Motion-Compensated Prediction Method Based on Perspective Transform for Coding of Moving Images (Special Issue on Very Low Bit-Rate Video Coding)

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概要

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• Hybrid image coding method is one of the most promising methods for efficient coding of moving images.The method makes use of a jointly motion-compensated predication and orthogonal transform like DCT. This type of coding scheme was adopted in several world standards such as H.261 and MPEG in ITU-T and ISO as a basic framework [1], [2].Most of the work done in motion-compensated prediction has been based on a block matching method. However, when input moving images include complicated motion like rotation or enlargement, it often causes block distortion in decoded images,especially in the case of very low bit-rate image coding. Recently, as one way of solving this problem, some motion-compensated prediction methods based on an affine transform or bilinear transform were developed [3]-[8]. These methods,however, cannot always express the appearance of the motion in the image plane, which is a projected plane form 3-D space to a 2-D plane, since the perspective transform, is usually assumed.Also, a motion-compensation method using a perspective transform was discussed in Ref. [6]. Since the motion detection method is defined as an extension of the block matching method,it can not always detect motion parameters accurately when compared to gradient-based motion detection. In this paper, we propose a new motion-compensated prediction method for coding of moving images, especially for very low bit-rate image coding such as less than 64 kbit/s. The proposed method is based on a perspective transform and the constraint principle for the temporal and spatial gradients of pixel value, and complicated motion in the image plane including rotation and enlargement based on camera zooming can also be detected theoretically in addition to translational motion. A computer simulation was performed using moving test images, and the resulting predicted images were compared with conventional methods such as the block matching method using the criteria of SNR and entropy.The results showed that SNR and entropy of the proposed method are better than those of conventional methods. Also, the proposed method was applied to very low bit-rate image coding at 16 kbit/s, and was compared with a conventional method, H.261. The resulting SNR and decoded images in the proposed method were better than those of H.261 , We conclude that the proposed method is effective as a motion-compensated prediction method.

• 社団法人電子情報通信学会の論文
• 1996-10-25

著者

• KOIKE Atsushi

  Visual Communications Laboratory, KDDI R&D Laboratories Inc.

• Katsuno Satoshi

  Visual Communications Laboratory Research And Development Laboratories

• HATORI Yoshinori

  Visual Communications Laboratory, Research and Development Laboratories

• Hatori Yoshinori

  Visual Communications Laboratory Research And Development Laboratories

• Koike Atsushi

  Visual Communications Lab. Kddi R & D Laboratories Inc.

• Koike Atsushi

  Visual Communications Laboratory Research And Development Laboratories

関連論文

• Optimization of MPEG-2 Bit Assignment Scheme with Full Use of Distortion Minimization Oriented Rate Control Technology
• A Study on Priority-Based Scalable Coding (マルチメディア情報処理,映像表現,ネットワーク映像メディア,画像情報システム第3回International Workshop on Advanced Image Technology(IWAIT2001))
• Remote Monitoring Scheme for Output Video of Standards Convertors(Multimedia Systems for Communications)
• Motion-Compensated Prediction Method Based on Perspective Transform for Coding of Moving Images (Special Issue on Very Low Bit-Rate Video Coding)
• A Study on Priority-Based Scalable Coding (第3回International Workshop on Advanced Image Technology(IWAIT2000)〔英文〕)

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