FLIR® thermal cameras like the FLIR ONE® include both a thermal and a visual light camera. The latter is used to enhance the thermal image using an edge detector.
The resulting image is saved as a jpg image but both the original visual image and the raw thermal sensor data are embedded in the jpg metadata.
This small Python tool/library allows to extract the original photo and thermal sensor values converted to temperatures.
This tool relies on exiftool
. It should be available in most Linux distributions (e.g. as perl-image-exiftool
in Arch Linux or libimage-exiftool-perl
in Debian and Ubuntu).
It also needs the Python packages numpy and matplotlib (the latter only if used interactively).
# sudo apt update
# sudo apt install exiftool
# sudo pip install numpy matplotlib
This module can be used by importing it:
import flir_image_extractor
fir = flir_image_extractor.FlirImageExtractor()
fir.process_image('examples/ax8.jpg')
fir.plot()
Or by calling it as a script:
python flir_image_extractor.py -p -i 'examples/zenmuse_xtr.jpg'
usage: flir_image_extractor.py [-h] -i INPUT [-p] [-exif EXIFTOOL]
[-csv EXTRACTCSV] [-d]
Extract and visualize Flir Image data
optional arguments:
-h, --help show this help message and exit
-i INPUT, --input INPUT
Input image. Ex. img.jpg
-p, --plot Generate a plot using matplotlib
-exif EXIFTOOL, --exiftool EXIFTOOL
Custom path to exiftool
-csv EXTRACTCSV, --extractcsv EXTRACTCSV
Export the thermal data per pixel encoded as csv file
-d, --debug Set the debug flag
This command will show an interactive plot of the thermal image using matplotlib and create two image files flir_example_thermal.png and flir_example_rgb_image.jpg.
Both are RGB images, the original temperature array is available using the get_thermal_np
or export_thermal_to_csv
functions.
The functions get_rgb_np
and get_thermal_np
yield numpy arrays and can be called from your own script after importing this lib.
Other cameras might need some small tweaks (the embedded raw data can be in multiple image formats)
Raw value to temperature conversion is ported from this R package: https://github.com/gtatters/Thermimage/blob/master/R/raw2temp.R Original Python code from: https://github.com/Nervengift/read_thermal.py