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 | 1 | initial version |
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);
| | 2 | No.2 Revision |
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);
| | 3 | No.3 Revision |
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);
| | 4 | No.4 Revision |
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:
| | 5 | added boundingbox for lowering computation in rotation |
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:
| | 6 | removed link to a page not existing on my website anymore (may add it later again) |
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: