Extraction of Potential Sunny Region for Background Subtraction under Sudden Illumination Changes

This paper proposes a novel background subtraction method robust for sudden illumination changes that often happen in outdoor scenes. The method first estimates regions where are sunny regions or would become sunny regions when the sun is not behind clouds, which we call “po-tential sunny regions. ” For the estimation, spatio-temporal analysis is applied to image sequences of the recent days of a target day consid-ering the periodicity of the sun’s movement. Once the potential sunny regions are obtained, they are used for judging if the sudden illumination change happens in the target scene. When it happens, then the illumi-nation changes within the sunny regions are suppressed to obtain better subtraction results. Experimental results in several outdoor scenes show effectiveness of the proposed method