9.3.4. Operational Workflow

1. Setup and Calibration: Install and level the scanner on site.

The first step in the operational workflow of Terrestrial Laser Scanning (TLS) is to set up the laser scanner at the site where data collection will occur. This involves finding a suitable and stable location for the scanner, ensuring that it is correctly leveled, and that it has a clear line of sight to the areas you want to scan. Proper setup is crucial as it affects the accuracy and quality of the scans that will be collected.

Think of setting up a camera on a tripod for a photograph. Just like you want the camera to be stable and correctly pointed to capture the best image, the laser scanner needs to be stable and well-positioned to collect accurate data.

2. Scan Planning: Determine locations and settings for optimal coverage.

After the scanner is set up, the next step is scan planning. This involves deciding where the scans will take place and what settings to use for the scanner (like the resolution and range of the scans). Effective planning ensures that all necessary areas are covered without missing critical details. This step may also require examining the site to identify potential obstacles like buildings or trees that might block the scanner's line of sight.

Imagine you're laying out a treasure map; you need to consider where the important landmarks are and how to best navigate to get all clues. Similarly, in scan planning, you plot out your scanning positions and ensure the whole area of interest is included.

3. Data Collection: Perform multiple scans to cover occlusions and blind spots.

During data collection, the laser scanner takes multiple scans from its setup location, capturing three-dimensional data of the objects in view. This is necessary because some areas might be obstructed from one angle (these are known as occlusions), so by scanning from different positions or angles, the scanner can gather data that covers these blind spots. For complex structures, several scans may be needed to create a comprehensive dataset.

It’s like taking a series of photographs of a complex sculpture from different angles. If you only take a picture from one side, you might miss details on the back or underneath. Multiple scans ensure that all parts of the object are documented.

4. Registration: Align and merge multiple scans using reference points or cloud-matching.

Once multiple scans are completed, the next step is to register or align them into a single cohesive point cloud. This is done by identifying common reference points between the scans or using a method called cloud-matching, which aligns overlapping areas from different scans to seamlessly integrate them into a unified model. Registration is key for ensuring that all data accurately reflects the same spatial location.

Imagine running a puzzle where you have pieces from different sets. Registration is like matching the edge pieces that fit together to create the complete image. It ensures that each scan aligns correctly to form the whole picture.

5. Post-Processing: Generate 3D models, CAD drawings, or other outputs.

The final step in the operational workflow is post-processing. Here, the registered scans are processed further to create 3D models, CAD drawings, or other outputs that present the collected data in a usable format. This might also involve additional steps like cleaning the data to remove any noise or artifacts and converting it into formats suitable for analysis or presentation.

Consider this step like editing a film after it's been shot; the raw footage is arranged, cut, and enhanced to create a polished final product. Similarly, post-processing takes the raw scan data and transforms it into a clear and usable model.

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