Enabling mobile camera calibration
View Patent ↗Cameras can be used in applications that provide measurements of objects in the field of view. These applications can include advanced driver assistance systems (ADAS). Cameras used this way may require calibration in order to correctly map offsets in the camera image to measurements in the environment. This calibration may involve imaging a known target with a known position and orientation relative to the camera and known patterns on the target. It may be desirable to bring the target to the location of the camera, rather than bringing the camera to the location of the vehicle. The present invention provides a mobile calibration stand for enabling the accurate positioning of a calibration target relative to a vehicle in order to successfully calibrate a camera associated with the vehicle.
1 . A system for calibrating a camera, comprising:
a calibration stand having a central vertical support, a first horizontal support having a first pair of lockably extended and collapsable extensions, and a first calibration target;
a first configuration of the calibration stand to facilitate the calibrating; and
a second configuration of the calibration stand to facilitate transporting the calibration stand;
a retractable filament attached to the first horizontal support at the central vertical support; and
a magnet attached to the end of the filament;
wherein the central vertical support is extended in the first configuration and collapsed for the second configuration, each of the first pair of lockably extended and collapsable extensions of the first horizontal support are locked and extended outward in opposing directions from the central vertical support in the first configuration and collapsed toward the central vertical support in the second configuration, and the first calibration target is attached to the first horizontal support on the first pair of extensions in the first configuration and detached from the calibration stand in the second configuration;
wherein the camera is mounted behind a windshield of a vehicle;
wherein the magnet is removably attached to a hood of the vehicle and used to observe whether the calibration stand is correctly aligned and oriented with the vehicle.
2 . The system of claim 1 , wherein the first pair of lockably extended and collapsable extensions are each connected by a toggle latch and a hinge in the first configuration and the first pair of lockably extended and collapsable extensions are only connected by the hinge with the toggle latch disconnected when collapsed in the second configuration.
3 . The system of claim 1 , further comprising:
a tripod base supporting the central vertical support including three leg assemblies having a foot comprising an adjustment to change the height of the leg assembly.
4 . The system of claim 1 , further comprising a leveling mechanism attached to the first horizontal support, comprising at least one bubble level.
5 . The system of claim 1 , wherein the camera is a sensor for an advanced driver assistance system (ADAS) of the vehicle.
6 . The system of claim 1 , further comprising:
a secondary tape measure for each of the first pair of lockably extended and collapsable extensions of the first horizontal support;
wherein the secondary tape measure is attached to each of the first pair of lockably extended and collapsable extensions of the first horizontal support in the first configuration and detached from the calibration stand in the second configuration, and a movable end of the secondary tape measure is extended to the ground below the calibration stand to measure the height of the first horizontal support member.
7 . The system of claim 1 , further comprising:
a second horizontal support having a second pair of lockably extended and collapsable extensions;
wherein the second pair of lockably extended and collapsable extensions are each locked and extended outward in opposing directions from the central vertical support in the first configuration and collapsed toward the central vertical support in the second configuration.
8 . The system of claim 7 , wherein the second pair of lockably extended and collapsable extensions are each connected by a toggle latch and a hinge in the first configuration and the second pair of lockably extended and collapsable extensions are only connected by the hinge with the toggle latch disconnected when collapsed in the second configuration.
9 . The system of claim 7 , further comprising:
a second calibration target;
wherein the second calibration target is attached to the second horizontal support on the second pair of extensions for the first configuration and detached from the second horizontal support in the second configuration.
10 . The system of claim 7 , further comprising:
a primary tape measure; and
a tire alignment bracket comprising a vertical alignment member and a horizontal base member;
wherein the primary tape measure is attached to the second horizontal support in the first configuration and detached from the calibration stand in the second configuration, the vertical alignment member is aligned with a tire of the vehicle, the horizontal base member rests on the ground, and a movable end of the primary tape measure is removably attached to the horizontal base member.