add getScaleFactor

opencv · Jul 28, 2022 · 7f8d4c1 · 7f8d4c1
1 parent 7ada289
commit 7f8d4c1
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Showing 3 changed files with 29 additions and 18 deletions.
diff --git a/modules/wechat_qrcode/include/opencv2/wechat_qrcode.hpp b/modules/wechat_qrcode/include/opencv2/wechat_qrcode.hpp
@@ -52,10 +52,21 @@ class CV_EXPORTS_W WeChatQRCode {
     CV_WRAP std::vector<std::string> detectAndDecode(InputArray img, OutputArrayOfArrays points = noArray());
 
     /**
-    * @brief set scaling factor
-    */
+    * @brief set scale factor
+    * QR code detector use neural network to detect QR.
+    * Before running the neural network, the input image is pre-processed by scaling.
+    * By default, the input image is scaled to an image with an area of 160000 pixels.
+    * The scale factor allows to use custom scale the input image:
+    * width = scaleFactor*width
+    * height = scaleFactor*width
+    * 
+    * scaleFactor valuse must be > 0 and <= 1, otherwise the scaleFactor value is set to -1
+    * and use default scaled to an image with an area of 160000 pixels.
+    */ 
     CV_WRAP void setScaleFactor(float _scalingFactor);
 
+    CV_WRAP float getScaleFactor();
+
 protected:
     class Impl;
     Ptr<Impl> p;

diff --git a/modules/wechat_qrcode/src/wechat_qrcode.cpp b/modules/wechat_qrcode/src/wechat_qrcode.cpp
@@ -110,9 +110,16 @@ vector<string> WeChatQRCode::detectAndDecode(InputArray img, OutputArrayOfArrays
     return ret;
 }
 
-    void WeChatQRCode::setScaleFactor(float _scaleFactor) {
+void WeChatQRCode::setScaleFactor(float _scaleFactor) {
+    if (_scaleFactor > 0 || _scaleFactor <= 1.f)
         p->scaleFactor = _scaleFactor;
-    };
+    else
+        p->scaleFactor = -1.f;
+};
+
+float WeChatQRCode::getScaleFactor() {
+    return p->scaleFactor;
+};
 
 vector<string> WeChatQRCode::Impl::decode(const Mat& img, vector<Mat>& candidate_points,
                                           vector<Mat>& points) {
@@ -178,10 +185,9 @@ int WeChatQRCode::Impl::applyDetector(const Mat& img, vector<Mat>& points) {
 
     const float targetArea = 400.f * 400.f;
     // hard code input size
-    if (scaleFactor <= 0 || scaleFactor > 1)
-        scaleFactor = sqrt(targetArea/(img_w*img_h));
-    int detect_width = img_w * scaleFactor;
-    int detect_height = img_h * scaleFactor;
+    const float tmpScaleFactor = scaleFactor == -1.f ? sqrt(targetArea / (img_w * img_h)) : scaleFactor;
+    int detect_width = img_w * tmpScaleFactor;
+    int detect_height = img_h * tmpScaleFactor;
 
     points = detector_->forward(img, detect_width, detect_height);
 

diff --git a/modules/wechat_qrcode/test/test_qrcode.cpp b/modules/wechat_qrcode/test/test_qrcode.cpp
@@ -292,16 +292,10 @@ INSTANTIATE_TEST_CASE_P(/**/, Objdetect_QRCode_Curved, testing::ValuesIn(qrcode_
 
 TEST(Objdetect_QRCode_Big, regression) {
     string path_detect_prototxt, path_detect_caffemodel, path_sr_prototxt, path_sr_caffemodel;
-    try {
-        path_detect_prototxt = findDataFile("../dnn/wechat/detect.prototxt");
-        path_detect_caffemodel = findDataFile("../dnn/wechat/detect.caffemodel");
-        path_sr_prototxt = findDataFile("../dnn/wechat/sr.prototxt");
-        path_sr_caffemodel = findDataFile("../dnn/wechat/sr.caffemodel");
-    }
-    catch (...) {
-        // unsuccessful model reading
-        return;
-    }
+    path_detect_prototxt = findDataFile("../dnn/wechat/detect.prototxt");
+    path_detect_caffemodel = findDataFile("../dnn/wechat/detect.caffemodel");
+    path_sr_prototxt = findDataFile("../dnn/wechat/sr.prototxt");
+    path_sr_caffemodel = findDataFile("../dnn/wechat/sr.caffemodel");
 
     auto detector = wechat_qrcode::WeChatQRCode(path_detect_prototxt, path_detect_caffemodel, path_sr_prototxt,
                                                 path_sr_caffemodel);