How to create QRcode page5
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If one color modules are much than other color or pattern like "finder pattern" exists, decoder application can have many mistake. To prevent above case,best mask pattern which is selected from among 8 pattern is covered in QRcode.
Range of masking is code words which is excepted "finder pattern","timing pattern" etc.
We have 8 mask pattern in QRcode.
Mask pattern indicator is 3 bit long binary representation.
| mask pattern indicator | condition |
|---|---|
| 000 | (i+j) mod 2 = 0 |
| 001 | i mod 2 = 0 |
| 010 | j mod 3 = 0 |
| 011 | (i+j) mod 3 = 0 |
| 100 | (( i div 2)+(j div 3)) mod 2 = 0 |
| 101 | (ij) mod 2 + (ij) mod 3 = 0 |
| 110 | ((ij) mod 2 +(ij) mod 3) mod 2 = 0 |
| 111 | ((ij)mod 3 + (i+j) mod 2) mod 2 = 0 |
in mask pattern 000....
at (20,20) : (20+20) mod 2 = 0 and reverse bit
at (19,20) : (20+19) mod 2 = 1 and do not reverse bit
We estimate result of above mask pattern to select. We select a mask pattern which has least down point to calculate in which below table. In addition conditions are applied to whole symbol.
| characteristics | condition | down point |
|---|---|---|
| concatenation of same color in a line or a column | count of modules=(5+i) | 3+i |
| module block of same color | block size 2*2 | 3 |
| 1:1:3:1:1(dark:bright:dark:bright:dark)pattern in a line or a column | 40 | |
| ration of dark modules in whole | from 50±(5+k)% to 50±(5+(k+1))% | 10*k |
I think it is not very important to select mask pattern exactly.
In fact there is different between result of JIS X0510(1999) appendix 8 and JIS X0510(2004) appendix G in same data.
And below result may is not exactly good.
We select a mask pattern "011" in example data.
next page : Format information.
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