Why is angle orientation inconsistent?

asked 2018-10-31 05:17:13 -0500

smidm gravatar image

updated 2018-10-31 05:44:43 -0500

While working with 2D transformations and ellipses I painfully found out that the orientation of the angle in ellipse and getRotationMatrix2D is different. What is the reason for this inconsistency?

The ellipse angle is positive in clockwise direction:ellipse parameters

The getRotationMatrix2D angle orientation is described as Positive values mean counter-clockwise rotation (the coordinate origin is assumed to be the top-left corner).

I assume that the coordinate system origin is in all OpenCV functions in the top-left corner, which is standard when working with images.

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