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Time of flight 3d scanner


3D Time of Flight (ToF)

Time of Flight Technology Overview

Time of Flight Products

3D Time of Flight Development Platform

Modular ToF solution, built on the industry-standard 96Boards platform, which enables measuring objects in the X, Y, and Z axis.

Visit the AD-96TOF1-EBZ Product Page

3D Time of Flight Platform Makes Machine Perception a Reality

Analog Devices prototyping 3D ToF platform can be used for software and algorithm development. As a start for the hardware design, the platform can be used for more rapid evaluation and implementation in Industrial, Automotive, and more.

Watch the video about ADI's Depth-Sensing Technology

AD-FXTOF1-EBZ - 3D ToF Development Kit

The AD-FXTOF1-EBZ is a depth sensing solution, ideal for developing 3D computer vision systems. It uses a VGA CCD that enables the capture of a 640×480 depth map of a scene at 30 frames per second, providing up to 4× higher resolution than many other TOF systems on the market. This enables the detection and measurement of distances to smaller and thinner objects that would otherwise be invisible to other ToF systems.

Visit the AD-FXTOF1-EBZ Evaluation Board Page

AD-3DSMARTCAM1-PRZ

The AD-3DSMARTCAM1-PRZ is a 2D & 3D machine vision solution with AI edge processing capabilities. It can be used for implementing advanced machine vision applications for different industry segments including logistics, robotics, agriculture and people activity monitoring.

Visit the AD-3DSMARTCAM1-PRZ Evaluation Board Page

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What is a ToF camera? Time-of-flight sensor explained

Over the past few years we've seen nearly all smartphone manufacturers trying various ways in which to build up some excitement for the smartphone market again. Whether it be adding more camera sensors to the back, adopting near bezel-less displays hole-punch selfie cameras, or foldable form factors.

While it's not all that popular now, there was a brief spell when Time-of-Flight (ToF) camera technology began appearing in many flagship smartphones alongside other lenses. You may also see it referred to as a range camera or even a 3D sensor. But what is it?

What is a time-of-flight camera?

  • Emits an infrared light signal
  • Measures how long the signal takes to return
  • Determines depth based on extracted data

A ToF camera uses infrared light (lasers invisible to human eyes) to determine depth information - a bit like how a bat senses it surroundings. The sensor emits a light signal, which hits the subject and returns to the sensor. The time it takes to bounce back is then measured and provides depth-mapping capabilities. This provides a huge advantage over other technologies, as it can accurately measure distances in a complete scene with a single laser pulse.

In comparison to other 3D-depth range scanning technologies available, such as a structured light camera/projector system, ToF technology is relatively cheap. The sensors can reach up to 160 frames per second - that's 160 relays of data every second - which means they're great for real-time applications such as background blur in on-the-fly video. Better yet, they use a small amount of processing power. And once distance data has been collected, features like object detection can be easily implemented with the right algorithms.

What can a time-of-flight camera do?

  • Object scanning, indoor navigation, gesture recognition
  • Also helps with 3D imaging and improving AR experiences
  • Theoretically, it can better blur backgrounds in 'portrait mode'

A ToF camera sensor can be used to measure distance and volume, as well as for object scanning, indoor navigation, obstacle avoidance, gesture recognition, object tracking, and reactive altimeters. Data from the sensor can also help with 3D imaging and improving augmented reality (AR) experiences. In phones, ToF camera sensors will likely be used for 3D photography, AR, and in particular portrait mode.

LG

Theoretically, ToF cameras can better blur photo backgrounds in portrait mode. We say "theoretically" because the process still requires software magic, and in the end, it's up to a manufacturer to decide how it applies the data that the ToF camera collects.

ToF cameras can also assist in low-light situations - since the sensor uses infrared light to pick up "distance-to-subject", it could help smartphones focus even in darkness.

Are time-of-flight cameras new?

  • Microsoft used ToF cameras in second-gen Kinect
  • Lidar sensors use ToF cameras 

ToF technology isn't very new, as various companies have been experimenting with it for at least the past decade. Microsoft, for instance, used ToF cameras in its second-generation of Kinect devices.

Lidar - which is popular in self-driving cars, but more recently appeared in the iPhone 13 Pro and Pro Max - also commonly features ToF sensors. The difference is that Lidar can use multiple to create 'point maps', which is why this multiple positioning makes great sense in car safety and automation systems.

Even drone companies have adopted them - the Chouette drone in the video above uses a TeraRanger ToF camera to surveil vineyards.

So, while ToF cameras weren't invented yesterday, they're still cutting-edge and rapidly becoming more efficient, affordable, and accessible.

One of the first consumer smartphones to use the tech was the Honor View 20, at the tail end of 2018. After that we saw a brief surge of phones with the technology, but that hype as since died off in favour of good quality zoom and ultrawide lenses. 

Who makes time-of-flight camera sensors?

Sony makes next-generation 3D sensors with ToF technology, which is the source used by Apple.

Other ToF camera sensor manufacturers include AMS/Heptagon, ASC TigerCub, TeraRanger One, Riegl, Lucid/Helios, and AdaFruit.

