Activity analysis of thermal imaging videos using a difference imaging approach

Area of Science:

• Thermography
• Biophysics
• Animal Behavior

Background:

• Infrared thermal imaging is a passive technique for estimating surface temperature and heat transfer.
• It offers potential for movement detection, overcoming limitations of visual imaging like glare and lighting changes.
• Existing methods lack quantitative activity assessment directly from thermal data.

Purpose of the Study:

• To introduce and validate a novel method, Difference Imaging Thermography (DIT), for quantitative activity assessment using infrared thermal imaging.
• To demonstrate the potential for standardizing activity data with energetic measurements.
• To explore the application of DIT in biological studies.

Main Methods:

• A frame subtraction algorithm was employed on fixed-focus thermal imaging videos to detect pixel-by-pixel signal changes.
• The sum of absolute differences across video frames was calculated to provide a quantitative activity score.
• The method was tested using a metronome for accuracy and applied to Darwin's finches.

Main Results:

• The Difference Imaging Thermography approach successfully quantified movement by analyzing changes in thermal signal.
• The method demonstrated accuracy in assessing activity levels.
• Example application showed potential for correlating thermal activity data with metabolic rates.

Conclusions:

• Difference Imaging Thermography provides a quantitative method for assessing movement from infrared thermal videos.
• This technique can standardize activity data for comparison with energetic measurements.
• DIT is a versatile tool applicable to any radiometric imaging system for activity monitoring.