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3D scanner working principle
How Does a 3D Scanner Work?
Many digital engineering strategies that enable the future of product development, manufacturing, quality control, and production begin with 3D scanning. 3D scanners work with advanced technology and specialized software to create a tool that delivers game-changing results. For those still working with mechanical tools and traditional coordinate measuring machine (CMM) technology, 3D scanners work as an easy gateway to advanced manufacturing and engineering strategies. Keep reading below to understand more about how 3D scanners work and what the technology is capable of so you can begin accessing its benefits now.
Understanding How a 3D Scanner Works
A 3D scanner works by capturing data from a physical object's surface to describe its shape in an accurate, digital, three-dimensional format. Unlike measurement data from a CMM, high-quality 3D scan data is used for more than just inspection and dimensional analysis. The resulting measurement data enables faster, more accessible digital analysis and inspection in a visual, in-depth reporting method. 3D scanners also work to replicate parts in reverse engineering, assure fit, form, and function of components in remote locations, validate CAD models of 3D printed parts, and open the door to more digital strategies.
What are the Different Types of 3D Scanners?
There are many different types of 3D scanners available for various applications. Creating a digital model of any physical part requires a 3D scanner to collect accurate data to form its geometric identity, but not every type of 3D scanner works for every type of application. For example, if you are a DIY at-home hobbyist, you can make a simple 3D scanner with your mobile phone or make a 3D scanner with a Microsoft Kinect. However, while these 3D scanners work well for fun projects, they won't deliver manufacturing-grade accuracy and detailed requirements. Metrology-grade 3D scanning equipment is necessary for industrial use.
A laser 3D scanner is another type of 3D scanner that uses specialized software and a laser probe to project a laser line along the part's surface while sensor cameras continuously record the changing distance and shape of the laser line, resulting in a collection of XYZ coordinates.
While these scanners are a quick way to collect data points from a physical object, other 3D scanners, such as structured light 3D scanners, can collect higher quality data. Structured light 3D scanners have established trust due to their high precision accuracy, which is why they're used widely throughout manufacturing.
How Does a 3D Scanner Work with Structured Light?
A 3D scanner works with structured light using the principles of triangulation. The sensor projects a precise shifting fringe pattern across the part's surface, and two cameras capture the surface geometry based on the pattern distortion, calculating 3D coordinate measurements. The 3D scanner collects and processes millions of X-Y-Z data points into a "point cloud," creating a detailed digital twin of the object. Since the distance between the sensor, cameras, and angles is all known, the principle of triangulation is applied, producing accurate, reliable measurement results.
This image depicts how structured light 3D scanners also work with the principle of triangulation.
A light source sits between two cameras set angled towards each other, projecting a heterodyne "fringe" stripe-like pattern onto the physical object's surface. The stripes change in size and direction during data collection. The sensing cameras observe the contrast along the stripes' edge and assign those pixels X-Y-Z coordinates, quickly collecting precise, crisp scan data containing very little texturing. The software then transforms the data points into visible data that comprise an accurate, digital replica of the physical part.
How Does a 3D Scanner Work with LED Technology?
Structured light 3D scanners traditionally used white light. Today, different light colors are available, but the most popular are blue light 3D scanners that use LED technology. Blue light helps capture data on shinier and darker colored surfaces and filters out the ambient light present inside labs or on the manufacturing shop floor. The result is a clean, clear, precise data set with low noise.
How Does a 3D Scanner Work for Quality 4.0?
The concept of Quality 4.0 incorporates advanced manufacturing technologies to propel quality processes into the future. Adopting 3D scanning lays the groundwork for these modernized dimensional inspection techniques while overcoming the shortcomings of traditional quality and manufacturing practices. For example, 3D scanners collect data that provides the ability to virtually deconstruct parts and pieces of an object without physically destructing anything. With this data, quality professionals also find problem areas, fix parts, validate and test objects before they're physically in production. The measurement data's high accuracy enables the fast and reliable creation of dimensional calculations such as CAD comparison, sectional analysis, GD&T, trend/SPC, and more.
