20130523_Lab_HW02_EdgeDetect

#include <stdio.h>
#include <stdlib.h>


#include "cv.h"
#include "highgui.h"

int main(int argc, char *argv[])
{
  IplImage *img1; IplImage *img2;
  int w,h,nc,step;



  if((img1 = cvLoadImage("step_up_rev.jpg", CV_LOAD_IMAGE_GRAYSCALE ))== 0) //CV_LOAD_IMAGE_GRAYSCALE ==> gray
         { printf("Can't opne image file\n");system("PAUSE"); return -1; }


   printf("Channels %d depth %d widthStep %d \n",
                         img1->nChannels, img1->depth, img1->widthStep);
   printf("The image Width by Height is %d * %d \n", img1->width,img1->height);
   printf("The image origin is  %d\n", img1->origin);

  w = img1 -> width ;
  h = img1 -> height ;
  nc = img1 -> nChannels ;
  step = img1 -> widthStep ;

  img2 = cvCreateImage(
                       cvSize(w, h), //CvSize size,
                       IPL_DEPTH_8U , //int depth,
                       nc ); //int channel


  cvNamedWindow( "Image 2", 1 );
  cvShowImage( "Image 2", img2 );
  cvNamedWindow( "Image 1", 1 );
  cvShowImage( "Image 1", img1 );
  cvWaitKey(0);

  uchar* ptr ;
  uchar* ptr2;
  int s=0,sum1 ,sum2;
  int x,y;

  for(x = 1 ; x < w-1 ; x ++)
   for(y = 1 ; y < h-1 ; y ++)
   {
    ptr = &CV_IMAGE_ELEM(img1, uchar, y, x * img1->nChannels);
    ptr2 = &CV_IMAGE_ELEM(img2, uchar, y, x * img2->nChannels);

    sum1 =
        (-1)*ptr[-1-step]  +  0*ptr[-step]  +  ptr[1-step]  +
        (-1)*ptr[-1]       +  0*ptr[0]      +  ptr[1]       +
        (-1)*ptr[-1+step]  +  0*ptr[step]   +  ptr[step+1]  ;
    sum2=
        (-1)*ptr[-1-step]  +  (-1)*ptr[-step]  +  (-1)*ptr[1-step]  +
        0*ptr[-1]          +  0*ptr[0]         +  0*ptr[1]          +
        ptr[-1+step]       +  ptr[step]      +  ptr[step+1]  ;


    if(sum1>255) sum1 = 255 ;
    else if(sum1<0) sum1 = -sum1 ;

    if(sum2>255) sum2 = 255 ;
    else if(sum2<0) sum2 = -sum2 ;

    sum1 = sum1 ;
    sum2 = sum2 ;

    s = sum1+sum2 ;
    ptr2[0] = s ;


   }


        cvShowImage( "Image 2", img2 );

        cvWaitKey(0);
        cvDestroyWindow( "Image 2" );
        cvDestroyWindow( "Image 1" );
        cvReleaseImage( &img1 );
        cvReleaseImage( &img2 );
        return 0;



  system("PAUSE");
  return 0;
}