[求助]读取BMP图象的R,G,B值到三个二维数组,请高手看一下问题出在哪!(页 1) - C语言论坛 - C图形专区 - 编程论坛

feixiang569 发表于 2007-4-1 09:41

[求助]读取BMP图象的R,G,B值到三个二维数组,请高手看一下问题出在哪!

[求助]读取BMP的R，G，B，值请高手看一下问题出在哪？ [em01] 我现在做的毕业设计是彩色图象的水印，需要把一副BMP图象的R，G，B，各个分量分别读出来然后再对各分量处理.最后再把处理后的数据写回BMP。下面的第一个程序我试了各种办法就是找不出错，请高手帮忙分析一下！ 程序可以在*.TXT文件中输出图象位图文件头，信息头的主要数据，但其中的调色板读出的各颜色索引值不对，还有就是读出的R，G，B，三个二维数组的数值也不对（用自己编的READ.EXE，读DAT文件到记事本中0有许多或是把三个分量分别写到BMP文件中但显示都只是一副紫色图）但大小是对的. 还想问一下就是数据处理完后怎么再把R，G，B值恢复为一副彩色图象，颜色索引值是不是还要重新确定一下？ 下面是从BMP读取的主要数据： bmp_img->width=256 and bmp_img->height=256 bits_per_pixel=8 bmp_type=g the bmp file is notcompressed! info_header_length = 1078 调色板的各颜色索引值： Blue =1 Green=0 Red =0 Blue =189 Green=202 Red =0 Blue =63 Green=114 Red =0 Blue =104 Green=201 Red =0 Blue =219 Green=251 Red =0 Blue =106 Green=150 Red =0 Blue =57 Green=154 Red =0 Blue =64 Green=120 Red =0 Blue =31 Green=84 Red =0 Blue =107 Green=199 Red =0 Blue =84 Green=176 Red =0 Blue =128 Green=228 Red =0 Blue =64 Green=152 Red =0 Blue =177 Green=211 Red =0 Blue =128 Green=185 Red =0 Blue =203 Green=241 Red =0 Blue =52 Green=130 Red =0 Blue =94 Green=202 Red =0 Blue =209 Green=245 Red =0 Blue =52 Green=106 Red =0 Blue =143 Green=186 Red =0 Blue =49 Green=173 Red =0 Blue =105 Green=201 Red =0 Blue =115 Green=154 Red =0 Blue =82 Green=177 Red =0 Blue =96 Green=138 Red =0 Blue =143 Green=212 Red =0 Blue =219 Green=239 Red =0
Blue =41 Green=107 Red =0 Blue =188 Green=220 Red =0 Blue =135 Green=195 Red =0 Blue =13 Green=81 Red =0 Blue =196 Green=234 Red =0 Blue =136 Green=228 Red =0 Blue =164 Green=192 Red =0 Blue =56 Green=126 Red =0 Blue =72 Green=155 Red =0 Blue =21 Green=102 Red =0 Blue =104 Green=140 Red =0 Blue =48 Green=151 Red =0 Blue =160 Green=236 Red =0 Blue =196 Green=245 Red =0 Blue =151 Green=190 Red =0 Blue =151 Green=168 Red =0 Blue =92 Green=188 Red =0 Blue =119 Green=212 Red =0 Blue =197 Green=236 Red =0 Blue =71 Green=135 Red =0 Blue =136 Green=172 Red =0 Blue =144 Green=220 Red =0 Blue =136 Green=196 Red =0 Blue =21 Green=116 Red =0 Blue =60 Green=188 Red =0 Blue =22 Green=92 Red =0 Blue =94 Green=164 Red =0 Blue =136 Green=230 Red =0 Blue =194 Green=220 Red =0 Blue =105 Green=212 Red =0 Blue =107 Green=221 Red =0 Blue =86 Green=188 Red =0 Blue =118 Green=199 Red =0 Blue =118 Green=164 Red =0 Blue =180 Green=244 Red =0 Blue =34 Green=116 Red =0 Blue =253 Green=253 Red =253 Blue =164 Green=2 Red =135 Blue =0 Green=0 Red =0 Blue =0 Green=0 Red =0 Blue =0 Green=0 Red =0 以下各值就全为0了，个数是对的一共读了256个索引值 程序如下（在VC中运行的）：
 
