Use of complementary wavelength bands for laser dazzle protection

Abstract

The use of complementary wavelength bands in camera systems is a long-known principle. The camera system's spectral range is split into several spectral channels, where each channel possesses its own imaging sensor. Such an optical setup is used, for example, in highquality three-sensor color cameras. A three-sensor camera is less vulnerable to laser dazzle than a single-sensor camera. However, the separation of the individual channels is not high enough to suppress cross talk, and thus, all three channels will suffer from laser dazzling. To solve that problem, we suggest two different optical designs in which the spectral separation of the channels is significantly increased. The first optical design is a three-channel camera system, which was already presented earlier. The second design is a two-channel camera system based on optical multiband elements, which delivers undisturbed color images even under laser dazzle.

Laser dazzling in the visible region: some issues

“…Atmospheric scatter functions for an optical depth of ×L=1. The approximation for the angular scatter is made using the Henyey-Greenstein function (10) for g=0.85 (fog) and 0.99 (rain). Eye scatter is calculated for a person of age 25 years and pigment factor p=0.5.…”

“…Laser dazzling is recently studied within a NATO group involving both modelling [3,4,5] and experiments in laser dazzling and its effect on different task performance [6,7,8] as well as protection against dazzling [9,10]. While laser dazzling against CCD/CMOS cameras, image intensifiers and IR cameras does not in general involve ethical considerations, eye dazzle will often be limited by eye safety demands and ethical aspects.…”

Laser dazzling: an overview

“…Severe dazzling occurs for laser irradiances in the 1-100 W/m 2 region. Ritt [8] has developed an analytical model for TV camera dazzling.…”

Long-range nanosecond pulsed laser damage of CMOS cameras

“…The measurement of laser-induced damage thresholds of imaging sensors is an important and ongoing topic in recent year, for the aim of better understanding the sensor vulnerability to laser hazards and threats, as well as improving the design for the high energy laser weapons in battlespace particularly UAVs, snipers, and imaging infrared seekers on missiles, etc. A fruitful work have analyzed the laser damage effect and laser induced damage thresholds on various types of optical sensors over several decades, either numerically or experimentally, including complementary metal-oxidesemiconductors (CMOS) detector 1,2 , silicon-based camera 3,4 , charge-coupled devices (CCD) cameras 1,2,5 , positiveintrinsic-negative (PIN) photodiode 6 , digital micromirror device (DMD) 7,8 , with different laser pulse width 7,9 or wavelength bands 3,10 . In general, these laboratory research primarily answer the question: if one has a known sensor and several known laser parameters, what laser fluence can damage the camera.…”