Line of Sight detection

i have simple question. do line of sight detects the collision box of an object or just the image point of the object?

i am trying to detect if there are walls ahead of my ai and i am having trouble on thick walls that my line of sight cannot reach.

ps.

especially on walls/solid objects that has irregular shape and arcs

I made a template for line of sight that uses a bounding box. I will make an example in the template to show how it can be done.

Link:

thanks — though i solved the problem by making an invisible sprite which will serve as bounding box detector. it was good alternative but not for long distance detection. hope you will able to finish your template to help others with same problem