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low-bit-rate coding of underwater color image using improved wavelet difference reduction

JOURNAL OF VISUAL COMMUNICATION AND IMAGE REPRESENTATION 2010年第7期21卷 762-769页

作者： Li, Qing-Zhong Wang, Wen-Jin Ocean Univ China Coll Engn Qingdao 266100 Peoples R China

Underwater image compression has been the key technology for transmitting massive amount of image data via underwater acoustic channel with limited bandwidth. According to the characteristics of underwater color images, an efficient underwater image compression method has been developed. The new coding scheme employs a wavelet-based preprocessing method to remove the visual redundancy, and adopts a Wavelet Tree-based Wavelet Difference Reduction (WTWDR) algorithm to remove the spatial redundancy of underwater color images. Instead of scanning whole transformed image like the WDR method, the difference reduction coding is used for each significant wavelet tree in the proposed WTWDR algorithm based on the correlation between the subbands of higher levels and lower levels of a transformed image. The experimental results show that for underwater color images the proposed method outperforms both WDR and SPIHT at very low bit rates in terms of compression ratio and reconstructed quality, while for natural images it has similar performance with WDR and SPIHT. Hence, the proposed approach is especially suitable for underwater color image compression at very low bit rates. (C) 2010 Elsevier Inc. All rights reserved.

关键词： Wavelet difference reduction (WDR) Underwater image compression Wavelet transform low-bit-rate coding Underwater acoustic channel Underwater color image Underwater observation Wavelet tree Image transmission

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Geometric-structure-based error concealment with novel applications in block-based low-bit-rate coding

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 1999年第4期9卷 648-665页

作者： Zeng, WJ Liu, BD Sharp Labs Amer Inc Digital Video Dept Camas WA 98607 USA Princeton Univ Dept Elect Engn Princeton NJ 08544 USA

This paper first proposes a computationally efficient spatial directional interpolation scheme, which makes use of the local geometric information extracted from the surrounding blocks. The proposed error-concealment scheme produces results that are superior to those of other approaches, in terms of both peak signal-to-noise ratio and visual quality. Then a novel approach that incorporates this directional spatial interpolation at the receiver is proposed for block-based low-bit-rate coding. The key observation is that the directional spatial interpolation at the receiver can reconstruct faithfully a large percentage of the blocks that are intentionally not sent: A rate-distortion optimal way to drop the blocks is shown. The new approach can be made compatible with standard JPEG and MPEG decoders. The block-dropping approach also has an important application for dynamic rate shaping in transmitting precompressed videos over channels of dynamic bandwidth. Experimental results show that the proposed coding and rate-shaping systems can provide significant subjective and objective gains ol er conventional approaches.

关键词： block dropping directional interpolation error concealment low-bit-rate coding rate shaping

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coding MOVING IMAGE SEQUENCES BY SEGMENTATION OF DIFFERENCE FRAMES AND MOTION-ADAPTIVE FRAME INTERPOLATION

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ELECTRONICS LETTERS 1989年第12期25卷 794-795页

作者： SORYANI, M CLARKE, RJ Heriot-Watt Univ. Edinburgh UK

Motion-compensated difference frames derived from a moving image sequence are adaptively segmented into regions of constant intensities. Region boundaries are then coded and transmitted together with region intensities. Only alternate frames are coded and transmitted, skipped frames being reproduced at the receiver by motion-adaptive interpolation. The resulting quality of the reconstructed sequence is markedly superior to that obtained when segmentation is applied to the image frames themselves.

关键词： alternate frames bandwidth compression computerised picture processing data compression encoding image encoding image processing low-bit-rate coding motion compensated difference frames motion-adaptive frame interpolation moving image sequences picture quality regions of constant intensities segmentation of difference frames television broadcasting

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Fast matching pursuit with vector norm comparison

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 2003年第4期13卷 338-342页

作者： Jeon, B Oh, S Sungkyunkwan Univ Sch Elect & Comp Engn Suwon 440746 South Korea LG Elect DM Lab IMT Team Seoul South Korea

Matching pursuit was demonstrated useful especially in low-bit-rate video coding. However, its massive computation required for finding atoms, hinders its use from practical application. This paper is to provide a new method that can drastically reduce the computational load without any degradation in performance of matching pursuit. We compare vector norms based on the Schwarz inequality to preclude substantial number of dictionary functions without actually evaluating their inner products in atom search. Experimental results show that the number of inner product calculation is only about 20%-35.% of the conventional separability-based fast method.

关键词： fast search low-bit-rate coding matching pursuit video coding

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Motion vector coding by using representation of norm and angle components

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ELECTRONICS AND COMMUNICATIONS IN JAPAN PART III-FUNDAMENTAL ELECTRONIC SCIENCE 2006年第10期89卷 54-62页

作者： Shimizu, A Sagata, A Kamikura, K Kobayashi, N NTT E Business Commun Headquarters Tokyo 1120004 Japan NTT Corp NTT Cyber Space Labs Yokosuka Kanagawa 2390847 Japan

Since many video coding methods use prediction between motion-compensated frames, the motion vector must be transmitted. A large amount of code is generated for DCT coefficients for the motion vector. Therefore, prediction is performed from the motion vectors of neighboring blocks and variable-length coding of the horizontal and vertical components of the prediction error vector is performed to reduce the amount of generated code. However, since this method handles the horizontal and vertical components as independent components, appropriate code assignment for coding the prediction error vector may not he possible. In this paper, the authors propose a method of coding by using norm and angle components to represent the prediction error vector and compare its coding efficiency with the conventional method to show its effectiveness. (C) 2006 Wiley Periodicals, Inc.

