wechat_qrcode: allow the model to be loaded from a buffer

modules/wechat_qrcode/include/opencv2/wechat_qrcode.hpp

@@ -33,6 +33,8 @@ class CV_EXPORTS_W WeChatQRCode {
      */
     CV_WRAP WeChatQRCode(const std::string& detector_model_path = "",
                          const std::string& super_resolution_model_path = "");
+    WeChatQRCode(const char* detector_model_buffer, size_t detector_model_len,
+                 const char* super_resolution_model_buffer, size_t super_resolution_model_len);
     ~WeChatQRCode(){};
 
     /**

modules/wechat_qrcode/src/detector/ssd_detector.cpp

@@ -14,6 +14,11 @@ int SSDDetector::init(const string& onnx_path) {
     return 0;
 }
 
+int SSDDetector::init(const char* model_buffer, size_t model_len) {
+    net_ = dnn::readNetFromONNX(model_buffer, model_len);
+    return 0;
+}
+
 vector<Mat> SSDDetector::forward(Mat img, const int target_width, const int target_height) {
     int img_w = img.cols;
     int img_h = img.rows;

modules/wechat_qrcode/src/detector/ssd_detector.hpp

@@ -20,6 +20,7 @@ class SSDDetector {
     SSDDetector(){};
     ~SSDDetector(){};
     int init(const std::string& onnx_path);
+    int init(const char* model_buffer, size_t model_len);
     std::vector<Mat> forward(Mat img, const int target_width, const int target_height);
 
 private:

modules/wechat_qrcode/src/scale/super_scale.cpp

@@ -17,6 +17,12 @@ int SuperScale::init(const std::string &onnx_path) {
     return 0;
 }
 
+int SuperScale::init(const char* model_buffer, size_t model_len) {
+  srnet_ = dnn::readNetFromONNX(model_buffer, model_len);
+  net_loaded_ = true;
+  return 0;
+}
+
 Mat SuperScale::processImageScale(const Mat &src, float scale, const bool &use_sr,
                                   int sr_max_size) {
     Mat dst = src;

modules/wechat_qrcode/src/scale/super_scale.hpp

@@ -19,6 +19,7 @@ class SuperScale {
     SuperScale(){};
     ~SuperScale(){};
     int init(const std::string &onnx_path);
+    int init(const char* model_buffer, size_t model_len);
     Mat processImageScale(const Mat &src, float scale, const bool &use_sr, int sr_max_size = 160);
 
 private:

modules/wechat_qrcode/src/wechat_qrcode.cpp

@@ -72,6 +72,28 @@ WeChatQRCode::WeChatQRCode(const String& detector_model_path,
     }
 }
 
+WeChatQRCode::WeChatQRCode(const char* detector_model_buffer, size_t detector_model_len,
+                           const char* super_resolution_model_buffer, size_t super_resolution_model_len) {
+  CV_Assert(detector_model_buffer != nullptr && detector_model_len > 0);
+  CV_Assert(super_resolution_model_buffer != nullptr && super_resolution_model_len > 0);
+
+  p = makePtr<WeChatQRCode::Impl>();
+  // initialize detector model
+  p->use_nn_detector_ = true;
+  p->detector_ = make_shared<SSDDetector>();
+  auto ret = p->detector_->init(detector_model_buffer, detector_model_len);
+  CV_Assert(ret == 0);
+
+  // initialize super_resolution_model
+  // it could also support non model weights by cubic resizing
+  // so, we initialize it first.
+  p->use_nn_sr_ = true;
+  p->super_resolution_model_ = make_shared<SuperScale>();
+  ret = p->super_resolution_model_->init(
+      super_resolution_model_buffer, super_resolution_model_len);
+  CV_Assert(ret == 0);
+}
+
 vector<string> WeChatQRCode::detectAndDecode(InputArray img, OutputArrayOfArrays points) {
     CV_Assert(!img.empty());
     CV_CheckDepthEQ(img.depth(), CV_8U, "");