bsol_hough_line_index is a class for indexing 2-d lines and tangent vectors in the space of orientation and distance to the origin.
The line index space is defined as follows:
o / line --> /\ . / |theta <-------------------o--/----------------->
The angle, theta, corresponding to the line tangent direction ranges from 0 to 180 degrees. The perpendicular distance to the origin, r, is defined as:
. / . / Line Line / . / Normal /^ . / r / . x Origin
The lines are stored in a two dimensional array of r_dim_ by th_dim_ bins of vector<vsol_line_2d_sptr>. The theta dimension of the array is typically 180/5, or 36. The r dimension is defined by the diagonal of the bounding box of the space containing the lines. The resolution in r is assumed to be 1. It is necessary to specify the bounding box of the line coordinate space at construction time, so that new lines entered into the index do not exceed array bounds.
Internally, the r space is defined on an origin at the center of the bounding box diagonal. This choice minimizes the error in normal distance due to variations in line orientation.
index = new bsol_hough_line_index(0.0, 0.0, 100.0, 100.0, 180.0, 5.0)
... vcl_vector<vsol_line_2d_sptr> lines; index->lines_in_interval(lines, l, 1.0, 5.0);//dr = 1.0, dtheta = 5.0 //i.e. +- 1.0 and +- 5.0
index->parallel_lines(lines, 45.0, 5.0); //Lines parallel to 45 deg. //+- 5 deg.
Modifications 10-sep-2004 Peter Vanroose Added copy ctor with explicit vbl_ref_count init
Definition in file bsol_hough_line_index.h.
Go to the source code of this file.