Base codes for Thermography

A python package for decoding and common processing for thermographs / thermograms

Install

1. This tool requires exiftool to be installed.
   • Linux: Run command sudo apt-get install exiftool
   • Windows: Download binary from https://exiftool.org/
2. This tool also requires you to have Python 3+ installed. You can install it from the official website (https://www.python.org/downloads/)
3. Install this package with python3 -m pip install git+https://github.com/detecttechnologies/thermal_base.git@main

Usage

Import and use the package as follows:

• Decoding

from thermal_base import ThermalImage

image = ThermalImage(image_path="path/to/image", camera_manufacturer="dji/flir")
thermal_np = image.thermal_np           # The temperature matrix as a np array
raw_sensor_np = image.raw_sensor_np     # The raw thermal sensor excitation values as a np array
meta = image.meta                       # Any other metadata that exiftool picked up

• Manipulation

from thermal_base import utils

print(dir(utils))                                   # View manipulation tools available
thermal_np = utils.change_emissivity_for_roi(...)   # Sample: Change the emissivity of an RoI

This repo can be used in conjunction with Thermal-Image-Analysis for an interactive experience.

Supported formats

Data Format	Sample Cameras	Support
FLIR RJPG with TIFF-format of thermal embedding	Zenmuse XT-2	✔️
FLIR RJPG with PNG-format of thermal embedding	FLIR E-4, T640, T660	✔️
DJI-encoded thermal image	Zenmuse H20-T	✔️
FLIR SEQ Thermal Video	Zenmuse XT-2	✔️
FLIR CSQ Thermal Video	Zenmuse XT-2	❌
Seek HIR Format Images	Seek Shot	❌

*RJPG is also known as R-JPEG

Notes

• The use case for h20T camera can also be developed with dji-thermal-tool-analysis. Refer to this link to know more about the implementation. Also note that this method can be performed only with a 32 bit python interpreter and only on windows platform.

Credits

• Exiftool is used to read metadata and raw values from thermal image files.
• The flyr_unpack.py file for PNG-encoded FLIR metadata was derived from the flyr library.
• The conversion from raw to temperature values is done using raw2temp from ThermImage-R