Optical Engineering article shows how to ‘dazzle them with brilliance'
An SPIE journal article describes three different methods of assessing the effects of dazzle with two different dazzle protection schemes.
A well-known sales motto, often attributed to W.C. Fields, says, "If you can't dazzle them with brilliance, baffle them with bull----."
The obvious first step for such an undertaking is to ascertain how well you can dazzle them. An open-access article entitled "Evaluation of protection measure against laser dazzling for imaging sensors," published in the March issue of Optical Engineering, provides insight into how to do just that.
Gunnar Ritt and Bernd Eberle of Fraunhofer IOSB (Germany) describe their use of three different methods of assessing the effects of dazzle with two different dazzle protection schemes.
The three techniques for assessment were overexposed pixel count (OPC), an automatic pattern recognition technique using a triangle orientation discrimination (TOD) test pattern, and the well-known structural similarity image metric (SSIM). This latter technique was used in both laboratory and field experiments.
Concept for hardening a sensor against laser dazzling using a DMD: (a) operation mode for regular imaging, (b) operation mode with high attenuation of dazzling laser light, and (c) photograph of the hardened
They tested two different types of dazzle mitigation schemes: one based on the use of a digital micromirror device (DMD) and the other using complementary filters. The OPC was the easiest evaluation technique to implement, while the TOD-based method was the most difficult. Both OPC and TOD yielded similar results with respect to measures like the obscuration radius of the laser illumination.
However, the TOD-based pattern analysis method and the SSIM-based method provided additional information concerning image information available with and without dazzle mitigation techniques applied. This information could be crucial in accurately determining targeting or recognition performance in the presence of laser countermeasures.
This article is well written, well sourced, and provides some great insights into laser dazzle characterization.
A brief skim or a deep dive would be fruitful and will keep you from having to resort to the second half of Mr. Fields' quote the next time someone asks you a question about laser dazzle.
-- SPIE Fellow Eddie L. Jacobs of University of Memphis is a member of the Optical Engineering editorial board.