Merge pull request #24426 from dkurt:qrcode_eci_encoding

Consider QRCode ECI encoding #24426

### Pull Request Readiness Checklist

related: https://github.com/opencv/opencv/pull/24350#pullrequestreview-1661658421

1. Add `getEncoding` method to obtain ECI number
2. Add `detectAndDecodeBytes`, `decodeBytes`, `decodeBytesMulti`, `detectAndDecodeBytesMulti` methods in Python (return `bytes`) and Java (return `byte[]`)
3. Allow Python bytes to std::string conversion in general and add `encode(byte[] encoded_info, Mat qrcode)` in Java


    Python example with Kanji encoding:
    ```python
    img = cv.imread("test.png")
    detect = cv.QRCodeDetector()
    data, points, straight_qrcode = detect.detectAndDecodeBytes(img)
    print(data)
    print(detect.getEncoding(), cv.QRCodeEncoder_ECI_SHIFT_JIS)
    print(data.decode("shift-jis"))
    ```
    ```
    b'\x82\xb1\x82\xf1\x82\xc9\x82\xbf\x82\xcd\x90\xa2\x8aE'
    20 20
    こんにちは世界
    ```

    source: https://github.com/opencv/opencv/blob/ba4d6c859d21536f84e0328c16f4cc3e96bf3065/modules/objdetect/test/test_qrcode_encode.cpp#L332

    ![test](https://github.com/opencv/opencv/assets/25801568/0b5eefa8-918a-4c42-9acb-830f23c0ea9f)


See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request

- [x] I agree to contribute to the project under Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
- [x] The PR is proposed to the proper branch
- [x] There is a reference to the original bug report and related work
- [x] There is accuracy test, performance test and test data in opencv_extra repository, if applicable
      Patch to opencv_extra has the same branch name.
- [x] The feature is well documented and sample code can be built with the project CMake

modules/objdetect/misc/python/pyopencv_objdetect.hpp

@@ -7,4 +7,31 @@ typedef QRCodeEncoder::Params QRCodeEncoder_Params;
 typedef HOGDescriptor::HistogramNormType HOGDescriptor_HistogramNormType;
 typedef HOGDescriptor::DescriptorStorageFormat HOGDescriptor_DescriptorStorageFormat;
 
+class NativeByteArray
+{
+public:
+    inline NativeByteArray& operator=(const std::string& from) {
+        val = from;
+        return *this;
+    }
+    std::string val;
+};
+
+class vector_NativeByteArray : public std::vector<std::string> {};
+
+template<>
+PyObject* pyopencv_from(const NativeByteArray& from)
+{
+    return PyBytes_FromStringAndSize(from.val.c_str(), from.val.size());
+}
+
+template<>
+PyObject* pyopencv_from(const vector_NativeByteArray& results)
+{
+    PyObject* list = PyList_New(results.size());
+    for(size_t i = 0; i < results.size(); ++i)
+        PyList_SetItem(list, i, PyBytes_FromStringAndSize(results[i].c_str(), results[i].size()));
+    return list;
+}
+
 #endif

modules/objdetect/misc/python/test/test_qrcode_detect.py

@@ -1,3 +1,4 @@
+# -*- coding: utf-8 -*-
 #!/usr/bin/env python
 '''
 ===============================================================================
@@ -8,7 +9,7 @@ import os
 import numpy as np
 import cv2 as cv
 
-from tests_common import NewOpenCVTests
+from tests_common import NewOpenCVTests, unittest
 
 class qrcode_detector_test(NewOpenCVTests):
 
@@ -50,3 +51,36 @@ class qrcode_detector_test(NewOpenCVTests):
         self.assertTrue("STEP BACK" in decoded_data)
         self.assertTrue("QUESTION" in decoded_data)
         self.assertEqual(points.shape, (6, 4, 2))
+
+    def test_decode_non_ascii(self):
+        import sys
+        if sys.version_info[0] < 3:
+            raise unittest.SkipTest('Python 2.x is not supported')
+
+        img = cv.imread(os.path.join(self.extraTestDataPath, 'cv/qrcode/umlaut.png'))
+        self.assertFalse(img is None)
+        detector = cv.QRCodeDetector()
+        decoded_data, _, _ = detector.detectAndDecode(img)
+        self.assertTrue(isinstance(decoded_data, str))
+        self.assertTrue("Müllheimstrasse" in decoded_data)
+
+    def test_kanji(self):
+        inp = "こんにちは世界"
+        inp_bytes = inp.encode("shift-jis")
+
+        params = cv.QRCodeEncoder_Params()
+        params.mode = cv.QRCodeEncoder_MODE_KANJI
+        encoder = cv.QRCodeEncoder_create(params)
+        qrcode = encoder.encode(inp_bytes)
+        qrcode = cv.resize(qrcode, (0, 0), fx=2, fy=2, interpolation=cv.INTER_NEAREST)
+
+        detector = cv.QRCodeDetector()
+        data, _, _ = detector.detectAndDecodeBytes(qrcode)
+        self.assertEqual(data, inp_bytes)
+        self.assertEqual(detector.getEncoding(), cv.QRCodeEncoder_ECI_SHIFT_JIS)
+        self.assertEqual(data.decode("shift-jis"), inp)
+
+        _, data, _, _ = detector.detectAndDecodeBytesMulti(qrcode)
+        self.assertEqual(data[0], inp_bytes)
+        self.assertEqual(detector.getEncoding(0), cv.QRCodeEncoder_ECI_SHIFT_JIS)
+        self.assertEqual(data[0].decode("shift-jis"), inp)