APPARATUS AND METHOD FOR HIGH DYNAMIC RANGE IMAGING USING SPATIALLY VARYING EXPOSURES

摘要

PROBLEM TO BE SOLVED: To provide an apparatus and method for obtaining high dynamic range images using a low dynamic range image sensor.

SOLUTION: A captured image is normalized with respect to an exposure function after calibration to compensate for nonlinear response of an image sensor. When the exposure function is implemented using a controllable attenuation cell array, the exposure function is adjusted to minimize the number of saturated or blackened pixels within an area of pixel array exposed through a cell, to maximize the signal-to-noise ratio of the average pixel value, and to maximize the spatial smoothness of the exposure function. A dynamic range compression technique on a low dynamic range display device entails applying a smoothing filter to the exposure function used to provide the high dynamic range image and then reapplying the smoothed exposure function. Also a method is provided for providing high dynamic range images by exposing a photographic film using a spatially varying exposure function. Thus, an electronic image provided by the same process as images captured using a fixed exposure function.

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