Passing custom objects to functions

I made a class for pixel perfect collision, but for it to work, i must send the entire object to it. How can i pass an entire object to a function. whati s the general name for objects, like integrals have int and so on. Or how can i send the specific part of the spritesheet to the function. Im using imageicon to draw the images on the board , adn all the movement and stuff is done with image icons.

So how to i send objects ingonito or how i send parts of imageicon?