When the K-NFB Reader Mobile was released in January 2008, it revolutionized how people with visual impairments could scan and read printed materials using their cell phone camera. The K-NFB Reader Mobile's software, an Optical Character Recognition (OCR) program, was developed by Ray Kurzweil and the National Federation of the Blind. That software, however, can only be used on a limited number of Nokia cell phones, which not all carriers support, and although the K-NFB Reader Mobile is self-voicing (which makes the cell phone fully accessible), a separate screen reader program must be purchased and installed. The K-NFB Reader, Nokia phone, and separate screen reader can be a very expensive combination.

Users of iOS devices (iPhone, iPod touch, iPad, etc.) now have several choices for OCR apps. Although these apps do not have all the capabilities of the pioneering K-NFB Reader Mobile, they are extremely inexpensive, and no additional screen reader is necessary.

The apps reviewed here are SayText, Prizmo, and TextDetective. SayText and TextDetective are designed specifically for people with visual impairments. For this review, each app was tested three times using a printed sheet (a letter), a glossy page from a magazine, and a book page, on both an iPhone 4 and an iPhone 4S. (The iPhone 4S has a more sophisticated camera than the iPhone 4, but the slight improvement in performance is not enough to warrant getting the 4S.) Lighting conditions were the same for all tests.

Getting Started

These apps need good light as they will not work in very dim lighting conditions. Finding the correct distance between the document and the camera lens takes some trial and error, and it's not always the distance that the app instructions recommend. Depending on the size of the page, it may take several scans to capture the entire document. The document needs to be flat, since any wrinkling or folds will cause the app to read as gibberish. If scanning results come back as a combination of words and gibberish, try a different scanning distance, make sure the document is completely flat, and try scanning with more available light (and be careful not to block the light with your body).

SayText Version 1.3

As described in the iTunes Store, SayText Version 1.3 is a free product created for users who are blind or visually impaired. It requires iOS 5.0 or later.

When the app loads, there are four available buttons: "Take Picture," "Tutorial," "Settings," and "Info." The tutorial is easy to follow, but unfortunately, the app does not work properly. According to the tutorial, the user must place the iOS device on the document with the camera facing down, then slowly lift the device up. When the document is in focus, a beep should sound. The camera takes the photo and then translates the result into text. While the document is processing, the user can tap the screen to check on progress. Once the document is converted, you swipe right to hear the text.

During all the testing, the iPhone 4 and the iPhone 4S never made a beep sound and never snapped a photo. You need to activate the "Take Picture" button, which brings up a new screen with a "Camera" button, and activating that button causes the camera to take a picture. When the app indicated that OCR was complete, I attempted to read the text, but all I got was gibberish.

The app did not read the printed page, the glossy magazine page, or the page from a book. I used sighted assistance to try to get a better image but still had the same result. My next step was to check the AppleVis website to determine if other users have the same problem. There are many comments, and everyone that posted a comment seems to have had the same experience.

SayText is a very disappointing product. According to the instructions, it's easy to use and gives good results, but we were unable to get the app to read anything during testing.

Prizmo Version 1.1.7

This $9.99 app works on all iOS devices running iOS 3.1 or later. The iTunes Store description of the app claims that Prizmo will scan and recognize the text from your photos of text documents, business cards, bills, and even whiteboards, and with the use of Cloud technology, you can share that information with your other devices as well as with other people. Another highlighted feature is that this app has speech-operated shooting for taking the image that you want read.

This app is somewhat complicated to use. When the app loads, there are several options from which to choose, including Settings, Text, and Business Card. In the Settings menu, you should turn off the alignment grid and turn on the speech control option, which allows the user to take a photo by voice rather than by activating the button. This can help with image stabilization. Since VoiceOver's volume will decrease significantly once the camera option in the app is activated, you might want to wear headphones in order to hear instructions at a normal volume.

Once out of the Settings menu, place the iPhone on the document with the camera's lens in the middle of the page, using the side of the document to ensure the phone is straight. After lifting the phone 7 to 9 inches from the paper, double tap the "Text" Button. When the next screen loads, activate the "Camera" button. Your phone will vibrate when the camera screen loads; you'll hear the VoiceOver prompt, "Say 'Take Picture' when ready."

Once you take the picture, activate the "Use" button, which is the last button at the bottom of the screen. On the next screen, activate the "Next" button at the top right, which activates the processing screen. Once processed, VoiceOver will announce that the document can be edited, and you can read the results by doing a two finger swipe down. After you have reviewed the document, activate the "Next" button. On the new screen, there will be several options, including "Save," "Translate," and "Copy." Doing a three finger left swipe will bring up additional options, such as "Mail" and the Cloud app. Activating any of these buttons will open up the appropriate page. Activating the "Done" button in the upper right corner of the screen will close the screen and bring the app back to its home screen.

Prizmo did best with the letter and the magazine page. Although one scan of each did not give all the information and resulted in some gibberish, most of the information was read. Prizmo had more trouble with the book, especially with text closest to the fold.

TextDetective version 1.0.4

This $1.99 app works on iOS 5 or later and was designed for people with visual impairments. The app description states that TextDetective allows you to read, edit, or copy and paste the recognized text from the image that you take into other documents or e-mails, and to store it in a History tab. While the description states that the app works best with the iPhone 4S and is also useable with the iPhone 4 and iPod Touch, it cautions iPad users due to the difference in that device's camera placement.

TextDetective is relatively easy to use. The user holds the device in landscape mode with the "Home" button to the left. When the app loads, there are four tabs on the bottom of the screen: Scan, History, Tips, and Feedback. By default, the Scan tab is selected.

To use the app, align the "Home" button with the edge of a document, then lift the phone up until it's about 8 to10 inches away from the document. Double tap the "Start Scan" button. When TextDetective finds the document, the phone will vibrate. This can take a few seconds, especially with the iPhone 4, but VoiceOver will speak conversion progress messages as it's happening. Once the app has finished processing the document, a new screen will appear with the text. At the top right of the screen is a button which allows for reading the entire text or individual segments. Whatever has been scanned is automatically saved in the History tab.

The TextDetective app did best with the printed page. Like Prizmo, it also worked well with the magazine page, and though it performed better than Prizmo with books, it still needed several scans for each page. TextDetective showed the most difference between the iPhone 4 and the iPhone 4S in processing speed, with the 4S giving a somewhat better scan.


By far, the best app of the three was TextDetective, with its solid performance and reasonable price. I do not recommend SayText as it had the least effective results by far.


For more information and to download these apps, use the following links:

SayText from the iTunes Store

Prizmo from the iTunes Store

The Prizmo Tutorial from AppleVis

TextDetective from the iTunes Store

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Janet Ingber
Article Topic
Product Evaluations