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Y.M. Yeung

Bio: Y.M. Yeung is an academic researcher from Hong Kong University of Science and Technology. The author has contributed to research in topics: Motion estimation & Motion compensation. The author has an hindex of 9, co-authored 11 publications receiving 423 citations.

Papers
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Journal ArticleDOI
TL;DR: Experimental results show that embedded watermarks using the proposed techniques can give good image quality and are robust in varying degree to JPEG compression, low-pass filtering, noise contamination, and print-and-scan.
Abstract: Three novel blind watermarking techniques are proposed to embed watermarks into digital images for different purposes. The watermarks are designed to be decoded or detected without the original images. The first one, called single watermark embedding (SWE), is used to embed a watermark bit sequence into digital images using two secret keys. The second technique, called multiple watermark embedding (MWE), extends SWE to embed multiple watermarks simultaneously in the same watermark space while minimizing the watermark (distortion) energy. The third technique, called iterative watermark embedding (IWE), embeds watermarks into JPEG-compressed images. The iterative approach of IWE can prevent the potential removal of a watermark in the JPEG recompression process. Experimental results show that embedded watermarks using the proposed techniques can give good image quality and are robust in varying degree to JPEG compression, low-pass filtering, noise contamination, and print-and-scan.

168 citations

Journal ArticleDOI
TL;DR: Three rate control methods are proposed to efficiently reduce both the computational complexity and memory usage over the conventional PCRD method and suggest that they provide different tradeoff among visual quality, computational complexity, coding delay and working memory size.
Abstract: JPEG2000 is the new image coding standard which can provide superior rate-distortion performance over the old JPEG standard. However, the conventional post-compression rate-distortion (PCRD) optimization scheme in JPEG2000 is not efficient. It requires entropy encoding all available data even though a large portion of them will not be included in the final output. In this paper, three rate control methods are proposed to efficiently reduce both the computational complexity and memory usage over the conventional PCRD method. The first method, called successive bit-plane rate allocation (SBRA), allocates the bit rate by using the currently available rate-distortion information only. The second method, called priority scanning rate allocation (PSRA), allocates bits according to certain prioritized ordering. The third method uses PSRA to achieve optimal truncation as PCRD without encoding of all the image details and is called priority scanning with optimal truncation (PSOT). Simulation results suggest that the three proposed methods provide different tradeoff among visual quality, computational complexity, coding delay and working memory size. SBRA is memoryless and causal and requires the least computational complexity, lowest coding delay and achieves good visual quality. PSRA achieves higher PSNR than SBRA at the expense of larger working memory size and longer coding delay. PSOT gives the best PSNR but requires even more computation, delay and memory.

53 citations

Proceedings ArticleDOI
06 Apr 2003
TL;DR: A novel fast multi-frame selection method is proposed for H.264 video coding that can efficiently reduce the computational cost up to 70% with similiar quality and bit-rate and is highly suitable for real-time (or low delay) applications.
Abstract: The latest under development video coding standard, H.264, uses multiple reference frames to improve the rate-distortion performance. However, the motion estimation process involved is computational intensive and increases linearly with the number of allowed reference frames. In this paper, a novel fast multi-frame selection method is proposed for H.264 video coding. The proposed scheme can efficiently reduce the computational cost up to 70% with similiar quality and bit-rate. So the method is highly suitable for real-time (or low delay) applications while the benefits from multi-frame motion compensation can be preserved.

50 citations

Proceedings ArticleDOI
25 May 2003
TL;DR: A novel fast multi-frame selection method (FMFME) is proposed for H.264 video coding that can efficiently reduce the computational cost up to 76% with similar quality and bit-rate.
Abstract: The latest under development video coding standard, H.264, uses multiple reference frames to improve the rate-distortion performance. However, the motion estimation process involved is computational intensive and increases linearly with the number of allowed reference frames. In this paper, a novel fast multi-frame selection method (FMFME) is proposed for H.264 video coding. The proposed FMFME can efficiently reduce the computational cost up to 76% with similar quality and bit-rate.

32 citations

Proceedings ArticleDOI
06 Jul 2003
TL;DR: Experimental results show that the proposed FMBME can efficiently reduce the computational cost by 40.73% with similar visual quality and bit rate.
Abstract: The upcoming video coding standard, H.264, uses motion estimation with multiple block sizes to improve the rate-distortion performance. However, full exhaustive search of all block sizes is computational intensive with complexity increasing linearly with the number of allowed block size. In this paper, a novel fast multi-block motion estimation (FMBME) is proposed for H.264 video coding. Experimental results show that the proposed FMBME can efficiently reduce the computational cost by 40.73% with similar visual quality and bit rate.

