Re: [WM]: loading image & reading the pixel values

[maneli@ece.gatech.edu]

Rajan,

In a project I did few years ago, I had to read .bmp files in VC++. I wrote a code that read the pixel values. But later since I
wanted to implement it on 32-bit TI DSP board, I compressed each 4 pixel values in a 32-bit. You can find the code below. To get
read of the compression, just change width/4 to width and read and store one pixel in a variable. I hope it helps. Let me know if
you want the whole program. It opens a window and asks you to choose your .bmp file and you can browse and find it, and it loads the
image.

Maneli


--------------------------------------------------------------------------
   clock_t start, end;
   FILE *stream1;
   unsigned long int **data;
   unsigned long int *buffer;
   unsigned char *byteBuff;
   unsigned char header[54+4*256];
   int numread;

   if ((stream1 = fopen( fileName, "rb" )) == NULL)
   {
      MessageBox( "File could not be opened" );
      getch();
      exit(2);
   }
   // Reading hearder of Bitmap file
   numread = fread( header, sizeof(unsigned char ),(54+4*256), stream1 );
   if (header[0]!='B' && header[1]!='M')
   {
      MessageBox("Not a BMP file");
      getch();
      exit(2);
   }


   //  int
sizeOfFile=header[2]+header[3]*256+header[4]*(256*256)+header[5]*(256*256*256);

   // Computing width of Image
   int
width=header[18]+header[19]*256+header[20]*(256*256)+header[21]*(256*256*256);
   // Computing height of Image
   int
height=header[22]+header[23]*256+header[24]*(256*256)+header[25]*(256*256*256);

   // int
imageSize=header[34]+header[35]*256+header[36]*(256*256)+header[37]*(256*256*256);

   //  int
compression=header[30]+header[31]*256+header[32]*(256*256)+header[33]*(256*256*256);

   int
offset=header[10]+header[11]*256+header[12]*(256*256)+header[13]*(256*256*256);
   // Allocating memory for Image Data
   data=new unsigned long int *[height];
   for (int a=0;a<height; a++)
      data[a]=new unsigned long int [width/4];

   buffer=new unsigned long int[4];
   byteBuff= new unsigned char[4];
   for (int x1=(height-1);x1>=0;x1--)
   {
      for (int y1=0; y1<width/4; y1++)
      {
         // Reading intensity of 4 pixel of Image
         numread=fread(&byteBuff[0], sizeof(unsigned char),4, stream1 );
		 // Checking if data has been read
		 if (numread==0)
		 {
            MessageBox("All of file haven't been read");
            getch();
            exit(2);
		 }

	     for (int b=0;b<4;b++)
		    buffer[b]=(unsigned long int)byteBuff[b];
		 // Storing the intensity of 4 pixel in a 32 bits variable
		 // Just to conform with the algoritm used in the DSP card program
	     buffer[1]=buffer[1]<<8;
	     buffer[2]=buffer[2]<<16;
	     buffer[3]=buffer[3]<<24;
         buffer[0]=((buffer[0]|buffer[1])|(buffer[2]|buffer[3]));
	     data[x1][y1]=buffer[0];
	  }
   }

   fclose(stream1);


> hi friends
>
> can anyone help me in developing a code for loading the .bmp image and 
> reading the pixel values in VC++
>
> can anyone send me the code for it in VC++ / java or the link where i 
> can find it
>
> i need the pixel values for the DCT algorithm to process the image..
>
> thanking you in advance
>
> waiting.........
> rajan


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