caffe2/image/image_input_op.h

#ifndef CAFFE2_IMAGE_IMAGE_INPUT_OP_H_
#define CAFFE2_IMAGE_IMAGE_INPUT_OP_H_

#include <opencv2/opencv.hpp>

#include <algorithm>
#include <iostream>

#include "c10/core/thread_pool.h"
#include <c10/util/irange.h>
#include "caffe2/core/common.h"
#include "caffe2/core/db.h"
#include "caffe2/image/transform_gpu.h"
#include "caffe2/operators/prefetch_op.h"
#include "caffe2/proto/caffe2_legacy.pb.h"
#include "caffe2/utils/cast.h"
#include "caffe2/utils/math.h"

namespace caffe2 {

class CUDAContext;

template <class Context>
class ImageInputOp final : public PrefetchOperator<Context> {
  // SINGLE_LABEL: single integer label for multi-class classification
  // MULTI_LABEL_SPARSE: sparse active label indices for multi-label
  // classification MULTI_LABEL_DENSE: dense label embedding vector for label
  // embedding regression MULTI_LABEL_WEIGHTED_SPARSE: sparse active label
  // indices with per-label weights for multi-label classification
  // SINGLE_LABEL_WEIGHTED: single integer label for multi-class classification
  // with weighted sampling EMBEDDING_LABEL: an array of floating numbers
  // representing dense embedding.
  //   It is useful for model distillation
  enum LABEL_TYPE {
    SINGLE_LABEL = 0,
    MULTI_LABEL_SPARSE = 1,
    MULTI_LABEL_DENSE = 2,
    MULTI_LABEL_WEIGHTED_SPARSE = 3,
    SINGLE_LABEL_WEIGHTED = 4,
    EMBEDDING_LABEL = 5,
  };

  // INCEPTION_STYLE: Random crop with size 8% - 100% image area and aspect
  // ratio in [3/4, 4/3]. Reference: GoogleNet paper
  enum SCALE_JITTER_TYPE {
    NO_SCALE_JITTER = 0,
    INCEPTION_STYLE = 1
    // TODO(zyan3): ResNet-style random scale jitter
  };

 public:
  using OperatorBase::OutputSize;
  using PrefetchOperator<Context>::context_;
  using PrefetchOperator<Context>::prefetch_thread_;
  explicit ImageInputOp(const OperatorDef& operator_def, Workspace* ws);
  ~ImageInputOp() {
    PrefetchOperator<Context>::Finalize();
  }

  bool Prefetch() override;
  bool CopyPrefetched() override;

 private:
  struct BoundingBox {
    bool valid;
    int ymin;
    int xmin;
    int height;
    int width;
  };

  // Structure to store per-image information
  // This can be modified by the DecodeAnd* so needs
  // to be privatized per launch.
  struct PerImageArg { BoundingBox bounding_params; };

  bool GetImageAndLabelAndInfoFromDBValue(
      const string& value,
      cv::Mat* img,
      PerImageArg& info,
      int item_id,
      std::mt19937* randgen);
  void DecodeAndTransform(
      const std::string& value,
      float* image_data,
      int item_id,
      const int channels,
      std::size_t thread_index);
  void DecodeAndTransposeOnly(
      const std::string& value,
      uint8_t* image_data,
      int item_id,
      const int channels,
      std::size_t thread_index);
  bool ApplyTransformOnGPU(
      const std::vector<std::int64_t>& dims,
      const c10::Device& type);

  unique_ptr<db::DBReader> owned_reader_;
  const db::DBReader* reader_;
  Tensor prefetched_image_;
  Tensor prefetched_label_;
  vector<Tensor> prefetched_additional_outputs_;
  Tensor prefetched_image_on_device_;
  Tensor prefetched_label_on_device_;
  vector<Tensor> prefetched_additional_outputs_on_device_;
  // Default parameters for images
  PerImageArg default_arg_;
  int batch_size_;
  LABEL_TYPE label_type_;
  int num_labels_;

  bool color_;
  bool color_jitter_;
  float img_saturation_;
  float img_brightness_;
  float img_contrast_;
  bool color_lighting_;
  float color_lighting_std_;
  std::vector<std::vector<float>> color_lighting_eigvecs_;
  std::vector<float> color_lighting_eigvals_;
  SCALE_JITTER_TYPE scale_jitter_type_;
  int scale_;
  // Minsize is similar to scale except that it will only
  // force the image to scale up if it is too small. In other words,
  // it ensures that both dimensions of the image are at least minsize_
  int minsize_;
  bool warp_;
  int crop_;
  std::vector<float> mean_;
  std::vector<float> std_;
  Tensor mean_gpu_;
  Tensor std_gpu_;
  bool mirror_;
  bool is_test_;
  bool use_caffe_datum_;
  bool gpu_transform_;
  bool mean_std_copied_ = false;

  // thread pool for parse + decode
  int num_decode_threads_;
  int additional_inputs_offset_;
  int additional_inputs_count_;
  std::vector<int> additional_output_sizes_;
  std::shared_ptr<TaskThreadPool> thread_pool_;

  // Output type for GPU transform path
  TensorProto_DataType output_type_;

  // random minsize
  vector<int> random_scale_;
  bool random_scaling_;

  // Working variables
  std::vector<std::mt19937> randgen_per_thread_;

