Technologies for 3D Laser Scanning

Real-world things are increasingly being scanned in 3D to be digitized. These digital objects can subsequently be utilized for various purposes, including incorporating them into video games or virtual reality experiences and recreating them using 3D printers and a variety of other highly complex industrial uses.

In this article, I mainly talk about 3D laser scanning technologies, their significance, and the types of 3D laser scanning.

Know about 3D Scanning

One such technology is 3D laser scanning which captures a physical object’s exact size and shapes as a digital 3-dimensional representation in the computer world. This method collects information such as the 3D object’s complex geometry, intriguing shape, colorized texture, and other features. The user can then edit and 3D print this digital copy or 3D file according to their needs.

3D scanner files are generally compatible with CAD software and 3D printing slicer software. However, certain CAD program tweaks may be required to make the 3D scanner file compliant. A single scan is insufficient to produce an accurate model of the scanned object. Hundreds of scans are usually required to acquire all the data from all sides and perspectives. After that, all these scans must be combined using a common reference system called alignment. Scans are then amalgamated into a final model. Thus, 3D scanning refers to the complete process of combining and merging individual images.

Significance of 3D Scanning

From shoe design to supercar manufacture, 3D scanning has changed many industries. Scanners that use structured light work swiftly and accurately. Here are five reasons you should employ 3D scanning in your manufacturing process.

• 3D scanning is also used to make animated films and special effects. 3D scanning is used in the automotive and aeronautics industries to develop a 3D model from the point cloud. 3D scanning brings the physical and digital worlds closer together and lowers the gap between them.
• Perhaps a product requires the creation of a new portion based on pre-existing elements. The requirement to reverse-engineer a new thing is a fantastic match for the structured light 3D scanner’s capabilities. The scanner can reach every nook and cranny of an old product and offer exact measurements of the space where a new item must fit. When making changes to an existing design, 3D scanners also save time.
• When it’s time to remanufacture a part created before computer-aided design (CAD) software was available, 3D scanners make precise reproductions possible. Simply scan an old part and make a CAD model with reverse engineering software. The scanner can then check for correctness by comparing the freshly produced prototype to the scan of the old part.
• Real estate and tourism are two more intriguing industries where 3D scanning can be used. As part of a virtual tour, buildings can be scanned and exhibited to clients remotely. A tourist attraction can also be scanned and reconstructed in virtual reality.
• Another virtue of structured light 3D scans is comparing a product’s as-designed and as-built models. A key gauge of success is ensuring that the original goal was realized as planned. Comparing designs to made items is more than just quality control; it assures that the created product will fit as intended, such as in an automobile.

Types of 3D Scanning Technologies

3D scanning technologies are categorized into the following groups based on their physical principles:

Laser-based 3D Scanners

There are two basic technologies in 3D laser scanning, namely those that measure the time of flight and those that use triangulation. Many 3D scanners use time-of-flight technology, which involves beaming a laser at an item and measuring the time it takes for the light to bounce and return using a receiver in the scanner. We can use this technique to determine the distance between two points on an item by knowing the laser’s speed and performing easy calculations. We only need to do this a few times to get a three-dimensional map of the distance between the scanner and each point of the object, as well as a 3D scan of the object. Another one is triangulation. Triangulation is a comparable method of scanning a 3D object with a laser. In this scenario, we utilize trigonometry to measure the distance using a laser and a receiver. Laser scanners are extremely popular and come in a variety of styles. Handheld portable trackers, arm-based, CMM-based, long-range, and single-point long-range trackers are some examples that fall in this category.

Photogrammetry

It is the science of extracting measurements from photos, particularly for retracing the precise positions of surface objects. It employs a combination of computer vision and sophisticated computational geometry methods. It analyzes numerous pictures of a static subject taken from various angles and automatically detects pixels that correspond to a single physical point. This method of 3D scanning is revolutionary in that it simply requires photos of an object to convert it into a 3D model from the point cloud. Using camera drones, we can scan huge things such as statues, buildings, or even geographical characteristics such as mountains or rivers, which opens numerous opportunities compared to other systems requiring a 3D scanner. Aerial photogrammetry is the term for this technique, and it is becoming more popular in the industry. The fundamental issue of this 3D scanning technique is to accurately examine tens or hundreds of pictures and thousands of points. A powerful computer is required to perform such photogrammetry algorithms.

