Patent ID: 6151073
Filing Date: 2000-11-21
Classification: G03B,H04N

Abstract:
A flash method operable each time a flash picture is taken with a digital camera, said method comprising performing the following steps with the camera each time the camera takes a flash picture:(a) activating a flash with a flash energy lower than the energy required for an acceptable final flash energy level for achieving a correct exposure;(b) grabbing an image of a subject located a distance from said camera to create image intensity data;(c) analyzing said image intensity data to determine a flash degree of exposure, wherein the analyzing does not require knowledge of said distance and said analyzing including(i) creating a histogram of quantity of said image intensity data versus intensity;(ii) preparing a bar graph with a multiplicity of regions from said histogram; and(iii) evaluating the quantity of data in each said region of said bar graph;(d) calculating a subsequent flash energy level to achieve a corrected degree of exposure wherein said calculating includes scaling said image intensity data to determine a scaling factor to multiply times said flash energy to calculate a final acceptable flash energy if said degree of exposure is under exposed or over exposed, and wherein said scaling said image intensity data includes(i) evaluating said histogram to determine a first intensity level above which a predetermined percentage of said intensity data lie; and(ii) dividing a predetermined intensity level selected as a level at which said grabbing to create image intensity data becomes a non-linear, by said first intensity level to create said scaling factor.