Merge pull request #24426 from dkurt:qrcode_eci_encoding

dkurt · web-flow · commit 1c53fd3777d7 · 2025-06-19T10:12:15.000+03:00
Consider QRCode ECI encoding #24426 ### Pull Request Readiness Checklist related: #24350 (review) 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
diff --git a/modules/java/generator/gen_java.py b/modules/java/generator/gen_java.py
@@ -1002,6 +1002,9 @@ def gen_func(self, ci, fi, prop_name=''):
                 ret = "return (jlong) _retval_;"
             elif type_dict[fi.ctype]["jni_type"] == "jdoubleArray":
                 ret = "return _da_retval_;"
+            elif "jni_var" in type_dict[ret_type]:
+                c_epilogue.append(type_dict[ret_type]["jni_var"] % {"n" : '_retval_'})
+                ret = f"return {type_dict[ret_type]['jni_name'] % {'n' : '_retval_'}};"
 
             # hack: replacing func call with property set/get
             name = fi.name
diff --git a/modules/objdetect/include/opencv2/objdetect.hpp b/modules/objdetect/include/opencv2/objdetect.hpp
@@ -729,7 +729,8 @@ class CV_EXPORTS_W QRCodeEncoder {
     };
 
     enum ECIEncodings {
-        ECI_UTF8 = 26
+        ECI_SHIFT_JIS = 20,
+        ECI_UTF8 = 26,
     };
 
     /** @brief QR code encoder parameters. */
@@ -808,6 +809,13 @@ class CV_EXPORTS_W_SIMPLE QRCodeDetector : public GraphicalCodeDetector
      */
     CV_WRAP std::string detectAndDecodeCurved(InputArray img, OutputArray points=noArray(),
                                               OutputArray straight_qrcode = noArray());
+
+    /** @brief Returns a kind of encoding for the decoded info from the latest @ref decode or @ref detectAndDecode call
+    @param codeIdx an index of the previously decoded QR code.
+                   When @ref decode or @ref detectAndDecode is used, valid value is zero.
+                   For @ref decodeMulti or @ref detectAndDecodeMulti use indices corresponding to the output order.
+    */
+    CV_WRAP QRCodeEncoder::ECIEncodings getEncoding(int codeIdx = 0);
 };
 
