Human eyes, primarily sensitive to shorter wavelength visible light, are unable to detect or differentiate between the longer-wavelength thermal IR "signatures" given off both by living beings and inanimate objects.
While mechanical detection of IR radiation has been possible since Samuel Pierpont Langley invented the bolometer in 1880, devices that also can recognize and identify an IR source after detection have been more challenging to develop.
In a recent paper in the journal Review of Scientific Instruments, researchers at two Chinese universities describe a novel instrument that successfully does both tasks with extremely high sensitivity by splitting the IR radiation given off by an object into a long-wave portion for detection and a mid-wave portion that can be spectrally analyzed for accurate identification.
Conventional remote sensing systems share a single sensor for both imaging and spectral data processing. The new instrument designed by the Chinese researchers has separate sensors for each task and uses a dichoric beamsplitter to divide the IR signal from an object into two components, a long-wave IR (LWIR) beam and a mid-wave IR (MWIR) beam.
"The LWIR beam goes to the imaging sensor and the MWIR to the spectrum recognition sensor," said Tianxu Zhang, corresponding author on the RSI paper and a physicist at the Huazhong University of Science and Technology. "This allows us to simultaneously obtain high spatial resolution, frame rate and spectrum resolution, resulting in higher sensitivity for measuring the IR spectrum than currently available combined IR imaging and spectral-analysis devices."
The researchers increased the capability of their instrument by mounting it on a two-dimensional rotating stage. "Once we locate a target of interest, especially a moving one, the stage lets us keep the object in view and sample its IR," Zhang said. "This gives us the ability to define an object's IR spectral curve very precisely and better use the data to distinguish it from another IR radiating source."
In their experiment, the researchers used the dual-based IR remote sensing system to observe the spectral curves of the sun and airplanes in flight from distances up to 6 kilometers (4 miles). "We learned that spectral curves of aerial moving targets are different when measured from different directions," Zhang said. "So, the more data collecting multiple curves for an object, the more distinctive its IR signature."
The researchers say that they plan to use their remote sensing system to build a database of such highly defined signatures. "We want to add the spectra of as many objects as possible to our dataset, thereby increasing the accuracy and reliability with which we can identify objects," Zhang said.
The article, "Dual-band infrared remote sensing system with combined LWIR imaging and MWIR spectral analysis" by Z. Fang, X. Yi, X. Liu, W. Zhang and T. Zhang appears in the journal Review of Scientific Instruments. See: http://dx.doi.org/10.1063/1.4818668
ABOUT THE JOURNAL
The journal Review of Scientific Instruments, which is produced by AIP Publishing, presents innovation in instrumentation and methods across disciplines. See: http://rsi.aip.org/
Jason Socrates Bardi | Source: EurekAlert!
Further information: www.aip.org
Further Reports about: Chinese herbs > IR radiation > longer-wavelength thermal IR > remote sensing > Review of Scientific Instruments > spectral data processing > spectral-analysis devices > Thermal infrared
More articles from Physics and Astronomy:
Three-dimensional view helps laser in building new molecules
06.12.2013 | Max-Planck-Institut für Quantenoptik
NASA Goddard Planetary Instruments Score a Hat Trick
06.12.2013 | NASA/Goddard Space Flight Center
International team of scientists develops new feedback method for optimizing the laser pulse shapes used in the control of chemical reactions
In many ways, traditional chemical synthesis is similar to cooking. To alter the final product, you can change the ingredients or their ratio, change the method of mixing ingredients, or change the temperature or pressure of the environment of the ingredients.
Like an accomplished chef, chemists have become very skilled ...
A genetic defect protects mice from infection with influenza viruses
A new study published in the scientific journal PLOS Pathogens points out that mice lacking a protein called Tmprss2 are no longer affected by certain flu viruses.
The discovery was made by researchers from the Helmholtz Centre for Infection Research (HZI) in Braunschweig in collaboration with colleagues from Göttingen and ...
The Light: Global study gets underway with online user survey
Light has a fundamental impact on our sense of well-being and performance. In cooperation with Zumtobel, a supplier of lighting solutions, Fraunhofer IAO has launched a global user survey of lighting quality in offices. The objective is to identify the best lighting conditions for a variety of spaces and lighting ...
Quantum entanglement, a perplexing phenomenon of quantum mechanics that Albert Einstein once referred to as “spooky action at a distance,” could be even spookier than Einstein perceived.
Physicists at the University of Washington and Stony Brook University in New York believe the phenomenon might be intrinsically linked with wormholes, hypothetical features of space-time that in popular science fiction can provide a much-faster-than-light shortcut from one part of the universe to another.
But here’s the catch: One couldn’t actually ...
A star is formed when a large cloud of gas and dust condenses and eventually becomes so dense that it collapses into a ball of gas, where the pressure heats the matter, creating a glowing gas ball – a star is born.
New research from the Niels Bohr Institute, among others, shows that a young, newly formed star in the Milky Way had such an explosive growth, that it was initially about 100 times brighter than it is now. The results are published in the scientific journal, Astrophysical Journal Letters.
The young ...
06.12.2013 | Materials Sciences
06.12.2013 | Life Sciences
06.12.2013 | Life Sciences
05.12.2013 | Event News
04.12.2013 | Event News
12.11.2013 | Event News