透视变换+在OpenCV iOS中裁剪

我正在尝试在即将推出的应用中实施修剪和透视校正function。 在做研究的同时，我碰到：

执行cv :: warpPerspective在一组cv :: Point上进行假偏移

http://sudokugrab.blogspot.ch/2009/07/how-does-it-all-work.html

所以我决定尝试用OpenCV来实现这个function – 框架就在那里，所以安装速度很快。 但是，我没有得到我所希望的结果:(第二张照片是结果）

我已经翻译了所有的代码来处理Xcode和三重检查坐标。 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; } 

这是我的问题的正确方法？ 你有任何可以帮助我的示例代码吗？

感谢您阅读我的问题！

UDATE：

我实际上已经开放源代码UIImagePickerControllerreplace这里： https : //github.com/mmackh/MAImagePickerController-of-InstaPDF其中包括可调整的裁剪视图，filter和透视校正。

Answer 1

所以经过几天的努力解决之后，我想出了一个解决scheme（忽略第二个图像上的蓝点）：

按照承诺，这是一个完整的代码副本：

 - (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！

Answer 2

我觉得getAffineTransform的点对应是不正确的。

检查由box.points(pts);输出的点坐标box.points(pts);

为什么不使用p1 p2 p3 p4来计算转换呢？