Dual-channel NIR camera detects foreign material in cotton
APRIL 14, 2009--Up to now, spinning mills have used camera systems in the visible range of light to detect foreign matter like packaging materials in the raw cotton stream during cotton processing. These systems are limited to colored materials since they can not detect white or transparent foils.
Now, researchers at the Institute for Textile and Clothing Technology (Dresden, Germany) have used a 2-channel near-infrared (NIR) camera system to recognize these types of extraneous substances. The newly developed camera system is based on two InGaAs linescan sensors operating in the NIR range.
Both are installed in one single camera head. A 1520 nm/1720 nm filter pair makes each sensor selective for a specific spectral line within the NIR absorption spectrum that is characteristic for the materials to be detected. For more information, go to: http://qirt.gel.ulaval.ca/archives/qirt2006/papers/005.pdf
-- Posted by Conard Holton, Vision Systems Design, www.vision-systems.com