| 摘要 |
PURPOSE:To improve detecting accuracy and a detecting speed by using conditions such as a contrast existing between two straight lines when the straight line at an arbitrary tilt existing in an image is detected with the use of Hough transformation means. CONSTITUTION:For the inputted image, a concentration grade vector in each part in the image is calculated by a concentration grade detecting mechanism 1. As this result, a Hough transformation mechanism 2, which is inputted by a generated differential image 5 and takes an edge direction into consideration, converts the coordinates from an (x, y) plane to a (theta, rho) plane. One-dimensional data to accumulate the two-dimensional data of the (theta, rho) plane in a rho direction are obtained by plural straight line simultaneous searching mechanisms 3, and by using a constraint such as the contrast concerning the straight line pair out of them, the pair of the maximum theta is retrieved. Further, for the detected maximum pair, next, the maximum rho is obtained, and then, the maximum coordinates (theta, rho) are obtained. From this, by using a reverse converting mechanism 4, the equation of the straight line to be a target is obtained and the straight line is detected. |
