Patent ID: 8340433

Claim:
An image processing apparatus, comprising: a storage unit storing an image of a processing target; a tangent calculating unit extracting contours represented as sets of contour points from an image read from the storage unit and computing tangents with respect to the extracted contours; a projecting unit projecting tangents computed by the tangent calculating unit to axes in the direction orthogonal to the corresponding tangent, and computing coordinates of intersections where the tangents and the corresponding axes intersect; and a rectangle calculating unit selecting intersections with maximum values and minimum values of coordinates among intersections computed by the projecting unit for each direction of the axis, and computing a rectangle formed by a pair of parallel tangents passing through two intersections with maximum values and minimum values selected for a first axis and another pair of tangents passing through two intersections with maximum values and minimum values selected for a second axis orthogonal to the first axis.