Abstract
This disclosure describes techniques of camera characterization, calibration, and focus control that can achieve sub-pixel reprojection error. A calibration setup includes the camera-under-test, an actuator that can adjust the camera lens position, a thermal chamber with ambient temperature control, a calibration chart, etc. The actuator adjusts the camera lens along its optical axis. A temperature sensor integrated into the camera module by design detects the temperature of the camera module. A temperature sensor within the thermal chamber detects and enables closed-loop control of the ambient temperature via the temperature controller and integrated heating and cooling elements. A test control computer executes a characterization sequence that determines optimal focus and intrinsic camera characteristics at multiple temperatures. The characterization sequence includes scanning through a range of focus positions of the lens, capturing images of the calibration chart, computing a focus score for each captured image, and selecting the sharpest image as the one with the highest focus score. This is repeated at a variety of ambient temperature setpoints and/or thermal profiles to obtain focus setpoints and corresponding intrinsics parameters indexed against camera temperature. During operation, the operating temperature of the camera is used to index an array of intrinsic characterization data to determine the optimal focus position, optical center, and distortion compensation.
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
Recommended Citation
Li, Yinying Xiao; Juarez, Ronald; Block, Andrew; Troccoli, Alejandro; O'Rourke, Jimmy; Govenji, Punit; Ragel, Slavic; and Huibers, Andy, "Temperature-based Camera Characterization and Focus Control", Technical Disclosure Commons, (May 14, 2025)
https://www.tdcommons.org/dpubs_series/8126