All about 3D scanners: from varieties to applications

The 3D scanner is a special device that analyzes a specific physical object or space in order to obtain data on the shape of an object and, if possible, its appearance (for example , about color). The collected data is then used to create a digital three-dimensional model of this object.

To create 3D-scanner allows several technologies at once, differing from each other in certain advantages, disadvantages, as well as cost. In addition, there are some restrictions on the objects that can be digitized. In particular, there are difficulties with objects that are shiny, transparent or have mirror surfaces.

Don't forget that 3D data collection is also important for other applications. So, they are needed in the entertainment industry to create films and video games. Also, this technology is in demand in industrial design, orthopedics and prosthetics, reverse engineering, prototyping, as well as for quality control, inspection and documentation of cultural artifacts.

Functionality

The purpose of the 3D Scanner is to create a point cloud of geometric patterns on the surface of an object. These points can then be extrapolated to recreate the shape of the object (a process called reconstruction). If color data were obtained, then the color of the reconstructed surface can also be determined.

3D scanners are a bit like regular cameras. In particular, they have a cone-shaped field of view, and they can only receive information from surfaces that have not been darkened. The difference between these two devices is that the camera transmits only information about the color of the surface that fell into its field of view, but the 3D scanner collects information about the distances on the surface, which is also in its field of view. Thus the "picture" obtained with of the 3D scanner, describes the distance to the surface at each point in the image. This allows you to determine the position of each point in the picture in 3 planes at once.

In most cases, one scan is not enough to create a complete model of the object. Several such operations are required. As a rule, a decent number of scans from different directions will be needed in order to obtain information about all sides of the object. All scan results must be normalized to a common coordinate system, a process called image referencing or alignment, before a complete model is created. This whole procedure from a simple map with distances to a full-fledged model is called a 3D scanning pipeline.

Technology

There are several technologies for digitally scanning a mold and creating a 3D model of an object. However, a special classification has been developed that divides 3D scanners into 2 types: contact and non-contact. In turn, non-contact 3D scanners can be further divided into 2 groups - active and passive. Several technologies can fall under these categories of scanning devices.

Coordinated-measuring machine with two fixed mutually perpendicular measuring hands

Contact 3D scanners

Contact 3D-scanners Explore (probes) the object directly through physical contact, while the subject itself expenses itself, while the subject expenses itself. on a precision surface plate, ground and polished to a certain degree of surface roughness. If the scanned object is uneven or cannot lie stably on a horizontal surface, then a special vise will hold it.

The scanner mechanism comes in three different forms:

  • Carriage with a fixed measuring arm positioned perpendicularly, and measurement along the axes occurs while the arm slides along the carriage. This system is optimal for flat or regular convex curved surfaces.
  • Fixed component manipulator with high precision angle sensors. The location of the end of the measuring arm entails complex mathematical calculations regarding the angle of rotation of the wrist joint, as well as the angle of rotation of each of the joints of the arm. This mechanism is ideal for probing recesses or interior spaces with a small inlet.
  • Simultaneous use of the previous two methods. For example, a manipulator can be combined with a carriage, which allows you to get 3D data from large objects that have internal cavities or overlapping surfaces.
    • The

CMM (coordinate measuring machine) is a prime example of the contact 3D scanner . They are used mainly in manufacturing and can be ultra-precise. The disadvantages of CMM include the need for direct contact with the surface of the object. Therefore, it is possible to change the object or even damage it. This is very important if thin or valuable items such as historical artifacts are being scanned. Another disadvantage of CMM over other scanning methods is slowness. Moving the measuring arm with the probe in place can be very slow. The fastest result of CMM operation does not exceed a few hundred hertz. At the same time, optical systems, for example, a laser scanner, can operate from 10 to 500 kHz.

Another example is hand-held measuring probes used to digitize clay models for computer animation.

The Lidar device is used to scan buildings, rocks, etc., which makes it possible to create 3D models of them. The Lidar laser beam can be used in a wide range: its head rotates horizontally, and the mirror moves vertically. The laser beam itself is used to measure the distance to the first object in its path.

Non-contact active scanners

Active scanners use certain types of radiation or just light and scan an object through the reflection of light or the passage of radiation through an object or medium. These devices use light, ultrasound, or x-rays.

Time-of-Flight Scanners

Time-of-Flight Laser Scanner The 3D scanner is an active scanner that uses a laser beam to examine an object. This type of scanner is based on a time-of-flight laser range finder. In turn, the laser rangefinder determines the distance to the surface of the object, based on the time of flight of the laser back and forth. The laser itself is used to create a pulse of light, while the detector measures the time until the light is reflected. Given that the speed of light (c) is a constant value, knowing the time of flight of the beam back and forth, you can determine the distance over which the light has moved, it will be twice the distance between the scanner and the surface of the object. If (t) is the round-trip flight time of the laser beam, then the distance will be (c*t\2). Laser beam time-of-flight accuracy of the 3D scanner depends on how accurately we can measure time (t) itself: 3. 3 picoseconds (approximately) is needed for the laser to travel 1 millimeter.
The laser distance meter determines the distance of only one point in a given direction. Therefore, the device scans its entire field of view in separate points at a time, while changing the direction of scanning. You can change the direction of the laser rangefinder either by rotating the device itself, or using a system of rotating mirrors. The latter method is often used, because it is much faster, more accurate, and also easier to handle. For example, time-of-flight 3D scanners can measure distance from 10,000 to 100,000 points in one second.
TOF devices are also available in 2D configuration. Basically, this applies to time-of-flight cameras.

