Boundary line detecting method

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, given that a derivated value of luminance in each of adjacent unit blocks in an area including the boundary line is ai (i is a positive integer) and position coordinates of each unit block are Xi (or Yi), an X coordinate position (or Y coordinate position) of the boundary line is specified in accordance with Σ(ai×Xi)/Σai [or Σ(ai×Yi)/Σai].

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 if the boundary line is arcuate or curved and if a derivated value of luminance in each of adjacent blocks in an area including the boundary line is assumed to be ai (i is a positive integer) and the position of each unit block on X coordinates is Xi and that of each unit block on Y coordinates is Yi, a peak position of the derivated luminance value in one unit block is specified in accordance with Σ(ai×Xi)/Σai and Σ(ai×Yi)/Σai, and the boundary line is predicted by connecting said peak positions in the unit blocks.

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,
• wherein if the boundary line is arcuate or curved and if a derivated value of luminance in each of adjacent blocks in an area including the boundary line is assumed to be ai (i is a positive integer) and the position of each unit block on X coordinates is Xi and that of each unit block on Y coordinates is Yi, a peak position of the derivated luminance value in one unit block is specified in accordance with Σ(ai×Xi)/Σai and Σ(ai×Yi)/Σai, and the boundary line is predicted by connecting said peak positions in the unit blocks, and
• wherein if the boundary line is arcuate, the circular arc is specified by connecting arc passing points in the unit blocks, and a central position of a circle is predicted on the basis of the circular arc.