Duplicate title into caption

When I’m uploading images to the gallery titles of the images stay the same as filenames, but caption fields stay an empty. I need to make the same text in this fields and I wish to use this fields on different gallery interface spots.
I’ll put title to the overlay template and and caption to the popup this text should have different styles. Is the manual configuration only one option for this task?
I have huge amount of images and manual option is not the best solution for my gallery.
I hope to find some alternative solution for this task.