Add live laser pointer to USB Frame Grabber Powerpoint/Keynote source.

I may have mentioned this before, but I can’t find the discussion so please excuse if this is a repeat.


We want to superimpose a laser pointer in mimoLive onto a high quality framegrabber image using a location identified by capturing the physical laser location on a projected PowerPoint/Keynote screen.

Has anyone ever done this? Would this pseudo laser pointer require a custom layer?


Have an extra camera pointed at the screen. Use that image to capture the projected image and the green dot from our laser pointer. Use that green dot as a chroma key on a solid colored layer (red or green) to create a small dot and put this layer over the high quality frame-grabber image to mimic the laser pointer. We get a high quality image for PIP with a laser pointer.


We use 3 video cameras and a frame grabber (DVI2USB from Epiphan Systems) to capture presentations from a second laptop which also feeds, through a HDMI splitter, a projector feed. We often use PIP with a small talking head and a large live PowerPoint/Keynote feed from the computer. This optimizes the captured presentation quality and avoids a camera showing the presenter and the screen simultaneously where the presentation is brighter than the presenter and the captured presentation quality is poor.

What we don’t capture, however, is when the presenter uses a laser pointer to highlight parts of the presentation – and no we do not want them “driving” a mouse or trackpad.

We would be happy to have a 4th camera pointed directly at, and only at, the projector’s screen image.

Have you tried Logitech Spotlight? It looks like this is your original post:

So, if you wanted to catch up on any responses that you may not have seen from the original post.

Thanks @bjoebirk. I’ll give that a try … easier and more simple than another camera and the processing overhead on my MacBook. If not, I’ll be back here sharing how chroma layering works.

I’m very interested in achieving the same thing
My solution today is to point a camera at the projected screen, but the resolution is really poor.
I would love to hear if your chroma key works! but I wish there was a simpler way to do it…

@bjoebirk have you used the Logitech Spotlight? Does it work well with diferente projectors and TVs screens? I wonder how does it work… how does it know what is it pointing at?..

It points directly in the program, works probably with som accelerators. Just tested, but seems to be perfect for this use.