Evaluation value calculation device and electronic endoscope system

Abstract

An electronic endoscope system includes a plotting unit which plots pixel correspondence points, which correspond to pixels that constitute a color image that has multiple color components, on a first color plane according to color components of the pixel correspondence points, the first color plane intersecting the origin of a predetermined color space; an axis setting unit which sets a predetermined reference axis in the first color plane; a transform unit which defines a second color plane that includes the reference axis, and subjecting the pixel correspondence points on the first color plane to projective transformation onto the second color plane; and an evaluation value calculating unit which calculates a prescribed evaluation value with respect to the color image based on the pixel correspondence points subjected to projective transformation onto the second color plane.

What is claimed is: 
     
         1 . An evaluation value calculation device comprising:
 a plotting unit configured to plot pixel correspondence points, which correspond to pixels that constitute a color image that has a plurality of color components, on a first color plane according to color components of the pixel correspondence points, the first color plane intersecting an origin of a predetermined color space;   an axis setting unit configured to set a predetermined reference axis in the first color plane;   a transform unit configured to define a second color plane that includes the reference axis, and subject the pixel correspondence points on the first color plane to projective transformation onto the second color plane; and   an evaluation value calculating unit configured to calculate a prescribed evaluation value with respect to the color image based on the pixel correspondence points subjected to projective transformation onto the second color plane.   
     
     
         2 . An evaluation value calculation device comprising:
 a plotting unit configured to plot pixel correspondence points, which correspond to pixels that constitute a color image that has R (Red), G (Green), and B (Blue) color components, on a first plane according to color components of the pixel correspondence points, the first plane including a first axis that is an R component axis and a second axis that is a G component axis and is orthogonal to the first axis;   a transform unit configured to define a third axis that passes through an intersection of the first axis and the second axis in the first plane and is not parallel with each of the first axis and the second axis, define a second plane in which the first axis and the third axis are orthogonal, and subject the pixel correspondence points to projective transformation onto the second plane; and   an evaluation value calculating unit configured to calculate a prescribed evaluation value with respect to the color image based on the pixel correspondence points subjected to projective transformation onto the second plane.   
     
     
         3 . The evaluation value calculation device according to  claim 2 , wherein the third axis is an axis having a high correlation with a hue of a mucous membrane in a body cavity. 
     
     
         4 . The evaluation value calculation device according to  claim 3 , wherein:
 for each pixel correspondence point subjected to projective transformation onto the second plane, the evaluation value calculating unit applies a first coefficient that increases in proportion to a value of the pixel correspondence point on the first axis and a second coefficient that decreases the higher a value of the pixel correspondence point on the third axis is, and calculates an evaluation value for the pixel correspondence point based on the first and second coefficients that were applied, and   the evaluation value calculating unit calculates the prescribed evaluation value with respect to the color image based on the evaluation values of the pixel correspondence points that were calculated.   
     
     
         5 . The evaluation value calculation device according to  claim 4 , wherein the evaluation value calculating unit multiples the first coefficient and the second coefficient that were applied to the pixel correspondence point, and calculates the evaluation value for the pixel correspondence point based on a value obtained by the multiplication. 
     
     
         6 . The evaluation value calculation device according to  claim 2 , wherein the prescribed evaluation value is a numerical representation of an abnormal portion in a body cavity. 
     
     
         7 . The evaluation value calculation device according to  claim 2 , wherein the evaluation value calculation device is for incorporation in an electronic endoscope system.