METHOD AND APPARATUS FOR ADJUSTING LUMINANCE OF PICTURE IN CAMERA TYPE VEHICLE SENSOR

摘要

PROBLEM TO BE SOLVED: To provide a method for adjusting luminance of a picture that makes it possible to easily recognize a dark part of even a picture obtained by photographing a bright place and also makes it possible to easily recognize a light part of even a picture obtained by photographing a dark place. SOLUTION: On the basis of data of an image photographed by a camera type vehicle sensor, a ratioβof pixels having luminance equal to or higher than a high-luminance threshold and a ratioαof pixels having luminance equal to or lower than a low-luminance threshold are calculated, target luminance I0is set above a default value whenβ>αor below the default value whenβ<α, and exposure control is performed so that the difference between a mean luminance value in the picture and the target luminance is eliminated. Consequently, a picture in which a detailed structure of a subject is easy to recognize on the whole is obtained to accurately perform postprocessing such as vehicle identification. COPYRIGHT: (C)2006,JPO&NCIPI