Structured light 3D scanning is a non-contact, optical scanning technology that utilizes light patterns to take measurements of a part and produce a 3D scan. The resulting scans can be used for quality assurance, quality control, and reverse engineering. White light and blue light are the two types of structured light scanners available, but they are often confused as their properties are lumped together under the umbrella term of “structured light scanning”. In this article, we’ll discuss how structured light scanning works, the differences between white light and blue light scanning, and when structured light scanning will work best for you.
How Structured Light Scanning Works
Before we get into the differences between white and blue light scanning, it is perhaps best to discuss how the technology of structured light 3D scanning works. Both white and blue light scanning use the same technology and process described below.
A structured light scanner is made up of a projector and two cameras. To produce a scan, different patterns of light are projected onto an object and the scanner records where and how the light patterns are distorted by the object. Through simple trigonometry, the distance and location of thousands of data points where the light pattern hits the object are calculated. The location of these points on the object’s surface are triangulated, using the projector and cameras as reference points. The end result is a point cloud representing the geometry of your part.
Once one shot of the part is completed, the part is rotated or the projector is moved to capture a different angle of the part. More shots are taken in this fashion, and the process is repeated until a whole 360° rotation has been completed. Your 3D scan can then be cleaned up and prepared for use.
The Transition From White to Blue Light
White light and blue light scanners are closely related to each other. White light 3D scanning is the predecessor to blue light 3D scanning, which was created to be an improvement upon the original structured light scanning technology. Blue light scanning produces higher resolution and more accurate scans than white light scanning. This fact is causing white light scanners to be phased out in many companies and service providers in favor of blue light scanners.
Since white light scanning utilizes the entire visible spectrum, it is made of all the different wavelengths of visible light. As such, the scanner’s white light is easier to distort and scatter, resulting in a less accurate 3D scan. On the other hand, a blue light scanner only works with one color of light, which possesses a short wavelength. With blue light rays being shorter, they are not as prone to reflection, giving you a more accurate scan.
Aside from wavelength, the difference in the light sources for structured light scanners have other effects. While both blue and white light scanners must warm up before use to ensure they are operating at their calibrated temperature, white light is much warmer than blue light. Blue light scanners operate using LEDs, which make the light source longer-lasting and cooler than the output of white light scanners. This prevents heat from affecting the scan measurements.
Additionally, when using any type of light scanner, ambient light can pose problems. White light does not perform well in bright rooms because its light source and those typically found in office buildings will overlap and blend together. This often creates noise on the scan, resulting in loss of accuracy. This can make using a white light scanner impractical and inconvenient if you cannot control the lighting of the room to cater to the scanner. Blue light, however, is not as readily affected by this same ambient light. It is easier for the scanner to filter out the external light source since it is concentrated on reading blue light only. For further reading on blue light rays and the use of blue light scanners in the dental industry, click here.
When to Use Structured Light Scanning
Besides their differing levels of accuracy, both white and blue light scanners generally have the same pros, cons, and applications.
Because structured light scanning is non-contact, delicate parts can be scanned without risk of damaging fine features. Additionally, structured light scanners are typically mounted on tripods, making the scanners portable so that you can scan parts that are immobile.
While structured light scanning is one of the most accurate 3D scanning technologies, it is important to note that it does not work well with shiny, reflective, transparent, or black surfaces. This is because the light will be scattered or absorbed and alter the calculations for the scan. In order to successfully scan these types of surfaces with this technology, the part must be painted prior to scanning.
Ultimately, whether you should use white light versus blue light scanning, or structured light scanning at all, is a matter of your scan’s intended use.
3D Scanning at 3 Space
Here at 3 Space, we offer both white light and blue light 3D scanning. Our technicians have years of experience working with both technologies as well as others, which you can find a comparison of here. If you’re unsure which scanning technology will best suit your needs, our staff can make suggestions based on your intended use for the scan. Contact us for more information.