3D Laser Scanning Services – What is a Structured-Light 3D Scanner?

3D Laser Scanning Services – What is a Structured-Light 3D Scanner?

From the video game industry to the construction industry, 3D laser scanning services are used to record the spatial data of objects, structures and environments and reconstruct it into polygon mesh models, surface models and solid CAD models that can be used to produce a variety of products, preserve or re-engineer certain aspects of buildings or monuments and judge the best excavation or building practices in relation to a specific terrain. But to whatever end laser scanning is used, it all begins with using the right 3D laser scanning equipment. In general, using the right type of laser scanner depends first on the size of the subject matter. For example, surveying buildings or monuments requires laser surveying equipment that can gather data from a significant distance, such as a non-contact time-of-flight laser scanner, while smaller objects, especially those that have significant detail and whose surfaces make them a poor candidate for contact scanners, require a non-contact scanner that is capable of gathering detail at close range, such as triangulation laser scanner or a structured-light laser scanner. In this article, we present an overview of the latter.

Like triangulation laser scanners, structured light scanners use a camera to capture the spatial data of their subject. But instead of projecting a laser, they project light patterns that often take the form of stripes. By projecting narrow bands of light onto three-dimensional objects, structured-light scanners produce a line of illumination that appears distorted to the naked eye but is used to gather data for the precise geometric reconstruction of the subject. The applications for structured-light surveying are numerous and include the following: body shape measurements, forensic inspections, measurement of road surface quality, measurement of wrinkles in cloth and other materials, measurement of skin surface for cosmetics, gathering data on objects of cultural heritage, measurement for determining the radius of cutting tool blades, measurement for the classification of grinding surfaces, measurement of combustion chamber volume in machines, precision measurement for production control and reverse engineering.

Structured-light scanners can emit various patterns of structured light, but the emission of numerous stripes tends to be the preferred method and falls into two categories: laser interference and projection. Using two wide planar laser beam fronts, the interference method creates numerous lines of equal distance apart and is typically used for the precise and easy scanning of fine patterns at an unlimited depth of view, such as measuring skin surface for cosmetic purposes. The projection method, on the other hand, uses no coherent lighting pattern, instead working like a video projector and generating patterns from a display within the projector. While both methods of structured-light 3d laser scanning services are valued for their ability to scan fine surfaces at a great depth, they typically prove ineffective at scanning reflective, transparent and semi-transparent surfaces. Usually, however, a coating of thin opaque lacquer can be applied to the above surface qualities to remove the disadvantage.