transparency between crop and actual image

Hi I have an image which I cropped it using imcrop and then modified it a little bit, then I superimposed the cropped image on the actual image but I would like to know how I can get rid of side of smaller triangles (the one that contains the red part). Or I should say how can I make the crop image in upper left corner be transparent to actual image.

Answer 1

[Image Analyst]

See these:

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

[chess]

part 4 uses imread but I already have my image and I named it for example image2. but when I used that like [a,map,alpha]=image2; I receive error too few arguments in the right side. Perhaps it is better to ask how I can get the alpha value of my image without using imread.

[Image Analyst]

The line in the example said:

[a,map,alpha] = imread('foreground.png');

You used:

[a,map,alpha]=image2;

Notice any differences? LIke you're not calling the imread() function like the example did?

[chess]

I was asking Is there anyway not to call imread because I have image2 in my workspace and If I want to use imread then I need to save it first.

[Image Analyst]

I believe Steve's blog illustrates that case.

[chess]

No hope it does not remove the boundries.

[Image Analyst]

Are your images different sizes? That image does not look like an overlay, at least you didn't color it if it is. Attach your original image, and the image you want overlaid on top of it. Maybe you can just average the two images instead?