Merge pull request #18287 from mpashchenkov:mp/ocv-gapi-blue-branch

[G-API]: Add four kernels to parse NN outputs & provide information in Streaming scenarios

* Kernels from GL "blue" branch, acc and perf tests

* Code cleanup

* Output fix

* Comment fix

* Added new file for parsers, stylistic corrections

* Added end line

* Namespace fix

* Code cleanup

* nnparsers.hpp moved to gapi/infer/, nnparsers -> parsers

* Removed cv:: from parsers.hpp

modules/gapi/src/api/kernels_core.cpp

@@ -383,5 +383,15 @@ GMat warpAffine(const GMat& src, const Mat& M, const Size& dsize, int flags,
     return core::GWarpAffine::on(src, M, dsize, flags, borderMode, borderValue);
 }
 
+GOpaque<Size> size(const GMat& src)
+{
+    return core::GSize::on(src);
+}
+
+GOpaque<Size> size(const GOpaque<Rect>& r)
+{
+    return core::GSizeR::on(r);
+}
+
 } //namespace gapi
 } //namespace cv

modules/gapi/src/api/kernels_nnparsers.cpp

@@ -0,0 +1,44 @@
+// 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 http://opencv.org/license.html.
+//
+// Copyright (C) 2020 Intel Corporation
+
+
+#include "precomp.hpp"
+
+#include <opencv2/gapi/infer/parsers.hpp>
+
+#include <tuple>
+#include <numeric>
+
+namespace cv { namespace gapi {
+
+nn::parsers::GDetections parseSSD(const GMat& in,
+                                  const GOpaque<Size>& inSz,
+                                  const float confidenceThreshold,
+                                  const int filterLabel)
+{
+    return nn::parsers::GParseSSDBL::on(in, inSz, confidenceThreshold, filterLabel);
+}
+
+nn::parsers::GRects parseSSD(const GMat& in,
+                             const GOpaque<Size>& inSz,
+                             const float confidenceThreshold,
+                             const bool alignmentToSquare,
+                             const bool filterOutOfBounds)
+{
+    return nn::parsers::GParseSSD::on(in, inSz, confidenceThreshold, alignmentToSquare, filterOutOfBounds);
+}
+
+nn::parsers::GDetections parseYolo(const GMat& in,
+                                   const GOpaque<Size>& inSz,
+                                   const float confidenceThreshold,
+                                   const float nmsThreshold,
+                                   const std::vector<float>& anchors)
+{
+    return nn::parsers::GParseYolo::on(in, inSz, confidenceThreshold, nmsThreshold, anchors);
+}
+
+} //namespace gapi
+} //namespace cv