Most digital system manufacturers are highly acclaimed for the accuracy and effectiveness of their equipment under ideal conditions, but the results of experiments with different levels of complexity and material manufacturing refute the effects of these systems. In the reverse design process, based on the consideration of precision and triangular meshing, we compared the effects of five different systems to make the appropriate choice.
The three correction units are measured five times by five different systems to ensure their measurement accuracy, while the mesh is divided by five different packages for a comparative analysis of the quality of the scan measurements. The measured objects contain three Correction unit and a bone and a mobile phone. Finally, check the quality of the point cloud partition, and all the measurements are divided by the triangles in the module.
The rapidly evolving non-contact 3D digital data acquisition system provides support for reverse engineering in the design field. This is a special case in the field of industrial design - the use of computer-assisted reverse programs to generate surfaces (ordinary free-form surfaces), to reproduce point clouds and to visualize deformation, but generally does not satisfactorily capture the intent and point of the design. Our job is not to study the widespread reverse design approach but to compare different digital data acquisition systems. This is mainly done by preparing a point cloud to obtain a suitable segmentation surface for comparison, including denoising, removing points, mesh triangulation, repairing meshes, and void filling, as they are subsequently reconstructed in reverse engineering to reconstruct the surface. According to the general reverse design chart, our work compares different data acquisition systems with the divided modules and related point clouds.
Choosing to choose a data acquisition system in reverse design is not an easy task. It is usually based on the following requirements: accuracy, data model category, and data quality. Furthermore, considering the device information and technical effects provided by the manufacturers of different digital systems, the degree of matching between the demonstration effects and the real model is also necessary.
Currently, the most widely used data acquisition system in the reverse direction is an optical scanner. The following are practical problems based on the current point cloud mentioned:
- Surface roughness, a rough surface produces more noise than a smooth surface and its reflected light produces more noise.
- Incomplete data exists in fixed parts and surfaces that are difficult to scan due to shadows or other surfaces.
- calibration
- statistically distributed parts
- Precision. This is mainly determined by the distance between the scanner and the surface of the object being measured and the motion of the scanner.
- Noise points. Vibration, specular reflection, and so on can cause noise, and eliminating noise allows us to eliminate the edges.
—— Consider multi-angle scanning, we have to run the digital system from multiple aspects when moving the object, and then adjust the point cloud by positioning and rotation.
The main purpose of reverse engineering is to transform discrete model data into continuous model data based on the continuity determined by its surface. In general, discrete data refers to a point cloud that is digitized in a defined or random manner with three coordinates of X, Y, and Z. A scanner with a CMM (coordinate measurer) is a way to obtain ordered data, but when many different places pass the same node position, the nodes in the area will overlap and the points will be out of order. And unevenly distributed. If the scanner is manually controlled and its position is controlled by the camera or the object under test, the points collected are randomly and randomly distributed. The role of the ordered point cloud is to promote triangular meshing so that the file takes up less space. There are a lot of researches on algorithm design for reducing and optimizing point cloud partitioning, but we study the part of scanning technology that has applications in reverse design.