Patent ID: 6069981
Filing Date: 2000-05-30
Classification: H04N

Abstract:
A method of converting a negative image recorded on a negative image-recording medium into a positive image using a predetermined image-conversion rule said method comprising the steps of:(a) determining a gray condition defining achromatic colors on said negative image-recording medium;(b) determining a first combination of color components in a brightest region on said negative image;(c) determining whether or not said first combination of color components satisfies said gray condition;(d) determining said image-conversion rule using said first combination of color components if said first combination of color components satisfies said gray condition;(e) determining said image-conversion rule using an alternative combination of color components if said first combination of color components does not satisfy said gray condition; and(f) converting said negative image into a positive image using said image conversion rule;wherein the step (a) comprises the step of:(a-1) determining a gray reference line in a color coordinate space representing said gray condition; andthe step (c) comprises the step of:(c-1) determining whether or not said first combination of color components is in a neighborhood of said gray reference line;wherein the step (c-1) comprises the step of:extracting a first color component from said first combination of color components to obtain a first value;extracting other color components from said first combination of color components;applying said other color components to gray reference line to obtain other values;determining a maximum value and a minimum value among said first value and said other values;calculating a value reflecting a difference between said maximum value and said minimum value; andcomparing said value with a predetermined threshold value.