Add ShuffleChannel layer

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

@@ -361,6 +361,23 @@ CV__DNN_EXPERIMENTAL_NS_BEGIN
         static Ptr<PermuteLayer> create(const LayerParams& params);
     };
 
+    /**
+     * Permute channels of 4-dimensional input blob.
+     * @param group Number of groups to split input channels and pick in turns
+     *              into output blob.
+     *
+     * \f[ groupSize = \frac{number\ of\ channels}{group} \f]
+     * \f[ output(n, c, h, w) = input(n, groupSize \times (c \% group) + \lfloor \frac{c}{group} \rfloor, h, w) \f]
+     * Read more at https://arxiv.org/pdf/1707.01083.pdf
+     */
+    class CV_EXPORTS ShuffleChannelLayer : public Layer
+    {
+    public:
+        static Ptr<Layer> create(const LayerParams& params);
+
+        int group;
+    };
+
     /**
      * @brief Adds extra values for specific axes.
      * @param paddings Vector of paddings in format

modules/dnn/src/init.cpp

@@ -115,6 +115,7 @@ void initializeLayerFactory()
     CV_DNN_REGISTER_LAYER_CLASS(Crop,           CropLayer);
     CV_DNN_REGISTER_LAYER_CLASS(Eltwise,        EltwiseLayer);
     CV_DNN_REGISTER_LAYER_CLASS(Permute,        PermuteLayer);
+    CV_DNN_REGISTER_LAYER_CLASS(ShuffleChannel, ShuffleChannelLayer);
     CV_DNN_REGISTER_LAYER_CLASS(PriorBox,       PriorBoxLayer);
     CV_DNN_REGISTER_LAYER_CLASS(PriorBoxClustered, PriorBoxLayer);
     CV_DNN_REGISTER_LAYER_CLASS(Reorg,          ReorgLayer);

modules/dnn/src/layers/crop_and_resize_layer.cpp

@@ -1,3 +1,9 @@
+// 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) 2018, Intel Corporation, all rights reserved.
+// Third party copyrights are property of their respective owners.
 #include "../precomp.hpp"
 #include "layers_common.hpp"
 

