Scorpion Update – STC-0039-EllipseFit2D

We are working hard to improve our 2D and 3D capabilities. Our latest addition is a Scorpion Tool Component – STC-0039-EllipseFit2D. This component is a component in a family of components that handle polygons or collections of 2D points.

Another interesting component that will be described later post is the STC-0032-PolygonCorners that locates the corner or turning points of a path or a closed polygon.

Step 1 – Locate a circle

The image below shows the Scorpion tool RadialArcFinder that locates a circle. When used on an ellipse this tool “fail” by locating the center at the center of the “circle” and not the ellipse.

2D Circle Fit to an ellipse

Step 2 – Locate the ellipse

We use the “Fitted Points” results from the circle finder to estimate the true center of the ellipse.

STC-2012-EllipseFit2D locates the true center

The configuration dialog is simple and shown below.

STC-0039 FitEllipse3D Configuration Dialog


The ability to be able to locate the true center of an ellipse is a very valuable feature. It can be used in 2D machine vision and also in 3D machine vision where the intersection between two camera is more accurate and robust when the ellipse center is used than a poorer circle center estimate.

The image shows the difference between ellipse and circle center.

The STC-0039-FitEllipse2D is available in the  Scorpion Vision Software 9.3 release as a standard tool in the Basic and Premium versions.

One Response

  1. […] FindCircles that was based on Detect/Fitting Circles using Hough Transform in OpenCV and the STC-0039 EllipseFit that fits an ellipse from a collections of 2D points. The activities increased our understanding […]

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