[转帖]实现基本JPEG的压缩和编码

suffer

1. %%%%%%%%%% 实现基本JPEG的压缩和编码 %%%%%%%%%%%%
   
2. % 1． 首先通过DCT变换去除数据冗余；
   
3. % 2． 使用量化表对DCT系数进行量化；
   
4. % 3． 对量化后的系数进行Huffman编码。
   
5. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
   
6. 
   
7. clear;
   
8. clc;
   
9. %%%%%%%%%%%%%%%%%%%%%%
   
10. %%1．主程序
    
11. %%%%%%%%%%%%%%%%%%%%%%
    
12. I=imread('lenna.bmp');
    
13. yiq=rgb2ntsc(I); % transform RGB to NTSC
    
14. 
    
15. 
    
16. 
    
17. my=[16 11 10 16 24 40 51 61;
    
18. 12 12 14 19 26 58 60 55;
    
19. 14 13 16 24 40 57 69 56;
    
20. 14 17 22 29 51 87 80 62;
    
21. 18 22 37 56 68 109 103 77;
    
22. 24 35 55 64 81 104 113 92;
    
23. 49 64 78 87 103 121 120 101;
    
24. 72 92 95 98 112 100 103 99];
    
25. 
    
26. 
    
27. 
    
28. miq=[17 18 24 47 99 99 99 99;
    
29. 18 21 26 66 99 99 99 99;
    
30. 24 26 56 99 99 99 99 99;
    
31. 47 66 99 99 99 99 99 99;
    
32. 99 99 99 99 99 99 99 99;
    
33. 99 99 99 99 99 99 99 99;
    
34. 99 99 99 99 99 99 99 99;
    
35. 99 99 99 99 99 99 99 99];
    
36. 
    
37. 
    
38. 
    
39. I1=yiq(:, :, 1);
    
40. I2=yiq(:, :, 2);
    
41. [m n]=size(I1);
    
42. 
    
43. 
    
44. 
    
45. t1=8;
    
46. ti1=1;
    
47. while (t1<(m+8))
    
48. t1=t1+8;
    
49. ti1=ti1+1;
    
50. end
    
51. 
    
52. 
    
53. 
    
54. t2=8;
    
55. ti2=1;
    
56. while (t2<(n+8))
    
57. t2=t2+8;
    
58. ti2=ti2+1;
    
59. end
    
60. 
    
61. 
    
62. 
    
63. times=0;
    
64. for k=0:ti1-2
    
65. for j=0:ti2-2
    
66. dct8x8(I1(k*8+1:k*8+8,j*8+1:j*8+8),my,times*64+1);
    
67. dct8x8(I2(k*8+1:k*8+8,j*8+1:j*8+8),miq,times*64+1);
    
68. times=times+1;
    
69. end
    
70. block(I2(k*8+1:k*8+8,j*8+1:t2),[8 8], 'dctmtx(8)');
    
71. end
    
72. 
    
73. 
    
74. 
    
75. for j=0:ti2-2
    
76. dct8x8(I1(k*8+1:t1,j*8+1:j*8+8),times*64+1);
    
77. times=times+1;
    
78. end
    
79. 
    
80. 
    
81. 
    
82. dct8x8(I1(k*8+1:t1,j*8+1:t2),times*64+1);
    
83. 
    
84. 
    
85. 
    
86. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    
87. %%2．function dct8x8(I,m,s) %定义DCT量化子程序
    
88. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
    
89. function dct8x8(I,m,s)
    
90. T=inline('dctmtx(8)');
    
91. y=blkproc(I,[8 8],T);
    
92. y=round(y./m);
    
93. p=1;te=1;
    
94. while (p<=64)
    
95. for q=1:te
    
96. y1(s+p)=y(te-q+1,q);p=p+1;
    
97. end
    
98. for q=te:-1:1
    
99. y1(s+p)=y(te-q+1,q);p=p+1;
    
100. end
     
101. end
     
102. 
     
103. 
     
104. 
     
