[On hold] Add digit recognition example

[corneliusboehm]

The final layer of both backbone networks was trained to recognize digits drawn in the air and some display logic is added.

General updates:

• Support font_scale and thickness in put_text
• Fix the runtime_error handling in controller.py, because it was not showing the relevant exception, but only that runtime_error was used before declaration

Here's a perfect run where all digits are recognized (even though it doesn't always work): https://drive.google.com/file/d/1pEM0a2OYGxPvuqC9gvft8RQKb9iVdtkY/view?usp=sharing

Please try this out yourself and let me know if it's good enough to be a visible example in the README.

[floriandotpy]

I'm pretty sure this is unrelated to your example, but in a fresh installation of the repo and environment, I can't get the demo to work. It prints two lines, does not open a window, does not show an error, and simply terminates.

Have you seen this before?

$ PYTHONPATH=./ python scripts/run_digit_recognition.py --camera_id=1
Starting inference
Stopping inference

$ 

[corneliusboehm]

Don't think I have seen this :confused: Do any of the other demos work?