發(fā)布時(shí)間：2018-06-06 18:15

  本文選題：CCSDS圖像壓縮標(biāo)準(zhǔn) + 多級(jí)二維小波變換　； 參考：《中國(guó)科學(xué)院大學(xué)(中國(guó)科學(xué)院國(guó)家空間科學(xué)中心)》2017年碩士論文

【摘要】：隨著成像技術(shù)的飛速發(fā)展,衛(wèi)星圖像的分辨率和數(shù)據(jù)率越來(lái)越高,數(shù)據(jù)量呈幾何級(jí)增長(zhǎng),海量的圖像數(shù)據(jù)占用了大量的儲(chǔ)存容量和傳輸帶寬。因此,為了降低星上數(shù)據(jù)緩存壓力,減少對(duì)星地之間數(shù)據(jù)傳輸帶寬的需求,研制一種高效的星載圖像壓縮編碼系統(tǒng)十分必要。在現(xiàn)有的星載圖像壓縮系統(tǒng)中,基于DPCM以及DCT的編碼算法壓縮性能不高,基于DSP實(shí)現(xiàn)的算法處理速度較慢、功率消耗較大,FPGA雖然功耗較低,計(jì)算速度較快,但實(shí)現(xiàn)復(fù)雜的圖像處理算法較為困難。為了解決這些問(wèn)題,本文基于CCSDS 122.0-B-1圖像壓縮標(biāo)準(zhǔn),提出了一種多級(jí)二維高速小波變換的硬件架構(gòu),并采用FPGA器件實(shí)現(xiàn)。本文主要工作為:(1)詳細(xì)研究了CCSDS 122.0-B-1星載圖像壓縮標(biāo)準(zhǔn)中多級(jí)二維小波變換的算法,分析了其硬件可實(shí)現(xiàn)性以及一些影響性能的參數(shù),并與其他圖像壓縮標(biāo)準(zhǔn)中的去相關(guān)算法進(jìn)行了對(duì)比。(2)深入研究分析了二維小波變換的特點(diǎn),并設(shè)計(jì)了合理的多級(jí)二維9/7小波變換以及5/3小波變換的硬件架構(gòu),具有變換速率高、外部資源占用較少、能夠滿足實(shí)時(shí)性要求等特點(diǎn)。(3)根據(jù)星載圖像壓縮系統(tǒng)的任務(wù)需求,提出了合理的硬件設(shè)計(jì)方案,并進(jìn)行了相應(yīng)的電路設(shè)計(jì)。(4)本文使用Verilog HDL語(yǔ)言對(duì)多級(jí)二維小波變換進(jìn)行了實(shí)現(xiàn),驗(yàn)證了所提出架構(gòu)的正確性以及性能指標(biāo)。并將小波變換與其他主流變換編碼中的去相關(guān)方法進(jìn)行了對(duì)比,同時(shí)對(duì)于9/7小波與5/3小波的去相關(guān)性能也進(jìn)行了評(píng)估。實(shí)驗(yàn)結(jié)果表明,相對(duì)于傳統(tǒng)的復(fù)用濾波器進(jìn)行多級(jí)變換的結(jié)構(gòu),本文所提出的架構(gòu)在FPGA邏輯資源允許的情況下,能夠滿足對(duì)圖像進(jìn)行實(shí)時(shí)變換的速度要求,降低片外RAM的使用需求,并為后續(xù)的數(shù)據(jù)編碼和傳輸提供有利條件。
[Abstract]:With the rapid development of imaging technology, the resolution and data rate of satellite images are getting higher and higher, and the amount of data is increasing geometrically. Massive image data takes up a lot of storage capacity and transmission bandwidth. Therefore, in order to reduce the data cache pressure on the satellite and reduce the demand for data transmission bandwidth between the stars and ground, a kind of efficient satellite load is developed. The image compression coding system is very necessary. In the existing spaceborne image compression system, the compression performance based on DPCM and DCT is not high, the algorithm based on DSP is slow, the power consumption is large, the power consumption is low, and the computing speed is fast, but it is difficult to realize the complex image processing algorithm. In order to solve this problem, the algorithm is difficult to solve this problem. Some problems, based on CCSDS 122.0-B-1 image compression standard, a hardware architecture of multilevel two-dimensional high speed wavelet transform is proposed and implemented with FPGA devices. The main work of this paper is as follows: (1) the algorithm of multilevel two-dimensional wavelet transform in CCSDS 122.0-B-1 satellite image compression standard is studied in detail, and its hardware implementations and one are analyzed. Some parameters affecting the performance are compared with the other algorithms in the image compression standard. (2) the characteristics of the two-dimensional wavelet transform are studied and analyzed, and the hardware architecture of the reasonable multilevel two-dimensional 9/7 wavelet transform and the 5/3 wavelet transform is designed, which has high transformation rate, less external resources and can meet the real time property. Requirements and other characteristics. (3) according to the task requirements of the satellite borne image compression system, a reasonable hardware design scheme is proposed, and the corresponding circuit design is carried out. (4) this paper uses Verilog HDL language to implement the multilevel two-dimensional wavelet transform, verifies the correctness of the proposed architecture and the performance indicators. The correlation method in the transform coding is compared, and the correlation performance of the 9/7 wavelet and the 5/3 wavelet is also evaluated. The experimental results show that the proposed architecture can satisfy the real-time change of the image under the condition that the FPGA logical resource is allowed. The speed requirement of conversion can reduce the use requirement of off chip RAM and provide favorable conditions for subsequent data encoding and transmission.
【學(xué)位授予單位】：中國(guó)科學(xué)院大學(xué)(中國(guó)科學(xué)院國(guó)家空間科學(xué)中心)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TP391.41

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本文編號(hào)：1987662