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/java/test/QRCodeDetectorTest.java

@@ -2,13 +2,19 @@ package org.opencv.test.objdetect;
 
 import java.util.List;
 import org.opencv.core.Mat;
+import org.opencv.core.Size;
 import org.opencv.objdetect.QRCodeDetector;
+import org.opencv.objdetect.QRCodeEncoder;
+import org.opencv.objdetect.QRCodeEncoder_Params;
 import org.opencv.imgcodecs.Imgcodecs;
+import org.opencv.imgproc.Imgproc;
 import org.opencv.test.OpenCVTestCase;
 import java.util.Arrays;
 import java.util.ArrayList;
 import java.util.HashSet;
 import java.util.List;
+import java.io.UnsupportedEncodingException;
+import java.nio.charset.Charset;
 
 public class QRCodeDetectorTest extends OpenCVTestCase {
 
@@ -50,4 +56,26 @@ public class QRCodeDetectorTest extends OpenCVTestCase {
         List < String > expectedResults = Arrays.asList("SKIP", "EXTRA", "TWO STEPS FORWARD", "STEP BACK", "QUESTION", "STEP FORWARD");
         assertEquals(new HashSet<String>(output), new HashSet<String>(expectedResults));
     }
+
+    public void testKanji() {
+        byte[] inp = new byte[]{(byte)0x82, (byte)0xb1, (byte)0x82, (byte)0xf1, (byte)0x82, (byte)0xc9, (byte)0x82,
+                                (byte)0xbf, (byte)0x82, (byte)0xcd, (byte)0x90, (byte)0xa2, (byte)0x8a, (byte)0x45};
+        QRCodeEncoder_Params params = new QRCodeEncoder_Params();
+        params.set_mode(QRCodeEncoder.MODE_KANJI);
+        QRCodeEncoder encoder = QRCodeEncoder.create(params);
+
+        Mat qrcode = new Mat();
+        encoder.encode(inp, qrcode);
+        Imgproc.resize(qrcode, qrcode, new Size(0, 0), 2, 2, Imgproc.INTER_NEAREST);
+
+        QRCodeDetector detector = new QRCodeDetector();
+        byte[] output = detector.detectAndDecodeBytes(qrcode);
+        assertEquals(detector.getEncoding(), QRCodeEncoder.ECI_SHIFT_JIS);
+        assertArrayEquals(inp, output);
+
+        List < byte[] > outputs = new ArrayList< byte[] >();
+        assertTrue(detector.detectAndDecodeBytesMulti(qrcode, outputs));
+        assertEquals(detector.getEncoding(0), QRCodeEncoder.ECI_SHIFT_JIS);
+        assertArrayEquals(inp, outputs.get(0));
+    }
 }