There's a very similar thread going at the moment:
http://www.agisoft.com/forum/index.php?topic=3981.0Using the images from the previous post here, I tried the approach I'm currently exploring... using an edge filter on the image and measuring the stdev of the resulting image with ImageMagick (you can get the numbers without actually producing the images) I split the image into two, below the text, creating "sharp.tif" and "blurry.tif"
ImageMagick batch file:
convert @dir.txt -edge 2 -auto-level -format "%%f %%[fx:standard_deviation]" info: > stats2.txt
... where the files are listed in "dir.txt"
The result:
sharp.tif 0.135247
blurry.tif 0.0926683
There is no absolute value for a sharp or blurry image, but comparing similar images in a sequence may be feasible. Images with locally low values could be flagged for checking/ omission.
Attached the filtered images for reference.