Fusion of Time-of-Flight Depth and Stereo for High

Accuracy Depth Maps

Reporter：鄒嘉恆Date：2009/11/17

Introduction

They provide real time depth estimates by combine stereo and Time-of-flight.

Outline

MotivationMulti-sensor calibration

Geometric calibrationPhotometric calibrationCalibration verification

Sensor fusionExperimental resultsConclusion

Motivation

Problem:Laser scanner are too slow for real time use.Stereo fails on textureless scenes.TOF is low resolution, noisy, and poorly calibrated.

Multi-sensor setup

SR3000:176x144Operational range up to 7 meters

2 CCD stereo cameraslimit the calibration range from 1m to 1.4m

Multi-sensor calibration

Geometric calibration

Multi-sensor calibration

Photometric calibration

Multi-sensor calibration

Calibration verification-plane experiment

Multi-sensor calibration

Calibration verification-plane experiment

Multi-sensor calibration

Calibration verification-plane experiment

Calibration verification-box experiment

Sensor fusionfd : the local evidence for node i

fs : a symmetric function measures the smoothness assumption about the scene

fr : the additional local evidence based on the measurement from the TOF sensor.

Experimental results

Using TOF(A)local method(B)local method with LUT(C)global method(D)global method with LUT

Using stereo(E)local method(F)global method

(G)local fusion method(H)global fusion method

Experimental results

Experimental results

Conclusion

They present a simple and effective calibration method to improve the performance of time-of-flight sensors.

Their method can achieve an absolute accuracy of about 5mm over a range of one meter.

The fusion results reduce the over-all error by 50%.