Patent ID: 6647148
Filing Date: 2003-11-11
Classification: G11B,Y10T

Abstract:
A boundary line detecting method for detecting a boundary line between areas different in light reflectance by using a camera with a multitude of photodetectors arranged therein, said boundary line detecting method comprising the steps of:subjecting an image obtained by the camera to image processing on the basis of light intensities detected by said photodetectors; comparing luminances of plural unit blocks arranged in a predetermined direction, the luminances of said plural unit blocks corresponding respectively to the light intensities detected by said photodetectors; and specifying an actual position of the boundary line located in one unit block, wherein the actual position of the boundary line is located with a precision that is greater than a width of one unit block, wherein variations in luminance between unit blocks arranged in the predetermined direction are derivated, and a derivated value of luminance in the unit block of highest luminance and other derivated values of luminance in plural unit blocks adjacent thereto are compared to specify an actual position of the boundary line in one unit block, and wherein, in the case where said boundary line is a straight line, derivated values of luminance in a row of unit blocks arranged in parallel with an extending direction of the boundary line are added or a mean value thereof is calculated, the addition or calculation of a mean value is performed in plural rows of unit blocks, then the added values or mean values are compared between the rows to predict a peak position of the added values or the mean values in a direction intersecting the boundary line, and the position of the boundary line is specified on the basis of said peak position.