Run entire SSDs from TensorFlow using Intel's Inference Engine

modules/dnn/src/tensorflow/tf_importer.cpp

@@ -771,6 +771,13 @@ void TFImporter::populateNet(Net dstNet)
                 type = layer.op();
             }
 
+            // For the object detection networks, TensorFlow Object Detection API
+            // predicts deltas for bounding boxes in yxYX (ymin, xmin, ymax, xmax)
+            // order. We can manage it at DetectionOutput layer parsing predictions
+            // or shuffle last convolution's weights.
+            bool locPredTransposed = hasLayerAttr(layer, "loc_pred_transposed") &&
+                                     getLayerAttr(layer, "loc_pred_transposed").b();
+
             layerParams.set("bias_term", false);
             layerParams.blobs.resize(1);
 
@@ -784,18 +791,32 @@ void TFImporter::populateNet(Net dstNet)
                 blobFromTensor(getConstBlob(net.node(weights_layer_index), value_id), layerParams.blobs[1]);
                 ExcludeLayer(net, weights_layer_index, 0, false);
                 layers_to_ignore.insert(next_layers[0].first);
+
+                // Shuffle bias from yxYX to xyXY.
+                if (locPredTransposed)
+                {
+                    const int numWeights = layerParams.blobs[1].total();
+                    float* biasData = reinterpret_cast<float*>(layerParams.blobs[1].data);
+                    CV_Assert(numWeights % 4 == 0);
+                    for (int i = 0; i < numWeights; i += 2)
+                    {
+                        std::swap(biasData[i], biasData[i + 1]);
+                    }
+                }
             }
 
             const tensorflow::TensorProto& kernelTensor = getConstBlob(layer, value_id);
             kernelFromTensor(kernelTensor, layerParams.blobs[0]);
             releaseTensor(const_cast<tensorflow::TensorProto*>(&kernelTensor));
             int* kshape = layerParams.blobs[0].size.p;
-            if (type == "DepthwiseConv2dNative")
+            const int outCh = kshape[0];
-            {
-                const int chMultiplier = kshape[0];
             const int inCh = kshape[1];
             const int height = kshape[2];
             const int width = kshape[3];
+            if (type == "DepthwiseConv2dNative")
+            {
+                CV_Assert(!locPredTransposed);
+                const int chMultiplier = kshape[0];
 
                 Mat copy = layerParams.blobs[0].clone();
                 float* src = (float*)copy.data;
@@ -814,9 +835,21 @@ void TFImporter::populateNet(Net dstNet)
                 size_t* kstep = layerParams.blobs[0].step.p;
                 kstep[0] = kstep[1]; // fix steps too
             }
-            layerParams.set("kernel_h", kshape[2]);
+            layerParams.set("kernel_h", height);
-            layerParams.set("kernel_w", kshape[3]);
+            layerParams.set("kernel_w", width);
-            layerParams.set("num_output", kshape[0]);
+            layerParams.set("num_output", outCh);
+
+            // Shuffle output channels from yxYX to xyXY.
+            if (locPredTransposed)
+            {
+                const int slice = height * width * inCh;
+                for (int i = 0; i < outCh; i += 2)
+                {
+                    cv::Mat src(1, slice, CV_32F, layerParams.blobs[0].ptr<float>(i));
+                    cv::Mat dst(1, slice, CV_32F, layerParams.blobs[0].ptr<float>(i + 1));
+                    std::swap_ranges(src.begin<float>(), src.end<float>(), dst.begin<float>());
+                }
+            }
 
             setStrides(layerParams, layer);
             setPadding(layerParams, layer);

modules/dnn/test/test_tf_importer.cpp

@@ -309,7 +309,7 @@ TEST_P(Test_TensorFlow_nets, Inception_v2_SSD)
                                     0, 10, 0.95932811, 0.38349164, 0.32528657, 0.40387636, 0.39165527,
                                     0, 10, 0.93973452, 0.66561931, 0.37841269, 0.68074018, 0.42907384);
     double scoreDiff = (target == DNN_TARGET_OPENCL_FP16 || target == DNN_TARGET_MYRIAD) ? 5e-3 : default_l1;
-    double iouDiff = (target == DNN_TARGET_OPENCL_FP16 || target == DNN_TARGET_MYRIAD) ? 0.025 : default_lInf;
+    double iouDiff = (target == DNN_TARGET_OPENCL_FP16 || target == DNN_TARGET_MYRIAD) ? 0.09 : default_lInf;
     normAssertDetections(ref, out, "", 0.5, scoreDiff, iouDiff);
 }
 

samples/dnn/tf_text_graph_ssd.py

@@ -208,12 +208,18 @@ for label in ['ClassPredictor', 'BoxEncodingPredictor']:
         graph_def.node.extend([flatten])
     addConcatNode('%s/concat' % label, concatInputs, 'concat/axis_flatten')
 
+idx = 0
+for node in graph_def.node:
+    if node.name == ('BoxPredictor_%d/BoxEncodingPredictor/Conv2D' % idx):
+        text_format.Merge('b: true', node.attr["loc_pred_transposed"])
+        idx += 1
+assert(idx == args.num_layers)
+
 # Add layers that generate anchors (bounding boxes proposals).
 scales = [args.min_scale + (args.max_scale - args.min_scale) * i / (args.num_layers - 1)
           for i in range(args.num_layers)] + [1.0]
 
 priorBoxes = []
-addConstNode('reshape_prior_boxes_to_4d', [1, 2, -1, 1])
 for i in range(args.num_layers):
     priorBox = NodeDef()
     priorBox.name = 'PriorBox_%d' % i
@@ -240,18 +246,9 @@ for i in range(args.num_layers):
     text_format.Merge(tensorMsg([0.1, 0.1, 0.2, 0.2]), priorBox.attr["variance"])
 
     graph_def.node.extend([priorBox])
+    priorBoxes.append(priorBox.name)
 
-    # Reshape from 1x2xN to 1x2xNx1
+addConcatNode('PriorBox/concat', priorBoxes, 'concat/axis_flatten')
-    reshape = NodeDef()
-    reshape.name = priorBox.name + '/4d'
-    reshape.op = 'Reshape'
-    reshape.input.append(priorBox.name)
-    reshape.input.append('reshape_prior_boxes_to_4d')
-    graph_def.node.extend([reshape])
-
-    priorBoxes.append(reshape.name)
-
-addConcatNode('PriorBox/concat', priorBoxes, 'PriorBox/concat/axis')
 
 # Sigmoid for classes predictions and DetectionOutput layer
 sigmoid = NodeDef()
@@ -276,7 +273,6 @@ text_format.Merge('i: 100', detectionOut.attr['top_k'])
 text_format.Merge('s: "CENTER_SIZE"', detectionOut.attr['code_type'])
 text_format.Merge('i: 100', detectionOut.attr['keep_top_k'])
 text_format.Merge('f: 0.01', detectionOut.attr['confidence_threshold'])
-text_format.Merge('b: true', detectionOut.attr['loc_pred_transposed'])
 
 graph_def.node.extend([detectionOut])