Correct resolution for laser scanning

Which resolution is best for working with my laser scanner?

There is a simple rule: Don't let the scanner work at its highest resolution but only with as much resolution as necessary. Scanner resolution depends on the scanned object, project requirements (requirements of accuracy, time available for laser scanning) and the distance between laser scanner and object.

Basics – How does the laser scanner work?

The scanner sends a laser signal towards the object which reflects the beam. The object is scanned step by step and automatically by the laser scanner. A measuring grid results fromt the scan. It is determined by the distance between scanner and scanned object and the angle step size (horizontal and vertical). If the resolution is decreased, the distance between the scanner's measuring points increases. That distance also increases if object distance is increased while the resolution remains unchanged.

 

The following sketches illustrate how the measuring grid (the distance between the measuring points) depends on the distance between scanner and scanned object. The larger the distance between laser scanner and object, the larger the distance between the measuring points.

Laser scanner resolution 1/32Laser scanner resolution 1/32      Laser scanner resolution 1/8Laser scanner resolution 1/8

Resolution influence on the scan performance with the example of laser scanner FARO Focus3D

With the following chart, we show how the choice of scan resolution influences the scan time, the point quantity and the point distance. The chart shows that choosing the optimal resolution is crucial for your project. Otherwise, you risk achieving unnecessarily high resolutions with extremely long scan times.

Example scanner resolution FARO Focus3D

Overview of different scan resolutions

The following sections of a laser scanner point cloud deliver an impression of the scan results with different resolutions.

Scan with 1/20 resolution and 4x quality at 7m distanceScan with 1/20 resolution and 4x quality<br/> at 7m distance      Scan with 1/10 resolution and 4x quality at 7m distanceScan with 1/10 resolution and 4x quality<br/> at 7m distance

Scan with 1/5 resolution and 4x quality at 7m distanceScan with 1/5 resolution and 4x quality<br/> at 7m distance      Scan with 1/2 resolution and 4x quality at 7m distanceScan with 1/2 resolution and 4x quality<br/> at 7m distance

Different factors for scan resolutions

In order to find the correct resolution for your laser scanner, you should factor in the requirements of the scan results. Interior or exterior, the distance between scanner and object and the number of scans for avoiding shadowing effects play a role in choosing resolution. Also, the need for a colour or grey point cloud as well as the type of data processing and software in use should be kept in mind when choosing resolution.

Always keep in mind: The larger the distance between laser scanner and object, the higher the resolution should be chosen.

Do you have more questions? You might benefit from our technical helpdesk or an extensive training for laser scanner handling.