Removing headers & footers Use the crop tool to hide the parts of the page you don't want to translate. Export, translate then remove the crop to restore the original page size.
Removing unwanted text (not in a header or footer) For text not easily removed with the crop tool (see above), try the Delete Across Pages function. This enables you to select some text using the Object tool, then ask Infix Pro PDF Editor to remove it from a range of pages.
Forcing TransPDF to OCR a PDF TransPDF will automatically detect scanned PDFs and run OCR on them. However, if a PDF is a mix of scans and real text (even if that text is hidden behind the scanned images) it will not perform OCR on any of it. To force it to do so, remove all the real with the Convert To Outlines function available in Infix Pro PDF Editor.