- /** This class holds one extracted line. The field num contains the number of
- points in the line. The coordinates of the line points are given in the
- arrays row and col. The array angle contains the direction of the normal
- to each line point, as measured from the row-axis. Some people like to
- call the col-axis the x-axis and the row-axis the y-axis, and measure the
- angle from the x-axis. To convert the angle into this convention, subtract
- PI/2 from the angle and normalize it to be in the interval [0,2*PI). The
- array response contains the response of the operator, i.e., the second
- directional derivative in the direction of angle, at each line point. The
- arrays width_l and width_r contain the width information for each line point
- if the algorithm was requested to extract it; otherwise they are NULL. If
- the line position and width correction was applied the contents of width_l
- and width_r will be identical. The arrays asymmetry and contrast contain
- the true asymmetry and contrast of each line point if the algorithm was
- instructed to apply the width and position correction. Otherwise, they are
- set to NULL. If the asymmetry, i.e., the weaker gradient, is on the right
- side of the line, the asymmetry is set to a positive value, while if it is
- on the left side it is set to a negative value. */