What is Structured Light 3D Scanning and How It Works

What are Structured Light 3D Scanners?

A structured light 3D scanner measures an object's 3D shape by projecting a structured light pattern onto its surface. This pattern, often a grid or stripes, deforms when interacting with the object's contours. A camera or sensor captures images of the deformed pattern from various angles.

Imagine a dark room with a projector displaying stripes on a flat wall. If the wall has bumps or dips, the stripes become distorted. This principle underlies structured light technology.

Here are the specific steps:

1. Structured Light Projection
The scanner projects a light pattern (often stripes or a grid) onto the object's surface.

2. Image Capture
The scanner's camera captures surface deformations, allowing the scanner to determine the three-dimensional coordinates of each surface point.

3. Point Cloud Generation
Through the above process, the scanner converts the object's surface into a point cloud of numerous points, each with unique 3D coordinates.

4. Mesh Generation and Texturing
Connecting these points with triangles creates a mesh akin to a 3D "skin," then adds color and texture for realism.

What Can It Do

The 3D scanner converts objects' shapes, surface features, and colors into digital models that can be viewed, designed, and modified on a PC.

● Create Digital Models of Objects: It captures an object's shape and creates a digital model for design, analysis, or presentation, similar to scanning a statue to create a digital archive.

● Reverse Engineering: Scanning existing parts generates data for redesign or production, commonly used in the automotive industry to measure part dimensions.

● Quality Inspection: Compare the scanned model to the original design to ensure the parts meet specifications.

● Historical Conservation: Record every detail of historical items and even copy them with 3D printing technology.

● Healthcare: Scanning the body for prosthetics, braces, or surgery planning.

Object Size Matters!

Some scanners can create high-accuracy models for all sizes. However, if you mainly scan an object of a specific size, consider a specialized scanner designed to scan that size optimally.

● Select a high-accuracy scanner with a turntable, such as the Revopoint MINI2 or MetroX, for small items like springs or bolts.

● Consider the Revopoint INSPIRE, POP series, or MetroX for medium-sized objects in a desktop setting.

● For large objects, like a person or a car, the Revopoint RANGE or MIRACO series is suitable.

● If you need a portable scanner that handles both large and small objects, consider the Revopoint all-in-one MIRACO series.

Select your object size and see the right scanner for you

Advantages of Structured Light Scanners

Structured light 3D scanners have remained popular for years, offering unique advantages in 3D scanning compared to laser scanning and photogrammetry.

Accuracy and resolution: Structured light is among the best at capturing fine surface details for accurate 3D data. Structured light 3D scanners excel at capturing fine details by projecting high-resolution light patterns onto an object's surface. The camera detects how these patterns distort due to surface contours, allowing for accurate capture of slight variations in geometry, which is ideal for intricate details and delicate features.

Fast Scanning: A key advantage of structured light technology is its rapid scanning capability. Unlike laser scanning and photogrammetry, structured light captures extensive 3D data quickly. By collecting multiple points simultaneously, it swiftly generates 3D models, boosting productivity.

Cost Effective: Structured light systems have low equipment costs and appeal to small businesses and individuals. Structured light scanners offer high-quality 3D data at low investment and easy-to-use software, simplifying operation and learning.

Contactless Measurement: Structured light scans objects without contact, preventing damage and making it ideal for fragile or complex shapes. This method is essential in fields like medical imaging and artwork restoration, allowing data acquisition while protecting the items.

Safety: Class 1 infrared light is typically used in structured light, and 3D scanners can safely scan humans and animals without contact, capturing data without disturbance. It is used in medicine, sports, and entertainment, including facial recognition, motion capture, and medical imaging for 3D data acquisition.

Things You Should Know

The structured light 3D scanner is powerful, but like all tools, there are some things you need to know to get the most from it.

Dependence on Ambient Light

Issue: Structured light scanners can struggle to capture objects in strong light or direct sunlight. Structured light scanners often use infrared light, and sunlight, a significant infrared source, can confuse their sensors.

Solution: Use it in uniform indoor light or reduce ambient interference by shading the scanning area.

Reflective, Dark, or Transparent Surfaces

Issue: Reflective, dark, or transparent surfaces can cause data loss, as the light is either reflected or absorbed too much or not at all, preventing proper capture.

Solution: Use scanning spray to reduce the reflection so the surface becomes easily captured.

Limited Scanning Volume

Issue: Structured light scanners work best on small to medium objects.  Structured light scanners typically have a limited field of view and range for effectively projecting light patterns. The further the object is from the scanner, the more spread out the light pattern becomes, making it too diffuse to capture accurate surface details and depth. Large items, like cars and trucks, may need to be scanned in sections and merged.

Solution: Scan the object in sections and use Revo Scan's merging function to integrate data from multiple scans into a complete model.

Featurelss Surfaces

Issue: 3D scanners will lose track if there aren't any distinct features. This happens because structured light 3D scanners project patterns onto objects' surfaces, detecting distortions to infer shape. However, smooth or featureless objects lack the texture needed for these distortions, hindering the scanner's ability to capture accurate depth information and effectively scan such items.

Solution: Place markers on the object surface to give the scanner something to track.