Not Another PDF Scanner 2 (NAPS2) is an open source scanning application that works on Windows. Its source code can be found on Github here.
Features it seems to support include:
- Color, grayscale and black and white scan.
- Scanning to image file formats like JPEG and document file formats like PDF.
- Scanning multiple page documents.
- Rotation and flip of individual scanned pages.
- OCR of scanned pages.
Tried with: NAPS2 6.1.2 and Windows 10