关键词： motion vector coding orthogonal coordinate system polar coordinate system low-bit-rate coding

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Least-mean-squares design of filters controlling subband coefficient powers with applications to image coding

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ELECTRONICS AND COMMUNICATIONS IN JAPAN PART I-COMMUNICATIONS 2002年第5期85卷 11-24页

作者： Ito, H Mitsubishi Electr Corp Informat Technol R&D Ctr Kamakura Kanagawa 2478501 Japan

In image coding, the relationship between the coding rate and distortion depends on the input image. In coding that decomposes a signal into multiple frequency bands (subbands) as in the DCT and the wavelet transform, the power distribution of the decomposed signal (subband coefficients) is the primary factor that determines the rate-distortion characteristics. In this paper, we propose a design method for prefilters that controls the powers of the subband coefficients. This design method assigns a target gain for the prefilter to each subband and determines the filter coefficients by least mean squares estimation. The input signal is used in the least mean squares calculation. Thus, if this filter is used in the stage prior to coding, the target rate distortion characteristics adapted to the input signal can be more faithfully achieved. By smoothly assigning the target gains to adjacent subbands, this prefilter can accurately achieve the target gains even for a low-order analysis filter as in DCT. In addition, computer simulations demonstrated satisfactory performance when applied to image coding. (C) 2002 Scripta Technica.

关键词： image coding digital filter rate distortion function low-bit-rate coding subband coding

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A pitch detector based on the dyadic wavelet transform and the autocorrelation function 6

A pitch detector based on the dyadic wavelet transform and t...

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6th International Conference on Signal Processing

作者： Li, J Bao, CC Beijing Polytech Univ Elect Informat & Control Engn Coll Beijing 100022 Peoples R China

ISBN: (纸本)0780374886

The interest. in real-time, low-bit-rate speech coding dictates current research efforts in speech signal compression. This paper describes a pitch detection method based on the dyadic wavelet transform and the autocorrelation function (ACF). The proposed pitch detector ensures smooth pitch trajectory evolution. Experiments show the performance of the wavelet- and ACF-based pitch detector is superior to that of conventional pitch detector that uses the. ACF method to estimate the pitch period.

关键词： speech coding transform coding wavelet transforms correlation methods computational complexity pitch detection dyadic wavelet transform autocorrelation function low-bit-rate coding speech coding speech compression smooth pitch trajectory evolution computational complexity

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Seafloor Image Compression Using Hybrid Wavelets and Directional Filter Banks

Seafloor Image Compression Using Hybrid Wavelets and Directi...

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Oceans 2015 Genova

作者： Zhang, Y. Li, Q. -Z. Negahdaripour, S. Ocean Univ China Dept Ocean Engn Qingdao Peoples R China Ocean Univ China Dept Automat Engn Qingdao Peoples R China Univ Miami ECE Dept Coral Gables FL 33146 USA

ISBN: (纸本)9781479987375

We present an efficient compression method based on the hybrid wavelets and directional filter banks (HWD), to achieve high compression efficiency while keeping visually pleasing reconstruction quality for underwater images. According to the characteristics of underwater images and the human vision system (HVS), an improved just noticeable distortion (JND) model is initially employed to adaptively remove the visual redundancy of underwater images in the HWD domain. The low-frequency coefficients are then quantized in the fixed length and encoded losslessly. The high-frequency coefficients are quantized by variable precision and fixed length method, and are coded by the difference reduction algorithm based on HWD trees. The experimental results show that the proposed compression algorithm provides both high coding efficiency and satisfactory reconstruction quality, which is highly desired for the transmission of underwater images at very low-bit rates.

关键词： underwater imaging image compression HWD transform just noticeable distortion low-bit-rate coding

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Seafloor Video Compression Using Adaptive Hybrid Wavelets and Directional Filter Banks

Seafloor Video Compression Using Adaptive Hybrid Wavelets an...

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OCEANS MTS/IEEE Conference

作者： Zhang, Yang Li, Qingzhong Negahdaripour, S. Ocean Univ China Dept Ocean Engn Qingdao 266100 Peoples R China Ocean Univ China Dept Automat Engn Qingdao 266100 Peoples R China Univ Miami ECE Dept Coral Gables FL 33146 USA

ISBN: (纸本)9780933957435

In this paper, a new video compression technique based on adaptive hybrid wavelets and directional filter banks is proposed to achieve both high coding efficiency and good reconstruction quality at very low-bit rates. A key application is the real-time transmission of video from an autonomous underwater vehicle to a surface station, e.g., for man-in-the-loop monitoring and inspection operations, through acoustic channels that have limited bandwidth. The proposed method can maintain details in texture regions at relatively low bit rates, while overcoming the ringing artifacts within smooth regions, for intra-frame coding. For inter-frame coding, improved efficiency is achieved by making use of: 1) a new spatio-temporal just-noticeable-distortion model to remove perceptual redundancy;2) motion interpolation to reduce bit rate;3) variable-precision in quantizing the residual error;and 4) block inter-leaver to reduce transmission errors. Experiments with underwater video sequences are presented to assess the effectiveness of the proposed approach, in comparison to traditional wavelet-based techniques.

关键词： underwater imagery video compression wavelet directional filter banks just-noticeable distortion low-bit-rate coding

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Seafloor Video Compression Using Adaptive Hybrid Wavelets and Directional Filter Banks

Seafloor Video Compression Using Adaptive Hybrid Wavelets an...

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Oceans MTS/IEEE Washington (Conference)

作者： Yang Zhang Qingzhong Li S. Negahdaripour Dept. of Ocean Eng. Ocean University of China Qingdao China 266100

ISBN: (纸本)9781467393744

关键词： Underwater imagery Video compression Wavelet Directional filter banks Just-noticeable distortion low-bit-rate coding

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