In a digital camera, a CPU divides a multi-valued image into blocks and selects object blocks, which are to be the object of processing. A CCD outputs luminance values of the multi-valued image. A low luminance threshold value setter sets low luminance threshold values on the basis of mean luminance...http://www.google.com.au/patents/US6898329?utm_source=gb-gplus-sharePatent US6898329 - Image binarization apparatus, image binarization method, image pickup apparatus, image pickup method, and a computer product