  // number of exceptions produced by opencv while reading image data
  std::atomic<long> num_decode_errors_in_batch_{0};
  // opencv exceptions tolerance
  float max_decode_error_ratio_;
};

template <class Context>
ImageInputOp<Context>::ImageInputOp(
    const OperatorDef& operator_def,
    Workspace* ws)
    : PrefetchOperator<Context>(operator_def, ws),
      reader_(nullptr),
      batch_size_(
          OperatorBase::template GetSingleArgument<int>("batch_size", 0)),
      label_type_(static_cast<LABEL_TYPE>(
          OperatorBase::template GetSingleArgument<int>("label_type", 0))),
      num_labels_(
          OperatorBase::template GetSingleArgument<int>("num_labels", 0)),
      color_(OperatorBase::template GetSingleArgument<int>("color", 1)),
      color_jitter_(
          OperatorBase::template GetSingleArgument<int>("color_jitter", 0)),
      img_saturation_(OperatorBase::template GetSingleArgument<float>(
          "img_saturation",
          0.4)),
      img_brightness_(OperatorBase::template GetSingleArgument<float>(
          "img_brightness",
          0.4)),
      img_contrast_(
          OperatorBase::template GetSingleArgument<float>("img_contrast", 0.4)),
      color_lighting_(
          OperatorBase::template GetSingleArgument<int>("color_lighting", 0)),
      color_lighting_std_(OperatorBase::template GetSingleArgument<float>(
          "color_lighting_std",
          0.1)),
      scale_jitter_type_(static_cast<SCALE_JITTER_TYPE>(
          OperatorBase::template GetSingleArgument<int>(
              "scale_jitter_type",
              0))),
      scale_(OperatorBase::template GetSingleArgument<int>("scale", -1)),
      minsize_(OperatorBase::template GetSingleArgument<int>("minsize", -1)),
      warp_(OperatorBase::template GetSingleArgument<int>("warp", 0)),
      crop_(OperatorBase::template GetSingleArgument<int>("crop", -1)),
      mirror_(OperatorBase::template GetSingleArgument<int>("mirror", 0)),
      is_test_(OperatorBase::template GetSingleArgument<int>(
          OpSchema::Arg_IsTest,
          0)),
      use_caffe_datum_(
          OperatorBase::template GetSingleArgument<int>("use_caffe_datum", 0)),
      gpu_transform_(OperatorBase::template GetSingleArgument<int>(
          "use_gpu_transform",
          0)),
      num_decode_threads_(
          OperatorBase::template GetSingleArgument<int>("decode_threads", 4)),
      additional_output_sizes_(
          OperatorBase::template GetRepeatedArgument<int>("output_sizes", {})),
      thread_pool_(std::make_shared<TaskThreadPool>(num_decode_threads_)),
      // output type only supported with CUDA and use_gpu_transform for now
      output_type_(
          cast::GetCastDataType(ArgumentHelper(operator_def), "output_type")),
      random_scale_(OperatorBase::template GetRepeatedArgument<int>(
          "random_scale",
          {-1, -1})),
      max_decode_error_ratio_(OperatorBase::template GetSingleArgument<float>(
          "max_decode_error_ratio",
          1.0)) {
  if ((random_scale_[0] == -1) || (random_scale_[1] == -1)) {
    random_scaling_ = false;
  } else {
    random_scaling_ = true;
    minsize_ = random_scale_[0];
  }

  mean_ = OperatorBase::template GetRepeatedArgument<float>(
      "mean_per_channel",
      {OperatorBase::template GetSingleArgument<float>("mean", 0.)});

  std_ = OperatorBase::template GetRepeatedArgument<float>(
      "std_per_channel",
      {OperatorBase::template GetSingleArgument<float>("std", 1.)});

  if (additional_output_sizes_.size() == 0) {
    additional_output_sizes_ = std::vector<int>(OutputSize() - 2, 1);
  } else {
    CAFFE_ENFORCE(
        additional_output_sizes_.size() == OutputSize() - 2,
        "If the output sizes are specified, they must be specified for all "
        "additional outputs");
  }
  additional_inputs_count_ = OutputSize() - 2;

  default_arg_.bounding_params = {
      false,
      OperatorBase::template GetSingleArgument<int>("bounding_ymin", -1),
      OperatorBase::template GetSingleArgument<int>("bounding_xmin", -1),
      OperatorBase::template GetSingleArgument<int>("bounding_height", -1),
      OperatorBase::template GetSingleArgument<int>("bounding_width", -1),
  };

  if (operator_def.input_size() == 0) {
    LOG(ERROR) << "You are using an old ImageInputOp format that creates "
                  "a local db reader. Consider moving to the new style "
                  "that takes in a DBReader blob instead.";
    string db_name = OperatorBase::template GetSingleArgument<string>("db", "");
    CAFFE_ENFORCE_GT(db_name.size(), 0, "Must specify a db name.");
    owned_reader_.reset(new db::DBReader(
        OperatorBase::template GetSingleArgument<string>("db_type", "leveldb"),
        db_name));
    reader_ = owned_reader_.get();
  }

  // hard-coded PCA eigenvectors and eigenvalues, based on RBG channel order
  color_lighting_eigvecs_.push_back(
      std::vector<float>{-144.7125f, 183.396f, 102.2295f});
  color_lighting_eigvecs_.push_back(
      std::vector<float>{-148.104f, -1.1475f, -207.57f});
  color_lighting_eigvecs_.push_back(
      std::vector<float>{-148.818f, -177.174f, 107.1765f});

  color_lighting_eigvals_ = std::vector<float>{0.2175f, 0.0188f, 0.0045f};

  CAFFE_ENFORCE_GT(batch_size_, 0, "Batch size should be nonnegative.");
  if (use_caffe_datum_) {
    CAFFE_ENFORCE(
        label_type_ == SINGLE_LABEL || label_type_ == SINGLE_LABEL_WEIGHTED,
        "Caffe datum only supports single integer label");
  }
  if (label_type_ != SINGLE_LABEL && label_type_ != SINGLE_LABEL_WEIGHTED) {
    CAFFE_ENFORCE_GT(
        num_labels_,
        0,
        "Number of labels must be set for using either sparse label indices or dense label embedding.");
  }
  if (label_type_ == MULTI_LABEL_WEIGHTED_SPARSE ||
      label_type_ == SINGLE_LABEL_WEIGHTED) {
    additional_inputs_offset_ = 3;
  } else {
    additional_inputs_offset_ = 2;
  }
  CAFFE_ENFORCE(
      (scale_ > 0) != (minsize_ > 0),
      "Must provide one and only one of scaling or minsize");
  CAFFE_ENFORCE_GT(crop_, 0, "Must provide the cropping value.");
  CAFFE_ENFORCE_GE(
      scale_ > 0 ? scale_ : minsize_,
      crop_,
      "The scale/minsize value must be no smaller than the crop value.");

