| 摘要 |
PROBLEM TO BE SOLVED: To accurately detect lines indicating a detection object even at a place where the contrasts of hue and brightness are low.SOLUTION: A detection unit 14 detects change points of a pixel having the gradient of brightness in a first direction and a pixel having the gradient of brightness in a second direction opposite to the first direction, in a brightness image obtained from the brightness component of an input image. An extraction unit 16 extracts lines indicating a detection object from the lines connecting the change lines on the basis of at least one of the shape and length of the lines connecting the change points present within a predetermined distance. |
