How to extract nearest pixel value [roi] by selection of reference pixel on a image?

How to extract nearest pixel value [roi] by selection of reference pixel on a image?

Answer 1

[Swarooph]

Use the impoint function.

Example:

img = imread('peppers.png');
figure;imshow(img)
h = impoint(gca,[]);
position = wait(h); %Double click on a pixel in the figure window
pixelLoc = round(position) %Get nearest pixel location
img(pixelLoc(2),pixelLoc(1),1:3) %Use pixel location to index into RGB image

Result:

pixelVal = 

(:,:,1) =

     158

(:,:,2) =

     50

(:,:,3) =

     56

[Selva Karna]

Hi Swarooph , thanks for answer , actually my question is extract nearest pixel [ROI] its means region so , how to extract region by selection of pixel value?

[Binu]

Swarooph's answer gives you both the pixel position(x,y) and pixel value. If you are looking for a ROI and not just a pixel, try imrect or imellipse. They both use the imroi class and functions are similar to impoint.