[tabi] Re: technical info for users of the KNFB reader
- From: "Betsy" <betsaw@xxxxxxxxxxxxx>
- To: <tabi@xxxxxxxxxxxxx>
- Date: Tue, 25 Aug 2009 17:42:23 -0400
Thank you very much for this information Chip.
I reeealy want to get one of these in the next couple years. I've been waiting
and watching it evolve ever since it came out and it's only going to get better.
Betsy
----- Original Message -----
From: Chip Orange
To: tabi@xxxxxxxxxxxxx
Sent: Tuesday, August 25, 2009 4:25 PM
Subject: [tabi] technical info for users of the KNFB reader
>
> K-NFB Reading Technology, Inc.
>
>
>
> TECHNICAL ASSISTANCE BULLETIN
>
>
>
> Date: August 19, 2009
>
> SUBJECT: Advisory on use of polarizers
>
>
>
> Installation of polarizers over the camera lens and flash has been a
> specified procedure of K-NFB Reading Technology since the Mobile Reader
> products were first released in January 2008. The purpose was to improve
> the quality of images captured by the Nokia N 82, which uses xenon flash
> technology to illuminate target text. Polarizers minimize glare caused by
> the flash reflecting back to the camera lens when the text is printed on
> glossy material, or the image is captured through glass. The glare would
> otherwise prevent accurate text recognition.
>
>
>
> Polarizers do improve image quality, as confirmed by our direct observation
> and reports we continue to receive. But only if they are correctly
> installed and maintained in accordance with our specifications.
> Unfortunately, over time normal day-to-day use of the Mobile Reader often
> results in polarizers being moved or dislodged, such as when the phone is
> carried and frequently removed from a pocket, purse, or carrying case.
> Misaligned polarizers not only fail to improve images of glossy surfaces
> but
> also can distort all images, leading to unsatisfactory performance.
>
>
>
> To address this, we have decided to recommend polarizers as an optional
> rather than a required accessory. End-users may choose to have them
> installed or not based on individual needs, requirements and preferences.
> The information below is intended to help Mobile Reader distributors and
> end-users decide whether to recommend polarizers or use them, respectively.
> Additional assistance to address particular questions or concerns is
> available from K-NFB Reading Technology's technical support service.
>
>
>
> 1. Expected reading requirements
>
> As noted in the Mobile Reader Users Guide, polarizers are particularly
> essential when capturing images of text printed on glossy material or when
> a
> picture is taken through glass. An alternative to polarizers under these
> conditions is to switch off the flash, which can be done without
> sacrificing
> image quality provided the lighting in the room or area is moderate or
> better. Another alternative is to use a reading lamp, which can improve
> the
> brightness of the image and still avoid glare if the light is properly
> situated to avoid reflection from the glossy surface . So switching the
> flash off while attending to lighting conditions is a suitable alternative
> to polarizers, unless one needs to read glossy documents very frequently
> and
> under varying conditions of light.
>
>
>
> 2. Installation and maintenance requirements
>
> In order for polarizers to function as intended, installation must be
> performed in accordance with our specifications. Thereafter great care
> must
> be taken at all times to maintain the precise positioning of each
> polarizer.
> The end user must understand this.
>
>
>
> 3. Camera considerations -
>
> Two supported phones, the Nokia N 82 and the Nokia 6220 classic, are
> equipped with xenon flash, which produces the brightest light possible but
> also can introduce the most glare. The Nokia N 86, first announced as a
> supported phone in August 2009, is equipped with a camera which has been
> optimized for low light images, including an 8 megapixel camera and an
> advanced dual LED flash. Consequently, images of glossy content captured
> by
> the N 86 used without polarizers tend to show less distortion even with the
> flash turned on than comparable images taken with the xenon flash of the N
> 82 or 6220 Classic. Images taken by the N 86 without polarizers and the
> flash turned off usually compare favorably to images captured by the N 82
> or
> 6220 Classic when polarizers are installed and the xenon flash is turned
> on,
> provided there is moderate or better light. So there is less need of
> polarizers for the N 86 than there is for the N 82 or 6220 Classic.
>
>
>
> In summary: beginning August 2009, K-NFB Reading Technology will no longer
> specify pre-installation of polarizers as a product requirement. Decisions
> on installation and use of polarizers as an optional accessory should be
> made by distributors and end users based on individual needs and
> capabilities. Polarizers will remain available upon request for all
> supported phone models.
>
> Switching the flash on and off, while attending to lighting conditions, is
> recommended as the best all around option for end users who do not express
> a
> significant need to read glossy documents in low or fairly low light with
> the flash turned on. See the chart on the following page.
>
>
>
> For more information or to order polarizer sets, please contact K-NFB
> Reading Technology by email at: support@xxxxxxxxxxxxxx or by phone at:
> 1-877-547-1500. If ordering polarizers, please specify the quantity and
> supported phone model. Previously published rates for multiple polarizer
> sets shipped in quantity to distributors still apply.
>
>
>
> Explanations on the decision to use polarizers follow in both text and
> chart
>
>
>
>
> Our recommendation as to whether polarizers should be installed depends on
> 2
> questions:
>
>
>
> Do you frequently need to read glossy documents, and under varying light
> conditions?
>
>
>
> Would you carefully maintain the position of the polarizers on the camera
> lens and flash?
>
>
>
> If the answer to either of these questions is "No", our recommendation is
> not to have the polarizers installed. Turn off the flash before shooting
> glossy surfaces and make sure that there is at least moderate lighting.
>
>
>
> If the answer to both of the above questions is "Yes", then your preference
> should determine whether polarizers are installed on the Reader. N82 and
> 6220 Classic phones have a very bright xenon flash, which can produce a lot
> of glare in an image of a glossy document, whereas the N86 has a dual-LED
> flash which does not create as much glare. The polarizers will greatly
> diminish the glare which appears in an image of a glossy document, but you
> can also turn the flash off, which will eliminate the glare and still
> provide good reading performance if there is good ambient lighting.
>
>
>
> If you choose to have the polarizers installed, make sure that the
> polarizers are not rubbed against surfaces or put under stress, as this can
> cause them to move out of position. If you choose not to install
> polarizers, turn off the flash before shooting glossy surfaces and make
> sure
> that there is good ambient lighting.
>
>
>
> Best Regards,
>
>
>
> James Gashel
>
> Vice President of Business Development
>
> K-NFB Reading Technology, Inc.
>
> Direct phone: (720) 878-4248
>
> Fax: (781) 263-9999
>
> Skype: james.gashel
>
>
>
> email: jim@xxxxxxxxxxxxxx
>
> http://www.knfbreader.com
>
>
>
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