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This document delves into the fundamentals of digital image processing, focusing on the manipulation of bitmap and raw files. It provides a foundational understanding of reading, processing, and writing image data in C programming. The examples include error handling for file operations and pixel inversion techniques applicable to grayscale images. Additionally, the structural definitions for bitmap file headers are outlined to facilitate efficient image processing. This resource is aimed at learners and practitioners in the field of digital image processing.
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Digital Image Processing Kim Nam Woo
Bitmap-File & Raw-File Digital Image Processing, Kim Nam Woo, Dongseo Univ.
Structure(1) #include <stdio.h> void main() { int i, j; unsigned char OrgImg[256][256]; FILE *infile = fopen("coin.raw","rb"); if(infile==NULL) { printf("File open error !!"); return; } fread(OrgImg,sizeof(char),256*256,infile); fclose(infile); for(i=0; i<256; i++) { for(j=0; j<256; j++) { OrgImg[i][j] = 255-OrgImg[i][j]; } } FILE *outfile = fopen("coin_inv.raw","wb"); fwrite(OrgImg,sizeof(char),256*256,outfile); fclose(outfile); } Digital Image Processing, Kim Nam Woo, Dongseo Univ.
Structure(2) BYTE *lpImg = new BYTE [hInfo.biSizeImage]; fread(lpImg,sizeof(char),hInfo.biSizeImage,infile); fclose(infile); int rwsize = WIDTHBYTES(hInfo.biBitCount*hInfo.biWidth); for(int i=0; i<hInfo.biHeight; i++) { for(int j=0; j<hInfo.biWidth; j++) { lpImg[i*rwsize+j] = 255-lpImg[i*rwsize+j]; } } FILE *outfile = fopen("OutImg.bmp","wb"); fwrite(&hf,sizeof(char),sizeof(BITMAPFILEHEADER),outfile); fwrite(&hInfo,sizeof(char),sizeof(BITMAPINFOHEADER),outfile); fwrite(hRGB,sizeof(RGBQUAD),256,outfile); fwrite(lpImg,sizeof(char),hInfo.biSizeImage,outfile); fclose(outfile); delete []lpImg; } #include <stdio.h> #include <windows.h> #define WIDTHBYTES(bits) (((bits)+31)/32*4) #define BYTE unsigned char void main() { FILE *infile; infile=fopen("talent.bmp", "rb"); if(infile==NULL) { printf("There is no file!!!\n"); exit(1); } BITMAPFILEHEADER hf; fread(&hf,sizeof(BITMAPFILEHEADER),1,infile); if(hf.bfType!=0x4D42) exit(1); BITMAPINFOHEADER hInfo; fread(&hInfo,sizeof(BITMAPINFOHEADER),1,infile); printf("Image Size: (%3dx%3d)\n",hInfo.biWidth,hInfo.biHeight); printf("Pallete Type: %dbit Colors\n",hInfo.biBitCount); if(hInfo.biBitCount!=8 ) { printf("Bad File format!!"); exit(1); } RGBQUAD hRGB[256]; fread(hRGB,sizeof(RGBQUAD),256,infile); Digital Image Processing, Kim Nam Woo, Dongseo Univ.
Color 특징 • 8bit color • 각 픽셀이 1바이트의 R,G,B 값 중에 하나를 가짐 • 픽셀 자체가 색상정보를 가지고 있지 않기 때문에 팔레트 필요 • 출력 속도가 빠름 • 24bit color • 각 픽셀이 3바이트의 R,G,B 조합의 값으로 이루어져 있음 • 픽셀 자체가 색상정보를 가지고 있기 때문에 팔레트가 필요 없음 • 데이터의 용량이 커지고 출력속도가 느림 Digital Image Processing, Kim Nam Woo, Dongseo Univ.
Bitmap-File 구조 Digital Image Processing, Kim Nam Woo, Dongseo Univ.
BITMAPFILEHEADER typedef struct tagBITMAPFILEHEADER { WORD bfType; WORD bfSize; WORD bfReserved1; WORD bfReserved2; DWORD bfOffBits; } BITMAPFILEHEADER; Digital Image Processing, Kim Nam Woo, Dongseo Univ.
BITMAPINFOHEADER typedef struct tagBITMAPINFOHEADER { DWORD biSize; LONG biWidth; LONG biHeitht; WORD biplanes; WORD biBitCount; DWORD biCompression; DWORD biSizeImage; LONG biXPelsPerMeter; LONG biYPelsPerMeter; DWORD biClrUsed; DWORD biClrImportant; }BITMAPINFOHEADER; Digital Image Processing, Kim Nam Woo, Dongseo Univ.
RGBQUAD tydef struct tagRGBQUAD { BYTE rgbBlue; BYTE rgbGreen; BYTE rgbRed; BYTE rgbReserved; }RGBQUAD; Digital Image Processing, Kim Nam Woo, Dongseo Univ.
