hough_lines ( RegionIn : : AngleResolution, Threshold, AngleGap, DistGap : Angle, Dist )

Detects lines in edge images with the help of the Hough transform and returns it in HNF

The operator hough_lines allows the selection of linelike structures in a region, whereby it is not necessary that the individual points of a line are connected. This process is based on the Hough transform. The lines are returned in HNF, that is by the direction and length of their normal vector.

The parameter AngleResolution defines the degree of exactness concerning the determination of the angles. It amounts to 1 / AngleResolution degree. The parameter Threshold determines by how many points of the original region a line's hypothesis has to be supported at least in order to be taken over into the output. The parameters AngleGap and DistGap define a neighborhood of the points in the Hough image for in order to determine the local maximums. The lines are returned in HNF.


Parameters

RegionIn (input_object)
region -> object
Binary edge image in which the lines are to be detected.

AngleResolution (input_control)
integer -> integer
Adjusting the resolution in the angle area.
Default value: 4
List of values: 1, 2, 4, 8

Threshold (input_control)
integer -> integer
Threshold value in the Hough image
Default value: 100
Range of values: 1 <= Threshold

AngleGap (input_control)
integer -> integer
Minimal distance of two maximums in the Hough image (direction: angle)
Default value: 5
Range of values: 0 <= AngleGap

DistGap (input_control)
integer -> integer
Minimal distance of two maximums in the Hough image (direction: distance)
Default value: 5
Range of values: 0 <= DistGap

Angle (output_control)
hesseline.angle.deg-array -> real
Angles (in degrees) of the detected lines' normal vectors
Range of values: -90.0 <= Angle <= 180.0

Dist (output_control)
hesseline.distance-array -> real
Distance of the detected lines from the origin
Range of values: -90.0 <= Dist <= 180.0
Number of elements: Dist == Angle


Possible Predecessors

threshold__, skeleton


Possible Successors

matching_lines


See also

hough_line_trans, store_hesse_lines, hough_circles



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