Hi Michael,
You are partially correct.
The cameras going into cell phones in Japan are of often of higher quality
than those in the rest of the world. However, we have found that counter
intuitively (as Gerard states) that increasing imager resolution does not
improve code readability. Rather it is a mater of getting the code into
focus. As imager sizes increase, the lens diameter needs to increase as
well. With the larger lens, depth of field is reduced. Since fixed focus
lenses typically are set to 50cm - infinity (or there about) any code close
up to the phone will not be in focus. A case in point, the best code imaging
capabilities we ever saw in a phone was with the Mitac Mio which had a CIF
353x288 sensor. This is because the lens was so small.
Thus there are two ways to overcome this 1) add a macro lens to the phone;
2) Increase the module (block) size of the code.
In Japan macro has become the norm but this is not the case other places. In
the whole US market I know of only a few handsets with macro lenses.
Since QR codes are do not have an efficient and flexible code design,
increasing the module size is problematic. For example it is hard to provide
business card details in a code that does not fit on a business card or
consumes much of an ad. Northwest airlines did billboard promotions using QR
but codes were MASSSIVE.
After years of working with a range of traditional industrial codes we
realized that if code scanning was going to work widely we needed to create
a format that would work better on standard phones. Thus, that is why we
created mCode. I invite you to check it out at www.ConnexTo.com.
Jim Levinger
Nextcode Corporation
-----Original Message-----
From: keitai-l-bounce@appelsiini.net [mailto:keitai-l-bounce@appelsiini.net]
On Behalf Of Michael Sydenham
Sent: Wednesday, April 19, 2006 2:09 AM
To: keitai-l@appelsiini.net
Subject: (keitai-l) Re: QR codes
Gerhard
I said it was "CCD resolution and general QR block size" - note the latter
part. Also I think you'll find that generally the lens is not more expensive
compared to the CCD & necessary, accompanying processing electronics. Think
about it - we're not talking about multiple elements and groups nor
high-quality large diameter glass in a cameraphone ;-)
Michael.
On 4/19/06, Gerhard Fasol <fasol@eurotechnology.com> wrote:
>
> Since I got some off-list email on this subject:
>
> it's not the number of Megapixels that's critical -
> it's relatively easy and eye-catching for consumers
> to put a chip with a lot of Megapixels into a phone,
> what counts is the quality of the optical imaging,
> i.e. lens quality, focus, etc that's more expensive and
> difficult than the mexapixels
>
> Gerhard
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Received on Wed Apr 19 16:24:04 2006