Strange array error in OpenCV

Question

in this function i have a matrix of colors(each pixel can has a value from 0 to 9) and what i want to do is to reduce noise. pixels that have, more than 5 neighbor, with the same color are changed to that color! i define an array[0-9] to hold the number of neighbors color for example if 6 pixel has the value of 8 and 2 has the value of 5 the array should be like this [0,0,0,0,0,2,0,6,0,0] but when i print the array the value of first element( array[0]) is wrong ,it starts with 8 and each time pulse by 8 ! here is the code. can you help me pls ?

::Error image link::

void Noise_Reduction(CvMat* Color_mat,boolean showresult){
int tv[__COLORNUM]={0,0,0,0,0,0,0,0,0};
int counter;

for(int y=1;y<Color_mat->height-1;y++)
{
    for(int x=1;x<Color_mat->width-1;x++)
    {   
        for(int i=0;i<9;i++,tv[i]=0);           
        tv[CV_MAT_ELEM(*Color_mat,uchar,y-1,x-1)]++;
        tv[CV_MAT_ELEM(*Color_mat,uchar,y-1,x  )]++;
        tv[CV_MAT_ELEM(*Color_mat,uchar,y-1,x+1)]++;
        tv[CV_MAT_ELEM(*Color_mat,uchar,y  ,x-1)]++;
        tv[CV_MAT_ELEM(*Color_mat,uchar,y  ,x+1)]++;
        tv[CV_MAT_ELEM(*Color_mat,uchar,y+1,x-1)]++;
        tv[CV_MAT_ELEM(*Color_mat,uchar,y+1,x  )]++;
        tv[CV_MAT_ELEM(*Color_mat,uchar,y+1,x+1)]++;
        for(int i=0;i<9;i++){
        std::cout<<tv[i]<<",";}
        std::cout<<endl;
        int max=0;
        int indx=0; 
        max= tv[0];
        for(int i = 1; i<__COLORNUM; i++)
         {
             if(tv[i] > max){
                    max = tv[i];
                    indx=i;
             }

         }

        if(max>=5)
        {
            counter++;
            *( (uchar*)CV_MAT_ELEM_PTR( *Color_mat, y, x ))=(uchar)indx;
            //std::cout<<"times:"<<counter <<endl;

        }

    }
}
std::cout<<"times:"<<counter <<endl;    

if(showresult){
    IplImage* Noise_result = cvCreateImage(cvSize(Color_mat->width,Color_mat->height),IPL_DEPTH_8U,3);
    for( int y=0; y<Noise_result->height; y++ ) {
        uchar* ptr = (uchar*)(Color_mat->data.ptr + y * Color_mat->step);
        for( int x=0; x<Noise_result->width; x++ ) {
            switch ( *ptr) {

                          case 1 : 
                              cvSet2D(Noise_result,y,x,oo);
                              break;

                          case 2 : 
                              cvSet2D(Noise_result,y,x,bb);
                              break;

                          case 3 : 
                              cvSet2D(Noise_result,y,x,yy);
                              break;

                          case 4 : 
                              cvSet2D(Noise_result,y,x,gg);
                              break;

                          case 5 : 
                              cvSet2D(Noise_result,y,x,ww);
                              break;

                          default :  
                              cvSet2D(Noise_result,y,x,uk);
                              break;
            }
            ptr++;
        }
    }

    if(showresult)
{
    cvNamedWindow( "Noiseresult", CV_WINDOW_FREERATIO);
    cvShowImage( "Noise_result", Noise_result );
    cvWaitKey(0);

}



}

}

Uli Schlachter · Accepted Answer · 2011-12-31 11:08:04Z

3

for(int i=0;i<9;i++,tv[i]=0);

That line looks fishy (it will never set tv[0] to 0), don't you mean this instead:

for(int i=0;i<9;tv[i]=0,i++);

(Or even better: memset(tv, 0, sizeof(tv));)

answered Dec 31, 2011 at 11:08

Uli Schlachter

10k1 gold badge25 silver badges42 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

ugoren Over a year ago

memset is best. If you want to keep the loop, this is better: "for (int i=0; i<9; i++) tv[i]=0;". It's usually best to put the loop control in the for's parenthesis, and the real work outside.

Collectives™ on Stack Overflow

Strange array error in OpenCV

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related