Triangulation scanners

Laser triangulation sensor working principle. Two positions of the object are shown.

A point cloud is generated by triangulation and a laser stripe.

Triangulation laser scanners The 3D scanners are also active scanners that use a laser beam to probe an object. Like the time-of-flight 3D scanners, triangulation devices send a laser to the scanned object, and a separate camera captures the location of the point where the laser hit. Depending on how far the laser travels across the surface, the dot appears at different locations in the camera's field of view. This technology is called triangulation because the laser dot, the camera and the laser emitter itself form a kind of triangle. The length of one side of this triangle is known - the distance between the camera and the laser emitter. The angle of the laser emitter is also known. But the camera angle can be determined by the location of the laser dot in the field of view of the camera. These 3 indicators completely determine the shape and size of the triangle and indicate the location of the corner of the laser point. In most cases, to speed up the process of obtaining data, a laser strip is used instead of a laser dot. Thus, the National Research Council of Canada was among the first scientific organizations that developed the basics of triangulation laser scanning technology back in 1978 year.

Advantages and disadvantages of

scanners Both time-of-flight and triangulation scanners have their own strengths and weaknesses, which determines their choice for each specific situation. The advantage of time-of-flight devices is that they are optimally suited for operation over very long distances up to several kilometers. They are ideal for scanning buildings or geographic features. At the same time, their disadvantages include measurement accuracy. After all, the speed of light is quite high, so when calculating the time it takes for the beam to overcome the distance to and from the object, some flaws (up to 1 mm) are possible. And this makes the scan results approximate.

As for triangulation rangefinders, the situation is exactly the opposite. Their range is only a few meters, but the accuracy is relatively high. Such devices can measure distance with an accuracy of tens of micrometers.

The study of the edge of an object negatively affects the accuracy of the TOF scanners. The laser pulse is sent one, and is reflected from two places at once. The coordinates are calculated based on the position of the scanner itself, and the average value of the two reflections of the laser beam is taken. This causes the point to be defined in the wrong place. When using scanners with high resolution, the chances that the laser beam hits the exact edge of the object increase, but noise will appear behind the edge, which will negatively affect the scan results. Scanners with a small beam can solve the edge scanning problem, but they have limited range, so the beam width will exceed the distance. There is also special software that allows the scanner to perceive only the first reflection of the beam, while ignoring the second.

At 10,000 dots per second, low resolution scanners can do the job within seconds. But for scanners with high resolution, you need to do several million operations, which will take minutes. It should be borne in mind that the data may be distorted if the object or the scanner moves. So, each point is fixed at a certain point in time in a certain place. If the object or scanner moves in space, then the scan results will be false. That's why it's so important to mount both the object and the scanner on a fixed platform and keep the possibility of vibration to a minimum. Therefore, scanning objects in motion is practically impossible. Recently, however, there has been active research on how to compensate for the effect of vibration on data corruption.

It is also worth considering that when scanning in one position for a long time, a slight movement of the scanner may occur due to temperature changes. If the scanner is mounted on a tripod and one side of the scanner is exposed to strong sunlight, then the tripod will expand and the scan data will gradually distort from one side to the other. However, some laser scanners have built-in compensators that counteract any movement of the scanner during operation.

Conoscopic holography

In the conoscopic system, a laser beam is projected onto the surface of an object, after which the beam is reflected along the same path, but through a conoscopic crystal, and is projected onto a CCD (charge-coupled device). The result is a diffraction pattern from which frequency analysis can be used to determine the distance to the surface of an object. The main advantage of conoscopic holography is that only one beam path is needed to measure the distance, which makes it possible to determine, for example, the depth of a small hole.

Handheld laser scanners

Handheld laser scanners create a 3D image using the triangulation principle described above. A laser beam or stripe is projected onto an object from a hand-held emitter, and a sensor (often a CCD or position-sensitive detector) measures the distance to the surface of the object. The data is collected relative to the internal coordinate system and therefore, to obtain results, if the scanner is in motion, the position of the device must be accurately determined. This can be done using basic features on the scanned surface (adhesive reflective elements or natural features) or using the external tracking method. The latter method often takes the form of a laser tracker (providing a position sensor) with a built-in camera (to determine the orientation of the scanner). You can also use photogrammetry, provided by 3 cameras, which gives the scanner six degrees of freedom (the ability to make geometric movements in three-dimensional space). Both techniques typically use infrared LEDs connected to the scanner. They are observed by cameras through filters that ensure the stability of ambient lighting (reflecting light from different surfaces).