How Does a 3D Scanner Work for Digital Twin Strategies?
3D scanners work as a tool to access digital twin concepts in Quality 4.0.
The data captured with a 3D scanner becomes the physical object's digital twin; therefore, using an accurate 3D scanner matters. 3D scanners work for many digital twin applications, including digital assembly. In this method, engineers connect 3D scan data from multiple parts in remote locations for assembly within the software. The digital assembly process enables you to assess the fit of such components before physical parts are mass-produced and shipped.
3D scanners work for reverse engineering by using scan data from a physical object to create a 3D CAD model for product enhancements and archiving. Legacy parts are often described within two-dimensional drawings, not 3D CAD models. Accurate 3D scanners make it possible to reproduce legacy parts using precise three-dimensional data. The 3D scanner scans the part, and the resulting data becomes a reference to create a 3D CAD model that can be used to develop new molds, tooling, or new parts with the same dimensional characteristics as the original or engineering product enhancements.
Good quality 3D scan data with a watertight mesh can also be used to 3D print a duplicate of the original and improves efficiency in the reverse engineering process.
How Does a 3D Scanner Work for Adaptive machining?
Adaptive machining is a trending process popular with aerospace and power generation turbine engine components such as airfoils, blisks, molds, and dies. In adaptive machining, accurate structured light 3D scanners digitize a part's surface geometry and send the data back to process the updated machining tool paths, allowing for real-time adjustments without having to reposition in and out of the CNC machine. This process is used with new parts and parts that need repair to help reduce operating costs and lower cycle times while increasing accuracy.
Find Out if 3D Scanning is a Good Fit for Your Application
If you're ready to learn how 3D scanners will work for your specific application, contact a Capture 3D team member today. Our 3D scanners provide an accurate, reliable solution to the advanced metrology needs of industries with diverse applications everywhere.
During an in-person or virtual demo, our team will show you how 3D scanning improves product design, streamlines production lines, improves quality control, and unlocks Quality 4.0 strategies that will elevate your industry to new possibilities.
3D scanning technologies - what is 3D scanning and how does it work?
3D scanning is a technique used to capture the shape of an object using a 3D scanner. The result is a 3D file of the object which can be saved, edited, and even 3D printed. Many different 3D scanning technologies exist to 3D scan objects, environments, and people. Each 3D scanning technology comes with its own limitations, advantages, and costs.
Table of contents
Introduction
Laser triangulation 3D scanning technology
Structured light 3D scanning technology
Photogrammetry 3D scanning technology (photography)
Contact-based 3D scanning technology
Laser pulse-based 3D scanning technology
Introduction
The basic principle of 3D scanning is to use a 3D scanner to collect data about a subject.
The subject can be:
- an object
- an environment (such as a room or even a landscape)
- a person (3D body scanning)
Some 3D scanners can simultaneously collect shape and color data. A 3D scanned color surface is called a texture.
3D scans are compatible with Computer-Aided Design (CAD) software and also 3D printing, after preparing the 3D model via specific software. A 3D scan can give a lot of information about the design of an object, in a process called reverse engineering.
3D scanners are powerful tools for professionals in several industries, such as automotive, aerospace, dental, and jewelry, as well as in more artistic applications such as video games, special effects, and animation movies. 3D scanning technologies rely on different physical principles and can be classified into the following categories:
- Laser triangulation: Projects a laser beam onto a surface and measures the deformation of the laser ray.
- Structured light: Measures the deformation of a light pattern when projected onto a surface to 3D scan the shape of the surface.
- Photogrammetry: Also called “3D scan from photographs”, this technology reconstructs a subject in 3D from 2D captures (photos) with computer vision and computational geometry algorithms.
- Contact-based 3D scanning technology: Relies on the sampling of several points on a surface, measured by a mechanical, optical, or physical probe.
