KFNB Reader Vs. the Prizmo iPhone App for Blind Users.

KNFB Reader on a Nokia N82

A visually impaired client was recently referred to me by a funding agency to assist him in selecting the best assistive technology for him.  One of his requests was for a portable device which would allow him to do optical character recognition. He wanted something that he could carry with him to do portable reading, something with which he could snap a picture of a page and have it read it to him.

Prior to seeing me he had been into a Mac dealer who had recommended for this purpose an iPad 16 G Wi-Fi plus 3G and an App Store app called Prizmo.

Prizmo on an iPhone 4

I have some experience with OCR applications having worked with them for more than 20 years. Only recently have we been able to use portable devices to provide OCR. The first device of this kind was the KNFB Reader, which married a digital camera to a PDA. This later evolved into software which could be installed on selected Nokia cell phones.

Because of my experience with these types of devices I noticed one immediate flaw in the recommendation. To have effective OCR on any kind of camera type device you need a minimum of the five megapixel camera. The iPad has a 720P high definition camera, which is only the equivalent to .92 megapixels. No matter how good the Prizmo app was, there was no way it would be effective on an iPad.

I am an iPhone junkie. I love my iPhone and I have an iPad at home that I’m never able to use because I can’t pry it out of the hands of my children. The iPhone has a five megapixel digital camera which should be high enough resolution for OCR applications.

I went online and I looked for reviews of the Prizmo app and found them to be quite favorable. It was, according to some, the best OCR application available for the iPhone. I was dubious however about OCR on the iPhone for two reasons. First, I had another supplier who had, in the last year come out with an OCR app for the iPhone for people with low vision. I had seen it work when it was being demonstrated on a technology tour, and had been less than impressed with the OCR results. Secondly, at a recent trade show I had met an executive from the company which manufactured the KNFB mobile reader and had asked him if they plan to release their KNFB mobile reader software as an iPhone app now that the iPhone had a five megapixel camera. He saids quite simply, “no.” because the quality of the phones camera wasn’t sufficient.

But this new recommendation got me to wondering if perhaps the Prizmo application might work better than past iPhone OCR applications. The application was only $10 and the speech output for the application was only an additional $3, so I decided to foot the bill and give it a try.  The KNFB Reader in comparison is $995 US, or about 77 times the price.

The following is a comparison of the OCR results on three different types of documents. The first result is the output from the KNFB reader on a Nokia N82 cellular phone and the second is the output from the Prizmo app on an iPhone 4.  All documents were scanned under normal office florescent lighting on a desk with a plain light grey background.

Laser Printed Text

Moby Dick Laserprinted

The first document is one many will be familiar with.  It is the first page of Moby Dick. The original document is a plain, single column, black text on a white background, laserprinted document in a 10 point Arial font.  It doesn’t get much simpler than this.

Text Results (formatting has not been altered other than the font.)

Moby Dick from the KNFB reader:

Call me Ishmael. Some years ago-never mind how

long precisely -having little or no money in my purse, and nothing particular

to interest me on shore, I thought I would sail about a little and see the

watery part of the world. It is a way I have of driving off the spleen, and

regulating the circulation. Whenever I find myself growing grim about the

mouth: whenever it is a damp, drizzly November in my soul; whenever I find

myself involuntarily pausing before coffin warehouses, and bringing up the

rear of every funeral I meet; and especially whenever my hypos get such an

upper hand of me, that it requires a strong moral principle to prevent me

from deliberately stepping into the street, and methodically knocking

people’s hats off-then, I account it high time to get to sea as soon as I can.

This is my substitute for pistol and ball. With a philosophical flourish

Cato throws himself upon his sword; I quietly take to the ship. There is

nothing surprising in this. If they but knew it. almost all men in their

degree, some time or other, cherish very nearly the same feelings towards the

ocean with me. There now is your insular city of the Manhattoes, belted round

by wharves as Indian isles by coral reefs-commerce surrounds it with her surf.

Right and left, the streets take you waterward. Its extreme down-town is

the battery, where that noble mole is washed by waves, and cooled by

breezes, which a few hours previous were out of sight of land. Look at the

crowds of water-gazers there. Circumambulate the city of a dreamy Sabbath

afternoon. Go from Corlears Hook to Coenties Slip, and from thence, by

Whitehall northward. What do you see?-Posted like silent sentinels all

around the town, stand thousands upon thousands of mortal men fixed in ocean

reveries. Some leaning against the spiles; some seated upon the pier-heads;

some looking over the bulwarks glasses!

Conclusion:  Perfect.  Not a single mistake.  The formatting was even identical to the original document which was scanned.

