FP16 Caffe models import and export

modules/dnn/src/caffe/caffe.proto

@@ -50,6 +50,16 @@ syntax = "proto2";
 
 package caffe;
 
+// NVidia's Caffe feature is used to store fp16 weights, https://github.com/NVIDIA/caffe:
+// Math and storage types
+enum Type {
+  DOUBLE = 0;
+  FLOAT = 1;
+  FLOAT16 = 2;
+  INT = 3;  // math not supported
+  UINT = 4;  // math not supported
+}
+
 // Specifies the shape (dimensions) of a Blob.
 message BlobShape {
   repeated int64 dim = 1 [packed = true];
@@ -62,6 +72,11 @@ message BlobProto {
   repeated double double_data = 8 [packed = true];
   repeated double double_diff = 9 [packed = true];
 
+  // NVidia's Caffe fields begin.
+  optional Type raw_data_type = 10;
+  optional bytes raw_data = 12 [packed = false];
+  // NVidia's Caffe fields end.
+
   // 4D dimensions -- deprecated.  Use "shape" instead.
   optional int32 num = 1 [default = 0];
   optional int32 channels = 2 [default = 0];

modules/dnn/src/caffe/caffe_importer.cpp

@@ -225,13 +225,28 @@ public:
         blobShapeFromProto(pbBlob, shape);
 
         dstBlob.create((int)shape.size(), &shape[0], CV_32F);
-        CV_Assert(pbBlob.data_size() == (int)dstBlob.total());
-
-        CV_DbgAssert(pbBlob.GetDescriptor()->FindFieldByLowercaseName("data")->cpp_type() == FieldDescriptor::CPPTYPE_FLOAT);
         float *dstData = dstBlob.ptr<float>();
+        if (pbBlob.data_size())
+        {
+            // Single precision floats.
+            CV_Assert(pbBlob.data_size() == (int)dstBlob.total());
 
-        for (int i = 0; i < pbBlob.data_size(); i++)
-            dstData[i] = pbBlob.data(i);
+            CV_DbgAssert(pbBlob.GetDescriptor()->FindFieldByLowercaseName("data")->cpp_type() == FieldDescriptor::CPPTYPE_FLOAT);
+
+            for (int i = 0; i < pbBlob.data_size(); i++)
+                dstData[i] = pbBlob.data(i);
+        }
+        else
+        {
+            // Half precision floats.
+            CV_Assert(pbBlob.raw_data_type() == caffe::FLOAT16);
+            std::string raw_data = pbBlob.raw_data();
+
+            CV_Assert(raw_data.size() / 2 == (int)dstBlob.total());
+
+            Mat halfs((int)shape.size(), &shape[0], CV_16SC1, (void*)raw_data.c_str());
+            convertFp16(halfs, dstBlob);
+        }
     }
 
     void extractBinaryLayerParms(const caffe::LayerParameter& layer, LayerParams& layerParams)

modules/dnn/src/caffe/caffe_shrinker.cpp

@@ -0,0 +1,65 @@
+// 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) 2017, Intel Corporation, all rights reserved.
+// Third party copyrights are property of their respective owners.
+
+#include "../precomp.hpp"
+
+#ifdef HAVE_PROTOBUF
+#include <fstream>
+#include "caffe_io.hpp"
+#endif
+
+namespace cv { namespace dnn {
+CV__DNN_EXPERIMENTAL_NS_BEGIN
+
+#ifdef HAVE_PROTOBUF
+
+void shrinkCaffeModel(const String& src, const String& dst)
+{
+    CV_TRACE_FUNCTION();
+
+    caffe::NetParameter net;
+    ReadNetParamsFromBinaryFileOrDie(src.c_str(), &net);
+
+    for (int i = 0; i < net.layer_size(); ++i)
+    {
+        caffe::LayerParameter* lp = net.mutable_layer(i);
+        for (int j = 0; j < lp->blobs_size(); ++j)
+        {
+            caffe::BlobProto* blob = lp->mutable_blobs(j);
+            CV_Assert(blob->data_size() != 0);  // float32 array.
+
+            Mat floats(1, blob->data_size(), CV_32FC1, (void*)blob->data().data());
+            Mat halfs(1, blob->data_size(), CV_16SC1);
+            convertFp16(floats, halfs);  // Convert to float16.
+
+            blob->clear_data();  // Clear float32 data.
+
+            // Set float16 data.
+            blob->set_raw_data(halfs.data, halfs.total() * halfs.elemSize());
+            blob->set_raw_data_type(caffe::FLOAT16);
+        }
+    }
+    size_t msgSize = net.ByteSizeLong();
+    std::vector<uint8_t> output(msgSize);
+    net.SerializeWithCachedSizesToArray(&output[0]);
+
+    std::ofstream ofs(dst.c_str(), std::ios::binary);
+    ofs.write((const char*)&output[0], msgSize);
+    ofs.close();
+}
+
+#else
+
+void shrinkCaffeModel(const String& src, const String& dst)
+{
+    CV_Error(cv::Error::StsNotImplemented, "libprotobuf required to import data from Caffe models");
+}
+
+#endif  // HAVE_PROTOBUF
+
+CV__DNN_EXPERIMENTAL_NS_END
+}} // namespace