Scan data is collected by a computer and recorded as points in 3D space, which after processing are converted into a triangulated grid. The computer-aided design system then creates a model using a non-uniform rational B-spline, NURBS (a special mathematical form for creating curves and surfaces). Handheld laser scanners can combine this data with passive visible light sensors that capture surface texture and color to create or reverse engineer a complete 3D Models .

Structured light

3D scanners, working on structured light technology, represent a projection of a light grid directly onto an object, deformation of this pattern and is a model of the scanned object. The grid is projected onto the object using a liquid crystal projector or other constant light source. A camera positioned just to the side of the projector captures the shape of the network and calculates the distance to each point in the field of view.
Structured light scanning is still an active area of ​​research, with quite a few research papers devoted to it each year. Ideal maps are also recognized as useful as structured light patterns that can solve matching problems and allow errors to be corrected as well as detected.

The advantage of the Structured Light 3D Scanners is their speed and accuracy. Instead of scanning one point at a time, structured scanners scan several points at the same time or the entire field of view at once. Scanning the entire field of view takes a fraction of a second, and the generated profiles are more accurate than laser triangulations. This completely solves the problem of data corruption caused by motion. In addition, some existing systems are capable of scanning even moving objects in real time. For example, the VisionMaster, a 3D scanning system, has a 5-megapixel camera, so each frame contains 5 million dots.

Real-time scanners use digital edge projection and a phase-shifting technique (one of the techniques for using structured light) to capture, reconstruct and create a high-density computer model of dynamically changing objects (such as facial expressions) at 40 frames per second. A new type of scanner has recently been created. Various models can be used in this system. The frame rate for capturing and processing data reaches 120 frames per second. This scanner can also process individual surfaces. For example, 2 moving hands. Using the binary defocusing method, the shooting speed can reach hundreds or even thousands of frames per second.

Modulated light

When using the 3D scanners based on modulated light, the light beam directed at the object is constantly changing. Often the change of light passes along a sinusoid. The camera captures the reflected light and determines the distance to the object, taking into account the path that the light beam has traveled. Modulated light allows the scanner to ignore light from sources other than the laser, thus avoiding interference.

Volumetric techniques

Medicine

Computed tomography (CT) is a special medical imaging technique that creates a series of two-dimensional images of an object, a large three-dimensional image of the internal space. Magnetic resonance imaging works on a similar principle - another imaging technique in medicine, which is distinguished by a more contrast image of the soft tissues of the body than CT. Therefore, MRI is used to scan the brain, the musculoskeletal system, the cardiovascular system, and to search for oncology. These techniques produce volumetric voxel models that can be rendered, modified, and transformed into a traditional 3D surface using isosurface extraction algorithms.

Production

Although MRI, CT or microtomography are more widely used in medicine, they are also actively used in other areas to obtain a digital model of an object and its environment. This is important, for example, for non-destructive testing of materials, reverse engineering or the study of biological and paleontological samples.

Non-contact passive scanners

Passive scanners do not emit light, instead they use reflected light from the environment. Most scanners of this type are designed to detect visible light, which is the most accessible form of ambient radiation. Other types of radiation, such as infrared, may also be involved. Passive scanning methods are relatively cheap, because in most cases they do not need special equipment, a conventional digital camera is enough.
Stereoscopic systems involve the use of 2 video cameras located in different places, but in the same direction. By analyzing the differences in the images of each camera, you can determine the distance to each point in the image. This method is similar in principle to human stereoscopic vision.

Photometric systems typically use a single camera that captures multiple frames in all lighting conditions. These methods attempt to transform the object model in order to reconstruct the surface for each pixel.

Silhouette techniques use contours from successive photographs of a three-dimensional object against a contrasting background. These silhouettes are extruded and transformed to get the visible skin of the object. However, this method does not allow you to scan the recesses in the object (for example, the inner cavity of the bowl).

There are other methods that are based on the fact that the user himself discovers and identifies some features and shapes of the object, based on many different images of the object, which allow you to create an approximate model of this object. Such methods can be used to quickly create a three-dimensional model of objects of simple shapes, for example, a building. You can do this using one of the software applications: D-Sculptor, iModeller, Autodesk ImageModeler or PhotoModeler.

This 3D scan is based on the principles of photogrammetry. In addition, this technique is in some ways similar to panoramic photography, except that the photographs of the object are taken in three-dimensional space. Thus, it is possible to copy the object itself, rather than taking a series of photos from one point in three-dimensional space, which would lead to the reconstruction of the object's environment.

Reconstruction

From point clouds

The point clouds generated by the 3D Scanners can be directly used for measurement or visualization in architecture and engineering.
However, most applications use non-homogeneous rational B-spline, NURBS, or editable CAD models (also known as solid models) instead of polygonal 3D models.