Mobi Dick from the Prizmo app:

Call me Ishmael. Some years ago-never mind how long precisely -having little or no money in my purse, and nothing particular to interest me on shore, I thought I would sail about a little and see the watery part of the world. It is a way I have of driving off the spleen, and regulating the circulation. Whenever I find myself growing grim about the mouth; whenever it is a damp, drizzly November in my soul; whenever I find myself involuntarily pausing before coffin warehouses, and bringing up the rear of every funeral I meet; and especially whenever my hypos get such an upper hand of me, that it requtres a strong moral principle to prevent me from deliberately stepping into the street, and methodically knocking people’s hats off-then, I account it high time to get to sea as soon as I can.

r~ This is my substitute for pistol and ball With a philosophical flourish Cato throws himself upon his sword; I quietly take to the ship. There is nothing surprising in this. If they but knew it, almost all men in their degree, some time or other, chedsh very nearly the same feelings towards the ocean with me There now is your insular city of the Manhattoee, belted round by wharves as Indian isles by coral reefs-commerce surrounds it with her surf Right and left, the streets take you waterward. Its extreme down-town is the battery, where that noble mole is washed by waves, and cooled by breezes, which a few hours previous were out of sight of land. Look at the crowds of water-gazers there. Circumambulate the city of a dreamy Sabbath afternoon. Go from Corlears Hook to Coenties Slip, and from thence, by Whitehall northward. What do you see?-Posted like silent sentinels all around the town, stand thousands upon thousands of mortal men fixed in ocean reveries. Some leaning against the spites; some seated upon the pier-heads; some looking over the bulwarks glassesl

Conclusion:  Not bad!  4 errors in recognition, requires was recognized as requtres, there was an extra r~ added for no good reason, cherish became chedsh and the last exclamation point became a number 1.  All in all the text was readable.  Formatting was lost however.

Paperback Novel

Paperback Novel

The second document is a paperback novel.  A Wicked Snow by Gregg Olsen.  The scan was of two facing pages at a time, the start of chapter 12.  In typical paperback fashion the paper is thin and you can see some faint text from the pages behind.  Its quality is OK, but not as clear as something printed on a laser printer, and the text size is smaller.  The biggest problem with this type of document is that it is very difficult to get perfectly flat.  This can cause both focus issues for a camera as well as shadow issues for a camera.

When I scanned this document, I turned the book sideways as the cameras on both the Nokia N82 and the iPhone shoot longer up and down than they do sideways.  You can either turn the camera or turn the book.  This way you get the largest possible shooting area and get as close as possible to the document which should help get you more accurate OCR results.

However what I discovered was that the Prizmo app has no auto-rotate feature, so I couldn’t shoot the document this way.  The KNFB reader not only has an auto rotate feature, but it also has a field of view report which will tell you how much of a document is visible.  If you’re a blind user this is critical to help you frame the document in the camera.  Prizmo does not have this.  The KNFB reader also uses the phones built in level to tell you if you’re holding the camera level.  The iPhone has this feature, but Prizmo doesn’t make use of it.  So with the Prizmo really you’re shooting in the dark if you can’t use the viewfinder.  The Prizmo app has some features to help you adjust contrast of a document, but again unless you can see the screen it’s of no use.  KNFB reader does this automatically.  Essentially KNFB reader is designed from the ground up as a scanning product for the blind.  Prizmo is not.

In the interest of a fair comparison of the OCR results, I rescanned with both with the document and camera in their normal orientation.  Here are the results:

A Wicked Snow from the KNFB Reader:

Chapter Twelve

Patty Masour knew the scanner codes better than

anyone in Rock Point, Oregon. She was the part-time

dispatcher at the Spruce County SherifTs Department,

a job she shared with her sister. Sandy. The code sput-

tering over the scanner next to her davenport meant

trouble, big trouble. Multiple homicide in the woods of the

county. She turned ofTher TV and told her husband she

felt uneasy about what she had half heard crackle, and

she dialed her sister.

“County SherifT. Merry Christmas and hello,” a

woman’s voice answered. Her voice was flat. her words

sounded as though they were read from a card. not

words from the heart.

“Sandy?”

“Yes, Patty? Oh dear,” she said when recognition

came. “Have your heard? They’re hauling bodies out of

the Logan family’s tree farm. I haven’t had time to call

you; things have been off the meter over here for the

past two and half hours!”

  Logan?” Patty’s heart sank. She knew the family.

Everyone in Rock Point did. The Logan place had been

A WICKED SNOW

their destination just ten days before when she and her

children went to get their tree, a perfect, pyramidal-

shaped Noble fir.

“CIaire and her two little boys are missing. It’s real

bad out there. I mean realbadl Place is burning to the

ground and the girl…”

“Hannah?”

