The development of a time of flight range imager for mobile robotics

Drayton, Ben; Carnegie, Dale A.; Dorrington, Adrian A.

doi:10.1109/icara.2011.6144839

Cited by 4 publications

(3 citation statements)

References 10 publications

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“…A detailed description of this camera is not included here, but is described in an earlier paper [20]. This camera allows full control over the modulation waveforms, phase stepping and phase detection via programming of an on board FPGA.…”

Section: Hardware and Measurement Methodologymentioning

confidence: 98%

“…Again optical flow algorithms have been used [18] however the model used for this did not address the issue of harmonics and a rigorous investigation of the success of this method in eliminating axial motion error was not performed. Changing the order of the phase measurements has been investigated and shown to improve the motion error [20]. However, again, harmonics have not been taken into account.…”

Section: Axial Motion Errormentioning

confidence: 98%

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Phase Algorithms for Reducing Axial Motion and Linearity Error in Indirect Time of Flight Cameras

2013

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Indirect time of flight cameras are increasingly being used in a variety of applications to provide real-time full field of view range measurements. Current generation cameras suffer from systematic linearity errors due to the influence of harmonics in the system and motion errors due to the requirement of taking multiple measurements. This paper demonstrates that replacing the standard phase detection algorithm with the windowed discrete Fourier transform can improve the root mean square (RMS) axial motion error with distance from 0.044 ± 0.002 m to 0.009 ± 0.004 m and the range from 0.112 ± 0.007 m to 0.03 ± 0.01 m for an object with a velocity of 2 m/s using a measurement time of 125 ms. This algorithm also improves the linearity of the camera by removing systematic errors due to harmonics, decreasing the RMS linearity error from 0.018 ± 0.002 m to 0.003 ± 0.001 m. This paper establishes the robustness of the windowed discrete Fourier transform, demonstrating that it effectively eliminates axial motion error over a variety of velocities and modulation frequencies. The potential for tailoring phase detection algorithms to specific applications is also demonstrated.

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Section: Hardware and Measurement Methodologymentioning

confidence: 98%

Section: Axial Motion Errormentioning

confidence: 98%

Phase Algorithms for Reducing Axial Motion and Linearity Error in Indirect Time of Flight Cameras

2013

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“…Measurements in this paper were recorded using the Victoria University Range Imaging System [8], a custom developed indirect time of flight camera implementing a PMD19K-2 CMOS sensor (PMDTechnologies GmbH, Siegen, Germany). This camera allows control over the parameters and operation of the system.…”

Section: Background Theorymentioning

confidence: 99%

Variable frame time imaging for indirect time of flight range imaging cameras

Drayton

Carnegie

Dorrington

2013

2013 IEEE International Instrumentation and Measurement Technology Conference (I2MTC)

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This paper outlines a method for improving the precision of indirect time of flight range imaging cameras in high contrast scenes. Indirect time of flight cameras have potential applications in many fields including mobile robotics. However, current generation cameras are limited by their dynamic range. A method is proposed where, at the end of each measurement, the signal amplitude is compared to a threshold value on a pixelby-pixel basis with low quality pixels being integrated over multiple integration periods. This method sacrifices the uniformity of the frame rate over the image in return for maintaining a high frame rate in bright areas while still measuring quality data in darker areas. Experimental data are shown demonstrating the efficacy of this method.

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