[ANSWERED] How do I avoid infinite mirror effect (Droste effect)?
I want to use a camcorder to motion track dancers to create a water-ripple effect like this (https://youtu.be/1BZQdugLj5w) and project both dancers and ripples onto a a screen behind the dancers in real time. If I place the camcorder in the house (audience), it creates the infinite mirror effect. Is there a way to avoid the infinite mirror effect...? I feel this is such a fundamental technique but can't figure it out...
By the way, this is the patch. water-ripple-motion-track.izz
dbini last edited by dbini
there are a number of ways to solve the issue of video feedback, depending on what kind of image you need:
If I need full colour hi-res images of my dancers then i generally place my camera at the other side of the stage, in front of the screen, facing the audience.
if the camera needs to be facing the screen and I'm using it for motion tracking then i usually use a Kinect.
Sometimes Kinect isn't suitable (stage is too big, or the camera is positioned overhead so won't easily recognise human forms) - so the other option is to use an infra-red sensitive camera with an IR pass filter in front of the lens, and to flood the stage with IR light. (the projected image usually contains no IR frequencies)
Another option, though harder to source, is to use polarising filters in front of your projector and camera lenses. I've seen this working really well on stage - ironically to create a feedback loop of finite dancers that can be fully controlled by Isadora.
when I've created that water ripple effect on stage, I've always used the IR option, with a black and white CCTV camera in the grid and IR pass filters on profiles in the wings that light the dancers, but are shuttered off the floor. you can see IR floor tracking being used in various scenes in this show:
@dbini Thank you so much for your tips. I will definitely look into the IR option. I'm intrigued that CCTV camera can be used to create amazing effects like you did! At the moment, due to the budget restrictions, we may need to opt to the placing the camera in different area option.. haha.. Thanks, again!