  • Polygon mesh models: In polygon representation shapes curved surfaces consist of many small flat surfaces with edges (a striking example is a ball in discotheques). Polygonal models are very in demand for visualization in the field of CAM - an automated system for technological preparation of production (for example, mechanical processing). At the same time, such models are quite « heavy" (accommodate a large amount of data) and are quite difficult to edit in this format. Reconstruction into a polygonal model involves searching and combining neighboring points with straight lines until a continuous surface is formed. For this, you can use a number of paid and free programs (MeshLab, Kubit PointCloud for Au toCAD, 3D JRC Reconstructor, ImageModel, PolyWorks, Rapidform, Geomagic, Imageware, Rhino 3D, etc.).
  • Surface models: This method represents the next level of sophistication in the field of modeling. It applies a set of curved surfaces that give your object its shape. It can be NURBS, T-Spline or other curved objects from the topology. Using NURBS converts, for example, a sphere to its mathematical equivalent. Some applications require manual processing of the model, but more advanced programs also offer automatic mode. This option is not only easier to use, but also provides the ability to modify the model when exporting to a computer-aided design system (CAD). Surface models are editable, but only in a sculptural way. Organic and artistic forms lend themselves well to modeling. Surface modeling is available in Rapidform, Geomagic, Rhino 3D, Maya, T Splines.
  • 3D CAD Models: From an engineering and manufacturing perspective, this type of simulation is a full digitized form of a parametric CAD model. After all, CAD is the industry's common "language" for describing, editing, and preserving the shape of an enterprise's assets. For example, in CAD, a sphere can be described by parametric functions that are easy to edit by changing their value (say, radius or center point).

These CAD models don't just describe the shell or shape of an object, but they also enable design intent (ie, critical features and their relationship to other features). An example of design intent that is not expressed in form would be the ribbed bolts of a brake drum, which should be concentric with the hole in the center of the drum. This nuance determines the sequence and method of creating a CAD model, so the engineer, taking into account these features, will develop bolts tied not to the outer diameter, but, on the contrary, to the center. Thus, to create such a CAD model, you need to correlate the shape of the object with the design intent.

There are several approaches to get a parametric CAD model. Some involve only exporting a NURBS surface, leaving the CAD engineer to complete the modeling (Geomagic, Imageware, Rhino 3D). Others use the scan data to create an editable and verifiable function model that can be fully imported into CAD with an intact fully functional tree, providing a complete fusion of shape and design intent of the CAD model (Geomagic, Rapidform). However, other CAD applications are powerful enough to manipulate a limited number of points or polygonal models in a CAD environment (CATIA, AutoCAD, Revit).

From the 2D slice set

3D reconstruction of the brain or eyeballs based on CT results is performed using DICOM images. Their peculiarity is that the areas on which air is displayed, or bones with a high density are made transparent, and the sections are superimposed in a free alignment interval. The outer ring of biomaterial surrounding the brain is made up of the soft tissues of the skin and muscles on the outside of the skull. All sections are made on a black background. Since they are simple 2D images, when added one-to-one when viewed, the borders of each slice disappear due to their zero thickness. Each DICOM image is a slice about 5 mm thick.

CT, industrial CT, MRI or microCT scanners do not create a point cloud, but 2D slices (referred to as a “tomogram”) that are superimposed on each other, resulting in a kind of 3D model. There are several ways to do this, depending on the desired result:

  • Volume rendering: Different parts of an object usually have different thresholds and grayscale densities. Based on this, a three-dimensional model can be freely designed and displayed on the screen. Several models can be made from different thresholds, allowing different colors to represent a specific part of an object. Volumetric rendering is most often used to render a scanned object.
  • Image segmentation: When different structures have similar threshold or midtone values, it may not be possible to separate them simply by changing volume rendering parameters. The solution to the problem will be segmentation - a manual or automatic procedure that will remove unnecessary structures from the image. Special programs that support image segmentation allow you to export segmented structures to CAD or STL format, which will allow you to continue working with them.
  • Meshing based on image analysis: When 3D image data (CFD and FEA) is used for computer analysis, simple data segmentation and meshing from a CAD file can be quite time consuming. In addition, some typical image data may not be inherently suitable for a complex topology. The solution lies in image analysis meshing, which is an automated process for generating an accurate and realistic geometric description of the scanned data.

Application

Material Handling and Manufacturing

3D Laser Scanning describes a general way to measure or scan a surface using laser technology. It is used in several areas at once, differing mainly in the power of the lasers that are used and the results of the scan itself. Low laser power is needed when the scanned surface should not be influenced, for example, if it only needs to be digitized. Confocal or 3D laser scanning are methods that provide information about the scanned surface. Another low power application involves a projection system that uses structured light. It is applied to solar panel plane metrology involving voltage calculation with a throughput of more than 2,000 plates per hour.

The laser power used for laser scanning of industrial equipment is 1W. The power level is typically 200mW or less.

Construction industry

  • Robot control: Laser scanner acts as the eye of the robot
  • Executive drawings of bridges, industrial plants, monuments
  • Documentation of Historic Sites
  • Site modeling and layout
  • Quality control
  • Measurement of works
  • Reconstruction of highways
  • Marking an existing shape/state to identify structural changes after extreme events - earthquake, ship or truck impact, fire.
  • Creation of GIS (Geographic Information System), maps and geomatics
  • Scanning of subsurface in mines and karst voids
  • Court records

Benefits of 3D scanning

Creating a 3D model through scanning has the following benefits:

  • Increases efficiency in working with complex parts and shapes
  • Encourages product design when needed to add a part created by someone else.
  • If CAD models become outdated, 3D scanning will provide an updated version
  • Replaces missing or missing parts of

Entertainment

3D scanners are widely used in the entertainment industry to create 3D digital models in film and video games. If the model being created has a counterpart in the real world, then scanning will allow you to create a three-dimensional model much faster than developing the same model through 3D modeling. Quite often, artists first sculpt a physical model, which is then scanned to get a digital equivalent, instead of creating such a model on a computer.

