Method and device for encoding wavelet image

Abstract

The invention discloses a method for encoding a wavelet image. The method comprises the following steps of: classifying corresponding wavelet coefficients, which are obtained by wavelet decomposition, of each subband by using a pyramid structure; performing corresponding encoding operation on the classified wavelet coefficients to acquire a compressed code stream of each subband; according to a rate distortion characteristic of the compressed code stream of each subband, optimally allocating a target code rate between the compressed code streams of each subband; and according to the allocatedcode rate of each subband, cutting off the code stream of each subband to acquire the code stream for encoding the wavelet image. The invention also discloses a device for encoding the wavelet image.By the method and the device, the error-code-resisting capability of the code stream acquired by encoding can be enhanced and the code stream is decoded to obtain images of multiple spatial resolutions.

Description

technical field [0001] The invention relates to the technical fields of digital image coding and video coding, in particular to a wavelet image coding method and device. Background technique [0002] Since the 1980s, wavelet transform has been widely used in the field of image compression because of its unique multi-resolution analysis ability and direction selection ability consistent with human visual characteristics, and has achieved good results. [0003] After the image is decomposed by wavelet, a series of subbands with different resolutions can be obtained, and the frequencies corresponding to the subbands of different resolutions are also different, and then the obtained subbands are encoded, that is, the wavelet image is encoded, so as to achieve compressed image for the purpose of performing subsequent image transfer operations. The key to wavelet image coding is how to better organize and represent wavelet coefficients, so as to make better use of the statistical...

AI Technical Summary

Problems solved by technology

[0007] Although existing wavelet coding methods such as EZW, SPIHT, and SPECK have embedded characteristics, the embedded code streams obtained by these coding methods are very sensitive to bit errors. Correlation, then, if a bit error occurs during the transmission of the bit stream, the correlation between the wavelet coefficients is destroyed, and the bit stream after the bit error will lose synchronization, resulting in the subsequent image decoded from the bit stream "unrecognizable". ", it can be seen that the existing wavelet coding method has poor anti-error ability

In addition, due to the correlation between wavelet coefficients in the existing encoding process, the existing wavelet encoding method does not support multiple spatial resolution decoding, that is, the compressed code stream obtained by the existing wavelet encoding method is decoded Only fixed-resolution decoded images can be obtained, and the scope of application is limited

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