Thermal to Color

Changes a gray scale thermal image to color using a defined palette.

Eample input image:

Output images using different palettes:

Credits

• Blackbody color palette comes from Mitchell N. Charity project
• Gray Red color palette was proposed by Maria João Sousa, Alexandra Moutinho, and Miguel Almeida. "Thermal Infrared Sensing for Near Real-Time Data-Driven Fire Detection and Monitoring Systems", MDPI Sensors 20(3), 2020. paper
• Several palette files come from the palette archive at CPY-City
• CPT file loading based on Jonas pycpt

Install

mkdir <ROS-WORKSPACE>/thermal2color/src -p
cd <ROS-WORKSPACE>/thermal2color/src
git clone <THIS-CODE-REPOSITORY>
cd ../
catkin build  # <-- you can also use: colcon build --cmake-args -DCMAKE_BUILD_TYPE=Release

Usage

cd src/thermal2color/scripts
python  thermal2color thermal2color.py _image:=<INPUT_IMAGE_TOPIC> _palette:=<SOME_PALETTE_NAME> 

Available arguments are as follows:

• image Name of the input image topic, default "/image_raw"
• palette Name of the color palette name to use, default "cequal". Several palette CPT files, like ironbow, magma, grayred, and so on, useful for thermal imaging, are included.
• xmin Minimum X coordinate to define a ROI, default: np.NaN which means 0
• xmax Maximum X coordinate to define a ROI, default: np.NaN which means the image width
• ymin Minimum Y coordinate to define a ROI, default: np.NaN which means 0
• ymax Maximum Y coordinate to define a ROI, default: np.NaN which means the image height

The output image topic is defined by appending "_gray2color" to the input image topic.

You can visualize the output image using RVIZ or using "rosrun image_view image_view image:=<INPUT_IMAGE_TOPIC>_gray2color".

TODO

• Support getting the palette from a regular file. Code to extract a palette from a file is also included, but the program only accepts CPT palettes.
• This code has been only tested with FLIR/Teledyne ADK thermal images. Testing images from other sensors is necessary.
• The input is assumed to be gray scale, there maybe other thermal image formats we can support.