Here's a possible action based on the images being at least in generally the same location (HAS NOT BEEN TESTED...yet):
1. Make rectangular selection leaving approx. 1" of white space around image.
2. Edit>Copy
3. New document (this should retain the measure of the copy command)
4. Edit>Paste
5. Select>Color Range (based on background being close to a pure white)
6. Select>Invert
7. Image>Crop
8. Layer>Flatten Image
9. Save (see note at bottom)
10. Close (see note at bottom)
11. return to original document (document jumping is permitted in actions)
12. Move selection to second image area.
13. Edit>Copy
14. New document (this should retain the measure of the copy command)
15. Edit>Paste
16. Select>Color Range (based on background being close to a pure white)
17. Select>Invert
18. Image>Crop
19. Layer>Flatten Image
20. Save (see note at bottom)
21. Close (see note at bottom)
22. return to original document (document jumping is permitted in actions)
23. close without saving
The thing that's going to hang you here is saving. Because they are new documents they will be named Untitled-1.ext, Untitiled-2.ext, etc.
You can do a generic rename on windows by selecting all, right clicking, and selecting "rename". On a mac, I find an application called R-Name to be quite useful.
The other thing is that they'll still need to be cleaned up due to rotation, colour balance, etc. A good tip here is to use the ruler tool Click twice along a straight edge. Then go Image>Rotate Canvas>Arbitrary...
The correct rotation will be entered for you. This is also a handy tip for correcting crooked horizons (can't be automated though).
Like I said, hasn't been test, but it might cut down on some of your workload. And some is better than none.