Patent ID: 11914798
Assignee: PIXART IMAGING INC.
Field: Computer technology (Electrical engineering)
Classification: CPC G | IPC G

Claim 5:
6. A CPI calibration method, configured to calibrate a CPI of an optical navigation device comprising an optical sensor and a processing circuit, the CPI calibration method comprising:
(a) sensing optical data via the optical sensor;
(b)applying the processing circuit to compute motions of the optical navigation device based on the optical data by the optical sensor, and applying the processing circuit to output the motions, wherein a first CPI is set to the processing circuit;
(c) computing a real CPI corresponding to times of motions output by the processing circuit during a time interval that a relative displacement between the optical navigation device and a surface reaches a first predetermined distance;
(d) computing a ratio between the real CPI and the first CPI or a difference between the real CPI and the first CPI;
(e) generating a second CPI based on the ratio or the difference; and
(f)calibrating the first CPI to the second CPI;
wherein the step (c) further comprises:
providing a calibration ruler pattern, wherein the calibration ruler comprises a plurality of mark regions;
determining the relative displacement according to the mark regions.