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??????. ?. ???????? : <????> <?????> . . ????????????????,????????????????,?????,??????????(object-oriented)?????.. . ???(picture element, pixel)?????????,???????????(??????)??X,Y???R,G,B???. ????????????

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1. ???? (??????) ??:??? ??? ??? ??? ???

2. ?????? ?. ???????? : <????> <?????>

3. ?. ????: ???? ???? ???: ??????????????????.???dpi(dots per inch?pixels per inch)??. ????:Image Mode??????????????????????? ?.????????????. RGB CMYK Lab YUV&YIO Grayscale(????)??Graylevel---???256(8??)?????? ?????????????? Bitmap---?????????????????,??????bit?? ????????????? Duotone Indexed color ????

4. ?. ??????: ????????????,???????????? ???Image Processing. ??? ???? ???? ???? ???? ???? ???? ???? ?? ?. ??????: SNR(signal-to-noise ratio) PSNR(peak-signal-to-noise ratio)

5. ?????? ?. ?? ?. ??????: ????????????????????.?????????? ?:?????PCX?TGA?TIFF?GIF?JPEG?VQ?.??PCX?TIFF? TGA???????????????.GIF?JPEG????????? ??????????;??VQ,??????????.?PCX? GIF?TIFF??TGA????????????????.?????? ?????????????????,????????????? ??????????.??VQ?JPEG?????????????? ?.??????VQ?JPEG???????,??????????? ???????,???????????,??????????? ?????????????

6. <?????????> 1. PCX ??????????Zsoft??????????,?????? ????(Run Length Encoding ,??RLE)????????,? ????????,???(Row by Row) ?????.?????? ???,?????????????????????????? ??????,???????????????????. 2. TGA ??AT&T???????????,???????????????? ??.???????????(Pixel)?????????,????? ????????????,?TGA ??????????????,? ?????????????????????.TGA ?????PCX?? ?????(????????)?????????????.

7. 3. TIFF (Tagged Image File Format) ????????????????????????? Aldus Corporation?Aldus Developers?1986?????.?????(Tag)?????????,????????.??????????,TIFF ??????????: (1) ??????????????,??MS Windows?DOS?UNIX?OS/2 ?. (2) ????????,?????- ??- ?? ???(Lempel-Ziv- Welch Encoding,??LZW)???????(Huffman's Encoding)??????????;????????????,?? ???????? (3) ?????????,????????????????,TIFF? ???.??TIFF????????,?????????????? ??TIFF???????????,??TIFF?????????? ?.

8. 4. GIF ?1987??Compu-serve??????????,??????????? ?- ??- ??????,????????(String Table) ????.? ????????????????????????,???????? ????????????????,???????????????? ???????,?GIF ?????????.??,GIF ???????- ??- ????????????- ??- ???,????????? ?,???????- ??- ?????????????:GIF ???- ??- ??????????????????,??????????? ??????,?????????????,????????

9. 1. JPEG(Joint Photographic Coding Expert Group) ???????(International Organization for Standardization,?? ISO)????????????(International Telegraph and Telephone Consultative Committee,??CCITT)??????????????,? ????????????.JPEC ?????(Lossy) ??????,?? ???????(Discrete Cosine Transform,??DCT)???????? ???????,????????,??????????.???JPEC ?????????????,???JPEG ?????????????? ??;????,????(??????????????????)?5% ~15%???,JPEC?????????????,??????????? ?????.JPEG???????,????????????.????JPEG ???JFIF(JPEG File Interchange Format).??JPEG ?????,?? ???????,???????????????.JPEG ??????? ???8 ???????.????,????????????????? ???JPEG ???. <?????????>

10. 2. VQ (Vector Quantization) ???????????????.????????????(??JPEG) ????VQ?????;??,??VQ???????????????? ???????,?VQ????????????????????.??VQ ??????????????????????????.??????? ?????(Code book),?????????????(????)???? (Code word).??,????????????????,?????? ?,??????????.???????VQ??????,?????? ??????????????????,?VQ ?????????.?? ???256??????????,VQ????????????(?6%).? ?????,??VQ ???????????????????????? ??????,??????????.???????????????? ???????,???????.

