Preferences of Traffic Signs Detection

This page describes only the parameters and preferences of Automated Traffic Signs Detection.
Full documentation about concept, workflow and sidebar, see Automated Feature Extraction. General concepts of Detectors Preferences, see Preferences of Detectors.

Scanning grid cell size, Min pts sign, Height min and Ground margin
Scan the point cloud and exclude “signs-free” cells by checking Z-range inside the cell and number of points.

Adapt Reflectivity Threshold
The minimum reflection allowed for a traffic sign will depend on the surroundings. in case if Adapt Reflectivity Threshold is disabled

Min reflectivity value
Minimum intensity of the point which might belong to a traffic sign.

Null reflectivity value
Lower intensities will be ignored. The reflectivity threshold is based on minimum and maximum reflectivity within the cell, 'Null reflectivity value' is used if minimum intensity in the cell is lower than this value so it prevents too low values to affect the threshold.

N pts get max reflect
N most reflective points are taken to calculate maximum intensity of a grid cell, this reduces high intensity outliers affect on the reflectivity threshold.

Proximity distance
Defines the area in which points will be checked around originally detected candidate sign position to identify if it's a sign or some other high reflectivity object.

Min pts cluster
Minimum amount of points in the cluster to be considered in further processing.

Min pts sign
Minimum amount of points candidate traffic sign should consist of.

Ground margin
If the terrain is not exactly flat next to the traffic sign (high grass or other noise next to pole) the ground margin defines “thickness of the ground” (allowed from the lowest point of the point cloud defining ground level to the lowest point of the sign).

Scanning offset
'Scanning offset' together with 'Ground margin' defines Z limits of a possible traffic sign.

Horizontal slice Z size and Thickness max
Average thickness of horizontal slices of a traffic sign should be not bigger than Thickness max (thickness of the traffic sign plate).

Height min and Width min
Minimum size of the found traffic signs.

Neighborhood
Distance around the candidate sign considered as vicinity, points found in vicinity of the sign and in the same plane with the sign will be added to it.

Inclination max
Maximum inclination traffic sign is allowed to have (calculated from perfectly vertical).