<DIV class=htmlcode>
/* This program is to read and write bmp images 只是256色位图 图片为256*256的彩色LENA图*/ #include "Conio.h" #include "stdlib.h" #include "stdio.h" #include "malloc.h" #include "math.h"
#define SUCCESSED 0 #define FAILED 1 //typedef unsigned char BYTE /* ---------------------- */ /* Global Variables */ /* ---------------------- */
typedef struct BMP_img { long width; long height; char bmp_type; /* 'c'=color; 'g'=graymap; */ unsigned char **mono;
}BMP_IMG;
typedef struct tagRGBQUAD { unsigned char rgbBlue; unsigned char rgbGreen; unsigned char rgbRed; unsigned char rgbReserved; } RGBQUAD;
long info_header_length; /* the length of bmp image information head */ unsigned char *bmp_head_buffer; /* used for bmp head */ RGBQUAD *bmiColor; /*调色板数组*/ FILE *information; /*在.txt文件中输出BMP图象的主要数据*/ 
/* ---------------------- */ /* Global Functions */ /* ---------------------- */
int read_bmp(FILE *infile, BMP_IMG *bmp_img); void get_bmp(BMP_IMG *img, long height, long width, char bmp_type); void write_dat(FILE *fred,FILE *fgreen,FILE *fblue,BMP_IMG *bmp_img);
/* ------------ */ /* Main() */ /* ------------ */
int main() { int i,j; char infilename[10],redfilename[10],greenfilename[10],bluefilename[10],inma[10]; FILE *fin, *fred,*fgreen,*fblue; BMP_IMG img_in, img_out; 
printf("input the sourse filename:\n"); scanf("%s",infilename); if((fin=fopen(infilename,"rb"))==NULL) { printf("can't open the file\n"); exit(0); } printf("input the red filename(*.dat):\n"); scanf("%s",redfilename); if((fred=fopen(redfilename,"wb"))==NULL) { printf("can't open the file\n"); exit(0); } printf("input the green filename(*.dat):\n"); scanf("%s",greenfilename); if((fgreen=fopen(greenfilename,"wb"))==NULL) { printf("can't open the file\n"); exit(0); } printf("input the blue filename(*.dat):\n"); scanf("%s",bluefilename); if((fblue=fopen(bluefilename,"wb"))==NULL) { printf("can't open the file\n"); exit(0); } printf("input the information filename(*.txt):\n"); scanf("%s",inma); if((information=fopen(inma,"wb"))==NULL) {printf("can't open the file\n"); exit(0); } if((read_bmp(fin, &img_in))==FAILED) { fprintf(stderr, "\n Error: BMP read failed \n"); fclose(fin); exit(-1); } fclose(fin);
 if(img_in.bmp_type=='g') { /* set up structure for output image */ get_bmp(&img_out, img_in.height, img_in.width, 'g');
 /* pixel replication */ for(i=0;i<img_in.height;i++) for(j=0;j<img_in.width;j++) img_out.mono[i][j]=img_in.mono[i][j]; } else { fprintf(stderr, "\n Unknown image type \n"); exit(-1); }
write_dat(fred,fgreen,fblue,&img_out); fclose(information); return SUCCESSED; } /* ---------------- */ /* read_bmp() */ /* ---------------- */
int read_bmp(FILE *infile, BMP_IMG *bmp_img) { int i,j; long width, height; int bits_per_pixel; int compression; unsigned char *temp; /* used for read the image data */
 /* read the bmp image head information */
 /* read the length and width of the input image */ fseek(infile, 0x12, SEEK_SET); fread(&width, sizeof(long), 1, infile); fseek(infile, 0x16, SEEK_SET); fread(&height, sizeof(long), 1, infile);
 bmp_img->width=width; bmp_img->height=height;
 fprintf(information, "\n bmp_img->width=%d and bmp_img->height=%d \n", bmp_img->width, bmp_img->height);
 /* read bits/pixel and decide the type of the bmp image */ fseek(infile, 0x1C, SEEK_SET); fread(&bits_per_pixel, sizeof(int), 1, infile);
 if(bits_per_pixel==8) bmp_img->bmp_type='g'; fprintf(information, "\n bits_per_pixel=%d \n", bits_per_pixel); fprintf(information, "\n bmp_type=%c \n", bmp_img->bmp_type);
