Detect a pattern highlighted by infrared light with openCV

For a project I'v开发者_StackOverflow社区e to detect a pattern and track it in space despite rotation, noise, etc. It's highlighted with IR light and recorded with an IR camera:

Picture: https://i.stack.imgur.com/RJuVS.png

As on this picture it will be only very simple shape and we can choose which one we're gonna use. I need direction on how to process a recognition of these shapes please.

What I do currently is thresholding and erosion to get a cleaner shape and then a contour detection and a polygon approximation.

What should I do then? I tried hu-moments but it wasn't good at all.

Could you please give me a global approach to recognize and track such pattern in space?

Can you choose which shape to project? if so I would recomend using few concentric circles. Then using hough transform for circles you can easily find the center of the shape even when tracking is extremly hard (large movement/low frame rate).

If you must use rectangular shape then there is a good open source which does that. It is part of a project to read street signs and auto-translate them. Here is a link: http://code.google.com/p/signfinder/

This source is not large and it would be easy to cut out the relevant part. It uses "good features to track" of openCV in module CornerFinder.

Hope it helped

It is possible, you need following steps: thresholding image, some morphological enhancement, blob extraction and normalization of blob size, blobs shape analysis, comparison of analysis results with pattern that you want to track.

There is many methods for blobs shape analysis. Simple methods: geometric dimensions, area, perimeter, circularity measurement; bit quads and others (for example, William K. Pratt "Digital Image Processing", chapter 18). Complex methods: spacial moments, template matching, neural networks and others.

In any event, it is very hard to answer exactly without knowledge of pattern shapes that you want to track )

hope it helped