Image Processing Reference
closer to a straight line. Thus, a center of distortion can be estimated by computing the error
between the straight line and the distortion. To estimate the center of distortion, distances in
the row and column directions are added, and an equation for the straight line that is closest
to the center of distortion and C x , C y is solved. Therefore, the distances to the distortion points
, where there are error points with the straight line
FIGURE 3 Example of the detection window of the distortion center and straight-line com-
Figure 4 shows an example of errors between the distortion and a straight line, which rep-
resents distances d n between the blue-colored straight line and the distortion in the 2D chess-
board patern. The points detected in the igure are used to determine the degree of distortion.
That is, the distances between the crossing points and the straight line are computed in the
vertical and horizontal directions, thereby summing the distances of the inner points ( d 1 +
+ d n ) to calculate the distortion error.
FIGURE 4 Distortion error.