1. Field of the Invention
The present invention relates to a target marking system, and more particularly, to a handheld or weapon mounted device incorporating a gas laser such as a carbon dioxide (CO2) or carbon monoxide (CO) laser for generating and impinging a thermal infrared beam upon a target to create a corresponding image in a thermal imager.
2. Description of Related Art
Thermal imagers operate in the mid- and long-wave infrared bands (3-5 micron and 8-12 micron, respectively). Ideal “black bodies” radiate in a spectral region determined by their temperature. “Grey bodies” emit similarly, but the spectral radiance is mediated by material properties. All real objects are grey bodies, and radiate in a manner that can be related to temperature. For example, an object at a temperature of 98.6° F. is self-luminous in a broad infrared band, with a peak emission near 9 microns in wavelength. A thermal imager is sensitive at this wavelength and can be made to distinguish an object at that temperature to one that is either cooler or hotter. In contrast to image intensifier or I2 devices, thermal imagers do not require external illumination, whether from the ambient or laser or other sources. Conversely, image intensifier or I2 technology do not detect the thermal emissions.
Thermal imaging systems have been used in a variety of fields including medical and engineering as well as security, such as border and asset monitoring. While these applications allow monitoring and imaging of otherwise invisible radiation, the systems do not provide for a proactive approach to situational developments. No system exists for employing thermal imaging for actively marking targets.
The need exists for a target marking system having a handheld, portable target marker which can impinge a thermal infrared beam upon the target to create a corresponding infrared radiation in the sensitivity range of a thermal imager, thereby identifying the target when viewed with the thermal imager. The need also exists for a target marking system, wherein a thermally detectable beam cooperates with a thermal imager to provide for enhanced target marking as well as communication.