【3D Scanning Knowledge】A Comprehensive Analysis of 3D Scanning: A Quick Guide to Comparing 5 Technologies!
3D scanning is a form of "reverse engineering" that generates 3D digital models of physical objects through light or contact methods. These models can be digitally preserved, edited, or directly used for 3D printing production. Currently, there are various 3D scanning technologies available, catering to different applications, from small tool parts to medium-sized human limbs, and large objects like cars or even landscape environments. Let's take a simple look at them below!
Basic Concepts
Application Categories
I. Non-Contact Scanning
"Time of Flight" (TOF) primarily uses laser light to detect the target object, 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. It is primarily used for large industrial objects and areas, offering high precision but being relatively slower compared to other 3D scanning technologies.
．Laser Triangulation
"Laser Triangulation" means that the laser point on the object, the sensor, and the laser form a triangle. Laser light is projected onto the object to be measured, and the sensor records the reflection time and deviation angle of the laser point, which is then used 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 properties of the scanned object and is not suitable for objects with highly reflective or transparent surfaces.
．Photometric Stereo
Photometric stereo (or "stereo optical") works by analyzing static photos taken from different angles and automatically detecting corresponding pixels. Due to the large amount of information, high-power computers are required for processing.
Features and Limitations: Photometric stereo technology is very suitable for large-scale areas like surface models or aerial photography. One of its drawbacks is the lower resolution for details and the longer time required for model computation.
．Structured Lighting 3D Scanning
A linear pattern (or "grating") is 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 or blue light, making it widely used for human body or face imaging. Some 3D scanners can also read color effects; 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. (Extended reading: EinScan Pro 2X+ Challenge! Car bumper modeling in just 3 minutes!)
Features and Limitations: Structured light 3D scanning strikes 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. For outdoor environments, it is recommended to scan on overcast days without strong sunlight. (Extended reading: Reverse Engineering Test: Monsters and Their Models!)
II. Contact Scanning
This method uses physical contact to detect the object. A probe moves across various points on the surface to calculate a 3D image, which can be imagined as using a pen to draw a three-dimensional structure.
Features and Limitations: Contact-based 3D scanning offers higher accuracy and is largely unaffected by surface lighting. However, in terms of speed, it is only suitable for small to medium-sized objects, and due to the limitation of physical contact, it is not suitable for fragile cultural relics or artworks.
Key Summary
(Using 1-5 as a relative indicator, 1 is the smallest value, and 5 is the largest value.)
．Time of Flight: Depicts the geometric data of an object by measuring the round-trip time difference between emitted and received laser points.
．Laser Triangulation: Projects laser light onto an object's surface and measures the laser angle data to convert it into a 3D image.
．Photometric Stereo: Uses computers and visual images to reconstruct 3D images from a large number of overlapping 2D pixels.
．Structured Light: Constructs 3D scan images based on the deformation produced when a grating illuminates an object, typically using LED light sources.
．Contact 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? 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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