  CAFFE_ENFORCE_EQ(
      mean_.size(),
      std_.size(),
      "The mean and std. dev vectors must be of the same size.");
  CAFFE_ENFORCE(
      mean_.size() == 1 || mean_.size() == 3,
      "The mean and std. dev vectors must be of size 1 or 3");
  CAFFE_ENFORCE(
      !use_caffe_datum_ || OutputSize() == 2,
      "There can only be 2 outputs if the Caffe datum format is used");

  CAFFE_ENFORCE(
      random_scale_.size() == 2, "Must provide [scale_min, scale_max]");
  CAFFE_ENFORCE_GE(
      random_scale_[1],
      random_scale_[0],
      "random scale must provide a range [min, max]");

  if (default_arg_.bounding_params.ymin < 0 ||
      default_arg_.bounding_params.xmin < 0 ||
      default_arg_.bounding_params.height < 0 ||
      default_arg_.bounding_params.width < 0) {
    default_arg_.bounding_params.valid = false;
  } else {
    default_arg_.bounding_params.valid = true;
  }

  if (mean_.size() == 1) {
    // We are going to extend to 3 using the first value
    mean_.resize(3, mean_[0]);
    std_.resize(3, std_[0]);
  }

  LOG(INFO) << "Creating an image input op with the following setting: ";
  LOG(INFO) << "    Using " << num_decode_threads_ << " CPU threads;";
  if (gpu_transform_) {
    LOG(INFO) << "    Performing transformation on GPU";
  }
  LOG(INFO) << "    Outputting in batches of " << batch_size_ << " images;";
  LOG(INFO) << "    Treating input image as "
            << (color_ ? "color " : "grayscale ") << "image;";
  if (default_arg_.bounding_params.valid) {
    LOG(INFO) << "    Applying a default bounding box of Y ["
              << default_arg_.bounding_params.ymin << "; "
              << default_arg_.bounding_params.ymin +
            default_arg_.bounding_params.height
              << ") x X [" << default_arg_.bounding_params.xmin << "; "
              << default_arg_.bounding_params.xmin +
            default_arg_.bounding_params.width
              << ")";
  }
  if (scale_ > 0 && !random_scaling_) {
    LOG(INFO) << "    Scaling image to " << scale_
              << (warp_ ? " with " : " without ") << "warping;";
  } else {
    if (random_scaling_) {
      // randomly set min_size_ for each image
      LOG(INFO) << "    Randomly scaling shortest side between "
                << random_scale_[0] << " and " << random_scale_[1];
    } else {
      // Here, minsize_ > 0
      LOG(INFO) << "    Ensuring minimum image size of " << minsize_
                << (warp_ ? " with " : " without ") << "warping;";
    }
  }
  LOG(INFO) << "    " << (is_test_ ? "Central" : "Random")
            << " cropping image to " << crop_
            << (mirror_ ? " with " : " without ") << "random mirroring;";
  LOG(INFO) << "Label Type: " << label_type_;
  LOG(INFO) << "Num Labels: " << num_labels_;

  auto mit = mean_.begin();
  auto sit = std_.begin();

  for (int i = 0; mit != mean_.end() && sit != std_.end(); ++mit, ++sit, ++i) {
    LOG(INFO) << "    Default [Channel " << i << "] Subtract mean " << *mit
              << " and divide by std " << *sit << ".";
    // We actually will use the inverse of std, so inverse it here
    *sit = 1.f / *sit;
  }
  LOG(INFO) << "    Outputting images as "
            << OperatorBase::template GetSingleArgument<string>(
                   "output_type", "unknown")
            << ".";

  std::mt19937 meta_randgen(time(nullptr));
  for (const auto i : c10::irange(num_decode_threads_)) {
    randgen_per_thread_.emplace_back(meta_randgen());
  }
  ReinitializeTensor(
      &prefetched_image_,
      {int64_t(batch_size_),
       int64_t(crop_),
       int64_t(crop_),
       int64_t(color_ ? 3 : 1)},
      at::dtype<uint8_t>().device(CPU));
  std::vector<int64_t> sizes;
  if (label_type_ != SINGLE_LABEL && label_type_ != SINGLE_LABEL_WEIGHTED) {
    sizes = std::vector<int64_t>{int64_t(batch_size_), int64_t(num_labels_)};
  } else {
    sizes = std::vector<int64_t>{batch_size_};
  }
  // data type for prefetched_label_ is actually not known here..
  ReinitializeTensor(&prefetched_label_, sizes, at::dtype<int>().device(CPU));

  for (const auto i : c10::irange(additional_output_sizes_.size())) {
    prefetched_additional_outputs_on_device_.emplace_back();
    prefetched_additional_outputs_.emplace_back();
  }
}

// Inception-stype scale jittering
template <class Context>
bool RandomSizedCropping(cv::Mat* img, const int crop, std::mt19937* randgen) {
  cv::Mat scaled_img;
  bool inception_scale_jitter = false;
  int im_height = img->rows, im_width = img->cols;
  int area = im_height * im_width;
  std::uniform_real_distribution<> area_dis(0.08, 1.0);
  std::uniform_real_distribution<> aspect_ratio_dis(3.0 / 4.0, 4.0 / 3.0);

