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•Technical Article: Short-wave IR Offers Unique Remote Sensing Solutions

The shortwave infrared (SWIR) wavelength band is rich in potential for solving imaging challenges in measurement, inspection, and process-monitoring tasks. Spectral signatures in the SWIR can reveal the presence of contaminants or moisture in agricultural products. Hot-furnace processes and walls can be inspected through ordinary safety glass enclosures or with off-the-shelf glass lenses or optics. Glass manufacturers can image in the SWIR at high speed, monitoring the cooling process to identify costly defects inside bottles before waste costs balloon.

The SWIR, sometimes called the near-infrared (NIR) band, is generally defined as falling between 0.7 and 2.5 µm. The region starts where the human eye response falls off (beyond deep red) and extends to the longer wavelengths at which glass absorbs rather than transmits light. The SWIR region is distinguished from the mid-wave infrared (MWIR) at 3- to 5-µm and the long-wave infrared (LWIR) over the 7- to 14-µm waveband regions at boundaries marked by strong atmospheric absorption bands.

In NIR spectroscopy applications, the SWIR band is important for remote identification of materials and gases because of absorption of light at wavelengths that match the harmonic frequencies of unique molecular-bond vibrations. Water has strong absorbance at several key wavelengths in the SWIR, for instance, allowing users to detect and quantify the relative dryness of agricultural and textile products. Moisture uniformity and density in a product can be mapped by imaging light transmitted through or reflected from an object at specific wavelengths at which water absorption is highest. The image of interest is compared against a reference image taken of a similar object with known moisture content.

SOURCE: Sensors Unlimited - Goodrich ISR Systems

Click Here To Download:
•Technical Article: Short-wave IR Offers Unique Remote Sensing Solutions