Probably beginner questions about annotation


I don´t know if this is a question for this forum but I’ll give it a try.

I´m not sure if the question leads to the answer of the problem I have so please feel free to make your own interpretation of the combined information, I’m still new to the techniques.

I have a number of questions regarding annotation;

  1. lets say I would like to make a model that detects and identifies hockey pucks and different kinds of balls.

So I have one class named “Hockey Puck”. I also have a class named “balls”, but in this class I have a number of sub-classes (basket ball, soccer ball, volley ball etc), is there a way to make this sort of hierarchy?

  1. Lets say I have pictures of people holding a rope between them. I would like to make a class “rope”, one class “person” and one class “hand holding rope” (The actual spot where hand meets rope).
    When annotating this the complete annotation for “hand holding rope” would be in the “person” class, would this then mean that in the future this class only “works” when “submerged” in a “person”-class? For example, if i have a picture where one of the persons is wearing a horse-mask over his head so that the “person” class would not be detected, would the “hand holding rope” still be detected?

  2. Lets say I have 100 pictures with different objects that i would like to annotate but in all of them there is also a sleeping cat. Would i need to annotate the sleeping cat in all 100? If i annotate sleeping cat in 50 of them, would this be cancelled out from the 50 pictures where the cat is not annotated?

Is labelimg still a recommended software for annotations or is there something new that I should look into? (I would like to keep the pictures offline)

Best regard,