  cv::Mat cropping;
  for (const auto i : c10::irange(10)) {
    int target_area = int(ceil(area_dis(*randgen) * area));
    float aspect_ratio = aspect_ratio_dis(*randgen);
    int nh = floor(std::sqrt(((float)target_area / aspect_ratio)));
    int nw = floor(std::sqrt(((float)target_area * aspect_ratio)));
    if (nh >= 1 && nh <= im_height && nw >= 1 && nw <= im_width) {
      int height_offset =
          std::uniform_int_distribution<>(0, im_height - nh)(*randgen);
      int width_offset =
          std::uniform_int_distribution<>(0, im_width - nw)(*randgen);
      cv::Rect ROI(width_offset, height_offset, nw, nh);
      cropping = (*img)(ROI);
      cv::resize(
          cropping, scaled_img, cv::Size(crop, crop), 0, 0, cv::INTER_AREA);
      *img = scaled_img;
      inception_scale_jitter = true;
      break;
    }
  }
  return inception_scale_jitter;
}

template <class Context>
bool ImageInputOp<Context>::GetImageAndLabelAndInfoFromDBValue(
    const string& value,
    cv::Mat* img,
    PerImageArg& info,
    int item_id,
    std::mt19937* randgen) {
  //
  // recommend using --caffe2_use_fatal_for_enforce=1 when using ImageInputOp
  // as this function runs on a worker thread and the exceptions from
  // CAFFE_ENFORCE are silently dropped by the thread worker functions
  //
  cv::Mat src;

  // Use the default information for images
  info = default_arg_;
  if (use_caffe_datum_) {
    // The input is a caffe datum format.
    CaffeDatum datum;
    CAFFE_ENFORCE(datum.ParseFromString(value));

    prefetched_label_.mutable_data<int>()[item_id] = datum.label();
    if (datum.encoded()) {
      // encoded image in datum.
      // count the number of exceptions from opencv imdecode
      try {
        src = cv::imdecode(
            cv::Mat(
                1,
                datum.data().size(),
                CV_8UC1,
                const_cast<char*>(datum.data().data())),
            color_ ? cv::IMREAD_COLOR : cv::IMREAD_GRAYSCALE);
        if (src.rows == 0 || src.cols == 0) {
          num_decode_errors_in_batch_++;
          src = cv::Mat::zeros(cv::Size(224, 224), CV_8UC3);
        }
      } catch (cv::Exception& e) {
        num_decode_errors_in_batch_++;
        src = cv::Mat::zeros(cv::Size(224, 224), CV_8UC3);
      }
    } else {
      // Raw image in datum.
      CAFFE_ENFORCE(datum.channels() == 3 || datum.channels() == 1);

      int src_c = datum.channels();
      src.create(
          datum.height(), datum.width(), (src_c == 3) ? CV_8UC3 : CV_8UC1);

      if (src_c == 1) {
        memcpy(src.ptr<uchar>(0), datum.data().data(), datum.data().size());
      } else {
        // Datum stores things in CHW order, let's do HWC for images to make
        // things more consistent with conventional image storage.
        for (const auto c : c10::irange(3)) {
          const char* datum_buffer =
              datum.data().data() + datum.height() * datum.width() * c;
          uchar* ptr = src.ptr<uchar>(0) + c;
          for (const auto h : c10::irange(datum.height())) {
            for (const auto w : c10::irange(datum.width())) {
              *ptr = *(datum_buffer++);
              ptr += 3;
            }
          }
        }
      }
    }
  } else {
    // The input is a caffe2 format.
    TensorProtos protos;
    CAFFE_ENFORCE(protos.ParseFromString(value));
    const TensorProto& image_proto = protos.protos(0);
    const TensorProto& label_proto = protos.protos(1);
    // add handle protos
    vector<TensorProto> additional_output_protos;
    int start = additional_inputs_offset_;
    int end = start + additional_inputs_count_;
    for (const auto i : c10::irange(start, end)) {
      additional_output_protos.push_back(protos.protos(i));
    }

    if (protos.protos_size() == end + 1) {
      // We have bounding box information
      const TensorProto& bounding_proto = protos.protos(end);
      TORCH_DCHECK_EQ(bounding_proto.data_type(), TensorProto::INT32);
      TORCH_DCHECK_EQ(bounding_proto.int32_data_size(), 4);
      info.bounding_params.valid = true;
      info.bounding_params.ymin = bounding_proto.int32_data(0);
      info.bounding_params.xmin = bounding_proto.int32_data(1);
      info.bounding_params.height = bounding_proto.int32_data(2);
      info.bounding_params.width = bounding_proto.int32_data(3);
    }

    if (image_proto.data_type() == TensorProto::STRING) {
      // encoded image string.
      TORCH_DCHECK_EQ(image_proto.string_data_size(), 1);
      const string& encoded_image_str = image_proto.string_data(0);
      int encoded_size = encoded_image_str.size();
      // We use a cv::Mat to wrap the encoded str so we do not need a copy.
      // count the number of exceptions from opencv imdecode
      try {
        src = cv::imdecode(
            cv::Mat(
                1,
                &encoded_size,
                CV_8UC1,
                const_cast<char*>(encoded_image_str.data())),
            color_ ? cv::IMREAD_COLOR : cv::IMREAD_GRAYSCALE);
        if (src.rows == 0 || src.cols == 0) {
          num_decode_errors_in_batch_++;
          src = cv::Mat::zeros(cv::Size(224, 224), CV_8UC3);
        }
      } catch (cv::Exception& e) {
        num_decode_errors_in_batch_++;
        src = cv::Mat::zeros(cv::Size(224, 224), CV_8UC3);
      }
    } else if (image_proto.data_type() == TensorProto::BYTE) {
      // raw image content.
      int src_c = (image_proto.dims_size() == 3) ? image_proto.dims(2) : 1;
      CAFFE_ENFORCE(src_c == 3 || src_c == 1);

      src.create(
          image_proto.dims(0),
          image_proto.dims(1),
          (src_c == 3) ? CV_8UC3 : CV_8UC1);
      memcpy(
          src.ptr<uchar>(0),
          image_proto.byte_data().data(),
          image_proto.byte_data().size());
    } else {
      LOG(FATAL) << "Unknown image data type.";
    }

