Patent ID: 7342679

Claim:
An image evaluation method implemented in an image evaluation apparatus, comprising: evaluating a dot of an image that is reproduced on a support medium by an imaging apparatus and formed by a plurality of dots having a predetermined dimension arranged in a main scanning direction and a sub scanning direction, said image evaluation apparatus producing image signals at a resolution at least twice as high as a dot resolution of the image; measuring a dot position of each dot in the image; obtaining image signals of a portion of the image reproduced by the imaging apparatus, said portion of the image containing a dot line of at least three dots arranged in the main scanning direction; setting a dot detection start position within the portion of the image, detecting an image signal value of said dot detection start position, and accumulating the detected image signal value of the dot detection start position; successively determining a next dot detection position within the portion of the image based on the dot detection start position and the predetermined pitch in the main scanning direction, detecting the image signal value of the next dot detection position, and accumulating the detected image signal value of the next dot detection position; calculating an accumulation value of the detected image signal values of the dot detection start position and the next dot detection position; successively shifting the dot detection start position within the portion of the image and repeating the steps of detecting and accumulating the image signal value of the dot detection start position, determining the next dot detection position, detecting and accumulating the image signal value of the next dot detection position, and calculating the accumulation value to obtain a plurality of accumulation values; comparing the plurality of accumulation values and detecting a minimum accumulation value; and determining the dot positions of the dot line contained in the portion of the image based on the dot detection positions of which the accumulation value corresponds to the minimum accumulation value.