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Image compression method based on wavelet transformation

A technology of wavelet transform and image compression, applied in the information field, can solve the problems of increasing the theoretical delay of the encoding system, occupying a large number of cycles, increasing the number of clock cycles, etc., to achieve hardware pipeline operations, reduce the number of cycles, and reduce delays Effect

Inactive Publication Date: 2006-09-20
王国秋
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Problems solved by technology

However, this greatly increases the number of clock cycles required for encoding, and the use of global OT increases the theoretical delay of the encoding system. In addition, although this approach can accurately control the bit rate of each individual image, there is no effective method Stable control over the quality of image sequences composed of multiple images
[0004] The EBCOT encoder is the core of the JPEG2000 encoder. Since each bit plane is encoded layer by layer, and each bit plane needs to be scanned three times, the encoding process is very time-consuming, especially in the hardware implementation process. Especially many, far exceeding the wavelet transform part and the arithmetic coding part, becoming the bottleneck of the entire JPEG2000 coding system

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  • Image compression method based on wavelet transformation

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Embodiment Construction

[0022] The applicant has found through research and use that in the prior art, in order to realize embedded coding, JPEG2000 adopts bit-plane scanning one by one in the process of encoding wavelet coefficients, and performs block coding (EBC) by scanning each bit-plane three times. After all the coefficient blocks are encoded, the encoded coefficient blocks are optimized and truncated (OT) within the range of the image block. This method will greatly increase the number of clock cycles required for encoding, and optimize the encoded coefficient blocks. Truncation (OT) increases the theoretical delay of the encoding system. In addition, although this method can precisely control the bit rate of each individual image, there is no effective way to stably control the quality of the image sequence composed of multiple images.

[0023] Aiming at the above-mentioned defects, the present invention proposes a coding method for scanning one bit plane at a time. This method can cancel the...

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Abstract

The invention relates to a wavelet transformation image compression method, which is composed of the following steps. First, do the wavelet transformation to the digital image to get the wavelet coefficients. Second, each wavelet coefficient is divided by a quantization coefficient. Third, divide the wavelet coefficients into blocks according to its subband position. Fourth, scan every coefficient block along the level. During the scanning, each wavelet coefficient is classified into 13 types according to the significance of the peripheral wavelet coefficients, the sign of the coefficients, the refining and general output. The arithmetic coding is used according to the different distribution model. The invention may cancel the OT procedure, and decrease the needed number of the operating period and the coding system delay. The relative stability of the image quality is guaranteed during the coding procedure. And the coding symbol number is decreased to reduce the pressure on the binary arithmetic encoder.

Description

Technical field: [0001] The invention belongs to the field of information technology, and in particular relates to a digital image compression coding method based on wavelet transform. Background technique: [0002] At present, the digital image compression coding methods of wavelet transform all adopt the JPEG2000 standard coding method. The EBCOT coding process in the JPEG2000 standard is as follows: The wavelet coefficients of the sub-bands are divided into coefficient blocks (JPEG2000 recommends dividing them into 64×64 or 32×32), and each block is first implemented with importance priority coding (EBC), and then realizes global optimal truncation (OT). In order to realize importance-first coding, after each block of wavelet coefficients is represented by the original code, the highest bit is the sign bit (0 is positive, 1 is negative), and the other bits are the absolute value of the coefficient. The set of the same bit in the absolute value of the coefficient is calle...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G06T9/00
Inventor 王国秋
Owner 王国秋
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