Establish connections between the grid points of the rectification grid.
connect_grid_points searches for connecting lines between the grid points (Row,Col) of the rectification grid. The connecting lines are extracted from the input image Image by a combination of an edge detector, a smoothing filter, and a line detector, each of size sigma. The sigma to be used is determined as follows: When a single value is passed in Sigma, this value is used. When a tuple of three values (sigma_min, sigma_max, sigma_step) is passed, connect_grid_points tests every sigma within a range from sigma_min to sigma_max with a step width of sigma_step and chooses the sigma that causes the greatest number of connecting lines. The same happens when a tuple of only two values sigma_min and sigma_max is passed. However, in this case a fixed step width of 0.05 is used.
Then, the extracted connecting lines are split at the grid points and those line segments are selected that start as well as end at a grid point. Note that edge detectors typically don't work very accurately in the proximity of edge junctions, and thus in general the connecting lines will not hit the grid points. Therefore, actually those connecting lines are split and selected that start at, end at, or pass a grid point at a maximum distance of MaxDist. The connecting lines are modified in order to start and end exactly in the corresponding grid points, and are returned in ConnectingLines as XLD contours.
Additionally, connect_grid_points calculates for each output XLD contour its type of transition and stores it in its global attribute 'bright_dark'. The attribute is set to 1.0, if the connecting line forms a bright-dark transition (left to right, viewed from start point to end point), otherwise it is set to 0.0.
|
Image (input_object) |
singlechannelimage -> object : byte / uint2 |
| Input image. | |
|
ConnectingLines (output_object) |
xld-array -> object |
| Output contours. | |
|
Row (input_control) |
point.y-array -> real |
| Row coordinates of the grid points. | |
|
Col (input_control) |
point.x-array -> real |
| Column coordinates of the grid points. | |
| Restriction: number(Col) == number(Row) | |
|
Sigma (input_control) |
number(-array) -> integer / real |
| Size of the applied Gaussians. | |
| Default value: 0.9 | |
| Suggested values: 0.7, 0.9, 1.1, 1.3, 1.5 | |
| Number of elements: (1 <= Sigma) && (Sigma <= 3) | |
| Restriction: 0.7 <= Sigma | |
|
MaxDist (input_control) |
number -> real / integer |
| Maximum distance of the connecting lines from the grid points. | |
| Default value: 5.5 | |
| Suggested values: 1.5, 3.5, 5.5, 7.5, 9.5 | |
| Restriction: 0.0 <= MaxDist | |
connect_grid_points returns 2 (H_MSG_TRUE) if all parameter values are correct. If necessary, an exception handling is raised.
connect_grid_points is processed completely exclusively without parallelization.
Calibration
