When looking to purchase a 3D scanner, many consumers struggle to make sense of the product they’re looking to buy. The various types of scanners available to consumers, such as 3D laser scanners and structured light 3D scanners, consists of different 3D scanning technologies. It is important that buyers are knowledgeable of these different products in order to determine which type of scanner will best satisfy their needs. This guide is intended to help bring clarity to the various types of 3D scanning technologies and also assist in finding the best suited 3D scanner for you.

3D Scanner Technologies

•Photogrammetry

Stemming from photography, photogrammetry is an incredibly useful technology in various fields. The technology takes multiple images, taken at different positions, and triangulates points in these images to figure out the location of them in a three-dimensional space. For example, land surveyors utilize this technology when making maps. When dealing with inaccessible places, such as mountains, the surveyors are able to use photogrammetry to perform their measurements. Many modern technologies use photogrammetry, the major determiner in precision relies on the caliber of the images. If images are poor, there will be holes in the mesh. The more images that you can produce, the greater the accuracy of your scan will be.

•Structured Light

The technology here is created by casting geometric patterns onto an object while simultaneously taking images with a camera. When doing so, the camera logs the deviation of the image. Based on this displacement of the pattern, locations of all existing points are able to be determined. Numerous scans have to be conducted from different positions and then combined until the mesh can be 100% complete. Computer programs automatically combine all of the scans to form this complete mesh. The results formed using structured light 3D scanners are extremely precise, and the technology is available in both portable and stationary scanners.

•Time of Flight (TOF)

Slightly more scientifically oriented are Time of Flight (TOF) 3D scanners. These scanners measure how long it takes for a laser or infrared beam to be reflected back to the scanner, with the main component in the scanner being speed of light. Although the scanners contain highly accurate sensors, the precision of these devices is relatively low, ranging in centimeters. This is primarily a result of how the speed of light is affected by various factors, such as temperature and humidity. Hence the technology is primarily used in measuring large items like buildings. The technology requires multiple scans to be conducted in order to form a complete mesh, just as with other 3D scanning technologies. The majority of devices using Time of Flight can be found in portable scanners.

•Laser Scanning (Triangulation)

Perhaps the most accurate 3D scanning technology is that of laser scanning, also known to as triangulation.  Similar to structured light and photogrammetry scanners, laser scanning uses the same base principle of geometry to find a point’s location in space. By casting a laser beam upon the object being scanned, a camera is able to record where the beam and object intersect. Knowing both the angles of the laser beam and camera makes it possible to know the precise location of the laser dot that is hitting the object. The accuracy of laser scanners is exceptional, ranging in mere micrometers. The only downside to the scanners is the fact that they can only range in just a few meters and the technology is typically not found in portable scanning devices.

•Contact 

With a self-describing name, contact printers physically touch a resting object. The scanning process can be fairly timing, and the process is very sensitive to movements and vibrations during scanning. Contact scanners are primarily used in quality control due to the potential alterations that they cause to objects being scanned.  The technology is not used in conservation of objects as a result of this.

Choosing the Appropriate Scanner

This is the first determining question that needs to be asked when trying to choose the correct 3D scanner for a job. The field of application you are using the 3D scanning technology is extremely important. If you need a mesh that will be high in resolution, and also provide the substance of the material. you would probably choose a 3D scanner that uses photogrammetry technology. Whereas if you wanted to primarily get accurate measurements of an object, a structured-light 3D scanner would be the best option. Apart from what kind of scans you’re looking for, you must simultaneously decide where you will be scanning the devices in order to determine whether you’ll need to purchase a stationary 3D scanner or a portable one.

The second determining question in the selection process is what type of object is being scanned? Each type of 3D scanning technology is specific, not one technology covers every area of application.

• Photogrammetry: useful for scanning people, animals, etc.
• Structured Light: provides extremely precise measurements for small objects and those of delicacy.
• Time of Flight: effective in taking images of objects in real time, making the ability to track movements easy.
• Laser: extremely useful in scanning large objects, such as cars and buildings.
• Contact: primarily useful in quality control, can potentially deform or destroy original object.

As you can see from the previously discussed types of technologies that are listed above, the type of object is a huge component in determining what type of 3D scanner best suits your need.

Dimensions are the next determinant that needs to be addressed in selecting the appropriate 3D scanner.  3D laser scanners are primarily useful in scanning large objects. Photogrammetry may be a more cost-efficient scan for larger objects, depending on what needs and goals you have for the data produced. Opposite to this, structured light scanners are highly effective at scanning small items, such as a drinking glass. If object preservation is not a factor, and the item is not of great size, you could use a contact scanner.

The external surface of an object is a major factor is choosing the best 3D scanner for a job as well. The material can potentially cause major problems if the appropriate scanner is not used. For example, reflective surfaces can cause deformity in the data mesh of both photogrammetry and structured light technologies. This surface of an object can effect the end result of even the best 3D scanners. A solution to problems with surface material can be to apply an opaque layer to the object when scanning, if you are biased to one type of scanning technology.

Depending on what your use for a 3D scan is, the resolution may be one of the most pivotal attributes needed from the scan. If you are in need of a highly accurate scan, you’ll more than likely be spending a significant amount more of the 3D scanner. This takes us back to the question of, what are you using the scans for? Once you are able to answer this, how much resolution you need to complete the job should be more easily determined.

3D Scanners

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Original Source: https://all3dp.com/best-3d-scanner-guide-laser-diy-handheld-software-price/