A method of processing a digital image to improve contrast, the digital image being derived from an image captured by a recording medium having a nonlinear response to light, includes the steps of: applying a spatial filter to the digital image to produce a noise reduced digital image; subtracting the...http://www.google.com.tw/patents/US20030215153?utm_source=gb-gplus-share專利 US20030215153 - Method of enhancing the tone scale of a digital image to extend the linear response range without amplifying noise