- Laser pulse: Based on the Time of Flight (ToF) of a laser beam. The laser beam is projected onto a surface and recollected by a sensor. The time of travel of the laser between its emission and reception gives the surface’s geometrical information to the 3D scanner.
3D scanning technologies
Laser triangulation 3D scanning technology
Laser triangulation-based 3D scanners use either a laser line or a single laser point to scan across an object.
First, the 3D scanner casts its laser onto the object. As the laser light reflects off of the 3D scanned object, its initial trajectory is modified and picked up by a sensor.
Then, based on this modified trajectory and thanks to trigonometric triangulation, the system can detect the laser’s deviation angle. The calculated angle is directly linked to the distance from the object to the scanner. When the 3D scanner collects enough distances, it is capable of mapping the object’s surface to recreate it in 3D.
The main advantages of the laser triangulation technology for 3D scanning are its high resolution and accuracy.
One downside to laser triangulation technology is how sensitive it is to the properties of object’s surface; very shiny and/or transparent and/or dark surfaces are particularly problematic.
Structured light 3D scanning technology
Structured light 3D scanners use trigonometric triangulation but do not rely on a laser.
Instead, they project a series of linear patterns onto the object. The system is then able to examine the edges of each line in the pattern and how the lines are deformed and to calculate the distance from the scanner to the object’s surface.
The projected structured light used for 3D scanning can be white or blue and generated by numerous types of projectors, such as Digital Light Processing (DLP) technology. The projected pattern is usually a series of light rays but can also be a randomized dot matrix.
The main advantages of structured light technology for 3D scanning are its speed and resolution, and its non-harmful light can be used for 3D body scanning.
However, structured light 3D scanners are sensitive to lighting conditions and have trouble working outdoors in broad daylight.
Photogrammetry 3D scanning technology (photography)
Photogrammetry is the science of making measurements from photographs, especially for recovering the exact positions of surface points.
Photogrammetry is based on a mix of computer vision and powerful computational geometry algorithms.
The principle of photogrammetry is to analyze several photographs of a static subject, taken from different viewpoints, and to automatically detect pixels corresponding to a unique physical point.
This 3D scanning technology’s main challenge is to examine tens or hundreds of photos and thousands of points with high accuracy. To run such photogrammetry algorithms, a very powerful computer is required.
The main advantages of photogrammetry 3D scanning technology are its acquisition speed and ability to pick up colors and textures. Photogrammetric technology is also capable of reconstructing subjects at large scales, such as landscapes or monuments photographed from the ground or from the air, by a photography drone, for example.
The quality of the results generated by photogrammetry technology is dependent on the resolution of the input photographs.
This technology can also be quite slow, depending on your software and PC setup.
Contact-based 3D scanning is also known as digitizing. This 3D scanning technology implies a contact-based form of 3D data collection.
Contact 3D scanners probe the subject via physical touch, while the object is firmly held in place. A touching probe is moved along the surface to record 3D information. The probe is sometimes attached to an articulated arm capable of collecting all its respective configurations and angles for more precision.
Some specific configurations of contact-based 3D scanners are called Coordinate Measuring Machines (CMM).
Contact 3D scanning is widely used to perform quality control after fabrication or during maintenance operations. The main advantages of the contact technology for 3D scanning are its precision and ability to 3D scan transparent or reflective surfaces.
The downsides of contact 3D scanning technology include its slow speed and inability to work with organic, freeform shapes.
Laser pulse-based 3D scanning technology
Laser pulse-based 3D scanners, also known as Time-of-Flight scanners or Lidar laser 3D scanners, measure how long a casted laser takes to hit an object and come back.
Since the speed of light is exactly known, the time it takes for the laser to come all the way back gives the exact distance between the 3D scanner and the object. In order to precisely measure the distance, the 3D scanner computes millions of laser pulses with accuracy up to the picosecond (1 picosecond equals 0.000000000001 seconds!).
