Math Forum / Math Software / MATLAB / July 2008

Hello, im trying to create a 3 dimensional matrix to store
10 640x480 raster images. One set of these images i need
to apply thresholding to.

I first store the images into matrices the following way

ObjectImage(:,:,1) = imread('ImageA1.ras');
ObjectImage is 480,640 in row/column (mxn) size, ImageA1
is a raster image of resolution 640x480, and is purely
binary (255 or 0).

If i call imshow(ObjectImage(:,:,1)) OR image(ObjectImage
(:,:,1)), the picture is correctly displayed

Next, i do the same thing again  for a different set of
raster images (same dimension as the above case) however
they are not purely binary

ObjectImage(:,:,1) = imread('ImageB1.ras');

If i call imshow(ObjectImage(:,:,1)) the picture is shown
incorrectly, alot of it is missing. If i call image
(ObjectImage(:,:,1)), the picture is correctly displayed.

Another problem is that i need to threshold each image

for i=1:10
 level = graythresh(ObjectImage(:,:,i));  
 BW = im2bw (ObjectImage(:,:,i),level);
 ObjectImage(:,:,i) = BW(:,:);
end;

Thresholding works normally if i dont store the images in
the matrix (ie: graythreshold('filename.ras'), however
when i do this and try to view the new images they are
completely black. What am i doing wrong here?