support the split node of onnx opset >= 13

modules/dnn/src/onnx/onnx_importer.cpp

@@ -1467,6 +1467,10 @@ void ONNXImporter::parseSlice(LayerParams& layerParams, const opencv_onnx::NodeP
 
 void ONNXImporter::parseSplit(LayerParams& layerParams, const opencv_onnx::NodeProto& node_proto)
 {
+    int axis = layerParams.get<int>("axis", 0);
+    MatShape inpShape = outShapes[node_proto.input(0)];
+    axis = normalize_axis(axis, inpShape.size());
+
     if (layerParams.has("split"))
     {
         DictValue splits = layerParams.get("split");
@@ -1480,13 +1484,26 @@ void ONNXImporter::parseSplit(LayerParams& layerParams, const opencv_onnx::NodeP
         }
         layerParams.set("slice_point", DictValue::arrayInt(&slicePoints[0], slicePoints.size()));
     }
+    else if (node_proto.input_size() == 2) // opset >= 13, the split will be stored at the second input, instead of the attribute.
+    {
+        CV_Assert(constBlobs.find(node_proto.input(1)) != constBlobs.end());
+        Mat splitsBlob = getBlob(node_proto, 1);
+        int splitSize = splitsBlob.total();
+
+        std::vector<int> slicePoints(splitSize - 1, splitsBlob.at<int>(0));
+        for (int i = 1; i < splitSize - 1; ++i)
+        {
+            slicePoints[i] = slicePoints[i - 1] + splitsBlob.at<int>(i);
+        }
+        layerParams.set("slice_point", DictValue::arrayInt(&slicePoints[0], slicePoints.size()));
+    }
     else
     {
         layerParams.set("num_split", node_proto.output_size());
     }
     int depth = layerParams.get<int>("depth", CV_32F);
     layerParams.type = (depth == CV_8S) ? "SliceInt8" : "Slice";
-    layerParams.set("axis", layerParams.get<float>("axis", 0));
+    layerParams.set("axis", axis);
     addLayer(layerParams, node_proto);
 }
 

modules/dnn/test/test_onnx_importer.cpp

@@ -1149,6 +1149,8 @@ TEST_P(Test_ONNX_layers, Split)
     testONNXModels("split_2");
     testONNXModels("split_3");
     testONNXModels("split_4");
+    testONNXModels("split_5");
+    testONNXModels("split_6");
     testONNXModels("split_neg_axis");
 }