“Yeah, she’s the only survivor we know about”

Patty’s knees weakened, and she slid into the soft

folds of her velveteen davenport. “Michelle goes to

school with Hannah,” she said. Michelle was her daugh-

ter, thirteen. Patty hung on every word while her sister

went on about the investigation under way. She remem-

bered how Claire’s daughter had rung up the sale for

(lie Christmas tree in the little kiosk set up outside of

the wreath shed. She way a pretty girl, big brown eyes

with thick, ash-blond hair, held in a ponytail. Michelle

and Hannah had been in the same second- and fourth-

grade classes. They were best friends back then. By sev-

enth grade, though, they’d stopped seeing each other

outside of the classroom. Michelle told her mother that

Hannah was no longer much fun to be around. Patty

thought it might have had to do with what was going on

at home with the girl’s mother.

“They’re taking Hannah to the hospital for an exam,

then back here,” Sandy went on. “You got any clothes

that might fit her?”

UYcs,w Patty answered. “Hannah and Michelle are about

the same size.”

“Well, she hadn’t barely a stitch on when they found

her. She was wearing her nightgown and socks. Soaking

wet, too. The poor thing was out in the snow when they

Patty mumbled something about Christmas being

ruined, hung up, and spun around for her car keys. She

hurried to her daughter’s bedroom in search of some-

Conclusion:  Not bad!  There were five OCR errors, but for the most part the text was readable.  Most of the errors were from letters being joined together such as the word Sherrif’s becoming SherifTs.

A Wicked Snow from the Prizmo app.

J Chapter Twelve pmtv ~ knew the scanner codes ~ than amine in Rock Point, Oregon. She was the part-time d~her at the Spruce County Sheriff’s Department, a .~b ~ shared with her sister, Sand)’. The code sputtenng ~ the scanner next to her davenport meant troutae, big troutde. ~~/n atew0o oft~ wtmat She turned off her “IV and told her husband she felt uneasy abOut what she had half heard crackle, and dialed her sister.

“CounV~ Sheriff. Merry Christmas and hello,~ a womans voice answered. Her voice was flat, her words sounded as though they were read from a card, not words from the hea~ Patty? Oh dear.” she said when recogniOon came. “Have your heard? They’re hauling bodies out of the Loga~ family’s tree farm. I haven’t had time to yrm; things have been off the meter over here for the pa~ two and half hours!”

1~n?* Party’s heart sank. She knew the famlJy.

Everyone in Rock Point did. The Logan place had been ., ~. ~ ~-~:A~:~:~ ~’~ m ~st n d~ ~ wh~m sl~e and her im~ ou~ ~ 1 ~se-am ~d ~ IP~me~ m bmmmg to th~ l~t~’~ ~,ee~ i~r~ ~ she did into the f~alds ~ he~ ~ ~pocL ~MicF~elle goes to school ~ ~” ~ ~ .’~,~d~ehe was her daughbered lm~ ~’s daugh~er had rung up the sale for ~be ~ wee i~ the ~ ~ se~ up oumide c~ the ~r~ -~be~L ~e ~,~a~ • pr~uy g~l, big brown eyes dak:~ ~ bah-. hc’kl m a ponytail. Michene and Hannah had heen m the ~me second- and fourthgr~ dass~ Th¢~ ~’~re best friends baf._k then. By sev.

enth grade. ~ th~-‘d ~ seeing each Other outside of the ~ Miche~ told her mother that Hannah ~s no km~ much fun to be around. Patty tSo~ght i~ migh~ h~-e had to do with what was going on a~ home with tl~ girl’s mo~, ~’re taking Hannah tothe hospital [~ran exam.

then back here.” Sandy ~nt oo. “You go~ any dothes ttuu might fit her?.”

~’~x” Pa~ ~ ~ mxl Miche~ ~m~ ~ mine si~e ”

“Well” she ~’t bart4v a stiw.h on ~m they found ~oo. The ~her~ nightgown and socks. Soaking round her.~ ~ out in the mow when they ~o–nerda– v u spun, around for. her car key~ She.

ug~u~r s bedroom m search of som

Conclusion:  Simply awful.  The text was unreadable, and multiple attempts didn’t return any improved results.  Even the optimize feature built into the software, which can really only be used by someone sighted didn’t improve the output.

There was also a significant difference in the amount of time it took to yield the results.  The KNFB Reader scanned this document and was reading within 17 seconds.  The Prizmo app took 54 seconds before it yielded a result, and you have to manually tell it to start reading.  In all it was well over three times longer to get an unreadable result from Prizmo.  Very disappointing.

Bills

Security Bill

The third document I scanned was a security alarm bill from our security company.  Customers frequently ask for solutions to reading their bills.  There are multiple columns, tables and some places you want the reader to read across columns, and some places you don’t.  Most bills these days also have different colors and patterns in the background which can further confuse OCR applications.

