| CPC G01S 7/497 (2013.01) [G01S 7/4808 (2013.01); G01S 17/08 (2013.01)] | 10 Claims |
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1. A method of calibrating errors in a time-of-flight (ToF) sensor, the method comprising:
generating a modulation signal such that the modulation signal has different global delay phases respectively in a plurality of measurement cycles, wherein generating the modulation signal comprises:
generating, using a variable delay circuit, the modulation signal such that the modulation signal has a variable delay depending on a control code; and
changing the control code sequentially in the plurality of measurement cycles such that the modulation signal has the different global delay phases respectively in the plurality of measurement cycles;
illuminating a test object with a transmission light that is modulated based on the modulation signal;
generating, using a buffer chain circuit, a plurality of demodulation signals having different local delay phases among a plurality of local delay phases;
providing a plurality of measured phase differences by providing the plurality of demodulation signals to a plurality of pixel groups included in a ToF sensor to sample a reception light reflected from the test object based on the plurality of demodulation signals;
determining a wiggling error based on the plurality of measured phase differences, the wiggling error depending on a phase difference between the transmission light and the reception light; and
calibrating a measured distance from the ToF sensor to a target object based on the wiggling error.
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