    // TODO: if image decoding was unsuccessful, set label to 0
    if (label_proto.data_type() == TensorProto::FLOAT) {
      if (label_type_ == SINGLE_LABEL || label_type_ == SINGLE_LABEL_WEIGHTED) {
        TORCH_DCHECK_EQ(label_proto.float_data_size(), 1);
        prefetched_label_.mutable_data<float>()[item_id] =
            label_proto.float_data(0);
      } else if (label_type_ == MULTI_LABEL_SPARSE) {
        float* label_data =
            prefetched_label_.mutable_data<float>() + item_id * num_labels_;
        memset(label_data, 0, sizeof(float) * num_labels_);
        for (const auto i : c10::irange(label_proto.float_data_size())) {
          label_data[(int)label_proto.float_data(i)] = 1.0;
        }
      } else if (label_type_ == MULTI_LABEL_WEIGHTED_SPARSE) {
        const TensorProto& weight_proto = protos.protos(2);
        float* label_data =
            prefetched_label_.mutable_data<float>() + item_id * num_labels_;
        memset(label_data, 0, sizeof(float) * num_labels_);
        for (const auto i : c10::irange(label_proto.float_data_size())) {
          label_data[(int)label_proto.float_data(i)] =
              weight_proto.float_data(i);
        }
      } else if (
          label_type_ == MULTI_LABEL_DENSE || label_type_ == EMBEDDING_LABEL) {
        CAFFE_ENFORCE(label_proto.float_data_size() == num_labels_);
        float* label_data =
            prefetched_label_.mutable_data<float>() + item_id * num_labels_;
        for (const auto i : c10::irange(label_proto.float_data_size())) {
          label_data[i] = label_proto.float_data(i);
        }
      } else {
        LOG(ERROR) << "Unknown label type:" << label_type_;
      }
    } else if (label_proto.data_type() == TensorProto::INT32) {
      if (label_type_ == SINGLE_LABEL || label_type_ == SINGLE_LABEL_WEIGHTED) {
        TORCH_DCHECK_EQ(label_proto.int32_data_size(), 1);
        prefetched_label_.mutable_data<int>()[item_id] =
            label_proto.int32_data(0);
      } else if (label_type_ == MULTI_LABEL_SPARSE) {
        int* label_data =
            prefetched_label_.mutable_data<int>() + item_id * num_labels_;
        memset(label_data, 0, sizeof(int) * num_labels_);
        for (const auto i : c10::irange(label_proto.int32_data_size())) {
          label_data[label_proto.int32_data(i)] = 1;
        }
      } else if (label_type_ == MULTI_LABEL_WEIGHTED_SPARSE) {
        const TensorProto& weight_proto = protos.protos(2);
        float* label_data =
            prefetched_label_.mutable_data<float>() + item_id * num_labels_;
        memset(label_data, 0, sizeof(float) * num_labels_);
        for (const auto i : c10::irange(label_proto.int32_data_size())) {
          label_data[label_proto.int32_data(i)] = weight_proto.float_data(i);
        }
      } else if (
          label_type_ == MULTI_LABEL_DENSE || label_type_ == EMBEDDING_LABEL) {
        CAFFE_ENFORCE(label_proto.int32_data_size() == num_labels_);
        int* label_data =
            prefetched_label_.mutable_data<int>() + item_id * num_labels_;
        for (const auto i : c10::irange(label_proto.int32_data_size())) {
          label_data[i] = label_proto.int32_data(i);
        }
      } else {
        LOG(ERROR) << "Unknown label type:" << label_type_;
      }
    } else {
      LOG(FATAL) << "Unsupported label data type.";
    }

    for (const auto i : c10::irange(additional_output_protos.size())) {
      auto additional_output_proto = additional_output_protos[i];
      if (additional_output_proto.data_type() == TensorProto::FLOAT) {
        float* additional_output =
            prefetched_additional_outputs_[i].template mutable_data<float>() +
            item_id * additional_output_proto.float_data_size();

        for (const auto j : c10::irange(additional_output_proto.float_data_size())) {
          additional_output[j] = additional_output_proto.float_data(j);
        }
      } else if (additional_output_proto.data_type() == TensorProto::INT32) {
        int* additional_output =
            prefetched_additional_outputs_[i].template mutable_data<int>() +
            item_id * additional_output_proto.int32_data_size();

        for (const auto j : c10::irange(additional_output_proto.int32_data_size())) {
          additional_output[j] = additional_output_proto.int32_data(j);
        }
      } else if (additional_output_proto.data_type() == TensorProto::INT64) {
        int64_t* additional_output =
            prefetched_additional_outputs_[i].template mutable_data<int64_t>() +
            item_id * additional_output_proto.int64_data_size();

        for (const auto j : c10::irange(additional_output_proto.int64_data_size())) {
          additional_output[j] = additional_output_proto.int64_data(j);
        }
      } else if (additional_output_proto.data_type() == TensorProto::UINT8) {
        uint8_t* additional_output =
            prefetched_additional_outputs_[i].template mutable_data<uint8_t>() +
            item_id * additional_output_proto.int32_data_size();

        for (const auto j : c10::irange(additional_output_proto.int32_data_size())) {
          additional_output[j] =
              static_cast<uint8_t>(additional_output_proto.int32_data(j));
        }
      } else {
        LOG(FATAL) << "Unsupported output type.";
      }
    }
  }

  //
  // convert source to the color format requested from Op
  //
  int out_c = color_ ? 3 : 1;
  if (out_c == src.channels()) {
    *img = src;
  } else {
    cv::cvtColor(
        src, *img, (out_c == 1) ? cv::COLOR_BGR2GRAY : cv::COLOR_GRAY2BGR);
  }

  // Note(Yangqing): I believe that the mat should be created continuous.
  CAFFE_ENFORCE(img->isContinuous());

  // Sanity check now that we decoded everything

  // Ensure that the bounding box is legit
  if (info.bounding_params.valid &&
      (src.rows < info.bounding_params.ymin + info.bounding_params.height ||
       src.cols < info.bounding_params.xmin + info.bounding_params.width)) {
    info.bounding_params.valid = false;
  }

