Encoding method of remote sensing image

Abstract

The invention discloses an encoding method of a remote sensing image. The method comprises the following steps: performing preprocessing on an original remote sensing image, then performing discrete wavelet transformation and quantization processing on the original remote sensing image; dividing a quantized sub-brand coefficient into encoding blocks in smaller sizes, performing plane expansion of significant bit with the same bit depth on each encoding block, and then sequentially ordering each encoding block from small to large; performing embedded bit plane encoding and MQ (multiplier-quotient) arithmetic encoding on each encoding block; calculating rate distortion-slope and accumulation rate of each channel of each bit plane of each ordered encoding block and determining whether to stop accumulating or not; calculating threshold of the rate-distortion slope and screening the rate-distortion slope of remaining channels based on the threshold; and carrying out Tier2 encoding. By adopting the encoding method provided by the invention, coding redundancy of Tier1 can be greatly reduced, and searching range of threshold value of an optimal-rate distortion-slope and optimal cut-off point during the Tier2 encoding is narrowed, so that the encoding efficiency and speed of the remote sensing image are remarkably improved and the complexity is reduced.

Description

technical field [0001] The invention belongs to the field of image processing, in particular to a coding method for remote sensing images. Background technique [0002] With the improvement of the resolution of remote sensing images, the amount of remote sensing image data also increases, making the real-time transmission and storage of data more and more difficult, so effective image compression is particularly important. [0003] At present, remote sensing image compression coding usually adopts JPEG2000 compression coding standard. The coding method of JPEG2000 standard has a high complexity, and most of its complexity comes from the embedded block coding with optimized truncation (EBCOT) code rate control method. EBCOT consists of two parts: Tier 1 encoding and Tier 2 encoding. Among them, Tier 1 encoding accounts for about 45%-60% of the calculation time of the JPEG2000 encoder. Reducing the calculation of Tier 1 will greatly reduce the processing time of the encoding ...

AI Technical Summary

Problems solved by technology

[0004] Aiming at the shortcomings of the PCRD method, many scholars have proposed new methods, such as [Auli-Llinas F, Serra-Sagrista J, Monteagudo-Pereira J, et al.Efficient rate control for JPEG2000coder and decoder[J].Proc.IEEE DCC, Mar.2006, 1:282-291.] and literature [Qin Cheng, Chen Zhiyun, Yu Kun, Zhou Yan. Research on rate control algorithm based on JPEG2000[J]. Computer Application and Software, 2011, Volume 28 (Phase 2): 76-80.] The proposed algorithm is a code rate control algorithm based on the interlaced scanning coding channel, the JPEG2000 rate control method of real-time truncation with the patent No. 200410026016. The distributed JPEG2000 adaptive rate control system and method, etc. These papers and inventions have significantly improved the coding efficiency of JPEG2000, but the code rate control is not accurate enough, and the peak signal-to-noise ratio (PSNR) of the restored image has dropped significantly

Literature [Kim T., Kim H.M., Tsai P.S., et al.Memory efficient progressive rate-distortion algorithm for JPEG2000[J].IEEE Trans.on Circuits and Systems for Video Technology.2005,15(1):181-187. ] and [Wang Chao, Wang Jiong. An effective JPEG2000 compression rate control algorithm [J]. Journal of Donghua University (Natural Science Edition), 2011, Volume 37 (Phase 1): 76-80.] proposed The method reduces the amount of encoding calculation and storage, but the encoding redundancy is relatively large at high bit rates, and the minimum slope search operation is increased

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