Photograph image-processing method and device thereof

A photograph image-processing method, comprising the steps of:

• entering a film image by reading a film image by an image pickup device, generating a plurality of pieces of color image data and storing the generated color image data in a memory;
• generating concentration histograms for each of RGB color components from all of the color image data of one roll of a film which are stored in the memory;
• relative-stretch-processing that relatively stretch-process the concentration histograms in a concentration axial direction;
• calculating and deriving a relative stretch ratio which maximizes a superimposed area of each RGB concentration histogram which has undergone relative-stretch processing;
• calculating and deriving an evaluation value of reliability with respect to the relative stretch ratio;
• calculating and deriving a correction stretch ratio based on the evaluation value;
• and
• adjusting a photochromic filter included in an analog exposure unit for projecting and exposing a film fixed to a negative mask onto photographic printing paper based on the correction stretch ratio and exposing the film to the photographic printing paper to output a photo-print.

A photograph image-processing device, comprising:

• a film image entering unit that reads a film image by an image pickup device, generates a plurality of pieces of color image data and stores the generated color image data in a memory;
• a concentration histogram generating unit for generating each of RGB color components from all of the color image data of one roll of a film which are stored in the memory;
• a relative-stretch-processing unit that relatively stretch-processes the concentration histograms in a concentration axial direction;
• a relative stretch ratio calculating unit that calculates and derives a relative stretch ratio which maximizes a superimposed area of each RGB concentration histogram which has undergone relative-stretch processing;
• an evaluation value calculating unit that calculates and derives an evaluation value of reliability with respect to the relative stretch ratio;
• a correction stretch ratio calculating unit that calculates and derives a correction stretch ratio on the basis of the evaluation value;
• a color data conversion-processing unit which conversion-processes respective RGB components of each pixel of the color image data in accordance with the correction stretch ratio;
• and
• an output unit that exposes photographic printing paper with an exposure head in accordance with the color image data of which the RGB components of each pixel are conversion-processed to output a photo-print.

A photograph image-processing device, comprising:

• a film image entering unit that reads a film image by an image pickup device, generates a plurality of pieces of color image data and stores the generated color image data in a memory;
• a concentration histogram generating unit for generating each of RGB color components from all of the color image data of one roll of a film which are stored in the memory;
• a relative-stretch-processing unit that relatively stretch-processes the concentration histograms in a concentration axial direction;
• a relative stretch ratio calculating unit that calculates and derives a relative stretch ratio which maximizes a superimposed area of each RGB concentration histogram which has undergone relative-stretch processing;
• an evaluation value calculating unit that calculates and derives an evaluation value of reliability with respect to the relative stretch ratio;
• a correction stretch ratio calculating unit that calculates and derives a correction stretch ratio on the basis of the evaluation value;
• and
• an output unit that adjusts a photochromic filter included in an analog exposure unit for projecting and exposing a film fixed to a negative mask onto photographic printing paper on the basis of the correction stretch ratio and exposes the film to the photographic printing paper to output a photo-print.