Android OpenCV（C#）中的 UndistortPoints 并正确形成输入矩阵

Question

为了加快我正在为 Android 平台开发的计算机视觉实时应用程序中的某些处理，我想不扭曲一些关键点，而不是整个帧。我已尽我所能遵循文档，但收到以下错误：

OpenCV 错误：断言失败 (CV_IS_MAT(_cameraMatrix) && _cameraMatrix->rows == 3 && _cameraMatrix->cols == 3) in void cvUndistortPoints(const CvMat*, CvMat*, const CvMat*, const CvMat*, const CvMat*, const CvMat*)，文件 /Volumes/Linux/builds/master_pack-android/opencv/modules/imgproc/src/undistort.cpp，第 301 行

相应的文档在这里：http://docs.opencv.org/2.4/modules/imgproc/doc/geometric_transformations.html#undistortpoints

在我的代码中，我分别定义和填充矩阵元素，因为它们很小。我无法找到优雅地填充 MatofPoint2f 的方法，但搜索导致我从列表转换，如下所示。

Mat camMtx = new Mat(1, 5, CvType.Cv64fc1, new Scalar(0));
Mat distCoef = new Mat(3, 3, CvType.Cv64fc1, new Scalar(0));
MatOfPoint2f uncalibpoints = new MatOfPoint2f();
MatOfPoint2f calibpoints = new MatOfPoint2f();
List<Point> points = new List<Point>();
points.Add(center); //Some previously stored point
points.Add(apex1); //Some previously stored point
points.Add(apex2); //Some previously stored point
points.Add(apex3); //Some previously stored point
uncalibpoints.FromList(points); //Convert list of points to MatofPoint2f

Console.WriteLine(uncalibpoints.Channels());
Console.WriteLine(uncalibpoints.Size());
Console.WriteLine(uncalibpoints.GetType());

//Manually setting the matrix values
distCoef.Put(0, 0, 0.51165764);
distCoef.Put(0, 1, -1.96134156);
distCoef.Put(0, 2, 0.00600294);
distCoef.Put(0, 3, 0.00643735);
distCoef.Put(0, 4, 2.59503145);
camMtx.Put(0, 0, 1551.700);
camMtx.Put(0, 1, 0.0);
camMtx.Put(0, 2, 962.237163);
camMtx.Put(1, 0, 0.0);
camMtx.Put(1, 1, 1536.170);
camMtx.Put(1, 2, 589.418432);
camMtx.Put(2, 0, 0.0);
camMtx.Put(2, 1, 0.0);
camMtx.Put(2, 2, 1.0);

Imgproc.UndistortPoints(uncalibpoints, calibpoints, camMtx, distCoef);`

Answer 1

上述代码有两个问题：

1. camMtx 和 distCoeff 分配中的简单错误（在复制粘贴类型错误中反转了它们的分配）

2. Undistort Points 调用应如下所示：

   Imgproc.UndistortPoints(uncalibpoints, calibpoints, camMtx, distCoef, new Mat(), camMtx);