Reverse engineering

Reverse engineering of mechanical components requires a very accurate digital model of the objects to be recreated. This is a good alternative to converting many points of a digital model to a polygon mesh, using a set of NURBS flat and curved surfaces, or, ideally for mechanical components, creating a 3D CAD model. A 3D scanner can be used to digitize objects that freely change shape. As well as the prismatic configuration, for which a coordinate measuring machine is usually used. This will allow you to determine the simple dimensions of the prismatic model. This data is further processed by special programs for reverse engineering.

3D printing

3D scanners are also actively used in the field of 3D printing, as they allow you to create fairly accurate 3D models of various objects and surfaces in a short time, suitable for further refinement and printing. In this area, both contact and non-contact scanning methods are used, both methods have certain advantages.

Cultural heritage

An example of copying a real object through 3D scanning and 3D printing. There are many research projects that have been carried out using the scanning of historical sites and artifacts to document and analyze them. The combined use of 3D scanning and 3D printing makes it possible to replicate real objects without the use of a traditional plaster cast, which in many cases can damage a valuable or delicate cultural heritage artifact. The sculpture of the figure on the left was digitized using a 3D scanner, and the resulting data was converted in the MeshLab program. The resulting digital 3D model was printed using a rapid prototyping machine that allows you to create a real copy of the original object.

Michelangelo

There are many research projects that have been carried out using scanning of historical sites and artifacts to document and analyze them.

In 1999, 2 different research groups started scanning Michelangelo's statues. Stanford University, along with a team led by Mark Levoy, used a conventional laser triangulation scanner built by Cyberware specifically to scan Michelangelo's statues in Florence. In particular, the famous David, "Slaves" and 4 more statues from the Medici chapel. Scanning is performed with a dot density of 0.25 mm, sufficient to see the traces of Michelangelo's chisel. Such a detailed scan involves obtaining a huge amount of data (about 32 gigabytes). It took about 5 months to process them.

Around the same time, a research group from IBM was working, led by H. Raschmeyer and F. Bernardini. They were tasked with scanning the Florentine Pieta sculpture to obtain both geometric data and color information. The digital model obtained from a Stanford University scan was fully used in 2004 to further restore the statue.

Medical applications CAD/CAM

3D scanners are widely used in orthopedics and dentistry to create a 3D patient shape. Gradually, they replace the outdated gypsum technology. CAD/CAM software is used to create prostheses and implants.
Many dentistry uses CAD/CAM as well as 3D scanners to capture the 3D surface of a dentifrice (in vivo or in vitro) in order to create a digital model using CAD or CAM techniques (e.g. , for a CNC milling machine (computer numerical control), as well as a 3D printer). Such systems are designed to facilitate the process of 3D scanning of the drug in vivo with its further modeling (for example, for a crown, filling or inlay).

Quality assurance and industrial metrology

The digitization of real world objects is of great importance in various fields of application. 3D scanning is very actively used in industry to ensure product quality, for example, to measure geometric accuracy. Predominantly all industrial processes such as assembly are quite complex, they are also highly automated and are usually based on CAD (computer-aided design data). The problem is that the same degree of automation is required for quality assurance. A striking example is the automated assembly of modern cars, because they consist of many parts that must match exactly with each other.
Optimum performance levels are guaranteed by quality assurance systems. Geometrical metal parts need special checking, because they must be of the correct size, fit together to ensure reliable operation.
In highly automated processes, the results of geometric measurements are transferred to machines that produce the corresponding objects. Due to friction and other mechanical processes, the digital model may differ slightly from the real object. In order to automatically capture and evaluate these deviations, the manufactured parts must be rescanned. For this, 3D scanners are used, which create a reference model with which the received data are compared.
The process of comparing 3D data and CAD model is called CAD comparison, and can be a useful method for determining mold and machine wear, final assembly accuracy, gap analysis, and the volumetric surface of a disassembled part. Currently laser triangulation scanners, structured light devices and contact scanning are the leading technologies used in industrial applications. Contact scanning methods, although they are the slowest, but the most accurate option.

If you have a need for 3D scanning services and / or subsequent reverse engineering, please contact us at [email protected].

🔎 Scanner 3D - Know it all!

3D scanner is the acquisition of scanning and 3D

A three-dimensional scanner is a device that analyzes objects or their immediate surroundings to collect specific information about the shape and possibly the appearance (color, texture) of them.

Collected data can be used to create CGI 3D (digital objects) for various purposes.

These devices are used much in the entertainment industry for movies or video games. Digital representations of inspected objects in 3D are also used for industrial design, prosthesis design, reverse engineering, quality control (digital repository) or for documenting cultural objects.

