Products > Thermal Imaging

Temperature Range extender for thermal cameras - Cheap option from Fraser

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Fraser:
@tomas123,

I will test some other filters tomorrow. I have some single coating Skylight 1A filters that are a possibility. I chose the Tiffen Haze-1 because I already knew it had thermal transmission capabilities from tests I carried out some years ago. At the time I did not need an attenuator though so just filed the knowledge away.

I do not know the glass and coating spec used for the Haze-1 but doubt it is anything very exotic. Single coating appears important from your findings though.

Happy experimenting :)

Fraser

Fraser:
I will test some other glass and plastic products to see how they work as cheap thermal wavelength attenuators. Microscope slides and their associated thin glass cover slips come to mind as possible candidates :)

Some interesting filter passband details here from SCHOTT. We are making use of the camera filters low EM energy transmittance at um wavelengths.

http://www.schott.com/advanced_optics/english/download/schott-optical-filter-glass-description-2015-eng.pdf

Fraser

2lps:
There is some attenuation using the thin plastic screen protector of a new mobile phone (the one put in the factory, and you remove). MSX doesn't work with it, as it needs to be very close to the object, in order to see clearly through it.

left - the protector is in front of the camera. In the first one, it is very close.
right - without the protector for comparison.

Fraser:
You can also buy the armour glass type thin glass phone screen protectors. Not tried one of those yet but have a few somewhere.

I bought some more camera filters to test but have not tried them yet. From memory they are another Haze-1, two Skylight 1A's and a linear poloriser.

I have piles of unusual 20mm diameter Russian filters to test as well,

Materials that appear opaque at visible wavelengths can be transparent at thermal wavelengths so it is worth trying various plastics as well.

The advantage of clear attenuators is the continued presence of MSX data of course.

Fraser

Bill W:
Black bin bags are about 50% transmission

Regards

Bill

www.fire-tics.co.uk

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