Operation and applications of 3D scanners

3D scanners

For several years, we have witnessed rapid changes in technology, thanks to which the slogan INDUSTRY 4.0 takes real shape. What we once considered the song of the future becomes the basic working tool/p>

3D scanners are an excellent example of changes taking place. These devices have become one of the most important in the process of prototyping, designing and collecting information about the objects of interest to us. They are used in virtually every industry, from medicine to shipbuilding. From preserving cultural heritage to designing in the automotive industry. Their versatility and ease of use mean that in many cases their use becomes even necessary.

But let's ask ourselves: Do we know what 3D scanners are? How do they work? Can we harness their power to our needs? And most importantly: What scanner does our company need? After this introduction, you should start from the beginning and answer the above question: What is a 3D scanner?

A 3D scanner is a device that analyzes an object or its surroundings in order to collect / collect information about its shape or appearance (textural scanning) in order to create the most accurate three-dimensional digital model, thanks to which we are able to carry out the actions we need (prototyping, quality control, reverse engineering). Due to the light emitted by the scanner, used for data acquisition, devices can be divided into two types.

• 1. Scanners in which the light source is a diode or many LEDs emitting structural light.
• 2. Scanners with a laser light source.

It cannot be clearly stated that either of these two types of scanner operation mechanisms is better or worse. Each of them, when properly used, will fulfill its task to the best possible degree. However, one should bear in mind the limitations of both, which we will deal with later. For now, let's focus on the basic principles of the work of these two types of devices.

1. Structured light 3D scanner

Structured light scanners display a light pattern on the scanned object. Selection patterns are tracked simultaneously by one camera or multiple cameras. Color capture is also available with a special camera. The light pattern is created using light modulators.

Structured light 3D scanner can capture large size in seconds and also guarantees a high level of accuracy and high resolution. The light source is not dangerous to human eyesight, so structured light scanning technology can be used to scan people. Structured light scanners can be mounted on a stand for stationary scanning as well as used in manual mode. However, they are sensitive to ambient lighting conditions and have problems scanning glossy and dark objects.

2. 3D scanner with laser light

Laser scanning works by projecting a laser point, beam, or multiple beams onto an object and then capturing the laser reflections with sensors.

The main advantage of laser scanning is that it can achieve high resolution and accuracy. It is also less sensitive to ambient light and is better suited for scanning shiny or dark surfaces. Most of these types of scanners are handheld. Although they are better than structured light scanners for scanning glossy and dark objects, they have a problem with scanning transparent or transparent objects nonetheless.

In addition to choosing a scanner that suits our needs, whether it works on the basis of LED light or laser, we must also pay attention to several other factors that determine the use of a given scanner. These are:

Resolution

Resolution is the distance of the point that the scanner captures. The distance between two points in a 3D model is one of the most important factors when scanning. When scanning with high resolution, the distance between the points is very small and the details are more visible on the scan. If we choose a low resolution, the distance between the points is long, making the scanning process much faster. Unfortunately, its quality is much lower.

Examples of resolution values ​​and their application are presented below

Measuring accuracy

Accuracy provides information about the real mapping of the 3D model in relation to the real object. Knowing the accuracy of the scanner is very important because it determines what a specific device is suitable for, e.g. for quality control, design, reverse engineering, in medicine or others where the application of accuracy requirements is an important aspect. Usually, the higher the accuracy a scanner is able to generate, the more applications it could be suitable for, which also translates into the price of the device. So, in terms of accuracy, think about what you want to scan and is high accuracy absolutely necessary? Do you really need very high accuracy? The accuracy used in scanner specifications usually relates to the accuracy of a single scan. Volumetric accuracy refers to the relationship between the accuracy of 3D data and the size of the object.

Scanning speed

Scanning speed is a feature that determines how long it takes to scan an object. This is especially true when our goal is to scan a human figure (people have trouble standing still in one position for a long time. Scanning speed also affects work efficiency when scanning large objects such as cars, buildings, etc.) number of points collected per second, frames per second or number of seconds needed to perform a single scan The more points or frames are collected per second, the faster the scan speed.

Examples of the use of scanners in various industries and science:

1. In construction and protection of cultural goods:

• Documentation of monuments
• Create replicas of existing objects
• Digitization of museum collections
• Quality control
• Urban modeling
• Urban design
• Modeling of structural elements

2. During the design process, the scanner can be used to:

• Increase accuracy when working with complex parts and shapes
• Coordinate product design using parts from multiple sources
• Replacing missing or obsolete parts
• Create savings by enabling as-built design services, for example in automotive manufacturing facilities

3.Entertainment industry (movie, computer games, apps and shows)

3D scanners are used by the entertainment industry to create virtual 3D models for movies, computer games, and recreational purposes. They are heavily used in virtual cinematography. In cases where there is a real model counterpart, it is much easier to scan a real object than to manually create a model using 3D modeling software.

4. In reverse engineering

Reverse engineering of a mechanical component requires a precise digital model of the object in order to reproduce it. Instead of a set of points, an accurate digital model can be represented by a polygon mesh, or for mechanical components, a CAD model would be the ideal solution. A 3D scanner can be used to digitize freeforms, or to gradually change the shape of components, as well as prismatic geometries where the CMM is typically only used to define simple dimensions of a very prismatic model.

5. In medical science:

• making orthoses
• creating dentures
• dentistry and implantology
• advanced face prosthetics
• comparative dermatology

6. Forensics:

• digitization of crime scenes
• archiving of evidence

7. Quality control and industrial metrology:

• Digitize parts
• Assembly of complex parts in CAD / CAM systems
• Creation of quality control variance maps
• Streamline production processes

To sum up, 3D scanners are very versatile devices thanks to which you can greatly facilitate and accelerate work in many fields of science and in many industries. However, you should always keep in mind the goal you want to achieve using this type of equipment. Each of the above-mentioned features can affect the final result and whether we will be satisfied with it or not.

Most of the scanners produced now can cope in most cases as a result by offering satisfactory 3D models, but the use of a good scanner designed for a specific purpose will result in the highest quality reproduction.