How to use spatial image coordinates to get image pixel values??

Dear all I am working in hyperspectral image classification. I need to collect the training samples using the displayed image. I have gone through impoly, imrect.. It gives the coordinates. It doesnt help me much...

 does any one has any idea?? how to do it??

[Sean de Wolski]

So given a rectangle or other polygon, extract the pixel values inside it?

[Maria]

Could you please help with this. Yes I want the pixel values inside a polygon of an image(colored) only.how should I do that?

This is how the polygon has been made

rgbImage = imread('100_3816.jpg');

imshow(rgbImage);

BW = roipoly;

% Mask the image.

maskedRgbImage = bsxfun(@times, rgbImage, cast(BW,class(rgbImage)));

% Display it.

imshow(maskedRgbImage);

Answer 1

[Chaowei Chen]

You are almost there.

ROI=roipoly(img);

pixValue=img(ROI);