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Photogrammetry vs. 3D Scanning
Digital 3D models are used for many different purposes in a variety of industries, and there are multiple methods of making them from a real object. The two primary methods for digital 3D modeling are 3D scanning and photogrammetry. In this article, we’ll discuss the process, advantages, and disadvantages of each technology as well as some common applications for this type of digital 3D modeling.
3D scanning encompasses a variety of technologies. For sake of comparison, we have chosen to focus on the two varieties of 3D scanning that are most common and most resemble the abilities of photogrammetry: laser 3D scanning and structured light 3D scanning.
Laser 3D Scanning
Laser 3D scanning is a technology that uses a laser to take measurements of an object’s geometry and create a digital 3D model from this acquired data. This is done by running a laser point or line along every surface of the part to capture measurements from multiple viewpoints, which translates to thousands of data points in a specialized computer software.
There are two types of laser 3D scanners, and they differ from each other in how they calculate a part’s measurements. The calculations can be done via two different methods: triangulation and time-of-flight.
Triangulation works by using simple trigonometry. The laser on the scanner is paired with a camera, making them two vertices of a triangle. The third vertice, which completes the triangle, is the point on the object that is being scanned. Because the distance between the laser emitter and camera is known, as well as their angle relative to each other, the distance to the point of contact on the object being scanned can then be calculated and recorded.
As for a time-of-flight laser 3D scanner, a pulse of laser light is emitted at the object being scanned. Once the light makes contact with the object and returns to the sensor on the scanner, the scanner will calculate the location of the point based on how long it took the light to travel from the laser emitter to the object and back. This can be done because the s