colmap 相机模型及参数

https://github.com/colmap/colmap/blob/dev/src/base/camera_models.h#L178

// Pinhole camera model.
//    fx, fy, cx, cy
CAMERA_MODEL_DEFINITIONS(1, "PINHOLE", 4)

// Simple camera model with one focal length and one radial distortion
// parameter.
//    f, cx, cy, k
CAMERA_MODEL_DEFINITIONS(2, "SIMPLE_RADIAL", 4)

// Simple camera model with one focal length and two radial distortion
// parameters.
//    f, cx, cy, k1, k2
CAMERA_MODEL_DEFINITIONS(3, "RADIAL", 5)

// OpenCV camera model.
//    fx, fy, cx, cy, k1, k2, p1, p2
CAMERA_MODEL_DEFINITIONS(4, "OPENCV", 8)

// OpenCV fish-eye camera model.
//    fx, fy, cx, cy, k1, k2, k3, k4
CAMERA_MODEL_DEFINITIONS(5, "OPENCV_FISHEYE", 8)

// Full OpenCV camera model.
//    fx, fy, cx, cy, k1, k2, p1, p2, k3, k4, k5, k6
CAMERA_MODEL_DEFINITIONS(6, "FULL_OPENCV", 12)

// FOV camera model.
//    fx, fy, cx, cy, omega
CAMERA_MODEL_DEFINITIONS(7, "FOV", 5)

// Simple camera model with one focal length and one radial distortion
// parameter, suitable for fish-eye cameras.
//    f, cx, cy, k
CAMERA_MODEL_DEFINITIONS(8, "SIMPLE_RADIAL_FISHEYE", 4)

// Simple camera model with one focal length and two radial distortion
// parameters, suitable for fish-eye cameras.
//    f, cx, cy, k1, k2
CAMERA_MODEL_DEFINITIONS(9, "RADIAL_FISHEYE", 5)

// Camera model with radial and tangential distortion coefficients and
// additional coefficients accounting for thin-prism distortion.
//    fx, fy, cx, cy, k1, k2, p1, p2, k3, k4, sx1, sy1
CAMERA_MODEL_DEFINITIONS(10, "THIN_PRISM_FISHEYE", 12)