should i use Laser Scanning or photogrammetry for 3d documentation?
When deciding between methods to use for acquiring the 3D data required, it boils down to what is required of the scan. What tolerance of accuracy is needed, budget, visual representation, etc. Both method of documenting a project in 3D has been around for many years.
learn how laser scanning & Photogrammetry work
how laser scanning works
The laser scanner works by sending out millions of pulses and measuring the distance between the target and equipment. Over the years, advancement of technology has made scanning with the laser scanner a lot easier, faster, broader scope of field view, higher points recording/sec and higher accuracy. The newer equipment’s are able to handle the massive data in the form on point clouds. The data quality is mostly based on the equipment used.
how photogrammetry works
“Photogrammetry” – Image sourced from Medium Corporation (medium.com).
On the other hand, photogrammetry works by simply knowing the location and size reference of the target object scanned. 3D images can be produced using triangulation. In order to build a complete 3D object, several photos can be taken with 70 percent and above overlap and merging them together as one. In recent times, many software’s exist which are able to autonomously create the 3D object and calculate the triangulation of the targeted object. The accuracy of the results are wholly based on the software’s sides. Verification and improvement of the object can be done on the software side.
Scanning using the laser scanner can typically be more expensive as it takes a longer time to scan and the equipment itself is fairly expensive. Photogrammetry is fairly affordable for a low budget project as only a decent camera is required to get going. In more recent times, smart phones can be used for taking picture as smart phones has such high definition camera that it does the work fairly well.
So when it comes to deciding between the two, it really comes down to what is expected of the object scanned. If accuracy is needed then laser scanner would be more desirable. IF cost is an issue with the need for high visual representation, than photogrammetry would be the way to go. Sometimes to obtain the desired result, a combination of both method is required.