检索结果-内蒙古大学图书馆

Automatic scalable face model design for 2D model-based video coding

SIGNAL PROCESSING-IMAGE COMMUNICATION 2004年第5期19卷 421-436页

作者： Hu, M Worrall, S Sadka, AH Kondoz, AM Univ Surrey Sch Elect & Phys Sci Dept Elect Engn CCSR Surrey GU2 7XH England

Scalable low bit-rate video coding is vital for the transmission of video signals over wireless channels. A scalable model-based video coding scheme is proposed in this paper to achieve this. This paper mainly addresses automatic scalable face model design. Firstly, a robust and adaptive face segmentation method is proposed, which is based on piecewise skin-colour distributions. 43 million skin pixels from 900 images are used to train the skin-colour model, which can identify skin-colour pixels reliably under different lighting conditions. Next, reliable algorithms are proposed for detecting the eyes, mouth and chin that are used to verify the face candidatures. Then, based on the detected facial features and human face muscular distributions, a heuristic scalable face model is designed to represent the rigid and non-rigid motion of head and facial features. A novel motion estimation algorithm is proposed to estimate the object model motion hierarchically. Experimental results are provided to illustrate the performance of the proposed algorithms for facial feature detection and the accuracy of the designed scalable face model for representing face motion. (C) 2004 Elsevier B.V. All rights reserved.

关键词： face detection facial feature extraction scalable face modelling model-based video coding scalable compression

来源：评论

学校读者我要写书评

暂无评论

ESTIMATION OF CAMERA PARAMETERS FROM IMAGE SEQUENCE FOR model-based video coding

引用

IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR video TECHNOLOGY 1994年第3期4卷 288-296页

作者： PARK, JI YAGI, N ENAMI, K AIZAWA, K HATORI, M UNIV TOKYO DEPT ELECT ENGN TOKYO JAPAN NHK JAPAN BROADCASTING CORP SCI & TECH RES LABS TOKYO 157 JAPAN UNIV TOKYO DEPT INFORMAT & COMMUN SCI TOKYO 113 JAPAN

In this paper, we describe a method for estimating camera parameters from image sequences for application to emerging model-based;ideo coding systems. The parameters to be estimated include focal length, zoom, and 3-D rotation parameters. The method consists of first establishing correspondence and then, estimating the parameters by fitting the correspondence data to a transformation model based on a perspective mapping model and a 3-D rotation and zoom operation model. We show by simulations and experiments that the proposed method successfully estimates focal length from image sequences, that it explains very well the induced motion field of images undergoing camera operation (3-D rotation and zoom), and that it significantly outperforms conventional estimation methods, especially for wide-angled images. It is anticipated that the proposed method will be successfully applied to compensating for the motion field induced by camera operation in extracting 3-D object model and 3-D object motion and to synchronizing viewing direction and scale of image, in model-based video coding technology.

关键词： CAMERA PARAMETER PERSPECTIVE PROJECTION model-based video coding MOTION COMPENSATION CORRESPONDENCE ESTABLISHMENT NONLINEAR LEAST-SQUARE ESTIMATION

来源：评论

学校读者我要写书评

暂无评论

Real-time 2(1/2)-D head pose recovery for model-based video-coding

引用

IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT 2001年第4期50卷 1007-1013页

作者： Cordea, MD Petriu, EM Georganas, ND Petriu, DC Whalen, TE Univ Ottawa Sch Informat Technol & Engn Ottawa ON K1N 6N5 Canada Carleton Univ Dept Syst & Comp Engn Ottawa ON K1N 6N5 Canada CRC Commun Res Ctr Ottawa ON K1N 6N5 Canada

This paper discusses a 2(1/2)-D tracking method allowing real-time recovery of the three-dimensional (3-D) position and orientation of a head moving in its image plane. The described method uses a two-dimensional (2-D) elliptical head model, region- and edge-based matching algorithms, and a linear Kalman filter estimator. The resulting motion tracking system works in a realistic environment without makeup on the face, with an uncalibrated camera, normal lighting conditions, and an unknown background.

