Patent ID: 7593568

Claim:
A method of detecting a base concentration of a film comprising: a film image entering process of reading a developed film with an image pickup device to generate pixel values in each of RGB color components; a non-exposure region detecting step of detecting an edge of each frame-image on the developed film from the pixel values generated in the film image entering process and specifying as a non-exposure region each line of pixels disposed at an intermediate between any two adjacent frame-image edges from the detected edge data; and a base concentration calculating step of subjecting the pixel values in each non-exposure region specified in the non-exposure region detecting step based on two or more arithmetic operations for calculating two or more base concentration values and judging a highest of the two or more base concentration values as a true base concentration value, a shift processing step of shifting the pixel values of each frame-image on the developed film to modified pixel values based on a base concentration value judged as the true base concentration value in the base concentration calculating step, a displaying step of displaying the frame-image on the developed film of whose pixel values are modified in the shift processing step on a monitor.