Image Processing in ARM

[sadeghkarimi]

Hello everybody
Could you please F1 Me??!
I want to process an image in Keil using ARM Cortex M-3 (LPC1768). I want to move a window(vector) over my image and compute sth using those pixels in the Window;
The Vector is : [-1 0 1] , Means that minus last and first pixels and put it in the middle.
The compiler doesn’t allow me to access pixels. Also my image is in vector form. I need Sth like this :

For (i=0,i<1240,i++){
Pic(i)=image(i+1)-image(i-10);
}

Before performing such an action also I want to zero pad my image for margins.
But vector Analysis in Keil doesn’t allow me to do such an easy process.
So what( the h… ) should I do ? Please Help me?

 

[alex_r]

Hello,

To help you, we need to know in which format is stored the image in memory ( RGB 565/888 or YCrCb or other), the pixel order (X->Y or Y->X) and so on.

 

[sadeghkarimi]

Hello alex,
Thanks for replying.
The format is RGB 565 and camera sensor is Ov7670

Thanks in advance

 

[alex_r]

Hello,

Assuming that your camera driver store the image in a unsigned short array you can use a function similar to:

void make_filtered_image( unsigned short *source_array, //pointer to source array
                 unsigned short *dest_array,     //pointer to dest array
                 unsigned short x_size,             //x size in pixel
                 unsigned short y_size)            //y size in pixel

{
  unsigned short x,y,s0,s1,s2;
  int r0,g0,b0,r1,g1,b1,r2,g2,b2;

  for (y=0;y<y_size;y++)	//y loop
  {
    s0=0;s1=*source_array++;	//init s0 s1
    for (x=0;x<x_size;x++)	//x loop 
   {
      if (x<x_size)		//if no last x pixel 
        s2=*source_array++;	//   get s2
      else			//else s2=0
        s2=0;
		
      r0=s0&0xF800;		//split RGB components
      g0=s0&0x7e0;
      b0=s0&0x1f;
		
      r2=s2&0xF800;
      g2=s2&0x7e0;
      b2=s2&0x1f;

      r1=r2-r0;		//apply filter -1 0 +1
      if (r1<0) r1=0;		//clip 
 
      g1=g2-g0;		//apply filter -1 0 +1
      if (g1<0) g1=0;		//clip 

      b1=b2-b0;		//apply filter -1 0 +1
      if (b1<0) b1=0;		//clip 

      *dest_array++=(unsigned short)(r1|g1|b1);
      s0=s1;
      s1=s2;
    }
  }
}		
			
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