Accurate 3D Measurements in 2D Images – Part III

Have you ever wonder at what angle you can measure at when working in 2D. My rule of thumb has been 20 to 30 or maybe 45 degrees if you have a proper 3D calibration or if you take the effort to calibrate in the object plane.

This example has changed my understanding of extracting information from a 2D image. In this example I reconstruct a circle which is close to 90 degrees – the implication of this with regards to introduction is that as long as you see what you want to measure you can locate  and measure it .

By locating the four edge-points in 3D - i have the accurate 3D plane of the cylinder 🙂

What do I do?

  1. Select the cylinder to measure
  2. Locate the four edge points in 3D with the new tool component LocateEdgePoints3D
  3. Construct a 3D plane using the four point using ReferenceFromPoints3D

What do I have:

  1. The reference plane of the cylinder

What can I do?

  1. I can measure the 3D pose / position of the cylinder and the diameter

How do I do it?

  1. I use a 2D circle finder – RadialArcFinder – with the cylinder reference plane

How does it look like?

The circle is visualized - the cylinder center and the radius is on the label


What are the possibilities?

  1. This is very well suited for 3D objects like plastic parts
    • it is unbeatable when the plastic is transparent like the test images.
  2. It is real-time !
    • no time-consuming 3D scanning