Image compression method based on vectors among k-order zero trees

Abstract

The invention discloses an image compression method based on vectors among k-order zero trees. The image compression method is suitable for gradable compression of digit rates of digital images and capable of improving the code efficiency of the existing embedded images. The image compression method comprises firstly, finding zero trees under a current threshold from all sub-bands of images after wavelet decomposition according to the importance order and determining orders of the zero trees; then, establishing association among the zero trees through a vector representation method which records relative position relations among all orders of zero trees, wherein vectors connect root nodes of all k-order zero trees together and a coordinate of a next root node can be determined according to the position of the previous root node; and finally, coding significant coefficients by using successive approximation quantization based on a bit plane to guarantee the gradable characteristic of digit rates of formed code streams. By the aid of the image compression method, the repeated scanning times of insignificant coefficients can be reduced, bits of coding position information can be reduced, a representation mechanism of vectors among zero trees enables scattered zero trees to associate one another, and therefore expenses of synchronizing information in the existing zero tree coding algorithm are reduced.

Description

Technical field [0001] The invention relates to a digital image compression method, in particular to a data rate scalable compression suitable for digital images, which can improve the efficiency of existing embedded image coding based on k An image compression method for vectors between order zero trees. Background technique [0002] With the continuous development of network multimedia technology and its applications, people’s requirements for image coding continue to increase. This requires removing various redundancies on the premise of ensuring image quality, using as few bits as possible to characterize image information, and at the same time The image coding stream can well adapt to the fluctuation of network bandwidth and the decoding requirements of terminals with different computing capabilities. The scalability of the code stream of an image refers to the ability to use a part (or subset) of the code stream to produce a useful representation of the image, that is, the ...

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Problems solved by technology

However, these methods still spend a considerable amount of bit overhead on the synchronization information, which affects the quality of the reconstructed image (especially at low bit rates), and the synchronization information used to identify the position of important wavelet coefficients is inefficient. The phenomenon of repeated scanning for unimportant coefficients

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