extrinsic and depth calibration of tof-cameras reporter ：鄒嘉恆 date ： 2009/12/22

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.