 /* decide whether the bmp file is compressed */ fseek(infile, 0x1E, SEEK_SET); fread(&compression, sizeof(int), 1, infile); if(compression==0) { fprintf(information, "\n the bmp file is not compressed! \n"); }
 fseek(infile, 0x0A, SEEK_SET); fread(&info_header_length, sizeof(int), 1, infile); /* the length of bmp image information head */ fprintf(information, "\n info_header_length = %d \n", info_header_length);
 /* allocate the memory for bmp_head_buffer and read the info header of bmp file */ bmp_head_buffer=(unsigned char *)malloc(sizeof(unsigned char)*info_header_length); if(bmp_head_buffer==NULL) { fprintf(stderr, "\n Allocation error for bmp_head_buffer \n"); exit(-1); } fseek(infile, 0x00, SEEK_SET); fread(bmp_head_buffer, info_header_length, 1, infile);/*取从文件开始到位图数据开始之间的数据偏移量*/ /* end of read the bmp head information*/
 /*为调色板指针指向的地址分配一块内存空间*/ bmiColor = (RGBQUAD *)malloc(256 * sizeof(RGBQUAD)); /*从文件中读位图的调色板数据到bmiColor指向的缓冲区*/ fseek(infile,0x33,SEEK_SET);/*从此处读颜色索引值不知正确不？*/ fread(bmiColor, sizeof(RGBQUAD), 256, infile); /*查看调色板信息*/ for(i=0;i<256;i++) { fprintf(information, " Blue =%d" , (*(bmiColor+i*sizeof(RGBQUAD))).rgbBlue); fprintf(information, " Green=%d" , (*(bmiColor+i*sizeof(RGBQUAD))).rgbGreen); fprintf(information, " Red =%d\n\n\n\n", (*(bmiColor+i*sizeof(RGBQUAD))).rgbRed); } 
 /* allocate the memory for mono or color array */ if(bmp_img->bmp_type=='g')/*为**mono/***color分配存贮空间*/ get_bmp(bmp_img, bmp_img->height, bmp_img->width, 'g'); 
 /* read the image data to mono or color array */ if(bmp_img->bmp_type=='g') { temp=(unsigned char *)malloc(sizeof(unsigned char)*(bmp_img->width*bmp_img->height)); if(temp==NULL) { fprintf(stderr, "\n Allocation error for temp in read_bmp() \n"); exit(-1); }
 fseek(infile, info_header_length, SEEK_SET); if(fread(temp, sizeof(unsigned char), bmp_img->width*bmp_img->height, infile)!=(size_t)(bmp_img->width*bmp_img->height)) { if(feof(infile)) fprintf(stderr, "\n Premature end of file %s \n", infile); else fprintf(stderr, "\n File read error %s \n", infile); return FAILED; }
 for(i=0;i<bmp_img->height;i++) for(j=0;j<bmp_img->width;j++) bmp_img->mono[i][j]=temp[i*bmp_img->width+j]; } 
 return SUCCESSED; }
/* --------------- */ /* get_bmp() */ /* --------------- */
void get_bmp(BMP_IMG *img, long height, long width, char bmp_type)/*为**mono/***color分配存贮空间*/ { int i;
 img->width=width; img->height=height; img->bmp_type=bmp_type;
 /* allocate the memory for mono and color */ if(img->bmp_type=='g') { img->mono=(unsigned char **)malloc(sizeof(unsigned char *)*img->height); if(img->mono==NULL) { fprintf(stderr, "\n Allocation error for mono \n"); exit(-1); } for(i=0;i<img->height;i++) { img->mono[i]=(unsigned char *)malloc(sizeof(unsigned char)*img->width); if(img->mono[i]==NULL) { fprintf(stderr, "\n Allocation error for mono[%d] \n",i); exit(-1); } } }
}
/* ----------------- */ /* write_dat() */ /* ----------------- */ void write_dat(FILE *fred,FILE *fgreen,FILE *fblue,BMP_IMG *bmp_img) {int i,j,n; int red[256][256],green[256][256],blue[256][256]; for(i=255;i>=0;i--) for(j=0;j<256;j++) { n=bmp_img->mono[i][j];//找到对应的颜色索引号 red[255-i][j]=bmiColor[n].rgbRed; green[255-i][j]=bmiColor[n].rgbGreen; blue[255-i][j]=bmiColor[n].rgbBlue; }
 fwrite(red,sizeof(unsigned char),bmp_img->width*bmp_img->height,fred); fwrite(green,sizeof(unsigned char),bmp_img->width*bmp_img->height,fgreen); fwrite(blue,sizeof(unsigned char),bmp_img->width*bmp_img->height,fblue); fclose(fred); fclose(fgreen); fclose(fblue); }</DIV>
急切希望你的解答![em13]

