【3D Scanning Knowledge】A Comprehensive Analysis of 3D Scanning: A Layman's Guide to 5 Technologies!
3D scanning is a form of "reverse engineering" that uses light or contact to compute 3D models of physical objects. These models can be digitally saved, edited, or directly used for 3D printing production. There are various 3D scanning technologies available on the market today, each with different applications, ranging from small tool parts, medium-sized human limbs, or large cars, to landscapes and environments. Let's take a simple look at them below!
Basic Concepts
Application Categories
I. Non-Contact Scanning
"Time of Flight" or "ToF" primarily uses laser light to detect target objects, then calculates the surface image of the object based on the round-trip time of the laser light. Since each laser signal can only measure one endpoint, it is usually equipped with a rotating mirror to enable 360-degree scanning of the object.
Features and Limitations: "Time of Flight" can measure approximately 10,000 to 100,000 target points per second, primarily used for large industrial objects and sites with high precision. However, compared to other 3D scanning technologies, it is relatively slow.
．Laser Triangulation
As the name suggests, "Laser Triangulation" refers to a triangle formed by the laser spot on the object, the sensor, and the laser. It works by emitting a laser beam onto the object to be measured, and the sensor records the reflection time and deviation angle of the laser spot to calculate the object's shape.
Features and Limitations: "Laser Triangulation" is a 3D scanning technology with higher resolution and accuracy. However, it is relatively sensitive to the surface characteristics of the scanned object and is not suitable for objects with highly reflective or transparent surfaces.
．Photometric Stereo
Photometric stereo (or "stereoscopic optics") works by analyzing static photos taken from different angles and automatically detecting corresponding pixels. Due to the massive amount of information, high-power computers are needed for computation.
Features and Limitations: Photometric stereo technology is very suitable for large-scale areas such as terrain models or aerial photography. One of its drawbacks is its lower resolution for details and the long computation time required for modeling.
．Structured Lighting 3D Scanning
Linear patterns (or "gratings") are projected onto the object to be measured, and the deformation of the grating edges is used to calculate the object's surface shape. The light source is usually LED white light or blue light, making it widely used for human body or facial imaging. Some 3D scanners can also read color effects, and this full-color scanning auxiliary tool is often called a "texture camera." Because it can measure multiple points or large areas at once, it is often divided into two methods: fixed 360-degree scanning or handheld rapid scanning. (Further reading: EinScan Pro 2X+ Challenge! Car Bumper Modeling in Just 3 Minutes!)
Features and Limitations: Structured light 3D scanning achieves a balance between speed and imaging quality, and handheld scanning is relatively simple, making it a more common application technology. However, this technology is more sensitive to ambient light, so it is more suitable for indoor use. In outdoor environments, it is recommended to scan on cloudy days without strong sunlight. (Further reading: Reverse Engineering Test, Monsters and Their Models!)
II. Contact-Based Scanning
This method physically probes the object, using a probe that moves across its surface to various endpoints to calculate a 3D image. You can imagine it as a computational method that outlines a three-dimensional structure with a pen.
Features and Limitations: Contact-based 3D scanning offers high accuracy and is largely unaffected by object surface illumination. However, in terms of speed, it is only suitable for small to medium-sized objects, and due to the limitations of physical contact, it is not ideal for fragile cultural relics or artworks.
Key Summary
(Using 1-5 as relative indicators, with 1 being the lowest value and 5 being the highest value.)
．Time of Flight: Depicts the geometric data of an object by measuring the time difference between the emission and reception of laser light.
．Laser Triangulation: Projects laser light onto the object's surface and measures the laser angle data to convert it into a 3D image.
．Photogrammetry: Reconstructs images in 3D from a large number of 2D overlapping pixels using computers and visual images.
．Structured Light: Constructs a 3D scan image based on the deformation produced when a grating illuminates an object, typically using an LED light source.
．Contact-based scanning: Relies on physical multi-point sampling of a physical object and uses the contact trajectory of a probe to create an image.
After this introduction, do you have a better understanding of 3D scanning? Are you unsure if a 3D scanner can meet your needs? Feel free to contact us for answers, or we also offer high-quality on-demand scanning services.
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