What’s the difference in accuracy and features of ZoomReader, Prizmo and TextGrabber OCR scanning apps for clients with a print disability?

A few great questions from comments of readers inquired about the difference between OCR scanning apps mentioned in a prior post that are used to convert images to text for individuals with disabilities. So, I decided to do an informal comparison of the apps mentioned to determine the accuracy of the apps ability to perform OCR scans of images using with three apps typically mentioned or reviewed for individuals challenged with accessing text (e.g. low vision or print disabled).

Here is what I found in this informal research comparison:

Material used: A clean, hard copy document with 275 words with 12 point Arial black and blue font on white paper with no images was consistently used to scan with each app. The document has some text with blue font which was bold 12 point type as headings.

Apps used:

ZoomReader on an iPhone4 (only available for iPhone)

 TextGrabber + Translator (iPhone and iPad) and

 Prizmo (iPhone and iPad) apps were used on an iPad 3.

Camera use: The iPad 3 and iPhone 4 camera was used in natural lighting with the hard copy document  placed in the same location with same day lighting available within a 20 minute period of time (I find lighting to be a big factor with the use of the scanning apps). No flash component was used when taking the picture of the hard copy text with any of the devices. A consistent method of taking pictures was used (camera button was pressed while centering the iDevice over the hard copy then released when best image was in focus  to get the best still picture possible).  The iPad 3 was used with TextGrabber + Translator and Prizmo apps and iPhone 4 was used with ZoomReader app.

Results:

App	ZoomReader (iPhone4)	Prizmo (iPad3)	TextGrabber + Translator  (iPad3)
OCR character errors	5 errors( 4 character recognition errors, 1 spacing error; resulting in 3 word errors) Character recognition accuracy:272/275 words correct = 99% accuracy	4 errors(2 character errors, 2 spacing errors; resulting in 3 word errors)Character recognition accuracy:272/275 words correct = 99% accuracy	2 errors(1 character recognition error, 1 spacing error; resulting in 2 word errors)Character recognition accuracy:273/275 words correct = 99+% accuracy
Formatting	Detected 10/15 Enters or paragraph returns between sentences or paragraphs in the text. Formatting accuracy (% maintained from original): 67%	Detected 6/15 Enters or paragraph returns between sentences or paragraphs from the original text.Formatting accuracy (%maintained from original): 40%	0/15 Enters or paragraph returns were detected. OCR processed text was one block of text. Formatting accuracy (% maintained from original):0%
Other scanning app features	Provides voice feedback throughout the process No cropping available Provides contrast, highlight color and font size options in app Image saved to Photos, text converted must be emailed or copied for later use Imports images from Camera Roll	Provides cropping, perspective, rotating image to edit image prior to scan Translates text Provides text to speech after OCR processing performed Saves image and text for later use Provides ability to copy, email, move/link to Dropbox, Evernote, CloudApp, MobileMe or translate text Imports images from camera roll No options available for contrast of change of text size within app	Provides cropping editing Saves OCR text for later retrieval Translates text Provides ability to copy, Email, move/link Twitter, Facebook, EverNote, Messages Imports images from camera roll No options available for contrast of change of text size within app

Comments: There were minor differences between the OCR accuracy for character recognition on the trials performed using ZoomReader, TextGrabber + Translator and Prizmo apps.  Prizmo and ZoomReader apps showed greater detection of basic formating, maintaining paragraph Enters or blank lines at the end sentences to show paragraphs and line spacing present in the original text. TextGrabber did not detect any paragraph Enters from the orginal text scanned resulting in one block of text. A greater number of trials were needed to get a good scan using ZoomReader app in these informal tests. A document of the original text and results of the three app scans are available here.

The differences of features of each app need to be considered pending user, linking services for the user and reason for use of the app. Some individuals may need an immediate scan for access to text on the fly as opposed to scanning in text for later use. Prizmo and TextGrabber + Translator apps were more user friendly for this sighted user. Prizmo app provides a few more options of scanning in business cards, bills, whiteboard, and text as well as has a reader within the app for conversion and immediate access by a user. Prizmo also has numerous in app links to use the text for different reasons. TextGrabber is linked Evernote and social media services. ZoomReader provided contrast options, changing text size and voiced instructions with use of the app for individuals with visual challenges. ZoomReader linking options is limited to emailing or copying OCR results and pasting it into another app.

Results: As with many other apps or software, user characteristic or needs, features of the app and application purposes and where you want to use the information will depend on what app is most appropriate. I heavily rely on Dropbox to manage documents and am looking for tools for print diabled individuals to access text on the fly with text to speech making Prizmo a strong choice of mine. However if using social media and not concerned about extra steps to access a text to speech app (Speak Text tool was not offered within TextGrabber) or formating this may be the best option. For individuals needing low vision options of contrast and text enlargement, ZoomReader may be the tool of choice on an iPhone.  

Note: In prior trials there were little difference with the accuracy of scanning with Prizmo and TextGrabber apps with iPhone 4 and iPad 3. Scanning with the iPad 2 is a whole different ball game due to reduced megapixels in the iPad 2 camera. See prior post, New iPad 3 Features – A Boon for Individuals with LD for a comparison.

What app might be your choice for your OT iTool Kit?

Carol