105. f=haffman(y1);
     
106. c(s:s+64,1)=f(:,1);
     
107. c(s:s+64,2)=f(:,2);
     
108. c(s:s+64,3)=f(:,3)
     
109. 
     
110. 
     
111. 
     
112. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
     
113. %%3．function c=haffman(I) %定义Huffman编码子程序
     
114. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
     
115. [m,n]=size(I);
     
116. p1=1;
     
117. s=m*n;
     
118. for k=1:m
     
119. for h=1:n
     
120. f=0;
     
121. for b=1:p1-1
     
122. if (c(b,1)==I(k,h))
     
123. f=1;
     
124. break;
     
125. end
     
126. end
     
127. if (f==0)
     
128. c(p1,1)=I(k,h);
     
129. p1=p1+1;
     
130. end
     
131. end
     
132. end
     
133. 
     
134. 
     
135. 
     
136. for g=1:p1-1
     
137. p(g)=0;c(g,2)=0;
     
138. for k=1:m
     
139. for h=1:n
     
140. if (c(g,1)==I(k,h))
     
141. p(g)=p(g)+1;
     
142. end
     
143. end
     
144. end
     
145. p(g)=p(g)/s;
     
146. end
     
147. 
     
148. 
     
149. 
     
150. pn=0;po=1;
     
151. while (1)
     
152. if(pn>=1.0)
     
153. break;
     
154. else
     
155. [pm p2]=min(p(1:p1-1));
     
156. p(p2)=1.1;
     
157. [pm2,p3]=min(p(1:p1-1));
     
158. p(p3)=1.1;
     
159. pn=pm+pm2;
     
160. p(p1)=pn;
     
161. tree(po,1)=p2;
     
162. tree(po,2)=p3;
     
163. po=po+1;
     
164. p1=p1+1;
     
165. end
     
166. end
     
167. 
     
168. 
     
169. 
     
170. for k=1:po-1
     
171. tt=k;
     
172. m1=1;
     
173. if (or(tree(k,1)<9,tree(k,2)<9))
     
174. if (tree(k,1)<9)
     
175. c(tree(k,1),2)=c(tree(k,1),2)+m1;
     
176. m2=1;
     
177. while(tt)
     
178. m1=m1*2;
     
179. for h=tt:po-1
     
180. if (tree(h,1)==tt+g)
     
181. c(tree(k,1),2)=c(tree(k,1),2)+m1;
     
182. m2=m2+1;
     
183. tt=h;
     
184. break;
     
185. elseif (tree(h,2)==tt+g)
     
186. m2=m2+1;
     
187. tt=h;
     
188. break;
     
189. end
     
190. end
     
191. end
     
192. c(tree(k,1),3)=m2;
     
193. end
     
194. tt=k;
     
195. m1=1;
     
196. if (tree(k,2)<9)
     
197. m2=1;
     
198. while (tt)
     
199. m1=m1*2;
     
200. for h=tt:po-1
     
201. if (tree(h,1)==tt+g)
     
202. c(tree(k,2),2)=c(tree(k,2),2)+m1;
     
203. m2=m2+1;
     
204. tt=h;
     
205. break;
     
206. elseif (tree(l,2)==tt+g)
     
207. m2=m2+1,
     
208. tt=h;
     
209. break;
     
210. end
     
211. end
     
212. dct8x8(I1(k*8+1:k*8+8,j*8+1:j*8+8),my,times*64+1);
     
213. dct8x8(I2(k*8+1:k*8+8,j*8+1:j*8+8),miq,times*64+1);
     
214. times=times+1;
     
215. end
     
216. c(tree(k,2),3)=m2;
     
217. end
     
218. end
     
219. end

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[ 本帖最后由 suffer 于 2006-10-9 20:50 编辑 ]

zaisi

<P>好象有问题啊，不能运行？哪位大大能给修改修改，小弟先在这里谢了</P>

dragonkiss

不能运行的主要问题可能是子程序没有分开，不过我发现部分语句出现问题。比如times，被定义成了函数，又定义成了变量。呵呵。需要再调试。