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Extrinsic and Depth Calibration of TOF-
cameras
Reporter:鄒嘉恆Date:2009/12/22
IntroductionThis work presents a calibration
procedure that enable user to calibrate the distance- and amplitude-related error of a ToF-camera for a desire operating range.
outline
Distance-error modelDistance- and amplitude- related errorsLatency-related errorDepth calibration
Experimental resultsConclusion
Distance-error model(1/2)Emits incoherent NIR light :Remitted light : Correlation :
Phase delay :
Amplitude :
Distance :
Distance-error model(2/2)
P = {v1, …, vw} represent W image coordinates.
v = (r, c) where r and c denote the image row and column
Amplitude images :
Depth images :
Distance- and amplitude-related errors(1/4)
Non –ideal NIR-LED response
Correlation of the LED-signals with the control signal
Distance- and amplitude-related errors(2/4)This phenomenon results in phase-delay-
and distance-related error respectively.
Distance- and amplitude-related errors(3/4)Distance- and amplitude-related errors are
joined and approximated by M penalised splines :
Amplitude interval : Spline coefficients : K note points :
Distance- and amplitude-related errors(4/4)
Latency-related error
Different latencies for every pixel have to be taken into account
Depth calibration(1/2)
Overall error : Corrected distance
The distance between an measured point v and the calibration plane in a single shot i
Depth calibration(2/2)
S includes the spline
coefficients, (b1, b2),
(nc, dc), and tTs
Experimental results(1/7)
O3D100:50 x 64 pixelsCovers a measurement range up 7500mm
Experimental results(2/7)
Robustness
Experimental results(3/7)
Precision
Experimental results(4/7)
Precision Uncalibrated measurements
Experimental results(5/7)
Precision calibrated measurements
Experimental results(6/7)
Precision
Experimental results(7/7)
validity
Conclusion
The calibration procedure simultaneously estimates the distance parameter and the extrinsic parameters.
The calibration procedure considers the distance-related, the amplitude-related and latency-related error.