From f453b03f392ea77d091018a303a0c661770e4753 Mon Sep 17 00:00:00 2001
From: Davis King <davis@dlib.net>
Date: Wed, 22 Jun 2016 22:26:48 -0400
Subject: [PATCH] Added an example showing how to classify imagenet images.

---
 examples/CMakeLists.txt      |   1 +
 examples/dnn_imagenet_ex.cpp | 141 +++++++++++++++++++++++++++++++++++
 2 files changed, 142 insertions(+)
 create mode 100644 examples/dnn_imagenet_ex.cpp

diff --git a/examples/CMakeLists.txt b/examples/CMakeLists.txt
index 153fe6b0e..7500b5dc6 100644
--- a/examples/CMakeLists.txt
+++ b/examples/CMakeLists.txt
@@ -34,6 +34,7 @@ if (COMPILER_CAN_DO_CPP_11)
    add_example(dnn_mnist_ex)
    add_example(dnn_mnist_advanced_ex)
    add_example(dnn_inception_ex)
+   add_example(dnn_imagenet_ex)
 endif()
 
 #here we apply our macros 
diff --git a/examples/dnn_imagenet_ex.cpp b/examples/dnn_imagenet_ex.cpp
new file mode 100644
index 000000000..2c8d98bb6
--- /dev/null
+++ b/examples/dnn_imagenet_ex.cpp
@@ -0,0 +1,141 @@
+// The contents of this file are in the public domain. See LICENSE_FOR_EXAMPLE_PROGRAMS.txt
+/*
+    This example shows how to classify an image into one of the 1000 imagenet clategories
+    using the deep learning tools from the dlib C++ Library.  We will use the pretrained
+    ResNet34 model available on the dlib website.
+
+    
+    These tools will use CUDA and cuDNN to drastically accelerate network
+    training and testing.  CMake should automatically find them if they are
+    installed and configure things appropriately.  If not, the program will
+    still run but will be much slower to execute.
+*/
+
+
+
+#include <dlib/dnn.h>
+#include <iostream>
+#include <dlib/data_io.h>
+#include <dlib/gui_widgets.h>
+#include <dlib/image_transforms.h>
+
+using namespace std;
+using namespace dlib;
+ 
+// ----------------------------------------------------------------------------------------
+
+
+template <template <int,template<typename>class,int,typename> class block, int N, template<typename>class BN, typename SUBNET>
+using residual = add_prev1<block<N,BN,1,tag1<SUBNET>>>;
+
+template <template <int,template<typename>class,int,typename> class block, int N, template<typename>class BN, typename SUBNET>
+using residual_down = add_prev2<avg_pool<2,2,2,2,skip1<tag2<block<N,BN,2,tag1<SUBNET>>>>>>;
+
+template <int N, template <typename> class BN, int stride, typename SUBNET> 
+using block  = BN<con<N,3,3,1,1,relu<BN<con<N,3,3,stride,stride,SUBNET>>>>>;
+
+template <int N, typename SUBNET> using ares      = relu<residual<block,N,affine,SUBNET>>;
+template <int N, typename SUBNET> using ares_down = relu<residual_down<block,N,affine,SUBNET>>;
+
+
+typedef loss_multiclass_log<fc<1000,avg_pool_everything<
+                            ares<512,ares<512,ares_down<512,
+                            ares<256,ares<256,ares<256,ares<256,ares<256,ares_down<256,
+                            ares<128,ares<128,ares<128,ares_down<128,
+                            ares<64,ares<64,ares<64,
+                            max_pool<3,3,2,2,relu<affine<con<64,7,7,2,2,
+                            input_rgb_image_sized<227>
+                            >>>>>>>>>>>>>>>>>>>>>>> anet_type;
+
+// ----------------------------------------------------------------------------------------
+
+rectangle make_random_cropping_rect_resnet(
+    const matrix<rgb_pixel>& img,
+    dlib::rand& rnd
+)
+{
+    // figure out what rectangle we want to crop from the image
+    double mins = 0.466666666, maxs = 0.875;
+    auto scale = mins + rnd.get_random_double()*(maxs-mins);
+    auto size = scale*std::min(img.nr(), img.nc());
+    rectangle rect(size, size);
+    // randomly shift the box around
+    point offset(rnd.get_random_32bit_number()%(img.nc()-rect.width()),
+                 rnd.get_random_32bit_number()%(img.nr()-rect.height()));
+    return move_rect(rect, offset);
+}
+
+// ----------------------------------------------------------------------------------------
+
+void randomly_crop_images (
+    const matrix<rgb_pixel>& img,
+    dlib::array<matrix<rgb_pixel>>& crops,
+    dlib::rand& rnd,
+    long num_crops
+)
+{
+    std::vector<chip_details> dets;
+    for (long i = 0; i < num_crops; ++i)
+    {
+        auto rect = make_random_cropping_rect_resnet(img, rnd);
+        dets.push_back(chip_details(rect, chip_dims(227,227)));
+    }
+
+    extract_image_chips(img, dets, crops);
+
+    for (auto&& img : crops)
+    {
+        // Also randomly flip the image
+        if (rnd.get_random_double() > 0.5)
+            img = fliplr(img);
+
+        // And then randomly adjust the colors.
+        apply_random_color_offset(img, rnd);
+    }
+}
+
+// ----------------------------------------------------------------------------------------
+
+int main(int argc, char** argv) try
+{
+    std::vector<string> labels;
+    anet_type net;
+    // get this file from http://dlib.net/files/resnet34_1000_imagenet_classifier.dnn.bz2
+    deserialize("resnet34_1000_imagenet_classifier.dnn") >> net >> labels;
+
+
+    softmax<anet_type::subnet_type> snet; 
+    snet.subnet() = net.subnet();
+
+    dlib::array<matrix<rgb_pixel>> images;
+    matrix<rgb_pixel> img, crop;
+
+    dlib::rand rnd;
+    image_window win;
+
+    // read images from the command prompt and print the top 5 best labels.
+    for (int i = 1; i < argc; ++i)
+    {
+        load_image(img, argv[i]);
+        const int num_crops = 16;
+        randomly_crop_images(img, images, rnd, num_crops);
+
+        matrix<float,1,1000> p = sum_rows(mat(snet(images.begin(), images.end())))/num_crops;
+
+        win.set_image(img);
+        for (int k = 0; k < 5; ++k)
+        {
+            unsigned long predicted_label = index_of_max(p);
+            cout << p(predicted_label) << ": " << labels[predicted_label] << endl;
+            p(predicted_label) = 0;
+        }
+
+        cin.get();
+    }
+
+}
+catch(std::exception& e)
+{
+    cout << e.what() << endl;
+}
+