Reflecon Reference Points

In the field of 3D scanning, markers are known as "reference points", "target points", or "tracking points". These terms more accurately describe their role in the scanning process. Among them, scanning marker points represent a specific category, commonly referred to as uncoded marker points. Uncoded markers are the most commonly used in the field of 3D scanners, whether handheld laser scanners or fixed scanners. Marker point alignment is currently considered the most viable solution, and these markers usually have a circular design.

Now, from the manufacturer Reflecon, known for its 3D scanning products such as the sprays Tarnish 12 or TopoTrack, come adhesive and magnetic reference points. They have been specifically developed for use with structured light and laser scanners. They serve as precise markers for the spatial orientation of the scanner and for the accurate merging of individual scans. Depending on the scanner system, different variants are available that perfectly match the requirements, for example, in terms of size, adhesion, or reflective properties.

Reference points are essential to achieve high accuracy in complex geometries or large objects. They ensure stable point assignment and improve scan quality by minimizing motion errors and reducing the processing power required to merge scans. Using a handheld scanner implies working with a limited measurement area for each scan. Therefore, aligning data from multiple scans becomes essential.

Why choose circular shapes? In machine vision, circular marker stickers appear as ellipses in the images, regardless of the shooting angle. More importantly, the center of this ellipse remains constant in space, providing a stable reference point for determining the center. Different diameters are used to address various situations. For example, markers that are too small may not be clearly visible in the camera when changing the scanning distance, so different diameters are used to suit different scenarios.

Why choose reference cubes? Reference points are essential for capturing intricate details, but challenges arise when markers cannot be used due to the small size or delicate surface of the object. Moreover, achieving excellent scans with fewer reference points is key, especially when working with rotating illustrations or multiple different views during scanning. This is where Reflecon cubes come into play, as they not only improve the efficiency of 3D scanning complex objects but also reduce the dependence on reference points. Next time you scan an object on a tabletop, simply place some of these cubes around it to significantly enhance your workflow, as they remain visible even when the angle changes, assisting in scanning parts with flat surfaces.

What marker size do I need for my 3D scanners? Most handheld 3D laser scanners use 6 mm retroreflective target points. Structured light scanners offer a wider range of sizes depending on the resolution and measurement area. A good rule of thumb for calculating the dot size is to allow each to be visible with a distance of 8 to 15 pixels in the image. Take the following example: the measurement area has a width of 400 mm, and the scanner is equipped with 12-megapixel sensors (4000 x 3000 pixels). One pixel equals 400/4000 = 0.1 mm in width. Therefore, the appropriately sized targets should be 8 to 15 times larger; thus, 0.8 mm and 1.5 mm are good candidates for these applications.