Since each measure only collects one point, the 3D scanner needs to cast its laser 360 degrees around that point. To do so, the 3D scanner is usually fitted with a mirror that changes the orientation of the laser.
Time-of-Flight 3D scanners encompass both laser pulse and phase shift lasers.
Phase shift laser 3D scanners are a sub-category of laser pulse 3D scanners. In addition to pulsing the laser, phase shift systems also modulate the power of the laser beam. Phase shift lasers offer better overall performance.
The main advantage of laser pulse 3D scanners is their ability to 3D scan very big objects and environments. They are, however, quite slow.
Laser pulse technology is often used by terrestrial laser 3D scanners, which are mainly destined for land surveying or to 3D scan entire buildings. Some laser pulse 3D scanners also incorporate dynamic SLAM algorithms to enhance their ability to recognize their surroundings.
How does a 3d scanner work? Device, principle and technologies of 3D scanning
3D scanner is a stationary or small hand-held device for scanning objects with complex spatial geometry. Simple scanners process images in a plane, while 3d scans physical volumetric objects, displaying information as a polygonal model or a cloud of points.
Three-dimensional scanning devices are used in medicine (dentistry, plastic surgery, making prostheses, organ models, etc.), for creating computer games, in the film industry, design, architecture, engineering, for designing industrial parts, cars, for reconstructing objects in archeology. Scanners analyze and digitally recreate a three-dimensional model of an object, its shape and color with a high degree of detail, working in different conditions (with insufficient visibility, in the dark, with vibration), with any materials, provide the desired format of output information for software for work with her on the computer.
How does a 3D scanner work?
The principle of operation of the 3d scanner is the ability of the device to determine the distance to an object, convert the received data into a digital image (three-dimensional model), and transfer it to a computer. The scanner determines the coordinates of points in space on the surface of the processed object, analyzes them, and forms a detailed digital model.
Cameras, lasers, rangefinders, devices for illumination are involved in its work.
3D scanning technologies
- Contact (contacts with the object).
- Non-contact (without object contact). These are the most promising and new technologies that allow you to create models of objects simply by directing a laser beam, light, waves at them. The scanner is applied at a distance and is able to create a copy of a hard-to-reach object without physical contact with it.
Non-contact 3d scanners
The two most common scanning technologies are optical (passive and radiation) and active laser.
Active emission principle
Scanner emits structured, intermittent light, laser triangulation. A laser beam, a beam of light generated in a special way (diodes, lamp flashes), and waves are directed to the object under study. Based on the analysis of their reflection and position, a three-dimensional copy of the object is formed.
Passive radiation principle
Do not emit anything, analyze the light or infrared (thermal) radiation of an object. Work like a human eye;
Photometric non-contact passive 3d scanning technology
Scanners from this group are represented on the market by the XYZprinting model. These are quite compact simple models that have only basic 3D scanning functions.
Pluses: reasonable price and compactness.
Device
Passive 3d scanner device (on the example of the specified model): housing, one compact camera, USB cable for connecting to a computer and transferring the image of the scanned object to it. Scanner without stand, manual, made in the form of a stapler.
How it works
A light-sensitive camera captures light from an object, processes it, and forms a three-dimensional model, exporting it to a computer.
The user can have two modes of operation: scanning a person or objects. To get started, you need to install the software on your computer, connect the device to it via a USB cable, select the operating mode, press the button on the scanner and, slowly swiping it in front of the object, scan.
How the technology works
The device works with passive scanning photometric technology without any radiation and projection onto the object. The work is carried out with a slightly improved simple optical camera that captures visible light. The disadvantage is that if the lighting is insufficient, the object needs to be additionally illuminated.
Scanning is performed using the so-called silhouette method. It reproduces the contours of an object based on a sequence of frames captured by a video camera swept around the object against a well-contrasted background.
Stereoscopic non-contact passive 3d scanning system
Models with non-contact passive scanning technology
This type of device is represented by 3D Systems Sense, 4D Dynamics Gotcha models.
