Tracking a person in a scene with a varying amount of illumination

In computer vision, what would be a good approach to tracking a human in the black and white same scene at different times of the day (i.e. different levels of illumination)? The scene will never be dark so I don't need t开发者_如何学Goo worry about searching using infra-red or anything for heat sensing. I need to identify the people and then also track them so there are two parts.

Any advice would be great.

Thanks.

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SIFT feature matching works well for this purpose. It is implemented in OpenCV.