Saturday, January 26, 2019

IEEE Spectrum on Image Sensor Damage by Lasers

As PZ pointed in comments, IEEE Spectrum publishes its own research on the camera damage by Aeye LiDAR at CES. The Spectrum article has quite a few interesting links, including a pointer to International Laser Display Association web page talking about the laser damage to the image sensors and referring to Fraunhofer open-access paper "Laser-induced damage threshold of camera sensors and micro-optoelectromechanical systems" by Bastian Schwarz, Gunnar Ritt, Michael Koerber, and Bernd Eberle published in Optical Engineering in 2017.

"The continuous development of laser systems toward more compact and efficient devices constitutes an increasing threat to electro-optical imaging sensors, such as complementary metal–oxide–semiconductors (CMOS) and charge-coupled devices. These types of electronic sensors are used in day-to-day life but also in military or civil security applications. In camera systems dedicated to specific tasks, micro-optoelectromechanical systems, such as a digital micromirror device (DMD), are part of the optical setup. In such systems, the DMD can be located at an intermediate focal plane of the optics and it is also susceptible to laser damage. The goal of our work is to enhance the knowledge of damaging effects on such devices exposed to laser light. The experimental setup for the investigation of laser-induced damage is described in detail. As laser sources, both pulsed lasers and continuous-wave (CW)-lasers are used. The laser-induced damage threshold is determined by the single-shot method by increasing the pulse energy from pulse to pulse or in the case of CW-lasers, by increasing the laser power. Furthermore, we investigate the morphology of laser-induced damage patterns and the dependence of the number of destructive device elements on the laser pulse energy or laser power. In addition to the destruction of single pixels, we observe aftereffects, such as persistent dead columns or rows of pixels in the sensor image."

The paper has an interesting experimental data on laser damage at 532nm wavelength:


Then, Fraunhofer researchers determine the laser energy density needed for each type of the damage:


Another SPIE paper studies the CIS damage by 1064nm laser pulses: "Damage effect on CMOS detector irradiated by single-pulse laser" by Feng Guo, Rongzhen Zhu, Ang Wang, and Xiang’ai Cheng from National Univ. of Defense Technology (China).

5 comments:

  1. The most interesting thing about the damage at CES is the fact that when the LIDAR vendor offered to replace his camera with a new one, if they could have the old for analysis, he couldn't find it.

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    1. The camera might have a sentimental value for him. After all, this is the first camera in the world that has been damaged by a LiDAR.

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    2. The text of the article says he claimed that he threw it away during a recent move.

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    3. Interesting. If my memory serves me, the original version of the article said that he just cant's find the camera. It looks like the article has been edited since then.

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  2. I remain skeptical of this whole incident, both from a physics/optics standpoint and a behavioral one. As far as I could tell, AEye pretty much immediately offered to buy the damaged camera from him so he could get a new one. Doesn't make sense to me not to take that offer. Then again, I wouldn't ever throw out a camera like that, even with fried pixels.

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