METHOD FOR AUTOMATIC ENHANCING OF HALF-TONE IMAGE Russian patent published in 2001 - IPC

FIELD: digital procession of images. SUBSTANCE: method is based upon determination of unimodal or bimodal type of initial brightness bar chart and threshold level of brightness having property of dividing bimodal bar chart by two unimodal fragments; subsequent processing of bar chart fragments and reverse transition from bar chart fragments to image segments. Method comprises steps of automatic approximation of stepped initial brightness bar chart by means of approximation curve; plotting curve of dynamics of bar chart center; detecting brightness intervals for which brightness value of approximation curve is less than respective brightness values for dynamics curve of bar chart center or equal to them; calculating weight of division zone for each brightness interval; identifying brightness interval of division zone with maximum weight; comparing it with standard one; deciding that initial brightness bar chart is bimodal one when first of said values is more than second one; detecting division zone; equalizing remaining fragments with standard distribution and filtering them. EFFECT: improved reliability and noise stability of image enhancing process without operator. 4 dwg