Device and principle of operation of a 3d scanner based on the non-contact passive scanning system
Devices are equipped with two cameras and an infrared sensor. The 3D Systems Sense scanner is made in the form of a stapler, it is a compact handheld device, it can be used with a tripod, in Gotcha (with a tripod and a handle), it is included. The principle of operation is passive optical. In both cases, power and data transfer is carried out via a USB cable. The devices have standard modes: scanning a person and an object.
Scan technology
The camera uses this technology to detect infrared (thermal) radiation and normal light reflected from an object. The systems are stereoscopic, that is, they use two cameras. The device compares frames, based on small comparisons of differences between them, determines the distance at each point of the image and recreates the object in digital form.
3d scanners with laser active scanning
This group of devices is represented by the following scanner models: 3D Systems iSense, DAVID Starter-Kit ver.
2, MakerBot Digitizer.
Device
Devices have two lasers and a camera. It should be noted that the laser safety of gadgets corresponds to level I, which is completely safe for the eyes. The iSense scanner is designed to work only with the iOS operating system and with Apple iPad above 4 generations. It is made in a compact case, which is installed on a mobile gadget and connected to it with a USB cable, the battery lasts for 4 hours of its operation. It attaches like a webcam, scans and immediately displays the image on the iPad.
Models
DAVID Starter-Kit ver.2 3D scanner device: webcams and laser sensors with automatic adjustment function. The device comes with a tripod and tripod.
Maker Bot Digitizer is somewhat different in design from the previous model. The body of the scanner is made as a pedestal, one part of which is a rotating platform, the other is equipped with two lasers on the sides and a camera in the middle.
They scan an object located on the site.
How technology works
Let's describe how a 3D scanner works. Laser scanning is based on the triangulation method. This is an active scan tool. It uses laser beams by projecting it onto an object. The laser processes the surface of the object, its points are fixed on its different parts. The camera captures the laser dots on it, the angle of displacement of the laser beam and transmits the data to a computer with the appropriate software, which forms the object in digital form.
The scanning technology is called “triangulation”, because the triangle of functional elements of the device is involved in the work: the laser point on the object, its emitter, and the camera. In most cases, the dot is formed by a laser streak or spot passing over the surface of the object.
Structured light 3d scanning technology
Models that use structured or intermittent light technology in their work: DAVID SLS-2, RangeVision Smart, RangeVision Standard Plus, RangeVision Advanced, RangeVision Premium.
A separate group includes manual Artec Spider, Artec Eva, Artec Eva Lite.
Device
The main functional elements of these devices are cameras and a light source that structures it in a special way and directs it to the scanned object. In the DAVID SLS-2 model, a video projector serves as a light source. These are mounted on a tripod with a tripod, which are included. This allows you to set up and calibrate instruments, install them in different positions and securely fix them, reducing vibration. Light sources in devices are halogen lamps, diodes, video projector.
Artec Spider, Artec Eva, Artec Eva Lite are made in a compact body with an iron-like handle. The handle has control buttons and outputs for interface and power cords. At the bottom there is also a hole for standard photo tripods and legs for fixing the device on the surface. 3d scanner device has the following. From the bottom it is equipped with a 3D camera (there are three of them in Artec Spider) with increased resolution, from the top of the device - a flash (projector) of structured illumination, a central color texture camera in the middle, along with light sources in the form of 6 or 12 diode bulbs.
All light sources have white radiation. The device comes with a standard mini-USB interface cable and a power cable. Additionally, you can buy a rechargeable battery.
How the technology works
Such devices are also called structural-light 3D scanners. The scanning technology is similar to laser triangulation (light, emitter, camera). The important thing is that they can work without markers - the object does not need to be glued with a lot of markers and marks. The essence of structured light technology lies in projecting a pattern of light onto an object and fixing and analyzing its deformation. The luminous flux is projected onto the object by several types of light sources: LCD, video projector, diodes, halogen lamps.