modules/dnn/src/layers/shuffle_channel_layer.cpp

@@ -0,0 +1,104 @@
+// 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) 2018, Intel Corporation, all rights reserved.
+// Third party copyrights are property of their respective owners.
+#include "../precomp.hpp"
+
+namespace cv { namespace dnn {
+
+class ShuffleChannelLayerImpl CV_FINAL : public ShuffleChannelLayer
+{
+public:
+    ShuffleChannelLayerImpl(const LayerParams& params)
+    {
+        group = params.get<int>("group", 1);
+    }
+
+    bool getMemoryShapes(const std::vector<MatShape> &inputs,
+                         const int requiredOutputs,
+                         std::vector<MatShape> &outputs,
+                         std::vector<MatShape> &internals) const CV_OVERRIDE
+    {
+        CV_Assert(inputs.size() == 1 && inputs[0].size() == 4);
+        CV_Assert(inputs[0][1] % group == 0);
+        Layer::getMemoryShapes(inputs, requiredOutputs, outputs, internals);
+        return group == 1;
+    }
+
+    virtual void finalize(const std::vector<Mat*>& inputs, std::vector<Mat> &outputs) CV_OVERRIDE
+    {
+        if (group != 1)
+        {
+            LayerParams lp;
+            float order[] = {0, 2, 1, 3};
+            lp.set("order", DictValue::arrayInt(&order[0], 4));
+            permute = PermuteLayer::create(lp);
+
+            Mat inp = *inputs[0];
+            Mat out = outputs[0];
+
+            permuteInpShape.resize(4);
+            permuteInpShape[0] = inp.size[0];
+            permuteInpShape[1] = group;
+            permuteInpShape[2] = inp.size[1] / group;
+            permuteInpShape[3] = inp.size[2]*inp.size[3];
+
+            permuteOutShape.resize(4);
+            permuteOutShape[0] = permuteInpShape[0];
+            permuteOutShape[1] = permuteInpShape[2];
+            permuteOutShape[2] = permuteInpShape[1];
+            permuteOutShape[3] = permuteInpShape[3];
+
+            inp = inp.reshape(1, permuteInpShape);
+            out = out.reshape(1, permuteOutShape);
+
+            std::vector<Mat*> permuteInputs(1, &inp);
+            std::vector<Mat> permuteOutputs(1, out);
+            permute->finalize(permuteInputs, permuteOutputs);
+        }
+    }
+
+    void forward(InputArrayOfArrays inputs_arr, OutputArrayOfArrays outputs_arr, OutputArrayOfArrays internals_arr) CV_OVERRIDE
+    {
+        CV_TRACE_FUNCTION();
+        CV_TRACE_ARG_VALUE(name, "name", name.c_str());
+
+        Layer::forward_fallback(inputs_arr, outputs_arr, internals_arr);
+    }
+
+    void forward(std::vector<Mat*> &inputs, std::vector<Mat> &outputs, std::vector<Mat> &internals) CV_OVERRIDE
+    {
+        CV_TRACE_FUNCTION();
+        CV_TRACE_ARG_VALUE(name, "name", name.c_str());
+
+        Mat inp = *inputs[0];
+        Mat out = outputs[0];
+        if (inp.data != out.data)
+        {
+            if (!permute.empty())
+            {
+                inp = inp.reshape(1, permuteInpShape);
+                out = out.reshape(1, permuteOutShape);
+                std::vector<Mat*> permuteInputs(1, &inp);
+                std::vector<Mat> permuteOutputs(1, out);
+                permute->forward(permuteInputs, permuteOutputs, internals);
+            }
+            else
+                inp.copyTo(out);
+        }
+    }
+
+private:
+    Ptr<PermuteLayer> permute;
+    std::vector<int> permuteInpShape, permuteOutShape;
+};
+
+Ptr<Layer> ShuffleChannelLayer::create(const LayerParams& params)
+{
+    return Ptr<Layer>(new ShuffleChannelLayerImpl(params));
+}
+
+}  // namespace dnn
+}  // namespace cv

modules/dnn/test/test_layers.cpp

@@ -1186,4 +1186,41 @@ TEST(Layer_Test_PoolingIndices, Accuracy)
     normAssert(indices, outputs[1].reshape(1, 5));
 }
 
+typedef testing::TestWithParam<tuple<Vec4i, int> > Layer_Test_ShuffleChannel;
+TEST_P(Layer_Test_ShuffleChannel, Accuracy)
+{
+    Vec4i inpShapeVec = get<0>(GetParam());
+    int group = get<1>(GetParam());
+    ASSERT_EQ(inpShapeVec[1] % group, 0);
+    const int groupSize = inpShapeVec[1] / group;
+
+    Net net;
+    LayerParams lp;
+    lp.set("group", group);
+    lp.type = "ShuffleChannel";
+    lp.name = "testLayer";
+    net.addLayerToPrev(lp.name, lp.type, lp);
+
+    const int inpShape[] = {inpShapeVec[0], inpShapeVec[1], inpShapeVec[2], inpShapeVec[3]};
+    Mat inp(4, inpShape, CV_32F);
+    randu(inp, 0, 255);
+
+    net.setInput(inp);
+    Mat out = net.forward();
+
+    for (int n = 0; n < inpShapeVec[0]; ++n)
+    {
+        for (int c = 0; c < inpShapeVec[1]; ++c)
+        {
+            Mat outChannel = getPlane(out, n, c);
+            Mat inpChannel = getPlane(inp, n, groupSize * (c % group) + c / group);
+            normAssert(outChannel, inpChannel);
+        }
+    }
+}
+INSTANTIATE_TEST_CASE_P(/**/, Layer_Test_ShuffleChannel, Combine(
+/*input shape*/  Values(Vec4i(1, 6, 5, 7), Vec4i(3, 12, 1, 4)),
+/*group*/        Values(1, 2, 3, 6)
+));
+
 }} // namespace