/// <summary>
/// Serialize calibration points map to a file on the device.
/// </summary>
/// <param name="calibrationPointsMap">The calibration points map to serialize.</param>
/// <param name="writeFile">The device file to serialize to.</param>
/// <returns>A <see cref="Task{TResult}"/> representing the result of the asynchronous operation.</returns>
internal static async Task <bool> SerializeAsync(this CalibrationPointsMap calibrationPointsMap, StorageFile writeFile)
{
using var stream = await writeFile.OpenStreamForWriteAsync();
using var writer = new BinaryWriter(stream);
writer.Write(calibrationPointsMap.Width);
writer.Write(calibrationPointsMap.Height);
writer.Write(calibrationPointsMap.CameraUnitPlanePoints.Length);
foreach (var value in calibrationPointsMap.CameraUnitPlanePoints)
{
writer.Write(value);
}
return(true);
}
/// <summary>
/// Computes camera intrinsics from a map of calibration points.
/// </summary>
/// <param name="calibrationPointsMap">The map of calibration points to compute camera intrinsics from.</param>
/// <returns>The computed <see cref="CameraIntrinsics"/>.</returns>
internal static CameraIntrinsics ComputeCameraIntrinsics(this CalibrationPointsMap calibrationPointsMap)
{
var width = calibrationPointsMap.Width;
var height = calibrationPointsMap.Height;
// Convert unit plane points in the calibration map to a lookup table mapping image points to 3D points in camera space.
List <Point3D> cameraPoints = new ();
List <Point2D> imagePoints = new ();
int ci = 0;
for (int j = 0; j < height; j++)
{
for (int i = 0; i < width; i++)
{
var x = calibrationPointsMap.CameraUnitPlanePoints[ci++];
var y = calibrationPointsMap.CameraUnitPlanePoints[ci++];
if (!double.IsNaN(x) && !double.IsNaN(y))
{
var norm = Math.Sqrt((x * x) + (y * y) + 1.0);
imagePoints.Add(new Point2D(i + 0.5, j + 0.5));
cameraPoints.Add(new Point3D(x / norm, y / norm, 1.0 / norm));
}
}
}
// Initialize a starting camera matrix
var initialCameraMatrix = Matrix <double> .Build.Dense(3, 3);
var initialDistortion = VectorDouble.Build.Dense(2);
initialCameraMatrix[0, 0] = 250; // fx
initialCameraMatrix[1, 1] = 250; // fy
initialCameraMatrix[0, 2] = width / 2.0; // cx
initialCameraMatrix[1, 2] = height / 2.0; // cy
initialCameraMatrix[2, 2] = 1;
CalibrationExtensions.CalibrateCameraIntrinsics(
cameraPoints,
imagePoints,
initialCameraMatrix,
initialDistortion,
out var computedCameraMatrix,
out var computedDistortionCoefficients,
false);
return(new CameraIntrinsics(width, height, computedCameraMatrix, computedDistortionCoefficients));
}
