Method of adjusting the brightness of an image, digital camera and image processor using the method

摘要

The brightness of image data is previously defined based on the R, G, and B values of each pixel. In an image considered to have been exposed appropriately by a conventional method, when the brightness histogram for the defined image is computed, pixels having the maximum value in the definition of brightness always occupy a predetermined rate (1% or so) of all pixels. Based on this rule of thumb, the gain of an image acquisition device or the pixel value of acquired data is adjusted so that a brightness histogram ( 3 ) for image data which is an object of adjustment becomes a histogram ( 4 ) having the same characteristic as the above-mentioned appropriately exposed image.