How to mask one image overlay ontop of a video?

Hi guys,

I wonder if I can make a image semi-transparent and mask it onto a video output? For example, I have a mask image: https://dl.dropbox.com/u/10571500/mask.jpg

and an real time video output that looks like the following image: https://dl.dropbox.com/u/10571500/under%20layer.jpg

What kind of function in the Matlab image and video processing toolbox can make the mask semi-transparent and generate a mask layer that is adjustable which will overlaying on top of the video output?

Thanks, Gene

Answer 1

[Image Analyst]

Your mask doesn't look solid. Is it just a bunch of lines that you could use plot() to display? I draw outlines of things on live video all the time.

[Gene]

You can think the mask as a bunch of empty rectangles. And I want to adjust the mask layer size to map it onto a real time video. Is there anyway to do it?

Thanks, Gene

[Image Analyst]

You have live video in an axes already, right? So then just use plot() to plot the rectangles. The video should still be live under the rectangles in the overlay.

[Gene]

I tried to do the overlay by imshow() and set the image Alpha to semi-transparent. The imshow() is triggered through a button Callback in a GUI. But the image only displays for a second then disappear. How can I constantly show that image on top of the video as long as my "show image" button is clicked?