Patent ID: 8014689
Filing Date: 2011-09-06
Classification: G03G

Abstract:
1. An image forming apparatus configured to control the density of an output image based on an inherent gamma characteristic of the image forming apparatus which comprises: a patch image forming unit that forms a plurality of patch images having multiple gradation values on a specific medium; a measuring unit that measures the density or lightness of each of the patch images formed on the medium; a sample point arrangement unit that arranges sample points representative of measured density or lightness values in a descending or ascending order of the gradation values; an inflection point region detecting unit that detects any specific inflection point region from among regions defined between the consecutively arranged sample points; a straight line region detecting unit that detects any specific straight line region from among the regions defined between the consecutively arranged sample points; an interpolating operation unit that performs interpolating operation by adding and/or deleting a specific sample point depending on whether (i) an inflection point region is detected among regions defined by four consecutively arranged sample points S (i) in case the above condition (i) is met, (ii) in case the above condition (ii) is met, the interpolating operation unit adds the midpoint of the line segment S (iii) in case that the above condition (iii) is met, the interpolating operation unit adds a center of gravity of a triangle formed by the sample points S the interpolating operation unit adds an incenter of a triangle formed by the sample points S a characteristic acquisition unit that acquires a gradation characteristic by the interpolating operation; and a characteristic correction unit that corrects the gamma characteristic based on the acquired gradation characteristic.