关键词： Kalman filter model-based video coding real-time tracking 3-D head model

来源：评论

学校读者我要写书评

暂无评论

Real-time 2(1/2)-D head pose recovery for model-based video-coding

Real-time 2(1/2)-D head pose recovery for model-based video-...

引用

Instrumentation and Measurement Technology Conference (IMTC 2000)

ISBN: (纸本)0780358902

关键词： Kalman filter model-based video coding real-time tracking 3-D head model

来源：评论

学校读者我要写书评

暂无评论

Hybrid model-and-object-based real-time conversational video coding

引用

SIGNAL PROCESSING-IMAGE COMMUNICATION 2015年 35卷 9-19页

作者： Li, Yang Tao, Xiaoming Lu, Jianhua Tsinghua Univ Dept Elect Engn Beijing 100084 Peoples R China

Bandwidth-constrained real-time conversational video communications (such as mobile teleconferencing) require video codecs with good rate-distortion characteristics at low bit-rates and modest computational complexity. While target-specific object-based and model-based coding methods have been proposed for low bit-rate conversational video coding, difficulties in generalization and high computational complexity hinder their practical utilization. In this paper, we propose a low bit-rate coding method for typical conversational video by combining two-dimensional model-based coding of face regions and object-based coding of non-face head-shoulder regions, achieving high-quality face reconstruction and low overall bit-rate with real-time encoding capability. Experiments on typical conversational test sequences confirm that, compared to other conversational video codecs, our model-and-object-based coding method offers superior rate-distortion performance at low bit-rates. (C) 2015 Elsevier B.V. All rights reserved.

关键词： model-based video coding Object-based video coding Face mogdeling

来源：评论

学校读者我要写书评

暂无评论

CAPTURING LIGHT FIELD TEXTURES FOR video coding

CAPTURING LIGHT FIELD TEXTURES FOR VIDEO CODING

引用

15th IEEE International Conference on Image Processing (ICIP 2008)

作者： Mantzel, William Romberg, Justin Georgia Inst Technol Sch Elect & Comp Engn Atlanta GA 30332 USA

ISBN: (纸本)9781424417650

There is a significant amount of redundancy between video frames or images that can be explained by considering these observations as samples of a light field function. By using a compact depth-augmented representation for such a light field function, it may even be possible to tie-together inter-frame dependencies in a more meaningful way than conventional 2-D intensity based motion compensation methods. We propose a depth-augmented layered orthographic light field representation and show how it may be constructed from actual data at a basic level as the solution to an over-determined linear inverse problem. We finally demonstrate the potential utility of such information in video coding with a compression example when this light field side information is given as a simple texture map.

关键词： Orthographic texture mapping light field construction image-based rendering model-based video coding

来源：评论

学校读者我要写书评

暂无评论

Very low bit-rate video coding

Very low bit-rate video coding

引用

IEEE Region 10 Conference on Analog and Digital Techniques in Electrical Engineering

作者： Kocharoen, P Ahmed, KM Asian Inst Technol Telecommun Program Klongluang 12120 Pathumthani Thailand

ISBN: (纸本)0780385608

In this paper several very low bit-rate, below 64kbps, video coding schemes are reviewed. A typical application requiring very low bit-rute is video telephony that transmits video sequences through the existing plain old telephone line or via a mobile phone channel. Three types of potential coding techniques are presented: waveform-based video coding model-based video coding and mesh-based interpolative video coding.

