使用OpenCV在iOS中进行透视变换+裁剪
mma*_*ckh 51 opencv image-processing objective-c perspective ios
我正在尝试在即将推出的应用中实现裁剪和透视校正功能.在做研究的同时,我遇到了:
在一组cv :: Point上执行cv :: warpPerspective以进行伪偏移
http://sudokugrab.blogspot.ch/2009/07/how-does-it-all-work.html
所以我决定尝试用OpenCV实现这个功能 - 框架就在那里,所以安装很快.但是,我没有得到我希望的结果:(第二张图片是结果)
我已经翻译了所有代码以使用Xcode并三次检查坐标.你能告诉我我的代码有什么问题吗？为了完整起见,我还包括了UIImage - > Mat转换+反转:
- (void)confirmedImage
{
if ([_adjustRect frameEdited]) {
cv::Mat src = [self cvMatFromUIImage:_sourceImage];
// My original Coordinates
// 4-------3
// | |
// | |
// | |
// 1-------2
CGFloat scaleFactor = [_sourceImageView contentScale];
CGPoint p1 = [_adjustRect coordinatesForPoint:4 withScaleFactor:scaleFactor];
CGPoint p2 = [_adjustRect coordinatesForPoint:3 withScaleFactor:scaleFactor];
CGPoint p3 = [_adjustRect coordinatesForPoint:1 withScaleFactor:scaleFactor];
CGPoint p4 = [_adjustRect coordinatesForPoint:2 withScaleFactor:scaleFactor];
std::vector<cv::Point2f> c1;
c1.push_back(cv::Point2f(p1.x, p1.y));
c1.push_back(cv::Point2f(p2.x, p2.y));
c1.push_back(cv::Point2f(p3.x, p3.y));
c1.push_back(cv::Point2f(p4.x, p4.y));
cv::RotatedRect box = minAreaRect(cv::Mat(c1));
cv::Point2f pts[4];
box.points(pts);
cv::Point2f src_vertices[3];
src_vertices[0] = pts[0];
src_vertices[1] = pts[1];
src_vertices[2] = pts[3];
cv::Point2f dst_vertices[4];
dst_vertices[0].x = 0;
dst_vertices[0].y = 0;
dst_vertices[1].x = box.boundingRect().width-1;
dst_vertices[1].y = 0;
dst_vertices[2].x = 0;
dst_vertices[2].y = box.boundingRect().height-1;
dst_vertices[3].x = box.boundingRect().width-1;
dst_vertices[3].y = box.boundingRect().height-1;
cv::Mat warpAffineMatrix = getAffineTransform(src_vertices, dst_vertices);
cv::Mat rotated;
cv::Size size(box.boundingRect().width, box.boundingRect().height);
warpAffine(src, rotated, warpAffineMatrix, size, cv::INTER_LINEAR, cv::BORDER_CONSTANT);
[_sourceImageView setNeedsDisplay];
[_sourceImageView setImage:[self UIImageFromCVMat:rotated]];
[_sourceImageView setContentMode:UIViewContentModeScaleAspectFit];
rotated.release();
src.release();
}
}
- (UIImage *)UIImageFromCVMat:(cv::Mat)cvMat
{
NSData *data = [NSData dataWithBytes:cvMat.data length:cvMat.elemSize()*cvMat.total()];
CGColorSpaceRef colorSpace;
if ( cvMat.elemSize() == 1 ) {
colorSpace = CGColorSpaceCreateDeviceGray();
}
else {
colorSpace = CGColorSpaceCreateDeviceRGB();
}
CGDataProviderRef provider = CGDataProviderCreateWithCFData( (__bridge CFDataRef)data );
CGImageRef imageRef = CGImageCreate( cvMat.cols, cvMat.rows, 8, 8 * cvMat.elemSize(), cvMat.step[0], colorSpace, kCGImageAlphaNone|kCGBitmapByteOrderDefault, provider, NULL, false, kCGRenderingIntentDefault );
UIImage *finalImage = [UIImage imageWithCGImage:imageRef];
CGImageRelease( imageRef );
CGDataProviderRelease( provider );
CGColorSpaceRelease( colorSpace );
return finalImage;
}
- (cv::Mat)cvMatFromUIImage:(UIImage *)image
{
CGColorSpaceRef colorSpace = CGImageGetColorSpace( image.CGImage );
CGFloat cols = image.size.width;
CGFloat rows = image.size.height;
cv::Mat cvMat( rows, cols, CV_8UC4 );
CGContextRef contextRef = CGBitmapContextCreate( cvMat.data, cols, rows, 8, cvMat.step[0], colorSpace, kCGImageAlphaNoneSkipLast | kCGBitmapByteOrderDefault );
CGContextDrawImage( contextRef, CGRectMake(0, 0, rows, cols), image.CGImage );
CGContextRelease( contextRef );
CGColorSpaceRelease( colorSpace );
return cvMat;
}
这是解决我问题的正确方法吗？你有任何可以帮我解决的示例代码吗？
感谢您阅读我的问题!
