Wednesday, December 21, 2016
Using a Smartphone to Scan Documents
I have been using my iPhone to capture copies of documents and text from books to save the time and expense it takes to make a photocopy for the past few years. Presently, there are a huge number of scanning apps available for both the iOS and Android smartphones. The free apps are usually quite basic and really do little more than the standard camera app that comes with the device. You could spend a lot of time trying out different apps and there are a number of these that are targeted at the genealogy marketplace.
A while ago, I compared my new iPhone 7 Plus with my Sony camera. See "iPhone 7 Plus vs. Sony Cybershot DSC-HX400V." That post dealt with the issue of detail resolution between the two cameras. The main issue for genealogists is whether the cameras in the smartphones are an adequate replacement for a dedicated scanning device. The answer to this question is easy. NO, they are not. The issue is not the scanning app. The issue is the resolution or detail of the images produced. In addition, as I have learned over and over during the past years, you cannot take adequate photos of documents or photographs without a tripod or camera stand and uniform lighting.
In promoting the smartphone camera apps for scanning genealogically significant documents and as a replacement for a dedicated flatbed scanner or a very high-quality digital camera, the promoters are not being forthcoming with their intended customers. The phrase here to focus on is "quick and dirty."
Of the issues facing the use of a smartphone to replace a scanner, the most important ones are holding the camera steady, making an image when the camera is perpendicular to the surface of the paper, and obtaining uniform lighting over the surface of the paper. It is also important to remember that if we are making a copy of a copy, then we are already, at least, two generations away from an original.
Here are some example of the problems. I am using my iPhone 7 Plus with a 12 Megapixel camera. Your results using your own smartphone may vary. Hmm. What should I use for an example? How about a simple, rather crude eye test sheet like the ones you see in drugstores?
Here is a digital copy of one such sheet. This is directly from the website Readers.com.
This is not a photo. This is a screenshot of a PDF downloaded file. But I am going to show the detail in the PDF file. Here is part of the image at 1200% magnification.
Now, let me take a photo of the same page using my iPhone. First, handheld with the available light. First of all, I have to use a printed copy of the document. That means that the resolution of the print will be about 300 dpi or the resolution of my printer. Also, since I don't have a color printer, the image is in grayscale rather than color. Here is the image from my phone. Remember the image is handheld and uses available light.
Hmm again. It looks pretty good, all things considered. Now I will take the photo into Adobe Photoshop and magnify the same part of the photo.
This is the image from the iPhone at 1200% magnification. Pretty good actually. Certainly, acceptable for research purposes. It would also be sufficient quality for OCR (optical character recognition) purposes.
My conclusion is that using a smartphone for on demand note taking, casual scanning and use where permitted in a library or archive is perfectly acceptable. But I would stop short in encouraging anyone to use their smartphone for archive purposes especially for photographs.
Oh, by the way, I just used the camera app that comes with the iPhone. You would have to evaluate whether or not you want to use one of the multitude of other apps available for some reason.