Computer hw1

Computer hw1

• 1.
  Computer Project forChapter 1 1. (a) Obtain a set of YCrCb images for the set of 256x256 RGB Lena Images (Lena256C.bmp is a color input image) (b) Obtain a set of HIS images for the set of RGB images 2. Obtain images subsampled with (2:1)x(2:1), (4:1)x(4:1) from 512x512 Lena image. Display the original image and the subsampled ones with the same size and compare their qualities (Le512.raw is a gray input image). 3. Obtain 1-, 2-, 4-, 6-bit images from 8-bit 512x512 Lena image. Display the original image and the outputs, and compare their qualities (Le512.raw is a gray input image). Note: 1. Lena256C is a bitmap color image. You should read it out in your program using the following referenced function in C++, and then RGB images will be stored in * * * array for further processing ====== unsigned char*** ReadRGB(char *str, int &height, int &width, int &bit) { unsigned char ***rgb=NULL; FILE *fp; if((fp=fopen(str,"rb"))==NULL) { // AfxMessageBox("file open error"); return(rgb); } BITMAPFILEHEADER bmpfileheader; fread(&bmpfileheader,sizeof(BITMAPFILEHEADER),1,fp);
• 2.
  BITMAPINFOHEADER bmpinfoheader; fread(&bmpinfoheader,sizeof(BITMAPINFOHEADER),1,fp); bit=bmpinfoheader.biBitCount; int byte_count=bit/8; height=bmpinfoheader.biHeight; width=bmpinfoheader.biWidth; if(bit!=24&&bit!=8) { // AfxMessageBox("No 8bit or 24bit image!."); fclose(fp); return(rgb); } rgb=(unsigned char***)malloc(byte_count*sizeof(unsigned char**)); for(int i=0;i<byte_count;i++) { rgb[i]=(unsigned char**)malloc(height*sizeof(unsigned char*)); for(int y=0;y<height;y++) rgb[i][y]=(unsigned char*)malloc(width); }
• 3.
  for(int y=0;y<height;y++) for(int x=0;x<width;x++) { for(i=0;i<byte_count;i++) { rgb[byte_count-i-1][x][y]=getc(fp); } } fclose(fp); return(rgb); } ====== 2. Lena.raw is a 8-bit gray scale image. You may refer the following code: ====== float x[256][256], y[256][256]; //x array for in put, y array for output FILE *fo ,*fs ; int i,j; fo=fopen("lena.raw","rb");//for reading raw image for(i=0;i<256;i++) { for(j=0; j<256; j++) { x[i][j]=(float)getc(fo); } } fs=fopen("output.raw","wb");// for writing raw image for(i=0;i<256;i++) {
• 4.
  for(j=0;j<256;j++) { putc((unsigned char)y[i][j],fs); } } }