Addon

Do I need the PDF Rasterizer addon to convert scanned documents to PDF files?

No. Dynamic Web TWAIN can output images as image-based PDF files and this is built into the core module, so no addon is required to convert scanned documents to PDF files.

You need the PDF Rasterizer Add-on only if you load/download text-based PDF onto the viewer. To detect whether a PDF file is text-based or not, you can use the API IsTextBasedPDF.