Author Topic: laser spot thermometer measuring temp of laser spot itself - possible?  (Read 1464 times)

0 Members and 1 Guest are viewing this topic.

Offline calel

  • Regular Contributor
  • *
  • Posts: 97
  • Country: ch
Re: laser spot thermometer measuring temp of laser spot itself - possible?
« Reply #25 on: October 20, 2020, 08:23:24 pm »
cool that's what I needed to know  :-+

so I reckon the only reason Flir chose to make their TG series non-radiometric, is because a non-radiometric lepton core is cheaper then a radiometric lepton core?

 

Offline Bill W

  • Frequent Contributor
  • **
  • Posts: 565
  • Country: gb
    • Fire TICS
Re: laser spot thermometer measuring temp of laser spot itself - possible?
« Reply #26 on: October 21, 2020, 01:27:49 pm »

 ie. is it possible or not to have a 320x240 spot (non-radiometric) cam?

Yes - you can take any thermal camera and align it with a conventional spot thermometer.
Argus 2 and Argus 3 were just such because the BST core could not measure temperature.

These days though, I do not see why anyone would bother.  The unit cost trade off is a decent shutter and a thermistor versus the spot device and alignment hassles.

However, as you are finding out, cost and selling price are almost independent especially with FLIR.
If it does more - charge more anyway and hope market it so most people do not buy the bottom model which is likely quite close to cost price.

A non-radiometruic camera might be preferable if you object massively to FFC shutter events and could reduce/remove the FFC period without causing a bad image due to column drifts.  In a way this is where the shutterless camera systems sit.

Offline Bill W

  • Frequent Contributor
  • **
  • Posts: 565
  • Country: gb
    • Fire TICS
Re: laser spot thermometer measuring temp of laser spot itself - possible?
« Reply #27 on: October 21, 2020, 01:45:19 pm »
cool that's what I needed to know  :-+

so I reckon the only reason Flir chose to make their TG series non-radiometric, is because a non-radiometric lepton core is cheaper then a radiometric lepton core?

Maybe two reasons.

Lepton is cheap and yes part of that cheapening made it thermally unstable.  It will not produce the levels of accuracy expected in the professional tool market.  Note FLIR call these cameras 'infra-red guided measurement'.

The TG297 is for very high temperatures.  That must have the Lepton set into low gain to image to 1000°C and would even be pushing the accuracy on a good core.  For that use  a separate spot temperature unit has an advantage.  Separate spot units are also simpler for an end user to get recalibrated for traceable accuracy.


Bill

Offline calel

  • Regular Contributor
  • *
  • Posts: 97
  • Country: ch
Re: laser spot thermometer measuring temp of laser spot itself - possible?
« Reply #28 on: October 21, 2020, 04:31:31 pm »

 ie. is it possible or not to have a 320x240 spot (non-radiometric) cam?

Yes - you can take any thermal camera and align it with a conventional spot thermometer.
Argus 2 and Argus 3 were just such because the BST core could not measure temperature.

These days though, I do not see why anyone would bother.  The unit cost trade off is a decent shutter and a thermistor versus the spot device and alignment hassles.

However, as you are finding out, cost and selling price are almost independent especially with FLIR.
If it does more - charge more anyway and hope market it so most people do not buy the bottom model which is likely quite close to cost price.

A non-radiometruic camera might be preferable if you object massively to FFC shutter events and could reduce/remove the FFC period without causing a bad image due to column drifts.  In a way this is where the shutterless camera systems sit.

holys I remember now I once owned a 2nd hand Flir TG130 for a short time; lowest of the low end lol (eventually sold it back) and you're right I don't recall the image ever freezing. the only thing I really liked about it was that it used commercially available batteries (3x AAA)

so - somehow - non-radiometric cams dont need to recalibrate, only radiometric cams do?  ???
 

Offline Bill W

  • Frequent Contributor
  • **
  • Posts: 565
  • Country: gb
    • Fire TICS
Re: laser spot thermometer measuring temp of laser spot itself - possible?
« Reply #29 on: October 21, 2020, 05:07:24 pm »
so - somehow - non-radiometric cams dont need to recalibrate, only radiometric cams do?  ???

Not quite what I said.

Any camera where you turn off FFC will keep a 'pretty picture' a lot longer (many minutes or more)  than it will keep giving an approximately OK spot temperature (best a few minutes unless given a constant environment).

A camera can use software correction to pick up the typically dominant 'column drift' and fix it, so keeping a pretty picture for longer still and possible for 'long enough' depending on use.  This fiddling loses any pretence of temperature measurement.

The top end of software fixing gives you true shutterless camera designs such as from Thermoteknix, which indeed do not need FFC but neither do they measure temperature.

Bill



Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf