Scan and OCR

Hi, @pierret18811376, to consider scanners, there is one aspect you can't get past: which kind of sensor they have. There are two kinds of sensors: CCD and CIS (Based on CMOS).

CCD sensors (similar to camera sensors) are more expensive to manufacture and require more power to function, but they provide much higher-quality images with less noise. 

CIS sensors are much cheaper to manufacture, but their sensitivity to light is lower (thus more noise) and are limited to lower resolution. [To digitally remove the noise, it causes the images to be slightly soft, just as what happens within (say) Photoshop as one of the ways you can digitally remove noise.)

So, if it's an inexpensive scanner, it will be a CIS sensor. Plus, if you have any type of combo scanner/printer/fax/etc., it will also be a CIS sensor.

The good news is that any kind of high-end scanner you get will also have higher-end mechanics.

However, if all you are ever doing is scanning documents for OCR, either is fine. If you need to scan images, negatives, slides, etc., you are wasting your money with a CCD scanner. If you need to scan images, negatives, slides, etc., you are wasting your money with a CIS sensor.

Also, if you are scanning documents for OCR, then Silverfast is wasting your money. If you are scanning images, negatives, slides, etc., you might be wasting money if you consider your time. Besides having higher scanning capabilities, I think the thing you are paying for with Silverfast is efficiency, which I do not have time to get into in a message, but I can simplify an answer on one basis: If you are scanning (say) 35mm negatives, on my scanner, my template can hold three across and up to six or seven down. If you have things set up to do (say) 18 images, on non-Silverfast scanners, there would be 18 separate scans. If you are scanning for high-resolution, that can take a long long time to scan. With Silverfast, it would just be six scans because it would scan the three across concurently. Otherwise, stated, that's one-third the scanning time. That means a lot.

Oh, one other ability: if I am using my Epson scanning software (which otherwise is good scanning software), and I have two photos I wish to scan, let's say one is color and one is B&W. I can only scan color or B&W. With Silverfast, I can scan one at color and one as B&W and if they are alligned up next to each other (left & right), that would be done in one scan. [If they were alligned as one above the other, that would still have to be done as two scans, but I would not have to first do the color and then do the B&W, it would still be done as one sweep of the scanner.]

BTW, ALL scanners, regardless of manufacturer lie about their highest resolution capability (even Epson).

Oh, and for the record, my Epson is the V800, now sold as the V850.

@Abambo is correct. 

One of the failings of Acrobat's OCR is that it will only correct one word at a time. My point is that in Word, if you find a word misspelled and that same word is misspelled many times, you can do a global fix on all of those "many times" with a few clicks. In Acrobat, you have to do each word, one at a time. 

So, as I show in that Blog I linked to above, look for the red lines and try to see if there are many that can be fixed in a few clicks.

Levels is idealy in the scanner software (and hardware). You define the black point (everything left to this point will be perceived as 100% black) and the white point (everything right to this point will be 100 white) and the mid point (50% gray). That will allow you to "cut off" impurties and shine through, at the expense of eventually accuracy (what is light gray will eventually be white). 

Also, for OCR, best is to scan greyscale. 

HP MFP machines have a lousy quality, compared to the stand alone scanners of the time. They do their job, but the result could be better. I wouldn't scan high fidelity colour pictures with them, but for OCR, they do a nice job. 

Hi, @pierret18811376, did you remove any grey from the page via Levels, as I mentioned in my blog? Also, do scan at 300 ppi unless the text is very small, then go up to 600 ppi. (the latter will significantly increase the storage size of the TIF image, but once you PDF and OCR the page, it will be down to a "normal" size.

If you want to get the best quality, you need to do everything you can DURING THE SCAN. Even doing the same fixes in Photoshop that you're doing in the scan will not be as good as when they are done at creation in the scan.

At the outset, I must thank you for the word of caution, I am told by Adobe that I have to Install Asian Language support files,

Moreover, I am assigned this job by the Owners and Authors