A way to edit all images in a pdf quickly?

My all-in-one scanner has an auto document feeder which allows me to quickly scan multiple pages, duplexed if needed, to a pdf. The problem is that when scanning to PDF, there is no light/dark slider adjustment like you have with the copy and print function. It copies and prints fine but when going to pdf, the grayscale scans are alway washed out and don't come close to 100% Black. I have Acrobat, Photoshop, Indesign, etc and was looking to a way to automate opening up each image from the pdf page and applying a level or curve adjustment in photoshop as this would be to time consuming on a large document. Could this be done with a script of some sort?

I could scan to tiffs and then batch correct the images and then place in InDesign with an import script and save the pdf but it seems there should be an easier way.

Thanks