https://www.cin.ufpe.br/~rps/Artigos/Face%20Detection%20-%20%20A%20Survey.pdf

Face Detection

Computer and Robot Vision Vol. 1, by R.M. Haralick and Linda G. Shapiro, Addison-Wesley, 1992, ISBN 0-201-10887-1.

Computer and Robot Vision

MPEG-4 is the multimedia standard for combining interactivity, natural and synthetic digital video, audio and computer-graphics Typical applications are: internet, video conferencing, mobile videophones, multimedia cooperative work, teleteaching and games With MPEG-4 the next step from block-based video (ISO/IEC MPEG-1, MPEG-2, CCITT H261, ITU-T H263) to arbitrarily-shaped visual objects is taken This significant step demands a new methodology for system analysis and design to meet the considerably higher flexibility of MPEG-4 Motion estimation is a central part of MPEG-1/2/4 and H261/H263 video compression standards and has attracted much attention in research and industry, for the following reasons: it is computationally the most demanding algorithm of a video encoder (about 60-80% of the total computation time), it has a high impact on the visual quality of a video encoder, and it is not standardized, thus being open to competition Algorithms, Complexity Analysis, and VLSI Architectures for MPEG-4 Motion Estimation covers in detail every single step in the design of a MPEG-1/2/4 or H261/H263 compliant video encoder: Fast motion estimation algorithms Complexity analysis tools Detailed complexity analysis of a software implementation of MPEG-4 video Complexity and visual quality analysis of fast motion estimation algorithms within MPEG-4 Design space on motion estimation VLSI architectures Detailed VLSI design examples of (1) a high throughput and (2) a low-power MPEG-4 motion estimator Algorithms, Complexity Analysis and VLSI Architectures for MPEG-4 Motion Estimation is an important introduction to numerous algorithmic, architectural and system design aspects of the multimedia standard MPEG-4 As such, all researchers, students and practitioners working in image processing, video coding or system and VLSI design will find this book of interest

Algorithms, Complexity Analysis and VLSI Architectures for MPEG-4 Motion Estimation

A method of hierarchical digital video summarization and browsing includes inputting a digital video signal for a digital video sequence and generating a hierarchical summary based on keyframes of the video sequence. Additional steps may include computing histograms for the digital video sequence; detecting shot boundaries within the digital video sequence; determining the number of keyframes to be allocated within each shot; locating the actual position of each keyframe within each shot; identifying keyframe locations by the largest consecutive difference criteria; pruning keyframes for an shot without meaningful action; extracting keyframes efficiently in the case of compressed video; and browsing the shots using the hierarchical keyframe summary.

Method for hierarchical summarization and browsing of digital video

This paper describes an algorithm which can achieve a constant bit rate when coding multiple video objects. The implementation is a nontrivial extension of the MPEG-4 rate control algorithm for single video objects which employs a quadratic rate quantizer model. The algorithm is organized into two stages: a pre- and a post-encoding stage. In the pre-encoding stage, an initial target estimate is made for each object. Based on the buffer fullness, the total target is adjusted and then distributed proportional to the relative size, motion, and variance of each object. Based on the new individual targets and rate-quantizer relation for texture, appropriate quantization parameters are calculated. After each object is encoded, the model parameters for each object are updated, and if necessary, frames are skipped to ensure that the buffer does not overflow. A preframeskip control is exercised to avoid buffer overflow when the motion and shape information occupies a significant portion of the bit budget. The rate control algorithm switches between two operation modes so that the coder can reduce the spatial coding accuracy for an improved temporal resolution. A shape-coding control mechanism is also proposed, which provides a tradeoff between texture and shape coding accuracy. Overall, the algorithm is able to successfully achieve the target bit rate, effectively code arbitrarily shaped objects, and maintain a stable buffer level. These techniques have been adopted by the MPEG committee in July 1997 as part of the video verification model (VM8).

MPEG-4 rate control for multiple video objects

An automatic facial feature extraction algorithm is presented. The algorithm is composed of two main stages: the face region estimation stage and the feature extraction stage. In the face region estimation stage, a second-chance region growing method is adopted to estimate the face region of a target image. In the feature extraction stage, genetic search algorithms are applied to extract the facial feature points within the face region. It is shown by simulation results that the proposed algorithm can automatically and exactly extract facial features with limited computational complexity.

/pdf/automatic-facial-feature-extraction-by-genetic-algorithms-2bk1dwnckb.pdf

Automatic facial feature extraction by genetic algorithms

An automatic facial feature extraction algorithm is presented in this paper. The algorithm is composed of two main stages: the face region estimation stage and the feature extraction stage. In the face region estimation stage, a second-chance region growing method is adopted to estimate the face region of a target image. In the feature extraction stage, genetic search algorithms are applied to extract the facial feature points within the face region. It is shown by simulation results that the proposed algorithm can automatically and exactly extract facial features with limited computational complexity.

In the applications of very low bit-rate video coding, the quality of the encoded pictures always suffers from serious degradation due to limited bandwidth. The quantization levels, in typical video coding systems, are adjusted depending only on the fullness of the output buffer while the content of the video is not taken into account. This explains why the picture quality varies saliently in very low bit-rate applications. A content-based bit-rate control scheme is proposed. In this approach, the content of the coded picture is first analyzed to find the main attributes of each macroblock. The attributes of the macroblocks are then consulted while adjusting the quantization levels. In other words, the quantization levels are adjusted not only depending on the fullness of the output buffer but also on the content of the coded material. Simulation results show that the perceptual quality of the coded pictures, by using the proposed method, is better while comparing with the traditional non-content-based approach.

Content-based rate control scheme for very low bit-rate video coding

The paper proposes an effective and efficient browsing system which is capable of representing the contents of a video sequence in a multi-layer manner. In this system, users can rapidly preview some preprocessed video shots, based on some simple scene change detection algorithm, to find out the particular video segments which are of interest. Because users just preview some video shots instead of examining all the video frames, this shot-based browsing method is superior to the conventional frame-based browsing one from the view points of the network bandwidth, user friendliness, and/or browsing efficiency. Based on the proposed browsing tool, a video-on-demand (VOD) prototype system has been implemented in the Communication and Multimedia Laboratory of National Taiwan University in an Ethernet LAN environment. >

https://ieeexplore.ieee.org/iel3/3916/11346/00518028.pdf

A multi-layer video browsing system

Genetic algorithms (GAs) recently have been successfully applied to perform block-based motion estimation. It is shown that the performance of the GA-based motion estimation algorithms nearly approaches that of the full search algorithm (FSA). However, the computational complexity of the existing GA-based algorithms is too high to be used in practice. In this paper, a lightweight genetic search algorithm (LGSA) is proposed. It can be seen from the simulation results that the performance of the proposed LGSA is not only as good as that of the FSA, but the computational complexity is also much lower than that of the FSA and the other existing genetic motion estimation algorithms.

Chun-Hung Lin

Papers

Automatic facial feature extraction by genetic algorithms

Automatic facial feature extraction by genetic algorithms

Content-based rate control scheme for very low bit-rate video coding

A multi-layer video browsing system

Genetic block matching algorithm for video coding