untitled

Size: px

Start display at page:

Download "untitled"

臣细王
5 years ago
Views:

1 . JPEG 聯 Joint Photographic Experts GroupJPEG 986 年立數 JPEG 聯 Joint Photographic Experts Group 4 年 ISO/IEC 098- ITU-T Rec. T.8 "Information Technology Digital compression and coding of continuous-tone still images" JPEG 不離 Baseline Sequential DCT-based Coding 離 Progressive DCT-based CodingLossless CodingHierarchical Coding JPEG 離 Baseline Sequential DCT-based Coding JPEG 離 Baseline Sequential DCT-based Coding JPEG. 見流 RGB 理 YC b C r Y Cb C = 0.R G + 0.4B = 0.68R 0.33G + 0.4B r = 0.5R 0.49G 0.08B L () RGB JPEG 理 YC b C r 類亮度 luminance YC b C r Y 量了亮度度 chrominance 不 YC b C r C b C r 量度 SoC Design Lab., 004

2 . JPEG YC b C r 來見 4:4:44::4::0 JPEG 利 Block Coding 念切 88 來 JPEG 流 88 離 -D Discrete Cosine Transform-D DCT 率靈度離量 QuantizationQ 量零量留了不料量零料量 JPEG DC 利 Differential Pulse Code ModulationDPCM DC AC 利 Zig-Zag AC 利度 Run-Length CodingRLC Huffman Coding JPEG JPEG 流 JPEG 類流流理來度 Variable Length DecodingVLD 量 IQ 離 IDCT YC b C r RGB pixel with Y, Cr and Cb value 4 : 4 : 4 4 : : pixel with only Y value pixel with only Cr and Cb value 4 : : 4 : : 0 度例 SoC Design Lab., 004

3 切 f(i,j) DCT F(u,v) Quantization Fq(u,v) Header 8x8 Coding Tables Quantization Table Tables Data Entropy Coding DPCM RLC DC AC zig zag scan JPEG Header Tables Coding Tables Quantization Table Data Entropy Decoder Fq(u,v) Inverse Quantization F(u,v) IDCT f(i,j) 8x8 JPEG SoC Design Lab., 004 3

4 .3 離 -D Discrete Cosine Transform-D DCT X D DCT Unit Transpose Memory (Y) D DCT Unit Z Y=AX Z=YA T 利行列行離離數料率離 Forward Discrete Cosine TransformFDCT 率數料離 Inverse Discrete Cosine TransformIDCT 數料離 88 JPEG 離離 JPEG 理離 8 利離料率料理料率 8 離 X k, k N = ( ) ( ) N c k c k x N n = 0 n = 0 n n, cos ( n + ) k π ( n + ) N n, n, k, k = 0,, L, N L where c(0) = and c( n) = for n 0 N ( + ) ( + ), = ( ) ( ) cos cos N n k π n k π xn n c k c k X k, k N N N n, n, k, k k = 0 k = 0 = 0,, L, N where c(0) = and c( n) = cos kπ N L for n 0 ( ) () 3 離路行列 Row-Column Decomposition 念列兩行離列行離行累數念 Z=AXA T X 數 SoC Design Lab., 004 4

5 率數離離離 8 point -D DCT 離 F( v) = c( v) u, v = 0,, L, N f ( u) = N v= 0 N u= 0 f ( u) c( v) F( v) cos cos ( u + ) vπ N ( u + ) vπ N where c(0) = and c( v) = N N L for v 0 了離度論 Chen s Algorithm 率行 8 point -D DCT Chen s Algorithm 6 6 六 Chen s Algorithm ( 4) X0 X X X C4 x + x C4 C4 x x + -C4 C6 x + x -C C x x + C6 Y0 Y4 Y Y6 X4 X5 X6 X C4 x + x C4 C4 x x + C4 + x + C7 C3 x C - x + x C5 -C5 x - x + C3 C7 x -C + x + Y Y5 Y3 Y7 x y x + y x - y x c cx 六 Chen s Algorithm[] SoC Design Lab., 004 5

6 .4 量量量量不略理量 JPEG 亮度度量量不量參數亮度量度量.5 Differential Pulse Code ModulationDPCM 數理離量 DC AC 兩類 DC 88 JPEG 88 DC 利 88 DC 都 DC 不兩兩 DC 料易 SoC Design Lab., 004 6