 class CV_EXPORTS_W_SIMPLE QRCodeDetectorAruco : public GraphicalCodeDetector {
diff --git a/modules/objdetect/include/opencv2/objdetect/graphical_code_detector.hpp b/modules/objdetect/include/opencv2/objdetect/graphical_code_detector.hpp
@@ -73,6 +73,17 @@ class CV_EXPORTS_W_SIMPLE GraphicalCodeDetector {
     */
     CV_WRAP bool detectAndDecodeMulti(InputArray img, CV_OUT std::vector<std::string>& decoded_info, OutputArray points = noArray(),
                                       OutputArrayOfArrays straight_code = noArray()) const;
+
+#ifdef OPENCV_BINDINGS_PARSER
+    CV_WRAP_AS(detectAndDecodeBytes) NativeByteArray detectAndDecode(InputArray img, OutputArray points = noArray(),
+                                                                     OutputArray straight_code = noArray()) const;
+    CV_WRAP_AS(decodeBytes) NativeByteArray decode(InputArray img, InputArray points, OutputArray straight_code = noArray()) const;
+    CV_WRAP_AS(decodeBytesMulti) bool decodeMulti(InputArray img, InputArray points, CV_OUT std::vector<NativeByteArray>& decoded_info,
+                                                  OutputArrayOfArrays straight_code = noArray()) const;
+    CV_WRAP_AS(detectAndDecodeBytesMulti) bool detectAndDecodeMulti(InputArray img, CV_OUT std::vector<NativeByteArray>& decoded_info, OutputArray points = noArray(),
+                                                                    OutputArrayOfArrays straight_code = noArray()) const;
+#endif
+
     struct Impl;
 protected:
     Ptr<Impl> p;
diff --git a/modules/objdetect/misc/java/filelist_common b/modules/objdetect/misc/java/filelist_common
@@ -0,0 +1 @@
+misc/java/src/cpp/objdetect_converters.hpp
diff --git a/modules/objdetect/misc/java/gen_dict.json b/modules/objdetect/misc/java/gen_dict.json
@@ -0,0 +1,68 @@
+{
+    "ManualFuncs" : {
+        "QRCodeEncoder" : {
+            "QRCodeEncoder" : {
+                "j_code"   : [
+                    "\n",
+                    "/** Generates QR code from input string.",
+                    "@param encoded_info Input bytes to encode.",
+                    "@param qrcode Generated QR code.",
+                    "*/",
+                    "public void encode(byte[] encoded_info, Mat qrcode) {",
+                    "    encode_1(nativeObj, encoded_info, qrcode.nativeObj);",
+                    "}",
+                    "\n"
+                ],
+                "jn_code": [
+                    "\n",
+                    "private static native void encode_1(long nativeObj, byte[] encoded_info, long qrcode_nativeObj);",
+                    "\n"
+                ],
+                "cpp_code": [
+                    "//",
+                    "//  void cv::QRCodeEncoder::encode(String encoded_info, Mat& qrcode)",
+                    "//",
+                    "\n",
+                    "JNIEXPORT void JNICALL Java_org_opencv_objdetect_QRCodeEncoder_encode_11 (JNIEnv*, jclass, jlong, jbyteArray, jlong);",
+                    "\n",
+                    "JNIEXPORT void JNICALL Java_org_opencv_objdetect_QRCodeEncoder_encode_11",
+                    "(JNIEnv* env, jclass , jlong self, jbyteArray encoded_info, jlong qrcode_nativeObj)",
+                    "{",
+                    "",
+                    "    static const char method_name[] = \"objdetect::encode_11()\";",
+                    "    try {",
+                    "        LOGD(\"%s\", method_name);",
+                    "        Ptr<cv::QRCodeEncoder>* me = (Ptr<cv::QRCodeEncoder>*) self; //TODO: check for NULL",
+                    "        const char* n_encoded_info = reinterpret_cast<char*>(env->GetByteArrayElements(encoded_info, NULL));",
+                    "        Mat& qrcode = *((Mat*)qrcode_nativeObj);",
+                    "        (*me)->encode( n_encoded_info, qrcode );",
+                    "    } catch(const std::exception &e) {",
+                    "        throwJavaException(env, &e, method_name);",
+                    "    } catch (...) {",
+                    "        throwJavaException(env, 0, method_name);",
+                    "    }",
+                    "}",
+                    "\n"
+                ]
+            }
+        }
+    },
+    "type_dict": {
+        "NativeByteArray": {
+            "j_type" : "byte[]",
+            "jn_type": "byte[]",
+            "jni_type": "jbyteArray",
+            "jni_name": "n_%(n)s",
+            "jni_var": "jbyteArray n_%(n)s = env->NewByteArray(static_cast<jsize>(%(n)s.size())); env->SetByteArrayRegion(n_%(n)s, 0, static_cast<jsize>(%(n)s.size()), reinterpret_cast<const jbyte*>(%(n)s.c_str()));",
+            "cast_from": "std::string"
+        },
+        "vector_NativeByteArray": {
+            "j_type": "List<byte[]>",
+            "jn_type": "List<byte[]>",
+            "jni_type": "jobject",
+            "jni_var": "std::vector< std::string > %(n)s",
+            "suffix": "Ljava_util_List",
+            "v_type": "vector_NativeByteArray"
+        }
+    }
+}
diff --git a/modules/objdetect/misc/java/src/cpp/objdetect_converters.cpp b/modules/objdetect/misc/java/src/cpp/objdetect_converters.cpp
@@ -0,0 +1,20 @@
+#include "objdetect_converters.hpp"
+
+#define LOG_TAG "org.opencv.objdetect"
+
+void Copy_vector_NativeByteArray_to_List(JNIEnv* env, std::vector<std::string>& vs, jobject list)
+{
+    static jclass juArrayList       = ARRAYLIST(env);
+    jmethodID m_clear     = LIST_CLEAR(env, juArrayList);
+    jmethodID m_add       = LIST_ADD(env, juArrayList);
+
+    env->CallVoidMethod(list, m_clear);
+    for (std::vector<std::string>::iterator it = vs.begin(); it != vs.end(); ++it)
+    {
+        jsize sz = static_cast<jsize>((*it).size());
+        jbyteArray element = env->NewByteArray(sz);
+        env->SetByteArrayRegion(element, 0, sz, reinterpret_cast<const jbyte*>((*it).c_str()));
+        env->CallBooleanMethod(list, m_add, element);
+        env->DeleteLocalRef(element);
+    }
+}
diff --git a/modules/objdetect/misc/java/src/cpp/objdetect_converters.hpp b/modules/objdetect/misc/java/src/cpp/objdetect_converters.hpp
@@ -0,0 +1,14 @@
+// This file is part of OpenCV project.
+// It is subject to the license terms in the LICENSE file found in the top-level directory
+// of this distribution and at https://opencv.org/license.html
+
+#ifndef OBJDETECT_CONVERTERS_HPP
+#define	OBJDETECT_CONVERTERS_HPP
+
+#include <jni.h>
+#include "opencv_java.hpp"
+#include "opencv2/core.hpp"
+
+void Copy_vector_NativeByteArray_to_List(JNIEnv* env, std::vector<std::string>& vs, jobject list);
+
+#endif	/* OBJDETECT_CONVERTERS_HPP */
diff --git a/modules/objdetect/misc/java/test/QRCodeDetectorTest.java b/modules/objdetect/misc/java/test/QRCodeDetectorTest.java
@@ -2,13 +2,19 @@
 
