Amidst the continuous emergence of innovative technologies, the demand for presenting real-world objects in 3D is on the rise, particularly in the realms of machine vision and 3d visualization, where precise and adaptive 3D capture capabilities have become indispensable.
3D scanning serves as a method for extracting the surface and physical dimensions of an object, subsequently representing them in digital form. This data is gathered in the form of point clouds, delineating the external surface of the object through X, Y, and Z coordinates. An in-depth analysis of 3D scanning data allows for the determination of crucial information, including surface area, volume, shape, contour, and feature size of the scanned object.
To execute 3D measurement, a probe is employed to measure the distance to each point on the object’s surface. In theory, this probe could take the form of a tactile (physical contact) probe. However, given that numerous applications necessitate non-contact measurements, optical technologies provide viable solutions by relying solely on light-based to detect objects of interest.
What is structured light?
Structured light, employed as an optical method in 3D scanning, functions by projecting a series of meticulously designed light patterns onto the object under measurement in a specific sequence. During this process, a camera, positioned at a known distance from the projector, concurrently captures a sequence of images of the illuminated object.
The captured image undergoes distortion based on the surface shape being scanned in relation to the flat reference surface utilized for calibration. Leveraging the principles of geometric triangulation, the XYZ coordinates for each point on the scanned object’s surface can be computed. The resulting point cloud data is then utilized to construct a detailed 3D model of the scanned object’s surface.
Structured light scanning employs a single light source to project multiple lines onto an object, which are concurrently tracked by one or more cameras. This differs from laser scanners, which emit individual laser points onto an object sequentially. While the fundamentals of structured light 3D scanning have been in existence for decades, early models were often characterized by their rudimentary nature, bulkiness, high costs, and usability challenges.
However, by the late 1990s, advancements in computer and camera technologies rendered structured light 3D scanning more practical and suitable for smaller research initiatives, commercial enterprises, and casual users. The evolution of this technology not only enhances scanning precision but also improves the user-friendliness of the equipment, thereby unlocking new possibilities for structured light 3D scanning technology, widely applicable across diverse fields.
How does structured light 3D scanning work?
The functionality of structured light 3D scanning is rooted in utilizing optical techniques to project a series of uniformly intense beams, sequentially illuminating the object under measurement. A single beam proves insufficient for the 3D scanning of an object as it fails to capture the depth of distinct features. To address this limitation, structured light scanning employs intricate calibration patterns containing projections with alternating light gradient stripes. This design enables the camera to differentiate various depth values within the observed pattern, thereby facilitating the creation of a more precise 3D model.
Two methods generate these fringe patterns: the intersection of two laser beam fronts or the use of a single light source passing through a digital spatial light modulator. Both methods yield regular and evenly spaced light streaks. Although most structured light scanning traditionally utilizes white light, the adoption of blue light is becoming standard due to its superior accuracy and its capacity to mitigate the impact of reflections and transparency.
The generation of 3D models through structured light scanning necessitates sophisticated phase unwrapping algorithms, often integrated into the capabilities of 3D scanning platforms. The quality of the results is pivotal to the resulting model’s accuracy. Optical resolution relies on stripe width and optical quality, constrained by the wavelength of light. The phase-shift method enhances resolution by capturing multiple shots of slightly shifted fringes. Present-day optical stripe pattern profilometry supports detailed resolution down to the wavelength of light, surpassing 1 micron or approximately 1/10 of the stripe width. In terms of horizontal accuracy, interpolation ensures reliable height resolution and accuracy down to 1/50 pixel.
Advantages and Challenges of Structured Light 3D Scanning
Structured light 3D scanning stands out with numerous advantages, positioning itself as the preferred technology for users worldwide across various fields. Let’s delve into the key strengths of structured light scanning and its significant impacts in diverse applications:
Non-contact Measurement
Structured light scanning excels in capturing a wide array of objects comprehensively. In contrast to contact measurement methods like Coordinate Measuring Machines (CMM) or target photogrammetry, which are often impractical for unique artifacts, museum pieces, or high-value collections, structured light scanning facilitates non-contact measurements with sub-millimeter accuracy. This reduces the risk of damage, making it a valuable choice in sensitive scenarios.
High-Speed Scanning
Renowned for its exceptional speed, structured light 3D scanners outpace traditional photogrammetry, CMM machines, or manual measurement tools. Completing tasks in just one to two hours, these scanners significantly enhance work efficiency, especially in dynamic and time-sensitive environments.
