摘要 |
A calibration pattern is provided with a central portion and a frame pattern provided outside thereof, the central portion being provided with a rectangular light area in the central portion of the calibration pattern. The frame pattern has a horizontal pattern and a vertical pattern, the horizontal pattern extending to two horizontal sides centering the central portion and alternately provided with a light area and a dark area at a predetermined interval different from an equal interval, the vertical pattern extending to two vertical sides centering the central portion and alternately provided with a light area and a dark area at a predetermined interval different from an equal interval. The horizontal pattern and the vertical pattern include edges, each being positioned equally distant from a predetermined position in the central portion to the two sides, and the edges have an identical change direction of a gray value. |