Re: HELP :: if() problems encountered

[Paul Roberts]

If you want the row and column indicies for each non-zero element,
rather than setting them to zero, you could use:

[i,j] = find(monoColor < 1);

i will hold the row indicies for each element, and j will hold the
column indicies. So, the first element with intensity less than 1 is:

monoColor(i(1),j(1))

Paul

On 9/15/06, Quentin Spencer <address@hidden> wrote:
> shoker_17 wrote:
> > Status            : Beginner
> >
> > Version           : Octave 2.1.72
> > Purpose          : image Processing
> > Problem          : If () statement
> > Descriptions   : I was trying to manipulate a matrix in image intensity. The
> > main idea was to retrieve those data that were less than 1 from monoColor.
> >
> > ##to find the number of consecutive black pixels horizontally
> > ##monoColor : image intensity of 32 rows and columns
> > for x = 1 : row
> >       for y = 1 : column
> >               if(monoColor(x,y) < 1)                 //tryin to find values 
> in monoColor
> > less than 1
> >                       test(x,y)= monoColor(x, y);
> >               endif
> >           endfor
> > endfor
> >
> > In the above code, i was trying to find the values in the matrix which are
> > less than 1.
> > However, to my dismay, I did not manage to get results i wanted. Instead, i
> > obtained the same number of rows and columns. Besides thism the values
> > smaller than 1 and 1 were also obtained.
> >
> > Maybe i used the syntax wrongly  else "<1" doesnt seems to work at all.
> > *weird*
> >
> > =============some monoColor image intensity==================
> >
> > 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
> >  1 1 1 1 0.992156862745098 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
> > 0.996078431372549 1 0.988235294117647 1 0.996078431372549 0.996078431372549
> > 1
> >  0.988235294117647 1 1 1 1 1 0.988235294117647 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
> > 1 1 0.996078431372549 1 0.992156862745098 1 0.988235294117647 1
> > 0.996078431372549 0.996078431372549
> >
> > =============some monoColor image intensity==================
> >
> > =============corresponding values in test array=================
> >
> >  0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
> >  1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
> >  0 0 0 0 0.992156862745098 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
> > 0.996078431372549 0 0.988235294117647 0 0.996078431372549 0.996078431372549
> > 0
> >  0.988235294117647 1 1 1 1 1 0.988235294117647 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
> > 1 1 0.996078431372549 1 0.992156862745098 1 0.988235294117647 1
> > 0.996078431372549 0.996078431372549
> >
> > =============corresponding values in test array=================
> >
> > H E L P !!
> >
>
> It looks like what you're trying to do is set all the values that are
> ==1 to zero. Is that right? See if the following give you the results
> you were expecting:
>
> test = monoColor;
> test(test==1) = 0;
>
>
> Quentin
>
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