 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 void testDetectAndDecodeMulti() {
         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));
+    }
 }
diff --git a/modules/objdetect/misc/python/pyopencv_objdetect.hpp b/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
diff --git a/modules/objdetect/misc/python/test/test_qrcode_detect.py b/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 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 @@ def test_detect_and_decode_multi(self):
         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)
diff --git a/modules/objdetect/src/qrcode.cpp b/modules/objdetect/src/qrcode.cpp
@@ -963,6 +963,7 @@ struct ImplContour : public GraphicalCodeDetector::Impl
     double epsX, epsY;
     mutable vector<vector<Point2f>> alignmentMarkers;
     mutable vector<Point2f> updateQrCorners;
+    mutable vector<QRCodeEncoder::ECIEncodings> encodings;
     bool useAlignmentMarkers = true;
 
     bool detect(InputArray in, OutputArray points) const override;
@@ -978,6 +979,8 @@ struct ImplContour : public GraphicalCodeDetector::Impl
     String decodeCurved(InputArray in, InputArray points, OutputArray straight_qrcode);
 
     std::string detectAndDecodeCurved(InputArray in, OutputArray points, OutputArray straight_qrcode);
+
+    QRCodeEncoder::ECIEncodings getEncoding(int codeIdx);
 };
 
 QRCodeDetector::QRCodeDetector() {
@@ -994,6 +997,13 @@ QRCodeDetector& QRCodeDetector::setEpsY(double epsY) {
     return *this;
 }
 
+QRCodeEncoder::ECIEncodings QRCodeDetector::getEncoding(int codeIdx) {
+    auto& encodings = std::dynamic_pointer_cast<ImplContour>(p)->encodings;
+    CV_Assert(codeIdx >= 0);
+    CV_Assert(codeIdx < static_cast<int>(encodings.size()));
+    return encodings[codeIdx];
+}
+
 bool ImplContour::detect(InputArray in, OutputArray points) const
 {
     Mat inarr;
@@ -1035,6 +1045,8 @@ class QRDecode
         uint8_t total_num = 1;
     } structure_info;
 
+    QRCodeEncoder::ECIEncodings eci;
+
 protected:
     double getNumModules();
     Mat getHomography() {
@@ -2802,7 +2814,6 @@ static std::string encodeUTF8_bytesarray(const uint8_t* str, const size_t size)
 
 bool QRDecode::decodingProcess()
 {
-    QRCodeEncoder::ECIEncodings eci;
     const uint8_t* payload;
     size_t payload_len;
 #ifdef HAVE_QUIRC
@@ -2895,7 +2906,7 @@ bool QRDecode::decodingProcess()
             return true;
         case QRCodeEncoder::EncodeMode::MODE_KANJI:
             // FIXIT BUG: we must return UTF-8 compatible string
-            CV_LOG_WARNING(NULL, "QR: Kanji is not supported properly");
+            eci = QRCodeEncoder::ECIEncodings::ECI_SHIFT_JIS;
             result_info.assign((const char*)payload, payload_len);
             return true;
         case QRCodeEncoder::EncodeMode::MODE_ECI:
@@ -2966,6 +2977,7 @@ std::string ImplContour::decode(InputArray in, InputArray points, OutputArray st
         alignmentMarkers = {qrdec.alignment_coords};
         updateQrCorners = qrdec.getOriginalPoints();
     }
+    encodings.resize(1, qrdec.eci);
     return ok ? decoded_info : std::string();
 }
 
@@ -2999,6 +3011,7 @@ String ImplContour::decodeCurved(InputArray in, InputArray points, OutputArray s
     {
         qrdec.getStraightBarcode().convertTo(straight_qrcode, CV_8UC1);
     }
+    encodings.resize(1, qrdec.eci);
 
     return ok ? decoded_info : std::string();
 }
@@ -4111,20 +4124,22 @@ bool ImplContour::decodeMulti(
         straight_qrcode.assign(tmp_straight_qrcodes);
     }
 
-    decoded_info.clear();
+    decoded_info.resize(info.size());
+    encodings.resize(info.size());
     for (size_t i = 0; i < info.size(); i++)
     {
         auto& decoder = qrdec[i];
+        encodings[i] = decoder.eci;
         if (!decoder.isStructured())
         {
-            decoded_info.push_back(info[i]);
+            decoded_info[i] = info[i];
             continue;
         }
 
         // Store final message corresponding to 0-th code in a sequence.
         if (decoder.structure_info.sequence_num != 0)
         {
-            decoded_info.push_back("");
+            decoded_info[i] = "";
             continue;
         }
 
@@ -4145,7 +4160,7 @@ bool ImplContour::decodeMulti(
                 break;
             }
         }
-        decoded_info.push_back(decoded);
+        decoded_info[i] = decoded;
     }
 
     alignmentMarkers.resize(src_points.size());
diff --git a/modules/objdetect/test/test_qrcode_encode.cpp b/modules/objdetect/test/test_qrcode_encode.cpp
diff --git a/modules/python/src2/pycompat.hpp b/modules/python/src2/pycompat.hpp
diff --git a/modules/python/src2/typing_stubs_generation/predefined_types.py b/modules/python/src2/typing_stubs_generation/predefined_types.py

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1 @@`
	`1`	`+misc/java/src/cpp/objdetect_converters.hpp`