OpenCV: how to rotate IplImage?

user_11323 0
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I need to rotate an image by very small angle, like 1-5 degrees. Does OpenCV provide simple way of doing that? From reading docs i can assume that getAffineTransform() should be involved, but there is no direct example of doing something like:

IplImage *rotateImage( IplImage *source, double angle);
image-manipulation opencv
5 Answers

If you use OpenCV > 2.0 it is as easy as

using namespace cv;

Mat rotateImage(const Mat& source, double angle)
{
    Point2f src_center(source.cols/2.0F, source.rows/2.0F);
    Mat rot_mat = getRotationMatrix2D(src_center, angle, 1.0);
    Mat dst;
    warpAffine(source, dst, rot_mat, source.size());
    return dst;
}

Note: angle is in degrees, not radians.

See the C++ interface documentation for more details and adapt as you need:

Martin_529860

Check my answer to a similar problem:

Rotating an image in C/C++

Essentially, use cvWarpAffine - I've described how to get the 2x3 transformation matrix from the angle in my previous answer.

user_711310
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