Platform gauge instrument and platform gauge measuring method based on photogrammetric principle

A platform gauge measuring method based on a photogrammetric principle, comprising:

• arranging two measuring stations, namely a first measuring station and a second measuring station, wherein the first measuring station and the second measuring station are symmetrically arranged on both sides of a rail, the measuring station comprises a traveling mechanism, a stabilizing cradle head and a measuring pod, an outside of the measuring pod comprises a waterproof outer cover and a waterproof window, a laser line projector, a binocular navigation camera and a binocular measuring camera are arranged in the measuring pod, and the traveling mechanism is connected with the measuring pod by the stabilizing cradle head;
• mutually positioning a binocular measuring camera on the first measuring station and a binocular measuring camera on the second measuring station with unified coordinate systems;
• calibrating a focal length and an external orientation element of the binocular measuring camera on the first measuring station in a calibration field, photographing the binocular measuring camera on the second measuring station by the binocular measuring camera on the first measuring station, and measuring an external orientation element of the binocular measuring camera on the second measuring station and a corresponding station-moving key point;
• and
• after completing the calibration in the calibration field, adding a scene to be measured into the measuring station, photographing rails by the second binocular measuring camera, photographing the binocular measuring camera on the second measuring station by the binocular measuring camera on the first measuring station, and completing the calculation of the external orientation element of the binocular measuring camera on the second measuring station by re-measuring each positioning key point of the binocular measuring camera on the second measuring station in combination with a station-moving algorithm;
• wherein
• the station-moving algorithm obtains a rotation matrix R and a translation matrix S through singular value decomposition operation based on object-space coordinates of each point in a point system forming a rigid body with a coordinate system, so that after a parameter matrix P of each point in an original coordinate system and the station-moving operation are performed, a parameter matrix Q of each point meets the relation:
• Q=R·P+S;
• and
• the measuring station has automatic traveling capability to complete scanning of a whole platform, and platform information obtained by the scanning is automatically resolved by a measuring system, and a platform gauge dimension is resolved through object-space coordinates of platform edge points, a space equation of intersection lines of upper surfaces of rails and a measuring cross-section, and a parameter of the upper surfaces of two rails on the measuring cross-section, so that high-precision detection of the platform is achieved.