[attach]18583[/attach]

lyood 发表于 2007-4-4 15:37

位图文件结构表 位图文件头 14 字节 位图信息头 40 字节 彩色表（调色板） 4N 字节 位图数据 x 字节 调色板的信息应该从54字节读起! fseek(infile,54,SEEK_SET);

lyood 发表于 2007-4-4 15:44

你从51开始读起,正好r就是调色板的res值,所以全部是0;
struct regquad { char b; char g; char r; char res;//保留 }

feixiang569 发表于 2007-4-5 14:02

谢谢大家了！[em19] 是的你说的对调色板的位置写错了不是fseek(infile,0x33,SEEK_SET);而是第我54个字节（0x36H）我太粗心了！ 正确的应是 fseek(infile,0x36,SEEK_SET); 而且void write_dat（）也写错了，应是： [CODE]void write_dat(FILE *fred,FILE *fgreen,FILE *fblue,BMP_IMG *bmp_img) {int i,j,n; int red[256][256],green[256][256],blue[256][256]; unsigned char *temp; /* used for write the image data */ temp=(unsigned char *)malloc(sizeof(unsigned char)*(bmp_img->width*bmp_img->height)); for(i=0;i<256;i++) for(j=0;j<256;j++) { n=bmp_img->mono[i][j];//找到对应的颜色索引号 red[i][j]=bmiColor[n].rgbRed; green[i][j]=bmiColor[n].rgbGreen; blue[i][j]=bmiColor[n].rgbBlue; } /* 错误 fwrite(red,sizeof(unsigned char),bmp_img->width*bmp_img->height,fred); fwrite(green,sizeof(unsigned char),bmp_img->width*bmp_img->height,fgreen); fwrite(blue,sizeof(unsigned char),bmp_img->width*bmp_img->height,fblue); */ for(i=0;i<bmp_img->height;i++) for(j=0;j<bmp_img->width;j++) temp[i*bmp_img->width+j]=red[255-i][j]; fwrite(temp, sizeof(unsigned char), bmp_img->width*bmp_img->height, fred); for(i=0;i<bmp_img->height;i++) for(j=0;j<bmp_img->width;j++) temp[i*bmp_img->width+j]=green[255-i][j]; fwrite(temp, sizeof(unsigned char), bmp_img->width*bmp_img->height, fgreen); for(i=0;i<bmp_img->height;i++) for(j=0;j<bmp_img->width;j++) temp[i*bmp_img->width+j]=blue[255-i][j]; fwrite(temp, sizeof(unsigned char), bmp_img->width*bmp_img->height, fblue); fclose(fred); fclose(fgreen); fclose(fblue); }[/CODE] 最后的结果好多了把读出的R，G，B DAT文件显示后效果不错，但不明白的是调色板的数据依然有许多零，用256*4的空间存放的有效颜色数目竟是这样少不是浪费吗？难道还是错的？？？调色板数据如下： Blue =53 Green=5 Red =66 Blue =90 Green=80 Red =154 Blue =138 Green=160 Red =212 Blue =67 Green=38 Red =107 Blue =153 Green=160 Red =210 Blue =122 Green=127 Red =187 Blue =97 Green=106 Red =220 Blue =171 Green=188 Red =232 Blue =83 Green=79 Red =178 Blue =91 Green=84 Red =222 Blue =144 Green=106 Red =176 Blue =127 Green=81 Red =124 Blue =103 Green=49 Red =126 Blue =118 Green=117 Red =179 Blue =128 Green=107 Red =224 Blue =64 Green=20 Red =83 Blue =79 Green=69 Red =176 Blue =121 Green=129 Red =210 Blue =141 Green=144 Red =229 Blue =122 Green=175 Red =228 Blue =123 Green=180 Red =238 Blue =100 Green=64 Red =132 Blue =86 Green=32 Red =102 Blue =206 Green=236 Red =247 Blue =105 Green=52 Red =107 Blue =127 Green=119 Red =200 Blue =119 Green=144 Red =232 Blue =144 Green=119 Red =178 Blue =108 Green=117 Red =212 Blue =187 Green=159 Red =177 Blue =75 Green=59 Red =164 Blue =124 Green=136 Red =209 Blue =94 Green=96 Red =220 Blue =88 Green=72 Red =224 Blue =125 Green=120 Red =223 Blue =172 Green=138 Red =204 Blue =109 Green=97 Red =202 Blue =161 Green=167 Red =196 Blue =199 Green=167 Red =175 Blue =168 Green=121 Red =178 Blue =192 Green=206 Red =232 Blue =106 Green=135 Red =218 Blue =105 Green=87 Red =139 Blue =89 Green=85 Red =212 Blue =104 Green=121 Red =236 Blue =119 Green=94 Red =188 Blue =178 Green=137 Red =155 Blue =171 Green=136 Red =166 Blue =158 Green=161 Red =196 Blue =144 Green=128 Red =196 Blue =143 Green=152 Red =220 Blue =62 Green=34 Red =140 Blue =72 Green=31 Red =92 Blue =63 Green=31 Red =116 Blue =88 Green=52 Red =116 Blue =196 Green=214 Red =220 Blue =103 Green=82 Red =153 Blue =67 Green=40 Red =116 Blue =67 Green=43 Red =140 Blue =146 Green=107 Red =188 Blue =127 Green=105 Red =236 Blue =120 Green=94 Red =164 Blue =133 Green=181 Red =238 Blue =128 Green=118 Red =164 Blue =253 Green=253 Red =253 Blue =164 Green=2 Red =135 Blue =0 Green=0 Red =0 Blue =0 Green=0 Red =0 Blue =0 Green=0 Red =0以下又都是0了！ 用另外一个程序分别把R，G，B三个分量写到BMP文件中显示，但好像不对，还有就是把三个分量恢复成原图只有一个大概 轮廓，色彩不明显。是读的数据有问题还是调色板数据不对，但把R，G，B三分量的DAT文件分别显示又很清晰，看不出 什么毛病，问题在哪请您指点[em13][em13][em13] 此程序及相关数据在附件中请察看！[attach]18764[/attach]

