In a 3D robotic vision workflow, 3D cameras are often an essential step to facilitate object modeling. They

 can collect shape data and, sometimes depending on the 3D scanner, appearance (e.g., color) data. 3D 

scanning, therefore, enhances the design process, speeds up and reduces errors in data collection, and 

can also save time and money.

3D scanning can be based on different technologies, each with its own advantages and limitations. In this 

article, we explore the two main technologies used for 3D robotic vision cameras, laser triangulation and 

structured light cameras. So, how do laser cameras compare to structured light cameras? And most import

antly, which one should you choose for your project?

Laser cameras: technology, advantages and limitations

Laser cameras are based on triangulation and can capture 3D shapes with great accuracy (millions of 

points). More precisely, they work by projecting a laser dot or line onto an object and capturing its 

reflection with a sensor. Since the sensor is located at a known distance from the laser source, precise 

point measurements can be made by calculating the reflection angle of the laser. With the knowledge of 

the scanner-to-object distance, the scanning hardware can map the surface of the object and thus record

 a 3D scan.

This method is called triangulation, because the laser dot (or line), sensor and laser emitter form a triangle,

 as shown in the figure below. There are many different types of laser scanners on the market, and you 

can choose between handheld, desktop or professional/industrial devices. The key is that they can work 

at short distances. Lasers also have the strong advantage of directing strong light in a narrow range of 

wavelengths, so they work well and stably in almost any environment.

The strength of laser triangulation technology lies in its resolution and accuracy. When it comes to 

accuracy, it is on the order of tens of microns. However, you should be aware that the properties of the 

surface to be scanned can affect the scanning process. Therefore, very glossy or transparent surfaces 

may be problematic for this technology.

Structured light cameras: technology, advantages and limitations

Today, many handheld 3D scanners for 3D cameras use structured light technology. This technology also uses triangulation, but works by projecting a pattern of light onto the object to be scanned instead of a laser line (or point). The dynamic structured light 3D camera developed by Xiaoyou Intelligent projects a pattern onto the object, and one or more sensors (or cameras) are slightly offset from the projector. They observe the shape of the light pattern and calculate the distance of each point in the field of view. The light pattern is usually composed of a series of stripes.

The benefit of structured light technology is that it scans quickly. It can be done in about 0.2 seconds, and

 the scan area is also large. Just like laser scanners, structured light scanners are also very accurate and 

have high resolution.

One of the disadvantages of structured light cameras is that they are sensitive to the lighting conditions 

in a given environment.