion. Homographies which represent the camera motion for each grid cell are obtained using original vertices and new vertices. For each grid cell, homographies of corresponding grid cell of all the frames of the video are multiplied to get camera path of each grid cell representing the bundle of camera paths. These camera paths are smoothed adaptively. Adaptive smoothing handles cropping. Smoothed homographies are applied to original video to get the stabilized video.
49
Chang, Sheng-Hung, e 張盛紘. "Android Video Processing APP". Thesis, 2014. http://ndltd.ncl.edu.tw/handle/61903393845787879753.
Testo completoAbstract (sommario):
碩士明新科技大學
電子工程研究所
102
We implemented a visual-based image on the Android-based smartphone. This system uses only build-in camera in an Android phone. The system works with no other assisted equipment, today's information era action fast, real-time, so we are not in the image but rather to render the video. In this paper, using the Android system implements an Android phone application to study and explore the color space and skin detection technology and practical application, firstly, we use only build-in camera to setting in an Android phone, The enactment opens the lens while being like the image seeing to carry on decoding or wanting to circulate, the appearance seen by our lens carries on the processing of each 5 f/sec after, let us reach instant of the condition, we start carrying on detecting of some colors after, we used basic RGB in the color space to detect first black and white, then come to further skin color to detect, then want to use is like HSV, YIQ and technique with this type of YCbCr to carry on, these techniques want will by oneself the formula come to carry on again to detect after converting and also mix some more complicated and triangle functions to carry on an operation in the formula, however also increased the accuracy of technique like this.
50
Lin, Wei-Xian, e 林威憲. "Video Processing for an Object-Based Virtual Video Conferencing". Thesis, 2000. http://ndltd.ncl.edu.tw/handle/04899495861925372387.
Testo completoAbstract (sommario):
碩士國立清華大學
電機工程學系
88
In a general multipoint video conferencing, the participants focus on the other participants rather than the background, and they will pay more attention on the active conferees. Therefore, we propose a bit-allocation method which may distribute the constrained bit-rates to each object based on its characteristics. From the rate and distortion model proposed in ITU-T TMN8, we derive an object-based R-D optimized bit allocation equation, which only considers spatial activity. Then we introduce the factors of temporal activity and object size into the bit allocation equation to derive the joint bit-allocation method. Simulation results show that the image quality of interest is improved while the image quality of less interest is degraded. In this thesis, two multipoint virtual conferencing environments are proposed to provide a more realistic conference, the conferencing with two-dimensional virtual scene and the conferencing with three-dimensional virtual environment. In the conferencing with two-dimensional virtual scene, the objects are resized and composed onto a pre-designed virtual scene. In the conferencing with three-dimensional virtual environment, the objects are manipulated onto a three-dimensional environment based on their specific locations. An object-segmentation procedure is also proposed in this thesis to discriminate the objects from the video sequence based on the background subtraction, morphological operations, and row-column scan method.