New Release of OptoInspect3D Inline Version 2.7

May 2020 sees the release of OptoInspect3D Inline Version 2.7. The most important improvements are:

Significantly increased performance:

  • Additional parallelisation strategies and re-use of calculated results lead to a 100% faster setup of the internal data structures and thereby to a 15% time reduction in all functions using these data structures (compared with the prior Version 2.6)
  • New speed-optimised functions for the calculation of curvatures, surface normals and thinning of point clouds (70% time reduction compared with Version 2.6)

New Functions:

  • Curvature-dependent thinning of point clouds (reduction of point-densities)
  • Additional registration methods for point clouds, particularly for flat objects

A free, graphics-based demo version is available here

New Release of OptoInspect3D Inline Version 2.6

Our colleagues in the OptoInspect3D Inline development team at Fraunhofer IFF have provided us with an early Xmas present in the form of a new release of the software library.

The new Version 2.6 includes the following key features:

  • Performance improvement in the best-fit and registration algorithms now give up to 40% reduction in compute times compared with Version 2.4.
  • Maximal inscribed cylinders and spheres are now available.
  • Pointclouds can now be reduced in size (thinned out) to a user-defined number of points (ALG3D_computeThinningToPointNumber).

New Release of OptoInspect3D Inline Version 2.5

OptoInspect3D Inline Version 2.5 was released in early November 2018 and is now available. This new version contains performance improvements and additions to the functionality of the Chebyshev approximation method.

New key features and improvements in Version 2.5

  • Improved speed for distances and registration of points to mesh
  • Chebyshev(Minimum-Zone)-best fit torus added  [new feature]
  • Convenience function for distance computations to point clouds added
  • Convenience function for distance computations to meshes added
  • Overall performance optimization and minor fixes in the underlying library

Release of OptoInspect3D Inline Version 2.4

OptoInspect3D Inline Version 2.4 was released in July 2018. This version includes a number of functional and performance improvements and several new features. One of the most important new features is the improved numerical stability and accuracy of the Minimum Zone computations using Chebyshev approximation methods.

The key new features and improvements in Version 2.4:

  • Improved numerical stability and precision for Chebyshev approximation methods
  • Chebyshev(Minimum Zone)- best fit 3D line
  • Minimum Enclosing Cylinder [new feature]
  • Minimum Enclosing Planes [new feature]
  • Algorithm for the calculation of a 3D convex hull [new feature]
  • Improved speed of Least-squares (Gauss) approximation methods
  • Iterative Closest Point: improved performance and stability for meshes (Least-Squares and Chebyshev)
  • Iterative Closest Point: rotation center can optionally be fixed at the origin

Shape evaluation using the “minimum zone“

The “minimum zone“ is often used in metrology for the evaluation of the shape of a specific geometry. In this context, the “minimum zone” is defined as the smallest possible area or distance between two geometrical objects, which enclose the shape (surface) that is to be investigated from both sides. To evaluate the cylindricity of an object – for example – two parallel concentric cylinders with a minimum and maximum radius are positioned in such a way, that the shape is completely contained in the area between the two cylinders and that the area between the two cylinders is as small as possible (cf. picture). If the “minimum zone” is small, this means that the shape is close to a cylinder.

„Minimum zone” of a cylindrical point cloud: on the left-hand side the best fit cylinder (not visible for reasons of clarity) has been computed with the Gauss method. The resulting „minimum zone“ (distance between maximum and minimum bounding cylinders) is significantly larger than on the right-hand side where the best fit cylinder has been computed with the Chebyshev method.

Analogously, the planeness, roundness or straightness of geometrical shapes can be evaluated. For planeness – for example – the “minimum zone” is defined as the distance between two planes, for roundness as the distance between two concentric spheres.

„Minimum Zone“ with Chebyshev

To get an accurate description and evaluation of the geometrical shapes it is important to have a „minimum zone“ that is as small as possible and closely resembles the geometric shape. With OptoInspect3D Inline the smallest possible “minimum zone” can be constructed easily. In the following, we take the example of a cylindricity analysis. As a first step, a best fit cylinder has to be generated for the measured point cloud. This best fit cylinder is commonly created by minimizing the sum of the squares of differences between the point cloud and the cylinder (the least-squares / Gauss method). However, OptoInspect3D Inline provides the alternative to minimize the maximum distance between the best fit cylinder and the pointcloud (Chebyshev method). In this case, the „minimum zone“ constructed with the Chebyshev best fit cylinder is by design minimal (and smaller than that produced by the Gauss method). Indeed, the “minimum zone” computed with the Gauss method is not the smallest region that is needed for evaluating the shape. This is why the “minimum zone” with Chebyshev should always be used for evaluating geometrical shapes (for example when investigating whether a bolt would fit inside a bore hole).


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