select_matching

select_matching_lines ( RegionIn : RegionLines : AngleIn, DistIn, LineWidth, Thresh : AngleOut, DistOut )

Select those lines from a set of lines (in HNF) which fit best into a region.

Lines which fit best into a region can be selected from a set of lines which are available in HNF with the help of the operator select_matching_lines; the region itself is also transmitted as a parameter (RegionIn). The width of the lines can be indicated by the parameter LineWidth. The selected lines will be returned in HNF and as regions (RegionLines).

The lines are selected iteratively in a loop: At first, the line showing the greatest overlap with the input region is selected from the set of input lines. This line will then be taken over into the output set whereby all points belonging to that line will not be considered in the further steps determining overlaps. The loop will be left when the maximum overlap value of the region and the lines falls below a certain threshold value (Thresh). The selected lines will be returned as regions as well as in HNF.

Parameters

`RegionIn` (input_object)	region `->` object
Region in which the lines are to be matched.

`RegionLines` (output_object)	region(-array) `->` object
Region array containing the matched lines.

`AngleIn` (input_control)	hesseline.angle.rad(-array) `->` real
Angles (in radians) of the normal vectors of the input lines.
Typical range of values: `-1.5707963 <= AngleIn <= 3.1415927`

`DistIn` (input_control)	hesseline.distance(-array) `->` real
Distances of the input lines form the origin.
Number of elements: DistIn == AngleIn

`LineWidth` (input_control)	integer `->` integer
Widths of the lines.
Default value: 7
Typical range of values: `1 <= LineWidth`

`Thresh` (input_control)	integer `->` integer
Threshold value for the number of line points in the region.
Default value: 100
Typical range of values: `1 <= Thresh`

`AngleOut` (output_control)	hesseline.angle.rad(-array) `->` real
Angles (in radians) of the normal vectors of the selected lines.
Typical range of values: `-1.5707963 <= AngleOut <= 3.1415927`
Number of elements: AngleOut <= AngleIn

`DistOut` (output_control)	hesseline.distance(-array) `->` real
Distances of the selected lines from the origin.
Typical range of values: `0 <= DistOut`
Number of elements: DistOut == AngleOut

Result

The operator select_matching_lines returns the value 2 (H_MSG_TRUE) if the input is not empty. The behavior in case of empty input (no input regions available) is set via the operator set_system('no_object_result',<Result>), the behavior in case of empty region is set via set_system('empty_region_result',<Result>). If necessary an exception handling is raised.

Parallelization Information

select_matching_lines is reentrant and processed without parallelization.

Possible Predecessors

hough_lines

Module

Foundation