UDATE:
我实际上在这里开源我的UIImagePickerController替代品:https://github.com/mmackh/MAImagePickerController-of-InstaPDF ,其中包括可调裁剪视图,滤镜和透视校正.
mma*_*ckh 50
因此,在尝试解决它几天后,我想出了一个解决方案(忽略第二张图像上的蓝点):
正如所承诺的,这里是代码的完整副本:
- (void)confirmedImage
{
cv::Mat originalRot = [self cvMatFromUIImage:_sourceImage];
cv::Mat original;
cv::transpose(originalRot, original);
originalRot.release();
cv::flip(original, original, 1);
CGFloat scaleFactor = [_sourceImageView contentScale];
CGPoint ptBottomLeft = [_adjustRect coordinatesForPoint:1 withScaleFactor:scaleFactor];
CGPoint ptBottomRight = [_adjustRect coordinatesForPoint:2 withScaleFactor:scaleFactor];
CGPoint ptTopRight = [_adjustRect coordinatesForPoint:3 withScaleFactor:scaleFactor];
CGPoint ptTopLeft = [_adjustRect coordinatesForPoint:4 withScaleFactor:scaleFactor];
CGFloat w1 = sqrt( pow(ptBottomRight.x - ptBottomLeft.x , 2) + pow(ptBottomRight.x - ptBottomLeft.x, 2));
CGFloat w2 = sqrt( pow(ptTopRight.x - ptTopLeft.x , 2) + pow(ptTopRight.x - ptTopLeft.x, 2));
CGFloat h1 = sqrt( pow(ptTopRight.y - ptBottomRight.y , 2) + pow(ptTopRight.y - ptBottomRight.y, 2));
CGFloat h2 = sqrt( pow(ptTopLeft.y - ptBottomLeft.y , 2) + pow(ptTopLeft.y - ptBottomLeft.y, 2));
CGFloat maxWidth = (w1 < w2) ? w1 : w2;
CGFloat maxHeight = (h1 < h2) ? h1 : h2;
cv::Point2f src[4], dst[4];
src[0].x = ptTopLeft.x;
src[0].y = ptTopLeft.y;
src[1].x = ptTopRight.x;
src[1].y = ptTopRight.y;
src[2].x = ptBottomRight.x;
src[2].y = ptBottomRight.y;
src[3].x = ptBottomLeft.x;
src[3].y = ptBottomLeft.y;
dst[0].x = 0;
dst[0].y = 0;
dst[1].x = maxWidth - 1;
dst[1].y = 0;
dst[2].x = maxWidth - 1;
dst[2].y = maxHeight - 1;
dst[3].x = 0;
dst[3].y = maxHeight - 1;
cv::Mat undistorted = cv::Mat( cvSize(maxWidth,maxHeight), CV_8UC1);
cv::warpPerspective(original, undistorted, cv::getPerspectiveTransform(src, dst), cvSize(maxWidth, maxHeight));
UIImage *newImage = [self UIImageFromCVMat:undistorted];
undistorted.release();
original.release();
[_sourceImageView setNeedsDisplay];
[_sourceImageView setImage:newImage];
[_sourceImageView setContentMode:UIViewContentModeScaleAspectFit];
}
- (UIImage *)UIImageFromCVMat:(cv::Mat)cvMat
{
NSData *data = [NSData dataWithBytes:cvMat.data length:cvMat.elemSize() * cvMat.total()];
CGColorSpaceRef colorSpace;
if (cvMat.elemSize() == 1) {
colorSpace = CGColorSpaceCreateDeviceGray();
} else {
colorSpace = CGColorSpaceCreateDeviceRGB();
}
CGDataProviderRef provider = CGDataProviderCreateWithCFData((__bridge CFDataRef)data);
CGImageRef imageRef = CGImageCreate(cvMat.cols, // Width
cvMat.rows, // Height
8, // Bits per component
8 * cvMat.elemSize(), // Bits per pixel
cvMat.step[0], // Bytes per row
colorSpace, // Colorspace
kCGImageAlphaNone | kCGBitmapByteOrderDefault, // Bitmap info flags
provider, // CGDataProviderRef
NULL, // Decode
false, // Should interpolate
kCGRenderingIntentDefault); // Intent
UIImage *image = [[UIImage alloc] initWithCGImage:imageRef];
CGImageRelease(imageRef);
CGDataProviderRelease(provider);
CGColorSpaceRelease(colorSpace);
return image;
}
- (cv::Mat)cvMatFromUIImage:(UIImage *)image
{
CGColorSpaceRef colorSpace = CGImageGetColorSpace(image.CGImage);
CGFloat cols = image.size.height;
CGFloat rows = image.size.width;
cv::Mat cvMat(rows, cols, CV_8UC4); // 8 bits per component, 4 channels
CGContextRef contextRef = CGBitmapContextCreate(cvMat.data, // Pointer to backing data
cols, // Width of bitmap
rows, // Height of bitmap
8, // Bits per component
cvMat.step[0], // Bytes per row
colorSpace, // Colorspace
kCGImageAlphaNoneSkipLast |
kCGBitmapByteOrderDefault); // Bitmap info flags
CGContextDrawImage(contextRef, CGRectMake(0, 0, cols, rows), image.CGImage);
CGContextRelease(contextRef);
return cvMat;
}
希望它可以帮助你+快乐的编码!
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