Contact scanners can be divided into two main categories: active and passive scanners. They themselves are in many subcategories, based on their technological principle.

This scanner can be used to scan buildings

This Lidar scanner can be used to inspect buildings, geological formations, in order to make a model in three dimensions. Its radius is adjustable over a very wide horizon: thanks to the horizontal rotation of the head, the mirror directs it vertically. The laser beam is used to measure the distance from the first beam cutting object

3D Lidar Scanner is an active device that uses a laser beam to probe the subject. At the heart of this type of scanner is a laser rangefinder to determine the distance from the surface of an object, studied by counting the time required for the reflected laser beam pulse to return.

Since the speed of light c is known to be both ends of time, to determine the distance traveled by light, which is twice the distance between the scanner and the surface. Of course, the scanner's time-of-flight accuracy depends on the accuracy of the return time t, knowing that 3.3 picoseconds is roughly the time light travels one millimeter.

The laser distance meter detects only one point at a time in the direction it points. To do this, the device checks its entire field of view item and must change its direction of view for each measure. Can be changed by rotating the camera itself or by using a system of rotating mirrors. This last method is the most commonly used because mirrors are lighter and can change direction faster with greater accuracy.
Flight time 3D scanners can measure distance from 10,000 to 100,000 points in one second.

The scanner emits a laser beam that, upon contact with an object, reflects the laser scanner

Another laser scanner technology for measuring distances is the phase measure with

motion.

DVI

The "Digital Visual Interface" (DVI) or Digital Video Interface was invented by the Digital Display Working Group (DDWG).
This is the digital connection used to connect the graphics card to the screen. This is beneficial (compared to VGA) on screens where the physical

ha. The scanner emits a laser beam, which upon contact with an object reflects the laser scanner. The laser wavelength depends on the supplier. The mirror scanner returns the laser beam vertically to the same object. The vertical angle is encoded while measuring the distance.

Laser scanner rotates 360° horizontally on itself. The horizontal angle is calculated simultaneously with the distance measurement. Distance and angle of vertical and horizontal give polar coordinates (δ, α, β) converted to Cartesian coordinates (x, y, z). Some laser scanners use shift measurement technologies.

DVI

The "Digital Visual Interface" (DVI) or Digital Video Interface was invented by the Digital Display Working Group (DDWG).
This is the digital connection used to connect the graphics card to the screen. This is beneficial (compared to VGA) on screens where the fizi

ha phase to measure the distance to the surface. Designs for infrared laser beam devices that are reflected back to the scanner. It calculates the distance to the nearest millimeter by analyzing the phase shift

DVI

The "Digital Visual Interface" (DVI) or Digital Video Interface was invented by the Digital Display Working Group (DDWG).
This is the digital connection used to connect the graphics card to the screen. This is beneficial (compared to VGA) on screens where the fizi

ha between the emitted beam and the resulting radius.
Laser known sine wave is broadcast by a laser source.

This is "light". Some of the laser beam is reflected from the target object to the source. It's called "rear light". The phase of this "backlight" is compared to that of the light emitted is known to determine the "light story". The difference between two peaks is called "shift

DVI

The "Digital Visual Interface" (DVI) or Digital Video Interface was invented by the Digital Display Working Group (DDWG).
This is the digital connection used to connect the graphics card to the screen. This is beneficial (compared to VGA) on screens where the fizi

g phase. Phase shift

DVI

The "Digital Visual Interface" (DVI) or Digital Video Interface was invented by the Digital Display Working Group (DDWG).
This is the digital connection used to connect the graphics card to the screen. This is beneficial (compared to VGA) on screens where the physical

r received corresponds to 2π x flight time x modulation frequency. Shift scanners

DVI

The "Digital Visual Interface" (DVI) or Digital Video Interface was invented by the Digital Display Working Group (DDWG).
This is the digital connection used to connect the graphics card to the screen. This is beneficial (compared to VGA) on screens where the fizi

HA phases are usually faster and more accurate than 3D in-flight laser scanners, but they have a smaller volume.

Triangulation Laser Scanner is an active scanner that uses laser light to explore the environment

The principle of the detector using laser triangulation. Two positions of the object are displayed.

Triangulation Laser Scanner is an active scanner that also uses laser light to sense the environment. He points to the subject with a beam as for one flight time and uses the camera to locate the point. Depending on the distance to the surface, the dot appears at a different location in the camera's field of view. This method is called triangulation because the laser dot, camera and laser emitter form a triangle. The length of the side of the triangle is known as the distance between the camera and the laser transmitter.
The angle on the side of the laser transmitter is also known.

The angle on the camera side can be determined by looking at the location of the laser dot in the camera's field of view. These three data determine the shape and dimensions of the triangle and give the position of the laser dot. In most cases, a laser instead of a period band scans the object to speed up the acquisition process. The National Research Council of Canada was among the first institutions to develop scanning technology based on triangulation in 19782.

In the conoscopic system, a laser beam is projected onto the surface

In a conoscopic system, a laser beam is projected onto a surface then thinking through the same beam passes through a birefringent crystal and is sent to the CDD sensor.
Frequency diffraction patterns can be analyzed and used to determine the distance to the surface. The main advantage of conoscopic holographic collinearity, that is, a single beam (to and fro) is needed to perform measurements, such as measuring the depth of holes drilled finely which is impossible by triangulation.

