Abstract
It is a fundamental and important problem to detect Weak Perspective Projection invariant shapes from an image. Although there was the conventional method of using the tangent information on a figure outline, since the straight line figure was undetectable, we proposed the method of extracting an eternal axis for weak perspective projection conversion using the figure center of gravity. This method is applicable not only to curvilinear form but straight line form and the form containing both straight line and curve. However, For the method based on the result of center of gravity calculation, if a deficit occurs in the figure, the center of gravity will move and detection will become difficult. This paper proposes a new method without center of gravity calculation and it can detect a deficit figure.
