PHP and Inventory Tracking

Hello, I have client that has a PHP/mySQL web system that tracks inventory. They use iPads to access the system and this work well. They are wanting the ability to take photos of incoming inventory and use BARCODES to track it (ie… scan and generate barcode labels with their mobile devices) Can anyone offer some advise on the most efficient way to add these features to a website. Libraries, plug-ins, etc… I am gonna start digging around the NET, but thought I would throw a feeler out here in hope that someone has done this with PHP and had had success. Thanks in advance. Don