11. <?????> ?????????,???????,??????? ??????????????????????,?? ????????

12. ?. ????????????? <?> ?????????? ????????????????????,??,??????????????. ??????: ?????? ? ?????? ? DCT?? ? ??? ? ??? ? ???? ??????????: (?)????/?????????????. (?)????????????. (?)???????????????. ?????????(Compression) ????,??????? (Decompression)????.???????????:???? ???????,??????????? .

14. 1. RASTER -> BLOCK ?????????? ???(block) ?????.??????????????????. 2. RGB -> YUV ????????(??)???(R)??(G)??(B)??????,?????????????(Luminance)Y??????? (Chrominance)U?V.??????: Y = 77/256R + 150/256G + 29/256B U = -44/256R - 87/256G + 131/256B + 128 V = 131/256R - 110/256G - 21/256B + 128

15. 3. DCT (Discrete Cosine Transform;??????) ?????????? 8 x 8 ??,????8 x 8??? (coefficients).????????????(space domain)???? ????(frequency domain),??8 x 8???????????? ????,????????,??????,?????????. ????,????????????????,????????? ????????????,??????????????.??? ????????(quantization)??,????????????? 0.??????????????????????????,????????:????.?????????????,?????? ?????????????.????????????,?75%?? ????????????. 4. QUANTIZATION ?????(quantization)???????(linear quantization)???,?????????????????.

16. 5. RUN LENGTH ENCODE ??????,??8 x 8??????????????? ????? ?????0.?????0???????,???8 x 8??????? ??? (zigzag scan ),????????.???????,???? ?????? (run length encode),????????. 6. HUFFMAN ENCODE ???????????(Huffman coding)??????????.?? ?????????:????????????????,???? ????????????,?????????????. ????JPEG????????:??????RGB??????????DCT(Discrete Cosine transform)??,???????”????”?????,????????(??????JPEG???????), ?????????,???????????,????????,??????????,?????Huffman???????,????,??JPEG??.????????????.

17. <?> ???????? 1.??????????: Run Length Encoding(RLE)---- ???:???,???????????. ???????????????,????????????????. LZW(Lempel-Ziv-Welch)Coding---- ????????GIF(Graphics Interchange Format)??TIFF(Tag lmage File Format)??????? ??.???????????????,?????????????? ?,?????????????,?????????.??????? ????????,?????????????????. Huffman Coding ??????(Huffman’s Encode)---- ?????1952??????????????,?????????? ?,????,????????????(Single Character)???? ?,????,????????(Huffman’s Tree).???????, ?0?1????,???????,?????????,??????? ?????,???Huffman’s tree ,???????.

18. ??????????????????????????????.? ????????????????????,??????????? ????????????????????????????. ??????(Arithmetic Coding)---- ?Rissanen ?1979?????????? ?,??????????????????????,??????? ??????? ???????(Predictive Coding),??..

19. 1.??????????: DCT (Discrete Cosine Transform)???????????---- ????? ???????????????.DCT????????,?JPEG?? ??????.DCT???????,??DCT??????????,? ???DCT??????????????????. Quantization???(??)??---- ?????????????. ??(WAVELET)??---- WAVELET????????????????.???????????????????.????,????????????????,??????????????????,???????????,??????????????????.????????(Fourier)???????,???????????,?????????.????????,????????????.?????????1960??????????,???????????????,?????????????,???????????,????????????.

20. WAVELET????????????,??????????????,? ???????????????,????????,???????? ????.??????????,?????,?????????(? ???????).?????????????,?????????, ??????????????????,?????????????? ??.??WAVELET?????????????lossless???????? ???????,??????????????????,?????? ????????????,?????????????.?????? ???????????????,??????????,?????? ??,???????????,????????.????WAVELET?? ??????. ?????????: jpeg????????????,?jpeg2000??jpeg??? ?,?jpeg2000???DCT?????????????wavelet,?DCT? ?mpeg??????????,?DCT?????????. ? ? ? ? ( Perceptual coding ) ?????? (Vector quantization) ????? (Transfer coding) ?????(Subband coding)

21. ????????? 1. ???????????????????? 2. ???????????????????????? 3. ???????????? 4. ??????????? 5. ???????????????

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