Geerardyn, D., Ingelberts, H., Deleener, R., & Kuijk, M. (2015). Range imaging behind semi-transparent surfaces by high-speed modulated light. In Proc. SPIE 9530, Automated Visual Inspection and Machine Vision (Vol. 9530). SPIE.

@inproceedings{333efcd948a94442a566b759b2259dbd,
title = "Range imaging behind semi-transparent surfaces by high-speed modulated light",
abstract = "Range-imaging is a measurement technique able to generate an image which contains the distance information from the camera to all the points of a scene. This distance information can be captured by, amongst others, the Time-of-Flight principle which measures the time a light pulse needs to travel back and forth from the camera to the scene and converts this time into a depth value. For a good operation of the Time-of-Flight principle, a high-power, fast-modulated light source is required. Currently, most 3D cameras use laser diodes or LEDs. Moreover, most systems use square-wave modulation of the light source, requiring high bandwidths of the optical driver. To enhance both bandwidth and optical power, we developed a light source consisting of 16 high-power (50 mW) laser diodes using GHz laser drivers, combined with GHz buffers. Moreover, this light source can be integrated in a Time-of-Flight camera. Specifically, we designed and experimentally validated this new light source, based on ultra-fast laser diodes, allowing an increased performance of the current Time-of-Flight cameras. In this paper, we first discuss the development of a high-power illumination board, with a large beam divergence and suitable for high-speed square-wave modulation with a chosen duty-cycle. Our light source can be modulated faster than 1 GHz, which corresponds to optical pulses shorter than 500 ps. Moreover, the pulses can be shifted in time with sub-nanosecond precision. Secondly, we integrated this light source into a Time-of-Flight setup, able to measure the distances of objects behind a semi-transparent surface. The resulting images are compared with the image quality of commercially available Time-of-Flight cameras. From these results, we can conclude that our light source is suitable for Time-of-Flight measurements and gives a low-cost alternative for imaging purposes. Moreover, it can handle both pulsed as continuous-wave Time-of-Flight, to allow a broader range of applications.",
author = "Dave Geerardyn and Hans Ingelberts and Robin Deleener and Maarten Kuijk",
year = "2015",
month = jun,
day = "22",
language = "English",
volume = "9530",
booktitle = "Proc. SPIE 9530, Automated Visual Inspection and Machine Vision",
publisher = "SPIE",
address = "United States",
note = "SPIE Optical Metrology ; Conference date: 22-06-2015 Through 25-06-2015",
}