iPad Camera input is rotated 180 degrees.

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Is it possible that you are mixing up coördinate systems and in that case messing up the way you are visualizing the input?

OpenCV coordinate system

General coordinate system

Also a common made mistake is switching the cols and row parameter when defining width and height of an image. It is confusing I know. Maybe worth investigating this?

On the other hand, the suggestion of flipping will work, but is just going around the actual problem.

EDIT : looking through the internet, I have found the following image, which suggests the IPAD coordinate system:

If considering this coordinate system, considered to the actual OpenCV coordinate system, I guess it is normal that you have a 180 degree shift, since the y - axis is inverted. So take this into consideration and flip your image pixels along the horizontal axis to get good references.

flip image function can be a quick trick in your case, but maybe you should investigate more to find a more perennial solution...