3D scanner how it works

A 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 to 3d scan an object?

The principle of operation of a 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 contact with the object). 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 radiation principle

How to 3d scan an object? 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

They do not emit anything, they analyze the light or infrared (thermal) radiation of the object. 

Photometric non-contact passive 3d scanning technology

On the market, scanners from this group are represented by the XYZprinting model. These are quite compact simple models that have only basic 3D scanning functions.

Device

Passive 3d scanner device (using the specified model as an example): a case, one compact camera, a USB cable for connecting to a computer and transferring an image of the object being scanned to it. Scanner without stand, manual, made in the form of a stapler.

Principle of operation

A light-sensitive camera captures light from an object, processes it and forms a three-dimensional model, exporting it to a computer. How to scan an object for 3d printing? 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 on the photometric technology of passive scanning 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 by 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.

The device and principle of operation of a 3d scanner based on a non-contact passive scanning system

The 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 tripod and 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.

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

The 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 scanned objects: webcams and laser sensors with automatic adjustment function. The device comes with a tripod and tripod.

The 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 the 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”, since the triangle of the device’s functional elements 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.

3d scanning technology with structured lighting

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 the instruments, install them in different positions and securely fix them, reducing vibration. Light sources in devices are halogen lamps, diodes, video projector.

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 captures the displacement of the pattern of the light flux that enters its field of view and looks like moving lines of light on the surface of the object. It calculates and analyzes the distance from each illuminated point of the object and thus forms its detailed digital copy.