How do I rotate an elipse in opencv?

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Hi guys

I have a little project in opencv, just distinguishing coins from pens from a static image. All it does is basically find the contours of each object and draws a best fit elipse around it.

The coins are fine, problem I have is each elipse which is supposed to surround each pen is centered and the correct size but sits at a 90 degree angle to the object. Ive used the cvelipsebox function and I was wondering if there was a function to rotate this elipse 90 degrees? I've been googing but an't find a solution...If my code would make it easier, just let me know what you need to see

Any help would really be appriciated

Martyn

Posted 1-Mar-11 2:39am

kutalinelucas

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musefan · Answer 1 · 2011-03-01T02:45:00

not sure what this opencv is but if you are drawing an ellipse by specying X, Y, width and height then switch the width and hight values would produce a 90 degree rotation.

Sorry if I am off the mark with this one

EDIT: (Not quite sure how to work this Q&A stuff yet)

These functions? http://opencv.willowgarage.com/documentation/cpp/drawing_functions.html
...the first overload for ellipse function takes an angle value as the forth parameter. This could be set as -90 or 90 to give the correct rotation you would need. As you can see from the diagram in the link, the ellipse initially starts pointing to the right (90 degrees) so I would assume your drawing is defaulting to an angle of 0