LEICA SCANSTATION P40 There are different types of scanners but they all work with the same basic principle. A laser scanner emits a rapidly pulsing or continuous laser beam. As it emits the beam, the scanner automatically rotates around its vertical axis and a rapidly spinning or oscillating mirror also moves the beam up and down.
If some views may be obstructed or if a site is large enough that the scanner can’t reach all of it with one scan, the scanner is moved to different vantage points for more scans. The best vantage points will be based on Logistics and scanner capabilities. Multiple scans can be automatically aligned with each other.
The result is a systematic sweeping of the beam over the area. When the beam hits an object some of its energy bounces back to the scanner. If the returned energy signal is strong enough, a sensor detects it and a timer is used to calculate the distance from the scanner to the object.
In fact, users have several convenient options for post-processing that use handy scan targets or markers placed around the site. Other methods don’t need any targets. Regardless of which method is used it’s important that it be done accurately. To process point clouds into deliverables a dedicated stand-alone software or plugin software can be used to work efficiently with point cloud data.
For each distance measurement, additional critical data is recorded including the corresponding horizontal angle of the rotating laser and the corresponding vertical angle of the moving mirror. The scanner automatically combines these to calculate a 3D (X, Y and Z) coordinate position for each point. The resulting scan is a set of 3d coordinate measurements often called a “point cloud”. Textures can be added to the point cloud using either a camera that’s built into the scanner or using an external camera and automatically merging the photos with scan data. Also, scans can be easily geo-referenced to local coordinate systems like conventional surveys.
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