An efficient GPLv3-licensed Python package for extracting temperature data from FLIR IRT images.
Differences from existing libraries
There is an existing Python package for extracting temperature values from raw IRT images, see nationaldronesau/FlirImageExtractor. However, it has some issues that I didn't like:
- Most importantly, it is forked from the UNLICENSED Nervengift/read_thermal.py, so until Nervengift/read_thermal.py#4 is answered, this package cannot be legally used.
- Secondly, it is quite inefficient, as it runs a new exiftool process for each image, and it converts the temperature for each pixel, instead of using numpy's vectorized math.
You can install flirextractor from pip.
pip3 install flirextractor
Or, using the python package manger poetry (recommended):
poetry add flirextractor
Make sure you install exiftool as well.
On RHEL, this can be installed via:
sudo yum install perl-Image-ExifTool
On Debian, this can be installed via:
sudo apt update && sudo apt install libimage-exiftool-perl -y
Each FLIR infrared image is loaded in Celsius as a 2-dimensional
To load data from a single FLIR file, run:
from flirextractor import FlirExtractor with FlirExtractor() as extractor: thermal_data = extractor.get_thermal("path/to/FLIRimage.jpg")
Data can also be loaded from multiple FLIR files at once in batch mode, which is slightly more efficient:
from flirextractor import FlirExtractor with FlirExtractor() as extractor: list_of_thermal_data = extractor.get_thermal_batch( ["path/to/FLIRimage.jpg", "path/to/another/FLIRimage.jpg"])
Once you have the
numpy.ndarray, you can export the data as a csv with:
import numpy as np np.savetxt("output.csv", thermal_data, delimiter=",")
You can display the image for debugging by doing:
from PIL import Image thermal_image = Image.fromarray(thermal_data) thermal_image.show()
See ./scripts/example.py for more example usage.
Use the Python package manager
poetry to install test dependencies:
Then run pytest to run tests.
poetry run pytest
You can run linters with pre-commit:
poetry run pre-commit run --all-files
This work was supported by the Engineering and Physical Sciences Research Council [Doctoral Training Partnership Grant EP/R513325/1].
Additionally, many thanks to Glenn J. Tattersall, for their gtatters/Thermimage R package. This work uses an image and adapts part of gtatters/Thermimage under the GPLv3.0 License.