7 DC i DC i blocki blocki sample DCi Difference Previous sample DC i DC i DCi.6 Zig-Zag 度 Run-Length CodingRLC 了 DC 利 AC 度度 AC 率 Zig-Zag Zig-Zag 88 利離率量率來 Zig-Zag AC 零率 Zig-Zag 零連來度率說了 Zig-Zag 度率列 Row Scan 行 Column Scan SoC Design Lab., 004 7

8 DC (R,L) => (0,-3)(0,-)(0,-)(0,-)(0,-)(,-)(EOB) Zig-Zag 度度 R,L= 0 數, 零例 DC AC -3 零 -3 0 數零 0, 零 - 0 數零 0,- 類來 (0,-) 0,- 0,- 來兩 0 AC -, EOB Huffman CodingHuffman Table 精神率度料 JPEG DC AC DC 不亮度度亮度度 DC 易利率易不落亮度度 DC AC SoC Design Lab., 004 8

9 Size Length Codeword (a) 亮度 DC Size Length Codeword (b) 度 DC SoC Design Lab., 004 9

10 Category AC Coefficient Range -, -3,-,,3-7,,-4,4,,7-5,,-8,8,,5-3,,-6,6,,3-63,,-3,3,,63-7,,-64,64,,7-55,,-8,8,,55-5,,-56,56,,5-03,,-5,5,,03-047,,-04,04,,047 AC.8 離 Baseline Sequential DCT-based Coding 例離 Baseline Sequential DCT-based Coding 例例若不 88 來 888=5(bits) 88 98(bits) 量若理量都不數數 SoC Design Lab., 004 0

11 -8 Zig-Zag Run-length Q Table (6)(6),(0,)(-3), (0,3)(4),(0,)(-), (0,3)(-4),(0,)(), (,)(),(0,)(-), (0,)(-),(5,)(), (3,)(),(6,)(-), (,)(-),(4,)(- ), (7,)(-),(0,0) FDCT Huffman (0)(0)(0)(00)(00) (00)(00)(0)(00)(00)(0) (0)(0)(0)(0)(0)(0) (0)(0)(0)(00) ()(0)(0)(00)(0) (0)(0)(00)(0)(00) total 98 bits Q 離例.9 JPEG 流 JPEG 流 Start_of_image Frame End_of_image Tables, etc. header scan... scan Tables, etc. header segment Restart segment Restart... block block block... block JPEG 流 SoC Design Lab., 004

12 .. 行讀 *.bmp JPEG jpeg.cpp JPEG Codec JPEG 讀 bitstream stream.cpp. JPEG 索 ARM Integrator/AP 料理來 JPEG 例行 Hardware/Software Co-design JPEG 索 JPEG 裡 JPEG JPEG JPEG 料料參 JPEG: Still Image Data Compression Standard [] 參裡理 SoC Design Lab., 004

13 不來了離 JPEG 行 JPEG 了 JPEG 離 JPEG 離理料 4 Component Interleave and non-interleave scans JPEG Component 例 Red 綠 Green 藍 Blue 綠藍不 JPEG 裡 YC b C r 了 Y C b 類 4 不 JPEG 3 來 JPEG 理 88 來說切切數 8 Y 理理理 88 裡 Non-interleave order 3 理念不理 88 理 88 理理 Interleave orderyc b C r MCUMinimum Coded Unit SoC Design Lab., 004 3

14 8 8 Y C b C r MCU MCU Non-interleave ordermcu 料理說 MCU MCU 不 :4:4 4 Y C b C r 88 4:: MCU 88 數參數來省略了類來說 JPEG 都 4:4:4 YC b C r 4:: 4 Y C b C r DCT-based 理流說 88 DCT 量 QuantizeEntropy coding JPEG 裡了兩數 Arithmetic coding JPEG 度利說 3 3 度 SSSS 度 SSSS Category 0 3 度 0 數度 SSSS 3 0 數數 SoC Design Lab., 004 4

15 SSSS Value 0 -, -3,-,,3-7,,-4,4,,7-5,,-8,8,,5-3,,-6,6,,3 度 Category Code Word 度.3 流 JPEG bmp.cpppicture.cppjpeg.cpp stream.cpp 六列 bmp.cpp*.bmp 讀 picture.cpp 88 句說 88 裡 88 jpeg.cpp 裡離量度理 88 picture.cpp stream.cpp 讀流 bit-stream 說讀 bit 不 byte 0 6 SoC Design Lab., 004 5

