Merge pull request #14697 from l-bat:Slice_ONNX

* Support Slice layer in ONNX importer

* Add IE support

* Fix ONNX importer

* Fix Slice

modules/dnn/src/layers/slice_layer.cpp

@@ -174,16 +174,16 @@ public:
         for (int i = 0; i < outputs.size(); ++i)
         {
             CV_Assert(sliceRanges[i].size() <= inpShape.dims());
-            // Clamp.
-            for (int j = 0; j < sliceRanges[i].size(); ++j)
-            {
-                sliceRanges[i][j] = clamp(sliceRanges[i][j], inpShape[j]);
-            }
             // Fill the rest of ranges.
             for (int j = sliceRanges[i].size(); j < inpShape.dims(); ++j)
             {
                 sliceRanges[i].push_back(Range::all());
             }
+            // Clamp.
+            for (int j = 0; j < sliceRanges[i].size(); ++j)
+            {
+                sliceRanges[i][j] = clamp(sliceRanges[i][j], inpShape[j]);
+            }
         }
     }
 

modules/dnn/src/onnx/onnx_importer.cpp

@@ -401,6 +401,47 @@ void ONNXImporter::populateNet(Net dstNet)
             layerParams.set("pool", layer_type == "GlobalAveragePool" ? "AVE" : "MAX");
             layerParams.set("global_pooling", true);
         }
+        else if (layer_type == "Slice")
+        {
+            if (layerParams.has("steps")) {
+                DictValue steps = layerParams.get("steps");
+                for (int i = 0; i < steps.size(); ++i) {
+                    if (steps.get<int>(i) != 1)
+                        CV_Error(Error::StsNotImplemented,
+                                 "Slice layer only supports steps = 1");
+                }
+            }
+
+            int axis = 0;
+            if (layerParams.has("axes")) {
+                DictValue axes = layerParams.get("axes");
+                for (int i = 1; i < axes.size(); ++i) {
+                    CV_Assert(axes.get<int>(i - 1) == axes.get<int>(i) - 1);
+                }
+                axis = axes.get<int>(0);
+            }
+            layerParams.set("axis", axis);
+
+            DictValue starts = layerParams.get("starts");
+            DictValue ends = layerParams.get("ends");
+            CV_Assert(starts.size() == ends.size());
+
+            std::vector<int> begin;
+            std::vector<int> end;
+            if (axis > 0) {
+                begin.resize(axis, 0);
+                end.resize(axis, -1);
+            }
+
+            for (int i = 0; i < starts.size(); ++i)
+            {
+                begin.push_back(starts.get<int>(i));
+                int finish = ends.get<int>(i);
+                end.push_back((finish < 0) ? --finish : finish); // numpy doesn't include last dim
+            }
+            layerParams.set("begin", DictValue::arrayInt(&begin[0], begin.size()));
+            layerParams.set("end", DictValue::arrayInt(&end[0], end.size()));
+        }
         else if (layer_type == "Add" || layer_type == "Sum")
         {
             if (layer_id.find(node_proto.input(1)) == layer_id.end())

modules/dnn/test/test_onnx_importer.cpp

@@ -245,6 +245,11 @@ TEST_P(Test_ONNX_layers, Reshape)
     testONNXModels("unsqueeze");
 }
 
+TEST_P(Test_ONNX_layers, Slice)
+{
+    testONNXModels("slice");
+}
+
 TEST_P(Test_ONNX_layers, Softmax)
 {
     testONNXModels("softmax");