Handheld laser scanners create images from the principle of 3D triangulation

Handheld laser scanners create 3D images from the triangulation principle described above: a laser point or line is projected onto an object using a hand held device and a sensor (usually a CDD sensor or position sensitive device) measures the distance to the surface.

The positions are stored on the internal coordinate system and the scanner itself must be measured by moving its positions. The position can be determined by the scanner using characteristic landmarks on the scanning surface (usually self-adhesive reflective strips) or using an external tracking method. The unit responsible for identification comes in the form of a machine for three-dimensional measurement with the camera included (to set the orientation of the scanner) or as a device for photogrammetry, using three or more cameras, allowing six degrees of freedom of the scanner.

Both methods usually use infrared LEDs for the scanner, which the camera(s) sense through filters to see them despite ambient light.
Information collected by a computer and stored as coordinates of points in three-dimensional space, using computer processing, they can be triangulated into canvas and then into a computer model, most often in the form of NURBS surfaces. Handheld laser scanners can combine this data with passive visible light receivers - which record textures and colors - to reconstruct (see reverse engineering) the simulation to complete the 3D model.

Structured light 3D scanners project bright paintings on the theme

Structured light 3D scanners project bright patterns on the subject and observe deformation. The template can be in one or two dimensions.

Line example as a one-dimensional ground. It is supposed to be on a subject using an LCD projector or a laser. A slight displacement of the projector's camera records its possible deformation. A method similar to triangulation is used to calculate the distance and hence the position of the representation points. The earth sweeps the field of view in order to keep the pile at the time, the information about the distances.

Now take the example of a grid or stripe shaped pattern. A camera is used to record the deformation and a complex computer program is used to calculate the distance to the points that make up this land. The difficulty lies in the fact because of the ambiguity. Translate a group of vertical stripes, sweeping the subject horizontally. In the simplest case, the analysis is based on the premise that the sequence of bands seen from left to right matches the projected laser image such that the image of the group on the left is the first laser projection, the one below is the second, and so on.

However, in the case of non-triviales targets with holes, some occlusions, rapid changes, the order of necessarily checked bands is often hidden and may even appear in a different order, leading to ambiguity in the ranges of the lasers.

This particular problem has been solved recently by advanced Multistripe laser Triangulation (MLT) technology. Structured light 3D scanning is still an active area of ​​research, generating a number of publications each year.

The highlight of structured light 3D scanners is speed. Instead of scanning points at the time, they scan the entire field of view at the same time. This limits or eliminates distortion problems associated with motion.

DVI

The "Digital Visual Interface" (DVI) or Digital Video Interface was invented by the Digital Display Working Group (DDWG).
This is the digital connection used to connect the graphics card to the screen. This is beneficial (compared to VGA) on screens where the physical

zhenie. Existing systems have the ability to check objects in motion

DVI

The "Digital Visual Interface" (DVI) or Digital Video Interface was invented by the Digital Display Working Group (DDWG).
This is the digital connection used to connect the graphics card to the screen. This is beneficial (compared to VGA) on screens where the fizi

in real time. Recently Song Zhang and Huang Peisen from Stony Brook University have developed on-the-fly scanning using digital fringe projection and modulated phase technique (another structured light method).
This system has the ability to capture, restore and restore the details of objects deforming in time (like a facial expression) at a frequency of 40 frames per second.

Modulated light 3D scanners illuminate a subject using varying light

Modulated Light 3D scanners illuminate a subject using varying light. Typically, a light source has a cycle whose amplitude describes a sinusoidal pattern. The camera detects reflected light, measures the importance of its change, and determines the distance the light has traveled.
Modulated light also allows the scanner to ignore a light source other than the laser, so there is no interference.

Passive 3D non-contact scanners are based on the detection of reflected ambient radiation

Passive scanners without contact, issuing any type of radiation, based on the detection of reflected ambient radiation. Most scanners of this type detect visible light because it is immediately available. Other types of radiation like infrared can also be used. Passive methods can be cheap because in most cases they don't require a specific show device.

Stereoscopic 3D scanners using two video cameras

Stereoscopic systems usually have two video cameras, slightly apart, pointing at the same scene. By analyzing the slight differences between the images of the two devices, you can determine the distance of each dot in the image. This method is based on humaine5 stereoscopic vision.

These types of 3D scanners use outlines created from a sequence of photographs taken around an object in three dimensions.

These types of 3D scanners use contours created from a sequence of photographs around an object in three dimensions against a contrasting background. These silhouettes are separated from their origin and assembled towards each other at the location of the camera's axis of rotation to zoom in on the "visual body" object. With this type of technique, all kinds of concavity of the object - like inside a bowl - are not found.

Scanners seeking user assistance
There are other methods based on detection and identification that help the user characterize and form a number of different images of the object that allow you to build an approximation. This type of technology is useful to quickly achieve an approximation of an object consisting of simple shapes like buildings.

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