  // Apply the bounding box if requested
  if (info.bounding_params.valid) {
    // If we reach here, we know the parameters are sane
    cv::Rect bounding_box(
        info.bounding_params.xmin,
        info.bounding_params.ymin,
        info.bounding_params.width,
        info.bounding_params.height);
    *img = (*img)(bounding_box);

    /*
    LOG(INFO) << "Did bounding with ymin:"
              << info.bounding_params.ymin << " xmin:" <<
    info.bounding_params.xmin
              << " height:" << info.bounding_params.height
              << " width:" << info.bounding_params.width << "\n";
    LOG(INFO) << "Bounded matrix: " << img;
    */
  } else {
    // LOG(INFO) << "No bounding\n";
  }

  cv::Mat scaled_img;
  bool inception_scale_jitter = false;
  if (scale_jitter_type_ == INCEPTION_STYLE) {
    if (!is_test_) {
      // Inception-stype scale jittering is only used for training
      inception_scale_jitter =
          RandomSizedCropping<Context>(img, crop_, randgen);
      // if a random crop is still not found, do simple random cropping later
    }
  }

  if ((scale_jitter_type_ == NO_SCALE_JITTER) ||
      (scale_jitter_type_ == INCEPTION_STYLE && !inception_scale_jitter)) {
    int scaled_width, scaled_height;
    int scale_to_use = scale_ > 0 ? scale_ : minsize_;

    // set the random minsize
    if (random_scaling_) {
      scale_to_use = std::uniform_int_distribution<>(
          random_scale_[0], random_scale_[1])(*randgen);
    }

    if (warp_) {
      scaled_width = scale_to_use;
      scaled_height = scale_to_use;
    } else if (img->rows > img->cols) {
      scaled_width = scale_to_use;
      scaled_height = static_cast<float>(img->rows) * scale_to_use / img->cols;
    } else {
      scaled_height = scale_to_use;
      scaled_width = static_cast<float>(img->cols) * scale_to_use / img->rows;
    }
    if ((scale_ > 0 &&
         (scaled_height != img->rows || scaled_width != img->cols)) ||
        (scaled_height > img->rows || scaled_width > img->cols)) {
      // We rescale in all cases if we are using scale_
      // but only to make the image bigger if using minsize_
      /*
      LOG(INFO) << "Scaling to " << scaled_width << " x " << scaled_height
                << " From " << img->cols << " x " << img->rows;
      */
      cv::resize(
          *img,
          scaled_img,
          cv::Size(scaled_width, scaled_height),
          0,
          0,
          cv::INTER_AREA);
      *img = scaled_img;
    }
  }

  // TODO(Yangqing): return false if any error happens.
  return true;
}

// assume HWC order and color channels BGR
template <class Context>
void Saturation(
    float* img,
    const int img_size,
    const float alpha_rand,
    std::mt19937* randgen) {
  float alpha = 1.0f +
      std::uniform_real_distribution<float>(-alpha_rand, alpha_rand)(*randgen);
  // BGR to Gray scale image: R -> 0.299, G -> 0.587, B -> 0.114
  int p = 0;
  for (const auto h : c10::irange(img_size)) {
    for (const auto w : c10::irange(img_size)) {
      float gray_color = img[3 * p] * 0.114f + img[3 * p + 1] * 0.587f +
          img[3 * p + 2] * 0.299f;
      for (const auto c : c10::irange(3)) {
        img[3 * p + c] = img[3 * p + c] * alpha + gray_color * (1.0f - alpha);
      }
      p++;
    }
  }
}

// assume HWC order and color channels BGR
template <class Context>
void Brightness(
    float* img,
    const int img_size,
    const float alpha_rand,
    std::mt19937* randgen) {
  float alpha = 1.0f +
      std::uniform_real_distribution<float>(-alpha_rand, alpha_rand)(*randgen);
  int p = 0;
  for (const auto h : c10::irange(img_size)) {
    for (const auto w : c10::irange(img_size)) {
      for (const auto c : c10::irange(3)) {
        img[p++] *= alpha;
      }
    }
  }
}

// assume HWC order and color channels BGR
template <class Context>
void Contrast(
    float* img,
    const int img_size,
    const float alpha_rand,
    std::mt19937* randgen) {
  float gray_mean = 0;
  int p = 0;
  for (const auto h : c10::irange(img_size)) {
    for (const auto w : c10::irange(img_size)) {
      // BGR to Gray scale image: R -> 0.299, G -> 0.587, B -> 0.114
      gray_mean += img[3 * p] * 0.114f + img[3 * p + 1] * 0.587f +
          img[3 * p + 2] * 0.299f;
      p++;
    }
  }
  gray_mean /= (img_size * img_size);

  float alpha = 1.0f +
      std::uniform_real_distribution<float>(-alpha_rand, alpha_rand)(*randgen);
  p = 0;
  for (const auto h : c10::irange(img_size)) {
    for (const auto w : c10::irange(img_size)) {
      for (const auto c : c10::irange(3)) {
        img[p] = img[p] * alpha + gray_mean * (1.0f - alpha);
        p++;
      }
    }
  }
}

// assume HWC order and color channels BGR
template <class Context>
void ColorJitter(
    float* img,
    const int img_size,
    const float saturation,
    const float brightness,
    const float contrast,
    std::mt19937* randgen) {
  std::srand(unsigned(std::time(0)));
  std::vector<int> jitter_order{0, 1, 2};
  // obtain a time-based seed:
  unsigned seed = std::chrono::system_clock::now().time_since_epoch().count();
  std::shuffle(
      jitter_order.begin(),
      jitter_order.end(),
      std::default_random_engine(seed));

  for (const auto i : c10::irange(3)) {
    if (jitter_order[i] == 0) {
      Saturation<Context>(img, img_size, saturation, randgen);
    } else if (jitter_order[i] == 1) {
      Brightness<Context>(img, img_size, brightness, randgen);
    } else {
      Contrast<Context>(img, img_size, contrast, randgen);
    }
  }
}

