message: Added support for using CPU as the backend when working on image augmentation
diff: #include "inference_engine.h"
  #include "ngraph/event_tracing.hpp"
  +#include "ngraph_backend_manager.h"
  #include "version.h"
  #include "tensorflow/core/platform/macros.h"
  @@ -72,11 +73,16 @@ Status InferenceEngine::Load(const string& network, const string& image_file,
  // Preload the image is requested
  if (m_preload_images) {
  + // Set the CPU as the backend before these ops
  + string current_backend =
  + tf::ngraph_bridge::BackendManager::GetCurrentlySetBackendName();
  + tf::ngraph_bridge::BackendManager::SetBackendName("CPU");
  std::vector<tf::Tensor> resized_tensors;
  TF_CHECK_OK(ReadTensorFromImageFile(
  m_image_file, m_input_height, m_input_width, m_input_mean, m_input_std,
  m_use_NCHW, &resized_tensors));
  m_image_to_repeat = resized_tensors[0];
  + tf::ngraph_bridge::BackendManager::SetBackendName(current_backend);
  }
  // Now compile the graph if needed
  // This would be useful to detect errors early. For a graph
  @@ -119,12 +125,18 @@ void InferenceEngine::ThreadMain() {
  cout << "[" << m_name << "] " << step_count << ": Reading image\n";
  ngraph::Event read_event("Read", "", "");
  + string current_backend =
  + tf::ngraph_bridge::BackendManager::GetCurrentlySetBackendName();
  + tf::ngraph_bridge::BackendManager::SetBackendName("CPU");
  +
  std::vector<tf::Tensor> resized_tensors;
  TF_CHECK_OK(ReadTensorFromImageFile(
  m_image_file, m_input_height, m_input_width, m_input_mean,
  m_input_std, m_use_NCHW, &resized_tensors));
  m_image_to_repeat = resized_tensors[0];
  + tf::ngraph_bridge::BackendManager::SetBackendName(current_backend);
  +
  read_event.Stop();
  ngraph::Event::write_trace(read_event);
  }
  