PDF Processing with Background Overlay

I need a tool that accepts a PDF upload from users and modifies it based on specific keywords.

Requirements:
- Extract specific keywords from the PDF.
- Apply corresponding background images (APL, BPL, AAY) based on extracted keywords.
- Remove images from the PDF and layer it over the selected background image.
- If no keywords are found, use a plain white background as default.
- Output a modified PDF preview.

Ideal Skills and Experience:
- Proficiency in PDF processing
- Experience with image manipulation
- Ability to implement keyword extraction
using php

Please provide a sample of similar work done.