The SRE protocol has not change, we will leave it at 6.
What has changed is the way we handle the result itself.
We can now apply a “structure “ to the window result, telling it to add the grading and the separator we want.
So this structure is stored in the WRS keyword.
In our case we want:
– 1st digit is the camera # (1 here)
– 987654321 is the result of Win1 on Cam1
– 30 is the grade (B)
– 123456 is the result of Win2 on Cam1
So we will have to have:
– WRS=r.p (r says we want to sent the result, and p says we want the grade in numeric format, if we wanted it in Alpha format we would have entered q)
– “Quality” parameter set to 1 (under Window/Process)
NOTE: Even though we show the grade in a letter format on the screen, we will sent it in numeric format on the RS232.
Here is the numeric to letter format conversion table:
A = 4.0 (40)
B = 3.0 (30)
C = 2.0 (20)
D = 1.0 (10)
F = 0.0 (00)
Here is a screenshot of a good grade:
And a snapshot of a barcode that failed (under the threshold set by the operator on the Axode system):
NOTE: In our case, with the GT controller, we won’t setup a threshold in the Axode, but in the GT controller itself, by creating a “limit” control like we do with presence for example.
As far as control, here are the 7 ANSI based controls that we ensure:
Edge determination (pass / fail) :
According to the codification, it checks that we have enough transition for each scan.
We make sure those transitions correspond to a start bit + at least 1 digit + a stop bit.
Minimum reflectance (pass / fail) :
We check here that the minimum reflectance of a black line is at least ½ the maximal reflectance (of the paper; on white spaces between bars).
Symbol contrast (graded) :
This is the difference between the maximal reflectance value, and the minimum reflectance value.
Minimum edge contrast (pass / fail) :
this is the reflectance difference between the « lighter » dark bar and the “darker” white space. It must be over 15%.
Modulation (graded) :
“modulation” = “minimum edge contrast” / “symbol contrast”.
Defects (graded) :
This is given by the size of voids in black bars, and spots in white spaces.
Decode (pass / fail) :
We make sure we can decode the barcode.
Pass/failed: A or F
Graded: from A to F
For each scan, we calculate the “scan grade”. The scan grade is the lower mark given by the 7 controls above.
Then, we determine the “symbol grade”: average of all the scan grades.