討論區: English (Thread #13466)

Mr. Yanbe (2007-01-21 00:35 by aloknegi304 #27249)

Respected Sir,
Thanks for your consideration.
As far as my knowledge of Qr Code is concerned , the qr code image has modules say 4*4.
The modules are the black dots which appear in the qr code.The question i would like to ask is,
how is say "aloknegi" stored in qr code. You see at, some places the black dots are present while at some places they are not.
Can you suggest any encoding algorithm for the same.
Also one more questyion arises in my mind is that, how the data is compressed.
thanks
alok

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RE: Mr. Yanbe (2007-01-24 18:40 by yanbe #27302)

Alok,

I'm Sorry for late reply. I was writing paper for certain international conference. (I'm a graduate student in Japan)

> how is say "aloknegi" stored in qr code


To be brief,

At first, according to input data type , encoding mode is selected to optimize data size. There are 4 encoding modes(digit, capital-alphabet and digit, 8bit-byte includes ASCII, and kanji). And each mode requires different size of bits per character(3,5,8,13). In order to
optimize data size after it encoded, QR Code changes encode mode dynamically during seeking input data. In your example "aloknegi", 8bit-byte mode will be selected.


> how the data is compressed

Changing encoding type is also consume bits. Then, on encoding complex data includes many data types, selecting optimal encoding type described as a kind of data compression.

Another approach to compress data in QR Code is pre-compression using well-known compresing algorithm like zlib. But I'm afraid of its too
big over-head of this approach. And, this requires additional decoding process.

After encoding process includes mapping black dots is too complex to describe here, please check ISO specification.

For your information, QR Code encoding instruction by indivisual is available from here.
http://www.swetake.com/qr/qr1.html
Perhaps it is useful for you if you use babelfish or other Japanese-English translation service.

Good luck to your research.

Regards,

Yanbe
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RE: about usage of discussion forum (2007-01-24 18:46 by yanbe #27303)

To arrange process of discussion, please use same thread when you want to discuss same topic.

Additionally, please input specific thraed title, to make it informative for other people.
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