Guiguang Ding

Adaptive Key Frame Selection Wyner-Ziv Video Coding

In Wyner-Ziv video coding, efficient compression is achieved by exploiting source statistics at the decoder only, which is radically different from conventional video coding. The performance of a Wyner-Ziv video codec is greatly dependent on the quality of reconstructed side information, which is an estimation version of current frame. Therefore the correlation between Wyner-Ziv (WZ) frame and key frame implicitly affects the performance of a Wyner-Ziv video codec. In this paper, an adaptive key frame selection method is proposed. Firstly, a simply interest points detector is utilized to detect interest points of a video frame. Then, a kind of interest points based measure, which could represent the correlation between video frames, is performed. If the number of different interest points between two video frames is below a threshold, then it should be transmitted as a key frame, otherwise as a WZ frame. Our experimental results are promising. About 1 dB gain in the quality of reconstructed frames has been achieved

Affine-Invariant Image Retrieval Based on Wavelet Interest Points

This paper presents an affine-in variant image retrieval approach based on wavelet-based detector, which uses the space-tree property of the transform coefficients to estimate the interest points. Meanwhile, in order to retrieve images compressed by wavelet algorithm such as JPEG2000, the detector only uses the partial bit-planes of the wavelet coefficients to detect the interest points. To provide affine-invariant image matching, annular color histogram, annular texture histogram and spatial cohesion based on interest points are presented to describe image features. A series of experiments based on an image database consisting of 1000 images are performed to confirm the effectiveness of our method

Multi-View Images Coding Based on Multiterminal Source Coding

In this paper, we proposed a multi-view images coding method based on multiterminal source coding (MSC). Due to separate encoding in MSC, our coding scheme can achieve good random access performance and the spatial redundancy can be exploited even if the encoders can not communicate with each other. Because of joint decoding, the compression performance of our scheme is promising, far better than that of separate encoding and decoding scheme. Compared to multi-view coding based on Wyner Ziv coding, our coding scheme is more flexible and can be easily extended to N views coding. There is no need to classify the view images into key images and Wyner Ziv images, images can be compressed in the same way and we can easily change the compression rate of each view to adapt to the resource conditions, like network bandwidth or storage. Experiment results show that the compression performance of our scheme is better than that of JPEG encoder and decoder scheme.

Motion-compensated 3d wavelet video coding based on adaptive temporal lifting filter implementation

In wavelet-based video coding with motion-compensated lifting, efficient compression is achieved by exploiting motion-compensated temporal filtering (MCTF). The performance of a 3D wavelet video codec is greatly dependent on the efficient of MCTF. In this paper, an adaptive motion-compensated temporal filter scheme is proposed for wavelet video coding. Our method focused to control the level number of the temporal decomposition by detecting the number of the un-connection pixels in low-pass frame to avoid the inefficiency of MCTF while scene changing quickly. Moreover, this method has most useful features of predictive wavelet codecs, such as multiple reference frame and bi-directional prediction. Our experimental results show that, compared with the conventional MCTF, the proposed scheme has better coding performance for most sequences.

A distributed video coding scheme based on denoising techniques

Distributed source coding is a new paradigm for source compression, based on the information-theoretic results built upon by Slepian and Wolf, and Wyner and Ziv from the 1970s. Recently some practical applications of distributed source coding to video compression have been studied due to its advantage of lower encoding complexity over conventional video coding standards. In this paper, we proposed a new distributed source coding framework based on signal denoising techniques. To apply the proposed framework in video coding systems, we give a novel distributed video coding scheme. Our experimental results show that the proposed scheme can achieve better coding efficiency while keeping the simple encoding property.

A new region-of-interest image compression method based on Wyner-Ziv coding

The JPEG2000 image coding standard defines two kinds of region of interest (ROI) compression methods--the general scaling based method and the maximum shift (maxshift) method. There are two major drawbacks of the two methods. First, they would significantly reduce the compression efficiency by increasing the dynamic range (or number of bitplanes) of wavelet coefficients. Second, they do not have the especial protection for the ROI against the bit errors in image communication application, i.e., remote medical treatment and Satellite Communication. When the bit errors occurred, the reconstruction quality of ROI and BG would reduce at the same time. In this paper, a new and flexible ROI image compression method is proposed according to the Wyner-Ziv theorem on source coding with side information. The reconstructed low quality ROI is regard as a noisy version of original ROI in the proposed method. So, along with the parity bits from the original ROI, the reconstructed low quality ROI as side information can be utilized to Turbo decoder to decode the high quality ROI. Our experimental results show that the proposed method applying the Wyner-Ziv coding to ROI compression can highly improve the compression efficiency as well as efficiently protect the ROI against the bit errors.

Fast motion estimation algorithm based on predictive line diamond search technology

Motion estimation (ME) is one of the most time-consuming parts in video encoding systems, and significantly affects the output quality of an encoded sequence. In this paper, a new algorithm is presented, referred to as the predictive line diamond search (PLDS), which is a gradient descent search combined with a new search strategy, namely, one-dimensional line search (1DLS). 1DLS assists a local search around an initial search center with a low computational complexity. After performing 1DLS, a small diamond search pattern and a more compact line search pattern are adaptively used according to the results of the previous search. Our experimental results show that, compared with the previous techniques, the proposed algorithm has lower computational complexity and provides better prediction performance, especially for fast or complex motion sequences.