Live From DSS 2011: SWIR vs. Visible Imaging Demos

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In this video, Joel Bagwell, R&D manager with Edmund Optics, conducts two demonstrations with shortwave infrared imaging (SWIR). The demonstrations involve a visible camera from ADT and an InGaAs camera from Goodrich ISR Systems. Each camera is equipped with an Edmund Optics produced lens — the ADT camera with a lens optimized for the visible range (400 to 800 nm), and the Goodrich camera with a SWIR-optimized lens (0.9 to 1.7 um). Live feeds from both cameras are shown side-by-side on a monitor.

The first demo compares the images of a silicon wafer, which is reflective in the visible and completely transparent in the shortwave infrared. SWIR has some distinct advantages for quality control with silicon wafers and silicon wafer processing, Bagwell explained, because as the silicon is illuminated with different types of lasers, you can different defects that re-emit in the shortwave infrared band, but that you wouldn't see in the visible band.

In the second demo, Bagwell simulates a machine vision-type application, using SWIR to make a detergent bottle appear transparent, whereas it is completely opaque in the visible. This can allow manufacturers to monitor for things like liquid level and other defects.