Contact-based 3D Scanning

Digitizing is another term for contact-based 3D scanning. This 3D scanning technology entails a contact-based method of collecting 3D data. While the object is firmly held in place, contact 3D scanners investigate the topic via physical touch. To record 3D information, a touching probe is moved across the surface. The probe is occasionally coupled to an articulated arm capable of collecting all of its different configurations and angles for more precision. The touching probe is then moved all over the object to collect all of the object’s details as well as all of the 3D information needed to build a digital file. To generate an accurate model, enough points on the surface must be sampled. An articulated arm is occasionally used to control the touching probe and capture numerous angles/configurations with extreme precision. The precision and ability to 3D scan translucent or reflecting surfaces are the key advantages of contact technology for 3D scanning. The poor pace and difficulty of working with organic, freeform structures are two drawbacks of contact 3D scanning technology.

Laser Pulse 3D Scanning

This method is comparable to SONAR as a laser beam is projected onto the object’s surface being scanned by a light scanner. After that, the laser reflects and returns to a sensor. The duration between projection and reflection is measured and translated into geometric data. The distance between the scanner and the object is determined because the speed of light is a known variable. Because millions of laser pulses are projected and received in a short period, this approach has a high level of precision. A mirror, commonly used on laser scanners, allows the laser beams to alter orientation to cover all of an object’s points. The time it takes for the laser to return gives the exact distance between the 3D scanner and the object because the speed of light is known. The 3D scanner calculates millions of laser pulses accurately down to the picosecond to estimate the distance correctly.

Structured Light 3D Scanning

Trigonometric triangulation is used in structured light 3D scanners. However, they do not employ a laser. Rather, they use a succession of linear patterns to project onto the item. The system can then look at the edges of each line in the pattern and see how they have deformed, as well as calculate the distance between the scanner and the object’s surface. These 3D scanners project a pattern of light onto an item made up of bars, blocks, or other shapes. To detect the object’s 3D geometry, the 3D scanner has one or more sensors that look at the edge of those patterns or structural shapes. The white or blue projected structured light required for 3D scanning can be generated by various projectors, including those that use Digital Light Processing (DLP) technology. A randomized dot matrix or a series of light rays can be used as the projected pattern.

Medium and Long-Range 3D Scanning

The scanners are available in two main formats: pulse-based and phase-shift, both of which are well-suited for huge objects, including buildings, structures, airplanes, and military vehicles. Automobiles, huge pumps, and industrial equipment benefit from phase shift 3D scanners for medium-range scanning. These scanners rotate 360 degrees while spinning a mirror that guides the laser outward towards the object or areas to be 3D scanned, capturing millions of points. On the other hand, laser pulse-based scanners work on the basic premise that the speed of light is exactly known. As a result, if the time it takes a laser to reach an object and reflects a sensor is known, the distance between sensor and object may be calculated. These systems determine a distance by measuring the time it takes for millions of laser pulses to return to the sensor using accurate circuitry to picoseconds.

Tips and Tricks

Some of the tips and tricks that you must opt for are:

• If you’re scanning someone who wears glasses, it’s good to ask them to take them off first, as wearing those can cause light to reflect.
• When 3D scanning, it is best to use natural light as much as possible. A gloomy day with slightly above normal light penetration is ideal when employing photogrammetry or light-based scanning.
• Using a portable laser scanner, moving it in a wave-like up-and-down motion can help. You may change the spectrum of light and the consequent reflection by moving the scanner up and down.
• You have two options for scanning an object: place it on a spinning platform or walk around it and record all angles. Whatever choice you select, make certain that your shadow follows you.