The camera detects shifts in the light pattern that enters its field of view and looks like moving lines of light on the surface of an object. It calculates and analyzes the distance from each illuminated point of the object and thus forms its detailed digital copy.
The advantage of Light 3D scanners is speed and high accuracy. They scan not one or several points, but simultaneously a cluster of points or the entire field of view at once.
How a 3D scanner works, types of device and existing technologies
3D scanning and printing of 3D objects is a new technology that has quickly taken over the market. 3D scanners are in demand in medicine, the arts, the automotive and aviation industries. Work on a new product begins with a 3D design that can be created by hand, using 3D modeling software, or digitizing an existing item to be edited.
3D scanner - a device that allows you to create a computer model in volume.
Applications
There are tasks that can only be solved with the help of special equipment that operates in a non-contact way. Obtaining copies of works of art for restoration or production of reproductions and their subsequent mass production is possible by scanning with a 3D scanner. The equipment is also popular with archaeologists when there are difficulties with access to the area under study, or the object under study is so fragile that you need to touch it very carefully.
Faro photo.
Laser devices also help architects create 3D models of existing buildings for editing and virtual testing. The equipment is used in geodesy and cartography when studying the natural landscape.
More about the 3D scanner FARO Focus 3D
The 3D scanner is used in various sectors of industry and science, in design, in the development of augmented reality or computer games.
For example, Texel is building a system that allows shoppers to try on clothes online in virtual reality fitting rooms through their 3D-scanned avatar.
Installation of a virtual Texel fitting room in Dubai. Photo Texel.
Portal BX 3D Human Scanner. Photo Texel.
Texel parametric human body model, 3D digital avatar.
Photo Texel.
How the 3D scanner works
Volumetric scanning instruments measure objects with complex geometry and convert the processed information into a point cloud. The work of a 3D scanner involves the construction of a polygonal model that can be upgraded: make changes to the structure, experiment with resources and shape, and add new functions to the product. The device calculates the distance to the surface of the object, fixes the coordinates of these points on the scanned object, analyzes the data and builds a detailed 3D model. The structure of the device includes illumination, lasers, cameras, rangefinders.
There are two technologies for object processing: contact and non-contact. All scanning devices operate on their basis.
Contact - CMM (coordinate measuring machine - coordinate measuring machines).
When buying equipment for work, you need to study the basic characteristics of a 3D scanner:
• principle of operation;
• Scan accuracy;
• measurement range;
• Color rendition.
Properly selected technique allows you to get results when working in various conditions: in poor lighting, vibrations, if the subject of study is far away or underground.
3D scanner views
Several methods can be used to capture the characteristics of a structure in space and display the data in a computer layout. Manufacturers offer the following types of devices:
• 3D scanners, the principle of operation of which is the measurement of reflected structured light;
• photogrammetry equipment;
• laser models;
• Mechanical or ultrasonic scanning equipment.
Reflected structured light
This technology involves the use of equipment that works by projecting a light grid (pattern) onto the measured object. Its curvature on the surface is read by the camera, which helps to get a 3D layout. The equipment functions very quickly and in any light. The technique conveys information about the color of the item being scanned.
Photogrammetry
This method involves building layouts based on an array of images taken from different angles.
The more photos, the more detailed the model. The principle of operation of a 3D scanner is based on an algorithm that determines the location of the particles of an object through the study of their relative placement. This is the most widespread method of work that helps to obtain a digital image using professional cameras or using a smartphone camera.
Non-contact 3D laser scanner
This technology is more precise but slower. A technique that uses a laser to measure an object captures information about its configuration, dimensions, and the presence of porous structures. There are several variants of the method. Time-of-flight 3D scanners build the surface of the element under study by analyzing the change in the return time of the laser pulse reflected from the surface of the part. Triangulation devices measure the deviation of the angle of the reflected beam after passing through a special lens.
Mechanical method
The process of digitizing with a contact 3D scanner is the most accurate, but slow.
