Add support for loading ONNX model from in-memory buffer.

modules/dnn/include/opencv2/dnn/dnn.hpp

@@ -868,6 +868,23 @@ CV__DNN_EXPERIMENTAL_NS_BEGIN
      */
     CV_EXPORTS_W Net readNetFromONNX(const String &onnxFile);
 
+    /** @brief Reads a network model from <a href="https://onnx.ai/">ONNX</a>
+     *         in-memory buffer.
+     *  @param buffer memory address of the first byte of the buffer.
+     *  @param sizeBuffer size of the buffer.
+     *  @returns Network object that ready to do forward, throw an exception
+     *        in failure cases.
+     */
+    CV_EXPORTS Net readNetFromONNX(const char* buffer, size_t sizeBuffer);
+
+    /** @brief Reads a network model from <a href="https://onnx.ai/">ONNX</a>
+     *         in-memory buffer.
+     *  @param buffer in-memory buffer that stores the ONNX model bytes.
+     *  @returns Network object that ready to do forward, throw an exception
+     *        in failure cases.
+     */
+    CV_EXPORTS_W Net readNetFromONNX(const std::vector<uchar>& buffer);
+
     /** @brief Creates blob from .pb file.
      *  @param path to the .pb file with input tensor.
      *  @returns Mat.