Changes between Version 7 and Version 8 of Sensors/Owl


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Timestamp:
Nov 16, 2015 12:11:05 PM (3 years ago)
Author:
lah
Comment:

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  • Sensors/Owl

    v7 v8  
    33The Specim OWL is a multiband thermal instrument covering [http://en.wikipedia.org/wiki/Infrared#Commonly_used_sub-division_schemeen.wikipedia.org/wiki/Infrared LWIR] (specifically 7.6 to 12.3 μm) with 103 bands.  In combination with SWIR measurements, this range enables better classification of minerals, particularly silicates.  The sensitivity is sufficient to handle sub-zero temperatures and see differentiation (tested to -21C) and is capable of going up to fire temperatures (verified up to 900-1000C with a yellow-hot metal object, and plenty of headroom in the settings still).
    44
    5 As with the [wiki:Sensors/Hawk], the detector technology is [http://en.wikipedia.org/wiki/Mercury_cadmium_telluride Mercury Cadmium Telluride], this time tuned for LWIR rather than SWIR.  This means there may be a number of bad pixels that need to be masked out.  The OWL has also been found to have "blinking" pixels (also called "naughty", as they're not reliably bad), which switch between two different levels during the capture - at the time of writing, these are masked out, though it is hoped that data can be recovered from them in future.  The detector uses a full-frame readout method, so is not suspectible to straylight during readout (as is the case with the Eagle).
     5As with the [wiki:Sensors/Hawk], the detector technology is [http://en.wikipedia.org/wiki/Mercury_cadmium_telluride Mercury Cadmium Telluride], this time tuned for LWIR rather than SWIR.  This means there may be a number of bad pixels that need to be masked out.  The OWL has also been found to have "blinking" pixels (also called "naughty", as they're not reliably bad), which switch between two different levels during the capture - at the time of writing, these are masked out, though it is hoped that data can be recovered from them in future.  The detector uses a full-frame readout method, so is not susceptible to straylight during readout (as is the case with the Eagle). Please see the attachments for further information on blinkers provided by Specim.
    66
    77In order to calibrate the sensor, a pair of black bodies can be mechanically moved in front of the sensor lens one by one and a capture made.  Under normal operational conditions, this is done automatically at the end of every line, after the autodark (closed shutter dark frames) capture.  The black bodies should generally be set to bracket the temperature range of interest and can range from about 15C (lower is possible but risks condensation) to 120C.  The sensor response has been rated as essentially linear.