Human detection using thermal camera and openCV


I’m new in OpenCV and I’m trying to create a project for my school. I’m trying to detect if a person found inside of a thermal video using openCV (or other tools I can use) and Python. My video was taking in rainbow colors.
When I tried using HOG descriptor I wasn’t able to get any good results.
What are my best option for human detection? if its using HOG descriptor what definition should I change for best results?

Thank you very much for your help,
OpenCV beginner.