32 citations


Cited by
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Journal ArticleDOI
TL;DR: This paper is geared toward signal processing practitioners by emphasizing the practical digital realizations and applications of the FRFT, which is closely related to other mathematical transforms, such as time-frequency and linear canonical transforms.

335 citations

Journal ArticleDOI
TL;DR: Two oblivious watermarking methods for 3-D polygonal mesh models, which modify the distribution of vertex norms according to the watermark bit to be embedded, are proposed, which are remarkably robust against distortionless attacks.
Abstract: Although it has been known that oblivious (or blind) watermarking schemes are less robust than nonoblivious ones, they are more useful for various applications where a host signal is not available in the watermark detection procedure. From a viewpoint of oblivious watermarking for a three-dimensional (3-D) polygonal mesh model, distortionless attacks, such as similarity transforms and vertex reordering, might be more serious than distortion attacks including adding noise, smoothing, simplification, remeshing, clipping, and so on. Clearly, it is required to develop an oblivious watermarking that is robust against distortionless as well as distortion attacks. In this paper, we propose two oblivious watermarking methods for 3-D polygonal mesh models, which modify the distribution of vertex norms according to the watermark bit to be embedded. One method is to shift the mean value of the distribution and another is to change its variance. Histogram mapping functions are introduced to modify the distribution. These mapping functions are devised to reduce the visibility of watermark as much as possible. Since the statistical features of vertex norms are invariant to the distortionless attacks, the proposed methods are robust against such attacks. In addition, our methods employ an oblivious watermark detection scheme, which can extract the watermark without referring to the cover mesh model. Through simulations, we demonstrate that the proposed approaches are remarkably robust against distortionless attacks. In addition, they are fairly robust against various distortion attacks

209 citations

Proceedings ArticleDOI
25 Oct 2004
TL;DR: The experiments indicate that first level decomposition appear advantageous for two reasons: the area for watermark embedding is maximized, and the extracted watermarks are more textured with better visual quality.
Abstract: Because of the transition from analog to digital technologies, content owners are seeking technologies for the protection of copyrighted multimedia content. Encryption and watermarking are two major tools that can be used to prevent unauthorized consumption and duplication. In this paper, we generalize an idea in a recent paper that embeds a binary pattern in the form of a binary image in the LL and HH bands at the second level of Discrete Wavelet Transform (DWT) decomposition. Our generalization includes all four bands (LL, HL, LH, and HH), and a comparison of embedding a watermark at first and second level decompositions. We tested the proposed algorithm against fifteen attacks. Embedding the watermark in lower frequencies is robust to a group of attacks, and embedding the watermark in higher frequencies is robust to another set of attacks. Only for rewatermarking and collusion attacks, the watermarks extracted from all four bands are identical. Our experiments indicate that first level decomposition appear advantageous for two reasons: The area for watermark embedding is maximized, and the extracted watermarks are more textured with better visual quality.

155 citations

Patent
30 Sep 2003
TL;DR: A method of compressing a current image of a sequence of images that is transformed with a predetermined transform to provide a set of transform coefficients, which are divided into blocks.
Abstract: A method of compressing a current image of a sequence of images. The current image is transformed with a predetermined transform to provide a set of transform coefficients, which are divided into blocks. An encoding termination condition is determined for at least one block, and the block is encoded in a series of coding passes. In a current coding pass, a performance measure is predicted, and encoding is terminated if the performance measure satisfies the encoding termination condition. Different color components may be given different weightings.

153 citations

Journal ArticleDOI
TL;DR: It is shown that the algorithm effectively reduces the computations of MRF-ME, and achieves similar coding gain compared to the motion search approaches in the reference software.
Abstract: Multiple reference frame motion compensation is a new feature introduced in H.264/MPEG-4 AVC to improve video coding performance. However, the computational cost of multiple reference frame motion estimation (MRF-ME) is very high. In this paper, we propose an algorithm that takes into account the correlation/continuity of motion vectors among different reference frames. We show that the algorithm effectively reduces the computations of MRF-ME, and achieves similar coding gain compared to the motion search approaches in the reference software

125 citations