关键词： video coding telephony image sequences telecommunication channels mobile radio visual communication interpolation bit-rate video coding schemes video telephony video sequence transmission mobile phone channel potential coding techniques waveform-based video coding model-based video coding mesh-based interpolate video coding video coding video phone Telephone Mobile radios image sequences Interpolation telephone lines

来源：评论

学校读者我要写书评

暂无评论

MAP estimation of chin and cheek contours in video sequences

引用

EURASIP JOURNAL ON APPLIED SIGNAL PROCESSING 2004年第6期2004卷 913-922页

作者： Kampmann, M Ericsson Res D-52134 Herzogenrath Germany

An algorithm for the estimation of chin and cheek contours in video sequences is proposed. This algorithm exploits a priori knowledge about shape and position of chin and cheek contours in images. Exploiting knowledge about the shape, a parametric 2D model representing chin and cheek contours is introduced. Exploiting knowledge about the position, a MAP estimator is developed taking into account the observed luminance gradient as well as a priori probabilities of chin and cheek contours positions. The proposed algorithm was tested with head and shoulder video sequences (image resolution CIF). In nearly 70% of all investigated video frames, a subjectively error free estimation could be achieved. The 2D estimate error is measured as on average between 2.4 and 2.9 pel.

关键词： facial feature extraction model-based video coding parametric 2D model face contour face model

来源：评论

学校读者我要写书评

暂无评论

Digital watermarking of MPEG-4 facial animation parameters

引用

COMPUTERS & GRAPHICS 1998年第4期22卷 425-435页

作者： Hartung, F Eisert, P Girod, B Univ Erlangen Nurnberg Telecommun Inst 1 D-91058 Erlangen Germany

The enforcement of intellectual property rights is difficult for digital data. One possibility of supporting enforcement is the embedding of digital watermarks containing information about copyright owner and/or receiver of the data. Watermarking methods have already been presented for audio, images, video, and polygonal 3D models. In this paper, we present a method for digital watermarking of MPEG-4 facial animation parameter data sets. The watermarks are additively embedded into the parameter values and can be retrieved either from the watermarked parameters or from video sequences rendered using the watermarked animation parameters for head animation. For retrieval from rendered sequences, the facial animation parameters have to be estimated first. We use a model-based approach for the estimation of the facial parameters that combines a motion model of an explicit 3D textured wireframe with the optical flow constraint from the video data. This leads to a linear algorithm that is robustly solved in a hierarchical framework with low computational complexity. Experimental results confirm the applicability of the presented watermarking technique. (C) 1998 Elsevier Science Ltd. All rights reserved.

关键词： digital watermarking facial animation 3D head model model-based video coding MPEG-4

来源：评论

学校读者我要写书评

暂无评论

video representation with three-dimensional entities

引用

IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS 1998年第1期16卷 71-85页

作者： Martins, FCM Moura, JMF Carnegie Mellon Univ Dept Elect & Comp Engn Pittsburgh PA 15213 USA

Very low bit-rate coding requires new paradigms that go well beyond pixel-and frame-based video representations, We introduce a novel content-based video representation using tridimensional entities: textured object models and pose estimates, The multiproperty object models carry stochastic information about the shape and texture of each object present in the scene, The pose estimates define the position and orientation of the objects for each frame, This representation is compact, It provides alternative means for handling video by manipulating and compositing three-dimensional (3-D) entities, We call this representation tridimensional video compositing, or 3DVC for short, In this paper, we present the 3DVC framework and describe the methods used to construct incrementally the object models and the pose estimates from unregistered noisy depth and texture measurements, We also describe a method for video frame reconstruction based on 3-D scene assembly, and discuss potential applications of 3DVC to video coding and content-based handling, 3DVC assumes that the objects in the scene are rigid and segmented, By assuming segmentation, we do not address the difficult questions of nonrigid segmentation and multiple object segmentation, In our experiments, segmentation is obtained via depth thresholding, It is important to notice that 3DVC is independent of the segmentation technique adopted, Experimental results with synthetic and real video sequences where compression ratios in the range of 1:150-1:2700 are achieved demonstrate the applicability of the proposed representation to very low bit-rate coding.

关键词： content-based video handling model-based video coding range and image sequence processing 3-D object modeling video sequence representation

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：