Recent advancements in cooled mercury cadmium telluride (MCT or HgCdTe) infrared detector technology have made possible the development of high performance infrared cameras for use in a wide variety of demanding thermal imaging applications.
In addition, a variety of High-Sensitivity Industrial Cameras resolutions are available because of mid-size and large-size detector arrays and various pixel sizes. Also, camera features now include high frame rate imaging, adjustable exposure time and event triggering enabling the capture of temporal thermal events.
- Sophisticated processing algorithms are available that result in an expanded dynamic range to avoid saturation and optimize sensitivity.
- These infrared cameras can be calibrated so that the output digital values correspond to object temperatures. Non-uniformity correction calculations are included that are independent of exposure time. These performance capabilities and camera features enable a wide range of thermal imaging applications that were previously not possible.
At the heart of the high speed infrared camera is a cooled MCT detector that provides extraordinary sensitivity and versatility for viewing high speed thermal events.
- Infrared Spectral Sensitivity Bands
Because of the availability of a variety of MCT detectors, higher speed infrared cameras have been designed to operate in several distinct spectral bands. The spectral band can be manipulated by varying the alloy composition of the HgCdTe and the detector set-point temperature. The end result is a single ring infrared sensor with extraordinary quantum efficiency (typically above 70%) and large signal-to-noise ratio able to detect extremely small levels of infrared signal. Single-band MCT detectors typically fall in one of the five nominal spectral bands shown:
- Broad-band infrared (BBIR) cameras – 1.5-5 micron
- Long-wave infrared (LWIR) cameras – 7-10 micron response
Besides cameras that utilize “monospectral” infrared sensors which have a spectral response in 1 group, new systems are being developed that use infrared detectors which have a reaction in two bands (known as “two color” or double band). Examples include cameras using a MWIR/LWIR response covering both 3-5 micron and 7-11 micron, or alternatively certain SWIR and MWIR bands, or even two MW sub-bands. Click http://einstinc.com/wpccategories/nikon-inverted-microscopes/ to get affordable Nikon inverted microscopes.
There are a variety of reasons motivating the selection of the spectral band for an infrared camera. For specific applications, the spectral radiance or reflectance of the objects under observation is what decides the best spectral band. These programs include spectroscopy, laser beam viewing, detection and alignment, target signature analysis, phenomenology, cold-object surveillance and imaging in a marine environment.