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Participant
September 28, 2025
Question

Measuring electrical amounts on existing digital photos

  • September 28, 2025
  • 1 reply
  • 216 views

Can you apply real thermal imaging on existing digital photos to find out how hot is an item from digital photo?

1 reply

Community Expert
September 28, 2025

 

Unless the photo was originally taken with special equipment - it is not feasible to determine temperature from a photograph. 

 

Heat information in photos (such as, false-colour images showing the places where most heat is leaving a building) are taken using purpose-designed equipment. This works by the camera 'seeing' non human visible infra-red radiation, and only that, coming from the subject.

 

Standard cameras work by seeing a different band of frequencies and include an Infra-Red Filter which blocks off this "heat" radiation from also being captured. The lens would focus that differently adding blur, also the intention of camera designers is usually to mimic the response of the human eye: and the human eye does not "see" temperature.

 

Some cameras have this IR filter specially removed, because the pictorial effect of capturing some infre-red is desired. In this case a different filter may be fitted which largely blocks visible light while still letting IR light through. This contrived system is still less exact at evaluatiing subject temperatures, than a purpose-made thermal camera would be. A night-vision device, too, often does reflect differences of subject temperature but again not in a calibrated way. There would still need to be some interpretation - no reading off a number directly.

edblue10Author
Participant
October 1, 2025

Yes but the existing photo has very high resolution but I meant if there's a software developer who is working to make that happen in the future.

Community Expert
October 1, 2025

It's a different class of problem, than how detailed the photos are.

 

Say I have written down a list of items with their exact sizes and colours and weights. And someone asks me, so how much did they all cost on that day? My sheet of paper (considered on its own) cannot provide that information no matter what: if I did not write the prices down at the time, cost information is simply not on there.