Swiss QR-bills (ISO 20022) not decoded

[sbrunner]

System information (version)

• OpenCV => 4.5.5.64
• Operating System / Platform => Ubuntu Linux
• Compiler => gcc?

Detailed description

The Swiss QR-bills are detected but not decoded.

See also: https://scanbot.io/en/sdk/scanner-sdk/barcode-scanner-sdk/swiss-qr

Steps to reproduce

import cv2

image = cv2.imread("test-qr-code/155567196-54dbec58-7fa4-473a-a551-b52ecd04e11e.png")
detector = cv2.QRCodeDetector()
print(detector.detect(image))

data, bbox, straight_qrcode = detector.detectAndDecode(image)
print(data)
print(bbox)

With image:
=>

(True, array([[[ 42.,  42.],
        [433.,  42.],
        [433., 433.],
        [ 42., 433.]]], dtype=float32))

[[[ 42.  42.]
  [433.  42.]
  [433. 433.]
  [ 42. 433.]]]

Issue submission checklist

• I report the issue, it's not a question
• I checked the problem with documentation, FAQ, open issues,
  forum.opencv.org, Stack Overflow, etc and have not found any solution
• I updated to the latest OpenCV version and the issue is still there
• There is reproducer code and related data files: videos, images, onnx, etc

[Kumataro]

This image is a QR Code image consisting of 49x49 cells. In the samplingForVersion() function, it was determined as follows.

https://github.com/opencv/opencv/blob/4.5.5/modules/objdetect/src/qrcode.cpp#L2359

postIntermediate.rows/cols = 18000
version_size  = 49
delta_rows / cols = 367.

The 0/1 recognized logic of each cell using this parameter runs 50 * 50 = 2500 times.

// for (int r = 0; r <postIntermediate.rows; r + = delta_rows)

r = 0 // 0
r = 367 // 1
r = 734 // 2
r = 1101 // 3

r = 17249 // 47
r = 17616 // 48
r = 17983 // 49 !!!

The QR decoder knows that the QR Code image consists of 49x49 cells. Then, the 0/1 recognized results are adopted in the order in which they are detected. Therefore, the sampled image is skewed one cell per line.

 0 1 2 3 ... 47 48
49 0 1 2 ... 46 47
48 49 0 1 ... 45 46

The QR Code decode has failed because the sampled image is skewed and corrupted.

This patch replaces the delta_rows skip loop with a simpler version_size loop.

I'm sorry I didn't test with python, however my test with C++ works well.

[Baerbeisser]

Version: 4.5.5.64

I have the same problem.
Here are some samples: https://github.com/swico/qr-bill
Cutting the Qr Code out, preprocessing it and then feeding it to decode doesn't help much.

Attached is a log file of a Powershell foreach run over above samples.

edit: removed duplicate lines due to extracted pages from PDF

foreach-run.log

[AleksandrPanov]

fixed by #22025

SPC
0100
1
CH3709000000304442225
Stiftung Heilsarmee Schweiz


3000
Bern
CH







CHF







NON

Spende für die Aktion Winterfest
[[[ 42.  42.]
  [433.  42.]
  [433. 433.]
  [ 42. 433.]]]

[sbrunner]

Many thanks for your great effort :-)

[sbrunner]

In cases like this one, it steels not working...

I get the bbox:

[[ 21.436857  23.88773 ]
 [564.2752    25.00468 ]
 [559.34143  562.7794  ]
 [ 16.857067 559.7231  ]]

But no data...