Calibrating eye-tracking camera of head-mounted display device

A method of calibrating an eye-tracking camera included in a head-mounted display (HMD) device between a pancake lens and a display panel, the method comprising:

• receiving lens tolerance range data associated with:
• a plurality of intrinsic lens parameters of the pancake lens;
• and
• a plurality of lens position parameters of the pancake lens;
• receiving measured image data of one or more ground-truth features on a calibration target;
• over a plurality of solver iterations, computing calibration results as respective estimated values of the intrinsic lens parameters and the lens position parameters, wherein each of the solver iterations includes:
• computing one or more estimated feature locations based at least in part on the measured image data and on respective perturbed values of the intrinsic lens parameters and the lens position parameters, wherein the perturbed values are computed based at least in part on the lens tolerance range data;
• computing a value of a loss function based at least in part on the one or more estimated feature locations and one or more respective ground-truth locations of the one or more ground-truth features;
• and
• updating the perturbed values based at least in part on the value of the loss function;
• and
• outputting, as the calibration results, the perturbed values computed in a final solver iteration of the plurality of solver iterations.

A computing system comprising:

• one or more processing devices configured to:
• calibrate an eye-tracking camera included in a head-mounted display (HMD) device between a pancake lens and a display panel, wherein calibrating the eye-tracking camera includes:
• receiving lens tolerance range data associated with:
• a plurality of intrinsic lens parameters of the pancake lens;
• and
• a plurality of lens position parameters of the pancake lens;
• receiving measured image data of one or more ground-truth features on a calibration target;
• and
• over a plurality of solver iterations, computing calibration results at least in part by iteratively recomputing respective perturbed values of the intrinsic lens parameters and the lens position parameters that are located with respective tolerance ranges included the lens tolerance range data;
• transmit to the HMD device, as the calibration results, the perturbed values computed in a final solver iteration of the plurality of solver iterations;
• store the calibration results in HMD device memory included in the HMD device;
• and
• at an HMD device processor included in the HMD device:
• receive eye tracking data at the eye-tracking camera;
• compute a gaze direction of a user based at least in part on the eye tracking data and the calibration results;
• and
• output the gaze direction to an additional computing process.