16 連 6 0 JPEG Encoder Bmp.cpp Picture.cpp Jpeg.cpp Stream.cpp Bmp.cpp Picture.cpp Jpeg.cpp Decoder 六 JPEG 來數 type.h ByteWordDWord picture.cpp 都 bmp.cpp *.bmp 讀讀了讀 RGB JPEG 理 YC b C r YC b C r RGB stream.cpp BufferBufferLength 讀 byte Buffer 數裡 bit Buffer 數裡 BufferLength 來錄 Buffer 數裡 bit 數不 ByteStuffing ByteStuffing true 0xFF 0x00 讀 0xFF byte Name[3] 來錄 bool Open (const char* name, const char* attr) fopen() SoC Design Lab., 004 6

17 bool Close() fclose() bool IsEndOfStream() feof() bool PutStream(DWord code, Byte length) 來 Buffer 數參數 code 流 bit-streamlength code false 例 PutStream(0x9,5) 00 5 bit bool GetStream(DWord* code, Byte length) 來讀 Buffer 數 length 來讀讀參數 code false 例 GetStream(&strm, 5) 讀 5 strm 數裡 void Align(bool flag) flag true 若 BufferLength 不 8 Buffer 8 flag false 0 Buffer picture.cpp Pixel 3 4 欄 3-bits Y Cb Cr 8-bits Pixel 數欄 WidthHeight 錄 Pixel MCU88 來 88 Type 數錄 88 Y C b SoC Design Lab., 004 7

18 address MCU bool IsEmpty()Pixel 數 0NULL IsEmpty() false Pixel 不 0NULL true void Create(Word w, Word h) Pixel 數裡 void Release() Pixel 數 0NULL bool _get_min_code_unit(int address) Pixel MCU 數裡裡 8 8 參數 address 88 0 數參 address 88 Block_Address 數 Block_Address 88 0 SoC Design Lab., 004 8

19 0, 0 8, 0 6, 0 4, 0 address MCU 8 Y 8 Cb 8 Cr bool _get_min_code_unit(int address) bool _put_min_code_unit(int address) MCU 數 Pixel jpeg.cpp HuffmanDC DC[3] 錄數兩欄 CodeWord CodeLengthCodeWord 來錄 CodeLength 來錄 CodeWord 兩數都索 SSSS 例來說 5 SSSS 4 立 DC.CodeWord[4] 錄 0x0005DC.CodeLength[4] 數 HuffmanAC AC[3] CodeWord CodeLength 索 RRRR 數 0 索 SSSS void ChenFDCT(int (*block)[8]) 利 Chen s Algorithm 離 Chen s Algorithm 參 void ChenIDCT(int (*block)[8]) 利 Chen s Algorithm 離 SoC Design Lab., 004 9

20 參 void _initial_dc_table(byte identifier, Byte (*dc_length)[7], Byte (*dc_value)[]) DC 來說立 DCjpeg.h 34 行數數參數 identifier DC void _initial_ac_table(byte identifier, Byte (*ac_length)[7], Byte (*ac_value)[6]) void _encoding_block_value(byte identifier, int (*block)[8])vlc void _decoding_block_value(byte identifier, int (*block)[8])vlc.4 HW/SW Co-design JPEG JPEG CodecHW/SW Co-design HW/SW Partition 利 ARM JPEG 利行切兩利 Profiling JPEG Profiling 離 -D DCT/IDCT 量離 -D DCT/IDCT 路 AMBA Slave JPEG JPEG 行了了 sw.bat 行 JPEG ARM 行 sw.axf 利省略令利 CodeWarrior 連 C++ 了 bmp test.bmp test.bmp test3.bmp SoC Design Lab., 004 0

21 test4.bmp sw 料料 C++ 了念來參 [] W. Chen, CH Smith, and S. Fralic, "A fast computational algorithm for the discrete cosine transform," IEEE Trans. Commun., vol. COM-5, pp , Sept 977. [] JPEG: Still Image Data Compression Standard by William B. Pennebaker and Joan L. Mitchell, Kluwer Academic Publishers, ISBN: SoC Design Lab., 004

了立連立量領來例蘭便不數不論更更更力更參例來例見量度量量參論量行量量瑩理來錄量量不力省力立力量量量了量便錄錄錄料說省 6

了立連立量領來例蘭便不數不論更更更力更參例來例見量度量量參論量行量量瑩理來錄量量不力省力立力量量量了量便錄錄錄料說省 6 量領力不參劣說更省量量省狀切領量例類說留見省良料錄立料省力念了省良練理流論 5 了立連立量領來例蘭便不數不論更更更力更參例來例見量度量量參論量行量量瑩理來錄量量不力省力立力量量量了量便錄錄錄料說省 6 說量力量