// assume HWC order and color channels BGR
template <class Context>
void ColorLighting(
    float* img,
    const int img_size,
    const float alpha_std,
    const std::vector<std::vector<float>>& eigvecs,
    const std::vector<float>& eigvals,
    std::mt19937* randgen) {
  std::normal_distribution<float> d(0, alpha_std);
  std::vector<float> alphas(3);
  for (const auto i : c10::irange(3)) {
    alphas[i] = d(*randgen);
  }

  std::vector<float> delta_rgb(3, 0.0);
  for (const auto i : c10::irange(3)) {
    for (const auto j : c10::irange(3)) {
      delta_rgb[i] += eigvecs[i][j] * eigvals[j] * alphas[j];
    }
  }

  int p = 0;
  for (const auto h : c10::irange(img_size)) {
    for (const auto w : c10::irange(img_size)) {
      for (const auto c : c10::irange(3)) {
        img[p++] += delta_rgb[2 - c];
      }
    }
  }
}

// assume HWC order and color channels BGR
// mean subtraction and scaling.
template <class Context>
void ColorNormalization(
    float* img,
    const int img_size,
    const int channels,
    const std::vector<float>& mean,
    const std::vector<float>& std) {
  int p = 0;
  for (const auto h : c10::irange(img_size)) {
    for (const auto w : c10::irange(img_size)) {
      for (const auto c : c10::irange(channels)) {
        img[p] = (img[p] - mean[c]) * std[c];
        p++;
      }
    }
  }
}

// Factored out image transformation
template <class Context>
void TransformImage(
    const cv::Mat& scaled_img,
    const int channels,
    float* image_data,
    const bool color_jitter,
    const float saturation,
    const float brightness,
    const float contrast,
    const bool color_lighting,
    const float color_lighting_std,
    const std::vector<std::vector<float>>& color_lighting_eigvecs,
    const std::vector<float>& color_lighting_eigvals,
    const int crop,
    const bool mirror,
    const std::vector<float>& mean,
    const std::vector<float>& std,
    std::mt19937* randgen,
    std::bernoulli_distribution* mirror_this_image,
    bool is_test = false) {
  CAFFE_ENFORCE_GE(
      scaled_img.rows, crop, "Image height must be bigger than crop.");
  CAFFE_ENFORCE_GE(
      scaled_img.cols, crop, "Image width must be bigger than crop.");

  // find the cropped region, and copy it to the destination matrix
  int width_offset, height_offset;
  if (is_test) {
    width_offset = (scaled_img.cols - crop) / 2;
    height_offset = (scaled_img.rows - crop) / 2;
  } else {
    width_offset =
        std::uniform_int_distribution<>(0, scaled_img.cols - crop)(*randgen);
    height_offset =
        std::uniform_int_distribution<>(0, scaled_img.rows - crop)(*randgen);
  }

  float* image_data_ptr = image_data;
  if (!is_test && mirror && (*mirror_this_image)(*randgen)) {
    // Copy mirrored image.
    for (int h = height_offset; h < height_offset + crop; ++h) {
      for (int w = width_offset + crop - 1; w >= width_offset; --w) {
        const uint8_t* cv_data = scaled_img.ptr(h) + w * channels;
        for (const auto c : c10::irange(channels)) {
          *(image_data_ptr++) = static_cast<float>(cv_data[c]);
        }
      }
    }
  } else {
    // Copy normally.
    for (int h = height_offset; h < height_offset + crop; ++h) {
      for (int w = width_offset; w < width_offset + crop; ++w) {
        const uint8_t* cv_data = scaled_img.ptr(h) + w * channels;
        for (const auto c : c10::irange(channels)) {
          *(image_data_ptr++) = static_cast<float>(cv_data[c]);
        }
      }
    }
  }

  if (color_jitter && channels == 3 && !is_test) {
    ColorJitter<Context>(
        image_data, crop, saturation, brightness, contrast, randgen);
  }
  if (color_lighting && channels == 3 && !is_test) {
    ColorLighting<Context>(
        image_data,
        crop,
        color_lighting_std,
        color_lighting_eigvecs,
        color_lighting_eigvals,
        randgen);
  }

  // Color normalization
  // Mean subtraction and scaling.
  ColorNormalization<Context>(image_data, crop, channels, mean, std);
}

// Only crop / transpose the image
// leave in uint8_t dataType
template <class Context>
void CropTransposeImage(
    const cv::Mat& scaled_img,
    const int channels,
    uint8_t* cropped_data,
    const int crop,
    const bool mirror,
    std::mt19937* randgen,
    std::bernoulli_distribution* mirror_this_image,
    bool is_test = false) {
  CAFFE_ENFORCE_GE(
      scaled_img.rows, crop, "Image height must be bigger than crop.");
  CAFFE_ENFORCE_GE(
      scaled_img.cols, crop, "Image width must be bigger than crop.");

  // find the cropped region, and copy it to the destination matrix
  int width_offset, height_offset;
  if (is_test) {
    width_offset = (scaled_img.cols - crop) / 2;
    height_offset = (scaled_img.rows - crop) / 2;
  } else {
    width_offset =
        std::uniform_int_distribution<>(0, scaled_img.cols - crop)(*randgen);
    height_offset =
        std::uniform_int_distribution<>(0, scaled_img.rows - crop)(*randgen);
  }

  if (mirror && (*mirror_this_image)(*randgen)) {
    // Copy mirrored image.
    for (int h = height_offset; h < height_offset + crop; ++h) {
      for (int w = width_offset + crop - 1; w >= width_offset; --w) {
        const uint8_t* cv_data = scaled_img.ptr(h) + w * channels;
        for (const auto c : c10::irange(channels)) {
          *(cropped_data++) = cv_data[c];
        }
      }
    }
  } else {
    // Copy normally.
    for (int h = height_offset; h < height_offset + crop; ++h) {
      for (int w = width_offset; w < width_offset + crop; ++w) {
        const uint8_t* cv_data = scaled_img.ptr(h) + w * channels;
        for (const auto c : c10::irange(channels)) {
          *(cropped_data++) = cv_data[c];
        }
      }
    }
  }
}

