Questions about batch ocr images

You can try this website to convert scanned file to searchable pdf or editable word, maybe you can use it to make your scanned file to searchable pdf.
It's free, https://www.ocrterminal.com/
but it doesn't support to combine many files into a single pdf, so, this article may help, http://www.simpopdf.com/guide/how-to-com...

You can create a batch sequence that will run e.g. on all files in one directory. Here is how you would do this:
Select the "Advanced Batch Processing..." menu item - this will open up the "Batch Sequences" dialog.
On this dialog click on the "New Sequence" button, and give your new sequence a name.
On the "Edit Batch Sequences" dialog click on the "Select Commands..." button. Under the "Document" category select "Recognize Text Using OCR" and click the "Add" button. Double-click on the new entry on the right side of the window.
Specify your OCR settings and click OK on all the dialogs until you are back on the "Edit Batch Sequence" dialog.
Now you can select on which files/directories to run this sequence on, and what to do with the output.
To select the source, change the "Run commands on:" setting. Your choices are to prompt when the command is run, to specify selected files (it will always run on this these flles), select a folder (it will always run on all files in this directory), and all open files in Acrobat. In your case it's probably best to create an input directory.
To select the output option, change the "Select output location" setting. Your options are to write the output to a specific directory (this allows you to have one input and one output directory), to write teh files back to their original location (and therefore replacing the originals), to ask at the time the sequence is run, and to not write anything back. I would either use the same location, or a specific outptu directory.
To run the batch sequence, select the "Run Sequence" option on the "Batch Sequences" dialog.

1. Batch Conversion
2. OCR technology
3. Partial conversion
4. Add watermark property
5. Can extract images from pdf files
6. Preserve original file format.

You could try batching all of the PDF files into one file and run OCR on that single file.