lyood 发表于 2007-4-5 14:59

你读调色板数据不对，没有读完！！你在网上下一个二进制文件编辑器，打开bmp文件，看读出的数据是否正确！

feixiang569 发表于 2007-4-7 14:46

调色板数据读完了，一共读了256组，只是后边的不对全是零。 多谢了！[em19]我下了一个 UltraEdit 可以看到BMP里的具体存贮数据，一会儿再慢慢分析一下

feixiang569 发表于 2007-4-8 19:01

[em34][em34][em34]终于把错误全找出来了,读的数据一切正常,恢复图象和原来的一样. 多亏了 "UltraEdit "帮我分析了原图象的数据. 读调色板时下边的代码跳过了中间的四组值,难怪错了! [CODE]/*查看调色板信息*/ for(i=0;i<256;i++) { fprintf(information, " Blue =%d" , (*(bmiColor+i*sizeof(RGBQUAD))).rgbBlue); fprintf(information, " Green=%d" , (*(bmiColor+i*sizeof(RGBQUAD))).rgbGreen); fprintf(information, " Red =%d\n\n\n\n", (*(bmiColor+i*sizeof(RGBQUAD))).rgbRed); } 正确的应是: /*查看调色板信息*/ for(i=0;i<256;i++) { fprintf(information, " Blue =%d" , (*(bmiColor+i)).rgbBlue); fprintf(information, " Green=%d" , (*(bmiColor+i)).rgbGreen); fprintf(information, " Red =%d\n\n\n\n", (*(bmiColor+i)).rgbRed); } [/CODE] 此类问题希望大家以后注意![em16]

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[求助]读取BMP图象的R,G,B值到三个二维数组,请高手看一下问题出在哪!