Images appear black and white instead of coloured

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Jason
Jason 2015-2-20
编辑： Jason 2015-2-23
I plot a montage of images onto a UIPanel and it worked fine when the images were tiffs. My images are now jpgs and I notice that the coloured images now appear black and white. I can't see why this would be the case. Here is my code
This is in a loop for all images.
hp = handles.uipanelM;
h=subplot('Position',positionVector,'Parent',hp); %to enable deleting use handles
colormap (jet);
% update handle array
hSubplots = [hSubplots ; h]; %Concatenate
axis off;
hold off;
%Create thumbnail sized image
IM1=imresize(IM, 0.05);
allImgs{y1,x1} = IM1 ;
imagesc(Image,[mlo mhi])
colormap (jet);
axis off;
set(gca,'ytick',[]);
set(gca,'xtick',[]);
drawnow;
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Adam
Adam 2015-2-20
hp is a panel handle, it needs to be either a figure handle or an axes handle.
Jason
Jason 2015-2-20
OK, but I am plotting onto the panel handle. The only other handle I use is:
h=subplot('Position',positionVector,'Parent',hp)
Im not convinced this is the issue, as it works with 12 bit tiffs, but not with 8 bit jpgs.

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Image Analyst
Image Analyst 2015-2-20
编辑：Image Analyst 2015-2-21
JPG images are usually color, even if they appear as gray scale - it's just that all the color channels are the same. Try:
imshow(IM1, []); % Display color image
Or extract one of the color channels:
% Extract the individual red, green, and blue color channels.
redChannel = rgbImage(:, :, 1);
greenChannel = rgbImage(:, :, 2);
blueChannel = rgbImage(:, :, 3);
imshow(redChannel, []); % Display one monochrome color channel
colormap(jet(256));
Or convert to grayscale if the color channels are NOT all identical:
grayImage = rgb2gray(IM1);
imshow(grayImage); % Display converted image.
colormap(jet(256));
colorbar;
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Image Analyst
Image Analyst 2015-2-21
Jason: That won't do it. First of all, Image was not even defined in your code. You should use the red channel of IM or IM1. Second, Image is a bad name since image() is the name of a built in function. I know MATLAB is case sensitive, but nonetheless it's not a wise idea to use variables with the same names as the built in functions, even if the case of some of the letters is different.
Jason
Jason 2015-2-23
编辑：Jason 2015-2-23
Hi IA. I actually put Image(:,:,1) in a function that I pass IM1 to.
function Im_Scale(handles,Image,mlo, mhi,ext)
size(Image, 3) %If 3 then RGB, if not then grayscale
if ext=='.jpg'
imagesc(Image(:,:,1),[mlo mhi])
else
imagesc(Image,[mlo mhi])
end
colormap (jet);
axis off;
set(gca,'ytick',[]);
set(gca,'xtick',[]);
drawnow;
end
I will take your advice regarding the name Image. As I correct though to use the index 1 as representing the red channel?
Thanks

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