# Revision history [back]

There's a great article by Felix Abecassis on rotating and deskewing images. This also shows you how to extract the data in the RotatedRect:

You basically only need cv::getRotationMatrix2D to get the rotation matrix for the affine transformation with cv::warpAffine and cv::getRectSubPix to crop the rotated image.

If you need code samples on this, you can also have a look at:

The relevant lines in my application are:

        M = getRotationMatrix2D(rect.center, angle, 1.0);
warpAffine(src, rotated, M, src.size(), INTER_CUBIC);
getRectSubPix(rotated, rect_size, rect.center, cropped);


There's a great article by Felix Abecassis on rotating and deskewing images. This also shows you how to extract the data in the RotatedRect:

You basically only need cv::getRotationMatrix2D to get the rotation matrix for the affine transformation with cv::warpAffine and cv::getRectSubPix to crop the rotated image.

If you need code samples on this, you can also have a look at:

The relevant lines in my application are:

 // rect is the RotatedRect (I got it from a contour...)
RotatedRect rect;

// matrices we'll use
Mat M, rotated, cropped;

// get angle and size from the bounding box
float angle = rect.angle;
Size rect_size = rect.size;

// thanks to http://felix.abecassis.me/2011/10/opencv-rotation-deskewing/
if (rect.angle < -45.) {
angle += 90.0;
swap(rect_size.width, rect_size.height);
}
// get the rotation matrix
M = getRotationMatrix2D(rect.center, angle, 1.0);
// perform the affine transformation
warpAffine(src, rotated, M, src.size(), INTER_CUBIC);
// crop the resulting image
getRectSubPix(rotated, rect_size, rect.center, cropped);


There's a great article by Felix Abecassis on rotating and deskewing images. This also shows you how to extract the data in the RotatedRect:

You basically only need cv::getRotationMatrix2D to get the rotation matrix for the affine transformation with cv::warpAffine and cv::getRectSubPix to crop the rotated image.

If you need code samples on this, you can also have a look at:

The relevant lines in my application are:

        // rect is the RotatedRect (I got it from a contour...)
RotatedRect rect;
// matrices we'll use
Mat M, rotated, cropped;
// get angle and size from the bounding box
float angle = rect.angle;
Size rect_size = rect.size;
// thanks to http://felix.abecassis.me/2011/10/opencv-rotation-deskewing/
if (rect.angle < -45.) {
angle += 90.0;
swap(rect_size.width, rect_size.height);
}
// get the rotation matrix
M = getRotationMatrix2D(rect.center, angle, 1.0);
// perform the affine transformation
warpAffine(src, rotated, M, src.size(), INTER_CUBIC);
// crop the resulting image
getRectSubPix(rotated, rect_size, rect.center, cropped);


There's a great article by Felix Abecassis on rotating and deskewing images. This also shows you how to extract the data in the RotatedRect:

You basically only need cv::getRotationMatrix2D to get the rotation matrix for the affine transformation with cv::warpAffine and cv::getRectSubPix to crop the rotated image.

If you need code samples on this, you can also have a look at:

The relevant lines in my application are:

        // rect is the RotatedRect (I got it from a contour...)
RotatedRect rect;
// matrices we'll use
Mat M, rotated, cropped;
// get angle and size from the bounding box
float angle = rect.angle;
Size rect_size = rect.size;
// thanks to http://felix.abecassis.me/2011/10/opencv-rotation-deskewing/
if (rect.angle < -45.) {
angle += 90.0;
swap(rect_size.width, rect_size.height);
}
// get the rotation matrix
M = getRotationMatrix2D(rect.center, angle, 1.0);
// perform the affine transformation
warpAffine(src, rotated, M, src.size(), INTER_CUBIC);
// crop the resulting image
getRectSubPix(rotated, rect_size, rect.center, cropped);


Taken from a blog article I wrote at:

There's a great article by Felix Abecassis on rotating and deskewing images. This also shows you how to extract the data in the RotatedRect:

You basically only need cv::getRotationMatrix2D to get the rotation matrix for the affine transformation with cv::warpAffine and cv::getRectSubPix to crop the rotated image. The relevant lines in my application are:

        // rect is the RotatedRect (I got it from a contour...)
RotatedRect rect;
// matrices we'll use
Mat M, rotated, cropped;
// get angle and size from the bounding box
float angle = rect.angle;
Size rect_size = rect.size;
// thanks to http://felix.abecassis.me/2011/10/opencv-rotation-deskewing/
if (rect.angle < -45.) {
angle += 90.0;
swap(rect_size.width, rect_size.height);
}
// get the rotation matrix
M = getRotationMatrix2D(rect.center, angle, 1.0);
// perform the affine transformation
warpAffine(src, rotated, M, src.size(), INTER_CUBIC);
// crop the resulting image
getRectSubPix(rotated, rect_size, rect.center, cropped);


A simple trick to only rotate the content of the RotatedRect is to first get the ROI from the Bounding Box of the RotatedRect by using RotatedRect::boundingRect() and then perform the same as above, for cv::RotatedRect see:

Taken from a blog article I wrote at:

There's a great article by Felix Abecassis on rotating and deskewing images. This also shows you how to extract the data in the RotatedRect:

You basically only need cv::getRotationMatrix2D to get the rotation matrix for the affine transformation with cv::warpAffine and cv::getRectSubPix to crop the rotated image. The relevant lines in my application are:

        // rect is the RotatedRect (I got it from a contour...)
RotatedRect rect;
// matrices we'll use
Mat M, rotated, cropped;
// get angle and size from the bounding box
float angle = rect.angle;
Size rect_size = rect.size;
// thanks to http://felix.abecassis.me/2011/10/opencv-rotation-deskewing/
if (rect.angle < -45.) {
angle += 90.0;
swap(rect_size.width, rect_size.height);
}
// get the rotation matrix
M = getRotationMatrix2D(rect.center, angle, 1.0);
// perform the affine transformation
warpAffine(src, rotated, M, src.size(), INTER_CUBIC);
// crop the resulting image
getRectSubPix(rotated, rect_size, rect.center, cropped);


A simple trick to only rotate the content of the RotatedRect is to first get the ROI from the Bounding Box of the RotatedRect by using RotatedRect::boundingRect() and then perform the same as above, for cv::RotatedRect see:

Taken from a blog article I wrote at: