Abstract
We propose a simple correction method for perspective distortion by using the descriptive plane geometry. In this
proposed method, the inverted tracing for geometry of perspective projection is used to estimate an original aspect ratio of
target object. Four sides of rectangle in the object are calculated by line segment detector from the image captured on a slant,
and the varnishing point is estimated from the intersected point of four sides. The constraint of right angle in target object and
identified varnishing point provides us the original four corner points. By solving simultaneous equations, we can acquire the
projective transform matrix for the correction of perspective distortion. Our proposed method is based on the hypothesis that
target object has the rectangle shape on the plane, and center of target object fits the center of perspective transformation.
