AlfaTest presents its vision and classification of 3D Scanning.

About 3D Scanning

Scanner Types

Contact Scanning

Time of Flight (ToF)

3D Scanning Application

3D scanning is the process of analyzing a real-world object or environment to collect data on its shape and possibly its appearance (i.e. color). The collected data can then be used to construct digital three-dimensional models.

The first 3D scanning technology was created in the 1960s.

In modern engineering, the term `laser scanning’ is used to described two related, but separate meanings. The first, more general, meaning is the controlled deflection of laser beams, visible or invisible. Scanned laser beams are used in laser printers, in laser shows, in Laser TV, and in barcode scanners.

The second, more specific, meaning is the controlled steering of laser beams followed by a distance measurement at every pointing direction. This method, often called 3D object scanning or 3D laser scanning, is used to rapidly capture shapes of objects, buildings, and landscapes.

According to the Allied Market Research, significant factors that impact the growth of the global 3D scanning industry include ongoing technological advancements in 3D scanning paired with surge in need for highly accurate 3D scanning.

Moreover, growth in need to capture large volumes of 3D data for modeling and analysis is expected to drive the market opportunity. However, dependence of market growth on non-3D businesses coupled with high price of high-resolution 3D scanners acts as a prime barrier for early adoption, which hampers the growth of the market.

On the contrary, growth in 3D printing market generates demand paired with structured light-based 3D scanning, which is expected to offer potential growth opportunity for the 3D scanning market during the forecast period.

There are many classifications and categories of 3D scanners. We at AlfaTest see a global 3D scanning market consisting of the following scanning technologies:

Contact Scanning (Coordinate Measuring Machines – CMM)
Time of Flight (ToF)
Laser Scanning (Triangulation)
Structured Light
Volumetric (Computed Tomography)
Photogrammetry

CONTACT SCANNING (COORDINATE MEASURING MACHINES - CMM)

This 3D scanning method involves the physical contact of a probe onto the surface of the object being scanned. First, the object is firmly held in place so that it does not move. Then, the touching probe is moved all over the object in order to collect the details of the object and all the 3D information that is necessary to create a digital file.
The disadvantage with contact 3D scanning is its slow speed. Running the touching probe through all sections of an object in order to collect all the 3D information takes time. Tag: Jointed arms.

APPLICATION:

Quality control
Deformations or damages control
Highly accurate 3D modelling

ADVANTAGE:
Accuracy up to 0.0001 mm

DISADVANTAGE:
Timing
Sensitive to vibrations, etc
Stationary

APPROX COST:
Used: € 20.000-50.000

REPRESENTATIVE VIDEO:
Link 1; Link 2

TIME OF FLIGHT (ToF)

Is a method for measuring the distance between a sensor and an object, based on the time difference between the emission of a signal and its return to the sensor, after being reflected by an object. Tag: Light Detection and Ranging (LiDAR); Phase shift.

APPLICATION:
Large structures, such as buildings and other geographical features
Architecture, construction, and building facility management industries

ADVANTAGE:
Large distances use
Scanning in darkness (IR)

DISADVANTAGE:
Acquisition speed
Tolerances > 2 mm
Surface cannot be reflective or transparent
Light speed affected by environment
Multiple scans needed

APPROX COST:
Used: € 15.000-60.000

REPRESENTATIVE VIDEO:
Link 1; Link 2; Link 3

LASER SCANNING (TRIANGULATION)

By casting a laser beam upon the object being scanned, a camera is able to record where the beam and object intersect. Knowing both the angles of the laser beam and camera makes it possible to know the precise location of the laser dot that is hitting the object.

In most cases a laser stripe, instead of a single laser dot, is swept across the object to speed up the acquisition process.

The position can be determined by the scanner using reference features on the surface being scanned. Tag: Adhesive targets; Laser tracker.

APPLICATION:
Quality control
Reverse engineering
3D printing

ADVANTAGE:
Low price of stationary scanners
Acquisition speed
Accuracy 0.01 mm

DISADVANTAGE:
Surface cannot be reflective or transparent
Limited range
Time for applying positioning targets

APPROX COST:
New: € 20.000-30.000

REPRESENTATIVE VIDEO:
Link 1; Link 2

STRUCTURED LIGHT

Structured light 3D scanners project an image with a pre-determined pattern on the subject. Depending on the features of the subject, the pattern will then be distorted in a number of different ways. A camera records the image of the projected pattern and uses the data on the distortions to calculate the dimensions of the individual features.

APPLICATION:
Quality control
Reverse engineering
3D printing

ADVANTAGE:
Accuracy up to 0.001 mm
Acquisition speed
Relatively low cost

DISADVANTAGE:
Surface cannot be reflective or transparent
Need for dim lighting or total darkness

APPROX COST:
New: € 10.000-20.000

REPRESENTATIVE VIDEO:
Link 1; Link 2

VOLUMETRIC (COMPUTED TOMOGRAPHY)

The object is placed on a turntable in the middle of the CT scanner. The X-ray tube emits X-rays that penetrate the object. A detector receives the rays and creates a 2D X-ray section image.
Then the turntable is rotated minimally, and the scanner generates another X-ray image.
These 2D sectional images are then combined by the computer to form a 3D model. This process is called: “Creation of a volume graphic”.
MRIs (magnetic resonance imaging) use radio waves and CT (computed tomography) scans use X-rays. MRI is for softer tissue.

APPLICATION:
Medical industry
Industrial NDT
Security

ADVANTAGE:
Accuracy ≤0.005mm
External and internal inspection

DISADVANTAGE:
Can only penetrate certain materials. The denser the material, the more difficult it is for the CT scanner to create a 3D model. As for lead, it is almost impossible for X-rays to penetrate it.
Price

APPROX COST:
New: $ 285.000-2.100.000

REPRESENTATIVE VIDEO:
Link 1

PHOTOGRAMMETRY

The technology takes multiple images, taken at different positions, and triangulates points in these images to figure out the location of them in a three-dimensional space.