A METHOD OF ADAPTIVE CONTRAST ENHANCEMENT USING HYPERLOIC TANGENT CURVE AND IMAGE HISTOGRAM

摘要

PURPOSE: An adaptive contrast improving method which uses a hyperbolic tangent function is provided to prevent a phenomenon whose boundary between a bright part and a dark part is protruded. CONSTITUTION: A digital camera calculates an average brightness value and a brightness histogram of an image(S12). The digital camera determines the kind of the images(S13). The digital camera applies respectively different coefficient to a hyperbolic tangent function curve(S14). The digital camera improves the contrast of the image by using the generated contrast reference curve(S15). [Reference numerals] (AA) Start; (BB) End; (S11) Reading an image; (S12) Calculating an average brightness value and a histogram of the image; (S13) Determining the kind of the image; (S14) Determining a reference curve coefficient; (S15) Generating a contrast reference curve