fix bugs in wechatQRcode (#153)

demo.py

@@ -28,13 +28,13 @@ parser = argparse.ArgumentParser(
     description="WeChat QR code detector for detecting and parsing QR code (https://github.com/opencv/opencv_contrib/tree/master/modules/wechat_qrcode)")
 parser.add_argument('--input', '-i', type=str,
                     help='Usage: Set path to the input image. Omit for using default camera.')
-parser.add_argument('--detect_prototxt_path', type=str, default='detect_2021sep.prototxt',
+parser.add_argument('--detect_prototxt_path', type=str, default='detect_2021nov.prototxt',
                     help='Usage: Set path to detect.prototxt.')
-parser.add_argument('--detect_model_path', type=str, default='detect_2021sep.caffemodel',
+parser.add_argument('--detect_model_path', type=str, default='detect_2021nov.caffemodel',
                     help='Usage: Set path to detect.caffemodel.')
-parser.add_argument('--sr_prototxt_path', type=str, default='sr_2021sep.prototxt',
+parser.add_argument('--sr_prototxt_path', type=str, default='sr_2021nov.prototxt',
                     help='Usage: Set path to sr.prototxt.')
-parser.add_argument('--sr_model_path', type=str, default='sr_2021sep.caffemodel',
+parser.add_argument('--sr_model_path', type=str, default='sr_2021nov.caffemodel',
                     help='Usage: Set path to sr.caffemodel.')
 parser.add_argument('--backend_target', '-bt', type=int, default=0,
                     help='''Choose one of the backend-target pair to run this demo:

wechatqrcode.py

@@ -15,7 +15,7 @@ class WeChatQRCode:
             sr_prototxt_path,
             sr_model_path
         )
-        if backendId != 0:
+        if backendId != 0 and backendId != 3:
             raise NotImplementedError("Backend {} is not supported by cv.wechat_qrcode_WeChatQRCode()".format(backendId))
         if targetId != 0:
             raise NotImplementedError("Target {} is not supported by cv.wechat_qrcode_WeChatQRCode()")
@@ -25,7 +25,7 @@ class WeChatQRCode:
         return self.__class__.__name__
 
     def setBackendAndTarget(self, backendId, targetId):
-        if backendId != 0:
+        if backendId != 0 and backendId != 3:
             raise NotImplementedError("Backend {} is not supported by cv.wechat_qrcode_WeChatQRCode()".format(backendId))
         if targetId != 0:
             raise NotImplementedError("Target {} is not supported by cv.wechat_qrcode_WeChatQRCode()")