I want to extract object from an image using the following threshold value program how can i use a filter to get the good result.

a=imread('a6.jpg');
m=ones(600,800,3);
c=255.*m;
e=ones(600,800,3)
for i=1:600;
  for j=1:800;
      if a(i,j,1)<100
      if a(i,j,1)>55
       c(i,j,1)=a(i,j,1);
      if a(i,j,2)<104
          if a(i,j,2)>75
      c(i,j,2)=a(i,j,2);
          if a(i,j,3)<90
          if a(i,j,3)>56
           c(i,j,3)=a(i,j,3);
                          end
          end
          end
      end
  end
      end
  end        
end
e=c./255;
colormap(jet);
image(e);
...

[Walter Roberson]

Could you upload a copy of the image?

[shantanu shukla]

[shantanu shukla]

Here is the image file and there is a little bit change in code. plz rply me asp thank u

[Walter Roberson]

Which object(s) are you trying to extract?

[shantanu shukla]

Mr. Walter i want to extract tree ,river ,houses and roads. so plz help me regarding this

Answer 1

[Image Analyst]

You cannot get it from thresholding or even combined with texture classification. There is just too much higher level knowledge required. Maybe try this: http://www.mathworks.com/matlabcentral/fileexchange/37197-dem-diffused-expectation-maximisation-for-image-segmentation or similar. But even that won't be perfect. I suggest you use ginput or roipoly to manually locate them (unless you have thousands of images).