fSpy is a simple and powerful still image camera matching software available for Windows, Linux, and Mac. Vanishing points in fSpy are assumed to correspond to perpendicular directions in 3D space.
Camera matching, or camera calibration, is the process of estimating camera parameters from certain features in an image. fSpy computes the approximate focal length, orientation and position of the camera in 3D space based on user-defined control points in still images. The computed camera parameters can be used in other apps, for example, 3D modeling tools like Blender.
fSpy uses the position of vanishing points to estimate camera parameters. A vanishing point is specified using two line segments aligned with features in the image that correspond to parallel lines in 3D space.
Getting your camera parameters into an application without a dedicated importer is likely possible and involves copying the fSpy parameter values one by one and pasting them into the target program.