[Elphel-support] thermal correction

[support-list]

Gergely,
We did not measure temperature parameters of these lens, I would expect the thermal expansion causing the focal distance variation to be around 0.2-0.3 um/C. With the aluminum lens barrel and camera mount we measured 0.2 um/C for the f=4.5mm we use. THe SFE we use in Eyesis (and other calibrated cameras) is designed to compensate for the lens thermal expansion, that results in +/-0.02um/C (about 10 times better than without those measures). The revision "E" of the 10338 sensor boards have temperature sensor on the board and temperature is included in the Exif file header - theoretically that can be used to do software correction of the calibration results.

Andrey


---- On Wed, 10 Jul 2013 10:12:30 -0700 Gergely Debreczeni wrote ---- 

 > 
 > Hello, 
 >  
 >  We are calibrating our stereo camera indoor in 25 C, and using it outside in a car, 
 > where I guess the temperature can go up to 40 C especially in the black camera case. 
 > Is this thermal change requires a recalibration or the lenses (353-70-50) are stable enough 
 > against such a temperature change ? 
 >  
 > thanks, 
 > Gergely 
 >  
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