How to add transparency to a 2D colormap?

Does anyone know, how to add transparency to 2D colormaps? I would like it to be overlaid over an image, so that both are visible. I will base the code on this one:

if true
  % 
data = rand(10,10); 
minVal = min(min(data)); 
maxVal = max(max(data)); 
image(data,'CDataMapping','scaled'); 
cbar_labels = [0 0.12 0.2 0.3 0.5 0.6 0.75 0.8 1]; % user defined ranges 
user_cmap = jet(8); % user defined colormap 
customcmap(cbar_labels,user_cmap,[minVal maxVal])
end

Any hints will be appreciated!

Lukasz

Answer 1

[Image Analyst]

See http://blogs.mathworks.com/steve/2009/02/18/image-overlay-using-transparency/

http://www.mathworks.com/matlabcentral/answers/104889-how-to-overlay-a-foreground-image-over-a-background-image

[Lukasz Handzlik]

Thanks Image Analyst!

Your hints guided me towards the solution, which is:

if true
img=imread('picture.jpg');
imagesc(img);
hold on;
im=image(x,y,data,'CDataMapping','scaled');
alpha(im,0.5);
colorbar
end