The KNFB Reader has a bills mode.  By default it will start reading a document in a documents mode where it reads information in columns.  It’s bills mode is designed to turn off column recognition and to read things across a page rather than in columns.  Using a combination of the documents mode and the bills mode you can generally get a good idea of the information on the page, but there is no one mode that will do it perfectly.

The Prizmo app also has a bills mode, but I discovered when you use this mode, after capturing the image, it brings up a light blue bar on screen which it overlays on the picture that’s been captured.  You are supposed to drag this bar left and right with your finger to select the dividing line between item descriptions and the dollar amounts on the bill.  The problem with this is that it would only work with the very simplest of bills, and it can only be done by someone with very good eyesight.  Fortunately for me I have very good eyesight so I carried on.  The result is then output in a table format for reading.

Security Bill from KNFB Reader in Bills Mode

Reliance

KEEP THIS PORTION

Protectron

BILL TO: (E0281060)

SERVICE ADDRESS: (E0323534)

ATTN OEWONG

THE AROGA MARKETING GROUP

150 5055 JOYCE STREET

10621 100 AVENUE

MAILING ADDRESS

EDMONTON. AB

VANCOUVER. BC

T5J OB3

V5R 682

Invoice Date

Customer

Invoice

W.O. Number Call Number Ticket

P.O, Number

Number

Number

Number

Are you moving

2011/07/13

E0323534

20714422  0

Don’t forget to let us know in advance. Contact

DESCRIPTION

TOTAL

us during regular business hours:

Customer Service

From

1-800-653-9111

t • BASIC ALARM MONITORING

2011/08/05

2011/11/05

9-EXTV.AR – LIFETIME SERVICE PROTECTION BASIC INSTRUSION

2011/08’05

2011/11/05

6 . SPECIAL DISCOUNT

2011/0 05

2011/11/05

PROMOTION

For your convenience, make your payments

directly from your bank account or on your

credit

without additional fees I

See form on reverse side.

Visit our new website at: www protectron corn

Sub-Total

104.85

121314496

524

Total invoice

$110.09

Please remit payment to:

Reliance Protectron Inc.

8481 Langelier

Montreal, Quebec

H1P2C3

Invoicing due date

Amount due

If you have already mailed your payment,

pleas  disregard this notice

2011 0813

$110.09

Conclusion:  There were a few OCR errors, but the critical information, phone numbers, and most importantly the bills subtotals and totals were recognized properly.

Security Bill from the Prizmo App

Name	“Price”
KEEP THIS PORgON	“0”
( Reliance	“0”
BILL TO: (E0281080) SER	“0”
Protectron_	“0”
ATTN:-JOE WONG THE	“67	110″
150 5055 JOYCE STREET	“16”
MAIUNG ADDRESS	“10.8”
VAN~ BE; T~	“83”
VSR 6132	“0”
Inv~ Dale Cm~omef W~O-	“11	710.11″
Numb~ Nt~ber	“0”
Are you moving?	“0”
[2o11~7n3 tE0ZZZ~a	“0”
Donl forget to let us knc~v in advance. ~	“0”
,.~ during ula business I’xx~:	“0”
~ Secvice	“0”
1-800.-653-9111	“0”
PROMOTION	“0”
For ~ convenie¢,,~, mak, e your paymenls	“0”
a’edit card	“0”
without ~ fees !	“0”
,See form on reverse side.	“0”
S~b-To~l	“0”
G~T	“0”
Tel~i imi~ -~	“110”
~ nm~ paymm~:	“0”
m:mm~t Gudm¢	“0”
HIP 2C3	“0”

Conclusion:  Utterly useless.  Not only was it largely unreadable but none of the numbers presented made any sense.  There is no way anyone would be able to read this bill, or likely any other complex bill with this product.

Summary

The iPhone is a marvelous device.  As someone who remembers men flying to the moon when NASA had a total of 64k of memory in their computers, the idea of packing around a multi-purpose computer with Gigabytes of storage and such a staggering array of capabilities makes me fairly giddy.  As an OCR device for the blind however it falls far short of the mark when compared to a KNFB Reader.  Granted, the KNFB reader is substantially more expensive to purchase up front, but if you’re really looking for quality OCR results, you are not going to get them from the current technology offered on the iPhone.  Either the camera quality or the software quality or some combination of the two makes OCR on the iPhone impractical at best.  Perhaps the iPhone 5 will finally have the combination of a camera and a flash that can convince KNFB Reading Technologies to release a KNFB Reader App.  Until then, Nokia appears to have the ideal platform for the KNFB Reader.