Excellent Accuracy
Structured light ensures high-precision 3D scanning. Going beyond traditional measurement methods like calipers and rulers, it captures the entire object or scene from all angles, providing comprehensive data. This is particularly crucial for measuring complex objects, surpassing the limitations of merely capturing discrete points and linear extensions on the surface.
Absolute Safety
Structured light has a longstanding and safe track record in healthcare. Extensive testing and medical approval affirm its safety in various settings, including hospitals, schools, and businesses. Unlike certain laser scanners that pose potential risks of vision damage or employ radiation for scanning, structured light scanners offer a harmless and effective alternative.
However, structured light 3D scanning encounters challenges, including sensitivity to environmental factors such as scanning shadowed objects or areas with multiple light sources. Additionally, it may face challenges with transparent or reflective materials, potentially leading to the loss of details in the resulting model. Addressing these challenges requires specialized handling and remediation to ensure accurate and reliable scan results.
Structured Light 3D Scanning: Versatile Applications Across Diverse Industries
Structured light 3D scanning technology’s extensive applications extend beyond traditional fields, showcasing its adaptability and versatility.
Reverse Engineering of Objects
Structured light 3D scanning plays a pivotal role in reverse engineering, transforming real-world objects into digital models. This is particularly crucial for Computer-Aided Design (CAD) data generation in manufacturing, significantly expediting the product design and development process.
Records of Cultural and Historical Artifacts
Structured light scanning finds increasing significance in cultural relic protection and the preservation of cultural heritage. Through high-precision scanning, intricate details of cultural artifacts can be accurately recorded, supporting restoration, research, and digital preservation efforts.
Motion and Environment Capture for Augmented Reality Games
Game development leverages structured light 3D scanning to capture player movements and environments, enhancing the realism and immersion in augmented reality gaming experiences.
Body Measurements for Fashion Retail
Within the fashion industry, structured light scanning facilitates accurate body measurements. This aids customers in finding clothing that best suits their body shape, elevating the overall shopping experience.
Automotive Industry
In the automotive sector, structured light 3D scanning is used extensively for prototyping, design, and quality control. Manufacturers scan parts and assemblies to ensure they meet strict specifications and fit together precisely. This technology is crucial for reverse engineering components, especially when original CAD data might not be available, or when modifications are needed for aftermarket products.
As structured light technology continues to evolve, its applications are poised to expand, unlocking more intriguing and innovative possibilities. In the future, structured light 3D scanning is anticipated to become a standard tool across various industries, offering practical digital solutions to an even broader spectrum of users.
Structured light 3D scanning VS Laser 3D scanning
While structured light 3D scanning has proven its mettle across diverse applications, offering precision, speed, and safety, another technological marvel in the domain of 3D digitization is laser scanning. Laser 3D scanning, or laser triangulation, presents a distinct approach, harnessing the power of laser technology to capture the physical world in unparalleled detail.
Unlike structured light scanning, which relies on the projection of patterned light, laser scanning focuses on the interaction of a single laser point with the object’s surface. This method offers its unique set of advantages and challenges, tailored for specific applications where precision, resolution, or speed are paramount.
Advantages of Laser 3D Scanning
High Precision and Resolution: Laser 3D scanners are renowned for their high precision and resolution, such as Scantech KSCAN-Magic handheld 3D scanner, capable of capturing even the minutest details of an object. This makes them ideal for applications requiring meticulous detail and accuracy.
Versatility in Material Compatibility: Laser scanners exhibit less sensitivity to different surface types and colors compared to structured light scanners. They can efficiently scan metallic, dark, or shiny surfaces, which might pose challenges for structured light scanners.
Robust in Various Lighting Conditions: Laser scanners are less susceptible to ambient lighting conditions, allowing for consistent performance in diverse environments, whether indoors or outdoors.
Long-Range Scanning Capability: Certain laser scanners, like TrackScan-Sharp 3D system, are designed for long-range scanning, capable of accurately capturing large structures or environments from a distance. This is particularly beneficial in construction, architecture, and large-scale industrial applications.
Structured Light 3D Scanning Unleashes a New Era of Digital Solutions
Structured light 3D scanning technology emerges as a rapid, user-friendly, accurate, and highly effective method for capturing objects and scenes. Its widespread applications across medical, manufacturing, and cultural heritage fields underscore its indispensable role as a digital solution. As an increasing number of schools, universities, and industries integrate 3D scanning technology, the future for structured light 3D scanning appears promising, fostering advancements across diverse industries. This technology stands poised to shape the landscape of numerous sectors, contributing to their growth and innovation.
