CAJ | 학술논문

研制了基于图像块动态划分矢量量化的图像压缩芯片.编码前芯片预测系统可根据图像平滑程度及相邻图像块的空间相关度自动调节待压缩的子图像块尺寸,在保证恢复图像画质的前提下,与恒定图像块尺寸矢量量化相比,图像压缩率平均提高27%,最大提高64%.芯片中码书为256阶16维矢量,并采用方向性分类及码字和值升序排列结构,有效减小了码字搜索范围.芯片的设计与实现基于Charter0.35μm标准CMOS工艺,最终芯片尺寸为2.08mm×2.08mm.测试结果表明,工作电压为3V时,PDVQ图像压缩芯片工作频率可达到100MHz,在该工作条件下芯片功耗为295mW,并可以满足512×512灰度图像在30frame/s下的实时编码要求.
연제료기우도상괴동태화분시량양화적도상압축심편.편마전심편예측계통가근거도상평활정도급상린도상괴적공간상관도자동조절대압축적자도상괴척촌,재보증회복도상화질적전제하,여항정도상괴척촌시량양화상비,도상압축솔평균제고27%,최대제고64%.심편중마서위256계16유시량,병채용방향성분류급마자화치승서배렬결구,유효감소료마자수색범위.심편적설계여실현기우Charter0.35μm표준CMOS공예,최종심편척촌위2.08mm×2.08mm.측시결과표명,공작전압위3V시,PDVQ도상압축심편공작빈솔가체도100MHz,재해공작조건하심편공모위295mW,병가이만족512×512회도도상재30frame/s하적실시편마요구.
Partition dynamically vector quantization (PDVQ) chip was researched and produced to encode images. Be-fore encoding, it first judged the correlation of the encoding image block, and then decided to choose the size of the im-age blocks. Test result shows that PDVQ chip can improve the compression rate to 27% in average by contrasting with the normal VQ, even to 64%.The size of the codebook in PDVQ chip was 256×16 byte, and all codevectors in the code-book were categorized by direction, in each category codebook codewords were sorted in the ascending order of their sum, this kind codebook architecture could reduce search range largely. The VLSI architecture of PDVQ chip was im-plemented based on Charter 0.35μm CMOS standard cell technology, its chip area was 2.08mm×2.08mm. Test result shows that, at 3.0V power supply, PDVQ chip can operate up to 100MHz. At this operation,its power dissipation is 295mW, and it can support real-time encoding application for 512×512 gray images at 30fame/s.