Databar decoding - Revision history

PhilippeTeuwen: /* Code */

2016-06-22T20:37:51Z

Code

2016-06-22T12:28:13Z

Principles

← Older revision		Revision as of 12:28, 22 June 2016
Line 31:		Line 31:
	Note that the databars we got are 2 bytes longer than the ones described in the patent.		Note that the databars we got are 2 bytes longer than the ones described in the patent.
	===Principles===		===Principles===
	The high level steps of the Python script are:		The high level steps of the Python script are, for each input file:
	* Convert the image to 1-bit graylevels (not needed here but more future-proofs for other scan sources)		* Convert the image to 1-bit graylevels (not needed here but more future-proofs for other scan sources)
	* Scan horizontal lines, look for at least 30 consecutive lines with at least 20% black pixels, there is likely one databar there. Remember its middle line and its width.		* Scan horizontal lines, look for at least 30 consecutive lines with at least 20% black pixels, there is likely one databar there. Remember its middle line and its width.

2016-06-22T12:27:21Z

Principles

@@ Line 41: / Line 41: @@
 ** Check that the last stripe is at least 5x larger than the first one, that's our EOL symbol which is 7 or 8-unit large, depending on the previous symbol.
 ** Convert pulses/stripes into nibbles
 ** Parse nibbles
 ===Code===
 You can download the following Python script [{{#file: oscar.py}} as oscar.py]:

2016-06-22T12:12:10Z

=Principles

← Older revision		Revision as of 12:12, 22 June 2016
Line 30:		Line 30:
	With the patent in hands, it's doable to write a Python script to decode the symbols and do some consistency checks and interpretations.		With the patent in hands, it's doable to write a Python script to decode the symbols and do some consistency checks and interpretations.
	Note that the databars we got are 2 bytes longer than the ones described in the patent.		Note that the databars we got are 2 bytes longer than the ones described in the patent.
	===Principles==		===Principles===
	The high level steps of the Python script are:		The high level steps of the Python script are:
	* Convert the image to 1-bit graylevels (not needed here but more future-proofs for other scan sources)		* Convert the image to 1-bit graylevels (not needed here but more future-proofs for other scan sources)

2016-06-22T12:11:43Z

Python decoder

@@ Line 29: / Line 29: @@
 ==Python decoder==
 With the patent in hands, it's doable to write a Python script to decode the symbols and do some consistency checks and interpretations.
 ===Code===
 You can download the following Python script [{{#file: oscar.py}} as oscar.py]:
@@ Line 69: / Line 81: @@
         return line
-def line2nibbles(v):
+def findlines(pix):
     factor_learn=0.5
     factor_squeeze=0.95
@@ Line 127: / Line 186: @@
             break
     return nibbles
 def parsenibbles(nibbles):
@@ Line 228: / Line 240: @@
         # do we have a END marker?
         assert pulses[-1][1] > (pulses[0][1]*5)
-        nibbles=line2nibbles(pulses)
+        nibbles=pulses2nibbles(pulses)
         parsenibbles(nibbles)
 </source>

2016-06-22T11:51:27Z

TI99/4A format

@@ Line 273: / Line 273: @@
 <br>But we've seen in the User Manual that it's more likely to be for its successor TI99/4A.
-==TI99/4A format==
+==TI99/4A payload==
 So the databar payload is likely to be interpretable by a TI99/4A.
 <br>We can observe regular repetitions of "0000000000000000", let's realign the data:
@@ Line 504: / Line 504: @@
  IN THE NEXT FEW ISSUES.
 </pre>

2016-06-22T11:43:07Z

Usage=

← Older revision		Revision as of 11:43, 22 June 2016
Line 231:		Line 231:
	parsenibbles(nibbles)		parsenibbles(nibbles)
	</source>		</source>
	==Usage===		===Usage===

	First we've to extract the images from the Poc\|\|GTFO 12 pdf, then use our script:		First we've to extract the images from the Poc\|\|GTFO 12 pdf, then use our script:

2016-06-22T11:42:03Z

TI99/4A format

2016-06-22T11:07:02Z

Python decoder

@@ Line 30: / Line 30: @@
 With the patent in hands, it's doable to write a Python script to decode the symbols and do some consistency checks and interpretations.
 You can download the following Python script [{{#file: oscar.py}} as oscar.py]:
 <source lang=python>
@@ Line 236: / Line 230: @@
         nibbles=line2nibbles(pulses)
         parsenibbles(nibbles)
 </source>

2016-06-22T10:50:54Z

Patent