C語言實現(xiàn)將彩色bmp圖像轉(zhuǎn)化為灰圖、灰度圖像反色
本文實例為大家分享了C語言實現(xiàn)將彩色bmp圖像轉(zhuǎn)化為灰圖、灰度圖像反色的具體代碼,供大家參考,具體內(nèi)容如下
彩色圖像轉(zhuǎn)灰度圖像
彩色(24位)bmp圖像結(jié)構(gòu):
typedef struct{ bitmapFileHeader bfHeader; bitmapInfoHeader biHeader; unsigned char *imgData; }bmp;
灰度(8位)bmp圖像結(jié)構(gòu):
typedef struct{ bitmapFileHeader bfHeader; bitmapInfoHeader biHeader; rgbQUAD palette[256]; unsigned char *imgData; }bmp;
bmp灰度圖像比彩色圖像多了一個調(diào)色板,調(diào)色板中每個元素的類型是一個RGBQUAD結(jié)構(gòu),占四個字節(jié),其定義如下:
typedef struct{ unsigned char rgbBlue; unsigned char rgbGreen; unsigned char rgbRed; unsigned char rgbReserved; }rgbQUAD;
在實際的bmp圖像中調(diào)色板:
代碼實現(xiàn)將彩色bmp圖像轉(zhuǎn)化位灰值圖像:
#include<stdio.h> #include<stdlib.h> #include<string.h> #pragma pack(1) //全緊湊模式 typedef struct { unsigned char bfType[2]; unsigned int bfSize; unsigned short bfReserved1; unsigned short bfReserved2; unsigned int bfOffBits; }bitmapFileHeader; typedef struct { unsigned int biSize; unsigned int biWidth; unsigned int biHeight; unsigned short biPlanes; unsigned short biBitCount; unsigned int biCompression; unsigned int biSizeImage; unsigned int biXPixPerMeter; unsigned int biYPixPerMeter; unsigned int biClrUsed; unsigned int biClrImportant; }bitmapInfoHeader; typedef struct{ unsigned char rgbBlue; unsigned char rgbGreen; unsigned char rgbRed; unsigned char rgbReserved; }rgbQUAD; typedef struct{ bitmapFileHeader bfHeader; bitmapInfoHeader biHeader; rgbQUAD palette[256]; unsigned char *imgData; }bmp; int main(){ FILE *fp; if((fp=fopen("d:\Temp\\test.bmp","rb"))==NULL){ perror("can not open file!"); return -1; } //讀入彩色bmp圖像文件頭,信息頭和圖像數(shù)據(jù) bitmapFileHeader bfHeader; fread(&bfHeader,14,1,fp); bitmapInfoHeader biHeader; fread(&biHeader,40,1,fp); int imSize=biHeader.biSizeImage; int width=biHeader.biWidth; int height=biHeader.biHeight; int bitCount=biHeader.biBitCount; int lineBytes=(width*bitCount+31)/32*4; fseek(fp,bfHeader.bfOffBits,SEEK_SET); unsigned char*imageData=(unsigned char*)malloc(imSize*sizeof(unsigned char)); fread(imageData,imSize*sizeof(unsigned char),1,fp); fclose(fp); bmp b; int i,j,k; memcpy(&(b.bfHeader),&bfHeader,sizeof(bfHeader)); memcpy(&(b.biHeader),&biHeader,sizeof(biHeader)); b.bfHeader.bfOffBits=1078; //因新增了調(diào)色板,需調(diào)整圖像數(shù)據(jù)偏移位置 b.biHeader.biBitCount=8; //改變圖像位數(shù) int lineBytes_new=(width*8+31)/32*4; //重新計算每行數(shù)據(jù)字節(jié) b.biHeader.biSizeImage=lineBytes_new*height; //改變圖像數(shù)據(jù)大小 b.bfHeader.bfSize=1078+b.biHeader.biSizeImage; //改變文件數(shù)據(jù)大小 b.imgData=(unsigned char*)malloc(sizeof(unsigned char)*b.biHeader.biSizeImage); memset(b.imgData,0,sizeof(unsigned char)*b.biHeader.biSizeImage); for(i=0;i<256;i++){ b.palette[i].rgbBlue=i; b.palette[i].rgbGreen=i; b.palette[i].rgbRed=i; } for(i=0;i<height;i++){ for(j=0;j<width;j++){ //將每一個像素都按公式y(tǒng)=B*0.299+G*0.587+R*0.114進行轉(zhuǎn)化 b.imgData[lineBytes_new*i+j]=imageData[lineBytes*i+j*3]*0.299+imageData[lineBytes*i+j*3+1]*0.587+imageData[lineBytes*i+j*3+2]*0.114; } } char savePath[]="D:\Temp\\save_test.bmp"; FILE *f=fopen(savePath,"wb"); if(f==NULL){ perror("can not open file!"); return -2; } fwrite(&b.bfHeader,sizeof(bitmapFileHeader),1,f); fwrite(&b.biHeader,sizeof(bitmapInfoHeader),1,f); fwrite(&b.palette,1024,1,f); fwrite(b.imgData,sizeof(unsigned char)*b.biHeader.biSizeImage,1,f); fclose(f); free(imageData); free(b.imgData); return 0; }
代碼效果:
灰度圖像反色
int i,j; for(i=0;i<height;i++){ for(j=0;j<width;j++){ b.imgData[lineBytes*i+j]=255-imageData[lineBytes*i+j]; } }
代碼效果:
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