Misregister amount detection method and apparatus

Abstract

In a misregister amount detection method, printed register marks of colors are sensed, and the inverted R, G, and B image data of R, G, and B image data respectively containing R, G, and B as red, green, and blue color components of the register marks are extracted. The minimum value of the pixel values of corresponding pixels of the generated inverted R, G, and B image data is extracted and converted into the pixel value of a corresponding pixel of K image data containing K as a black color component. Differential R, G, and B image data are obtained by subtracting the pixel value of each pixel of the K image data from the pixel values of corresponding pixels of the inverted R, G, and B image data. Enhanced R, G, and B image data are obtained by adding the pixel values of pixels of the differential R, G, and B image data or values corresponding to the pixel values to the pixel values of corresponding pixels of the inverted R, G, and B image data. The misregister amount between the colors is obtained on the basis of the pixel values of pixels of the enhanced R, G, and B image data. A misregister amount detection apparatus is also disclosed.