Each cloud point returned from an ATS includes color information in Red, Green and Blue. These are used to indicate a quality matrix about the cloud point recorded.
Blue and green together represent the ATS return intensity value. Higher blue and green values mean higher intensity (usually good).
Red represents the broadening value. Higher red value means higher broadening (usually bad), meaning steeper incidence angles or beam splitting and deflection.
Both Intensity and Broadening values are in a range from 0-255. Leica’s recommended filter settings for broadening are as follows:
Off. Don’t reject any red value’s
Low filtering. Reject red values > 170
Med filtering. Reject red values > 42
High filtering. Reject red val > 2
In general terms the broadening value is a measure of the return pulse in comparison to the start pulse. It the intensity and duration of return is compared and the continuity of this return is computed. As an example, the signal broadening from a split surface might look like this, where the full peak is the intensity but the difference in front and back signal define the broadening value:
As shown in the picture below. Removing regions with low intensity and higher red or broadening values can provide a helpful way of re- moving unwanted data.
In order to filter out cloud points of a particular color right-click on the point cloud and select the RGB Filtering option.
For more information on RGB Filtering see: RGB Filtering
Using RGB Filtering with ATS600 in SpatialAnalyzer -