Docupen R-700 Rechargeable, Portable Scanner Review - Scan Quality and Readability
(Page 5 of 7 )
Scan Quality and Readability
It’s time for the most important thing about the scanner, besides how portable it is. Image quality is vital, and hard to come by in portable scanners. The Docupen gives us two quality settings. Clicking the power button once gives us 100dpi, and clicking it twice gives us 200dpi. Then, after downloading the scan onto your PC, the PaperPort software can convert the image file into text using OCR conversion. The OCR software tries to read the image and guess what letters belong where. Obviously, a higher resolution will mean a clearer image, which will mean the OCR software will have an easier time reading it.
So to test the software and scanner, I printed off a sheet of sentences in eight font sizes (20, 18, 16, 14, 12, 11, 10, 8) to see how they would turn out. I then scanned the sheet three times in 100dpi and three times in 200dpi. I took the best of the three in each resolution. This will show us two things: how well each resolution works with the OCR conversion and what font size becomes unreadable.
The OCR software will turn our scanned JPG files into editable text. But before we move beyond the image file, let’s look at the initial scan quality. Below is a sample of the sentences I had scanned in the two resolutions, 100dpi on the left and 200dpi on the right.
Scan paper quality at 100dpi and 200dpi
So, that gives you an idea of scanning a flat paper with no folds. That's a bit different that scanning a book. On most books, you can't just scan top to bottom. Because the pages often curve, you may miss scanning the part that bends into the spine.
The alternative is to scan sideways, like shown below. Then the PaperPort software has a handy feature that will rotate your scan 90 degrees, turning it upright. The one difficulty is that the area around the binding can still be a little hard to work with. I had a bit of trouble getting the scanner rolling at a steady pace at first, but once out of the binding area it was easy and smooth. With more practice, I may have done better.
Here's how an average book scan came out.
Scan book quality at 100dpi and 200dpi
You may see the some lines in the memo are squished or stretched, and the same is true for columns in the book's text. This is due to how the scanner moves over the page. If you pull one end of the scanner faster than another, the scan will look twist and distorted. This isn't hard to avoid because ollers on the bottom of the device keep you on track. The bigger trouble is trying to pull the Docupen at a constant rate. If you slow down the scan will stretch, and if you speed up it will sshrink. A red light on the Docupen alerts you when you are moving to quickly, which is a great help. More than anything, practice will help to reduce this distortion, but I would never expect it to be perfect.
It is pretty clear by this point that 200dpi looks good. It's readable, functional for all purposes you need a portable scanner, and we will probably see the OCR software pick up on it pretty well. However, I would avoid 100dpi. I can't read a lot of the scan in low quality, and it seems to be only useful for maximizing what you can store in the scanner.
Finally, before moving to the OCR text conversion, let's looks at making the scans shrper. You might notice that the text looked very big above. The scans are larger than they need to me, which leaves room for us to shrink them and increase their clarity. With an image editor, I took the 10 point font from the 200dpi scan above and shrunk it. It looks like a decent photocopy:
Shrinking may be one way of sharpening things, but OCR is the cooler way. We'll be able to edit the text, after all.
Next: OCR Font Size Test >>
More Peripherals Articles
More By Developer Shed
| Recommended by Dev Hardware |
|---|
|
