METHOD AND DEVICE FOR REMOVING BACKGROUND OF CHARACTER IN COLOR IMAGE, METHOD FOR ADJUSTING INSTALLATION OF LINE CAMERA, AND CHART FOR ADJUSTING INSTALLATION

摘要

In order to obtain a character image in which the background of a character is removed from a color image including the character, a character background removing method for obtaining a printing evaluation image by removing the back ground pattern of a character from a color image on a printed matter on which the character is printed comprises: a separation step for separating a color input image into a character portion and a background portion; a function calculation step for obtaining a discriminant function for separating the pixels of the character portion and the pixels of the background portion from each other on the basis of pixel values; a background removed image generation step for generating a background removed image in which the background portion is removed from the input image using the discriminant function. Further, a line camera installation adjustment method for adjusting the installation position of a line camera for capturing an image of a large printed matter on an inspection body on the basis of a signal obtained by capturing an image of an installation adjustment chart fixed to said inspection body is performed using an installation adjustment chart in which a plurality of patterns are arranged shifted in a vertical direction, said patterns being each formed by black vertical lines and a white background so that the vertical lines continue in a horizontal direction only within a predetermined rectangular region elongated in the scanning line direction of the line camera.