// Parse datum, decode image, perform transform
// Intended as entry point for binding to thread pool
template <class Context>
void ImageInputOp<Context>::DecodeAndTransform(
    const std::string& value,
    float* image_data,
    int item_id,
    const int channels,
    std::size_t thread_index) {
  CAFFE_ENFORCE((int)thread_index < num_decode_threads_);

  std::bernoulli_distribution mirror_this_image(0.5f);
  std::mt19937* randgen = &(randgen_per_thread_[thread_index]);

  cv::Mat img;
  // Decode the image
  PerImageArg info;
  CHECK(
      GetImageAndLabelAndInfoFromDBValue(value, &img, info, item_id, randgen));
  // Factor out the image transformation
  TransformImage<Context>(
      img,
      channels,
      image_data,
      color_jitter_,
      img_saturation_,
      img_brightness_,
      img_contrast_,
      color_lighting_,
      color_lighting_std_,
      color_lighting_eigvecs_,
      color_lighting_eigvals_,
      crop_,
      mirror_,
      mean_,
      std_,
      randgen,
      &mirror_this_image,
      is_test_);
}

template <class Context>
void ImageInputOp<Context>::DecodeAndTransposeOnly(
    const std::string& value,
    uint8_t* image_data,
    int item_id,
    const int channels,
    std::size_t thread_index) {
  CAFFE_ENFORCE((int)thread_index < num_decode_threads_);

  std::bernoulli_distribution mirror_this_image(0.5f);
  std::mt19937* randgen = &(randgen_per_thread_[thread_index]);

  cv::Mat img;
  // Decode the image
  PerImageArg info;
  CHECK(
      GetImageAndLabelAndInfoFromDBValue(value, &img, info, item_id, randgen));

  // Factor out the image transformation
  CropTransposeImage<Context>(
      img,
      channels,
      image_data,
      crop_,
      mirror_,
      randgen,
      &mirror_this_image,
      is_test_);
}

template <class Context>
bool ImageInputOp<Context>::Prefetch() {
  if (!owned_reader_.get()) {
    // if we are not owning the reader, we will get the reader pointer from
    // input. Otherwise the constructor should have already set the reader
    // pointer.
    reader_ = &OperatorBase::Input<db::DBReader>(0);
  }
  const int channels = color_ ? 3 : 1;
  // Call mutable_data() once to allocate the underlying memory.
  if (gpu_transform_) {
    // we'll transfer up in int8, then convert later
    prefetched_image_.mutable_data<uint8_t>();
  } else {
    prefetched_image_.mutable_data<float>();
  }

  prefetched_label_.mutable_data<int>();
  // Prefetching handled with a thread pool of "decode_threads" threads.

  for (const auto item_id : c10::irange(batch_size_)) {
    std::string key, value;
    cv::Mat img;

    // read data
    reader_->Read(&key, &value);

    // determine label type based on first item
    if (item_id == 0) {
      if (use_caffe_datum_) {
        prefetched_label_.mutable_data<int>();
      } else {
        TensorProtos protos;
        CAFFE_ENFORCE(protos.ParseFromString(value));
        TensorProto_DataType labeldt = protos.protos(1).data_type();
        if (labeldt == TensorProto::INT32) {
          prefetched_label_.mutable_data<int>();
        } else if (labeldt == TensorProto::FLOAT) {
          prefetched_label_.mutable_data<float>();
        } else {
          LOG(FATAL) << "Unsupported label type.";
        }

        for (const auto i : c10::irange(additional_inputs_count_)) {
          int index = additional_inputs_offset_ + i;
          TensorProto additional_output_proto = protos.protos(index);
          auto sizes =
              std::vector<int64_t>({batch_size_, additional_output_sizes_[i]});
          if (additional_output_proto.data_type() == TensorProto::FLOAT) {
            prefetched_additional_outputs_[i] =
                caffe2::empty(sizes, at::dtype<float>().device(CPU));
          } else if (
              additional_output_proto.data_type() == TensorProto::INT32) {
            prefetched_additional_outputs_[i] =
                caffe2::empty(sizes, at::dtype<int>().device(CPU));
          } else if (
              additional_output_proto.data_type() == TensorProto::INT64) {
            prefetched_additional_outputs_[i] =
                caffe2::empty(sizes, at::dtype<int64_t>().device(CPU));
          } else if (
              additional_output_proto.data_type() == TensorProto::UINT8) {
            prefetched_additional_outputs_[i] =
                caffe2::empty(sizes, at::dtype<uint8_t>().device(CPU));
          } else {
            LOG(FATAL) << "Unsupported output type.";
          }
        }
      }
    }

    // launch into thread pool for processing
    // TODO: support color jitter and color lighting in gpu_transform
    if (gpu_transform_) {
      // output of decode will still be int8
      uint8_t* image_data = prefetched_image_.mutable_data<uint8_t>() +
          crop_ * crop_ * channels * item_id;
      thread_pool_->runTaskWithID(std::bind(
          &ImageInputOp<Context>::DecodeAndTransposeOnly,
          this,
          std::string(value),
          image_data,
          item_id,
          channels,
          std::placeholders::_1));
    } else {
      float* image_data = prefetched_image_.mutable_data<float>() +
          crop_ * crop_ * channels * item_id;
      thread_pool_->runTaskWithID(std::bind(
          &ImageInputOp<Context>::DecodeAndTransform,
          this,
          std::string(value),
          image_data,
          item_id,
          channels,
          std::placeholders::_1));
    }
  }
  thread_pool_->waitWorkComplete();

  // we allow to get at most max_decode_error_ratio from
  // opencv imdecode until raising a runtime exception
  if ((float)num_decode_errors_in_batch_ / batch_size_ >
      max_decode_error_ratio_) {
    throw std::runtime_error(
        "max_decode_error_ratio exceeded " +
        c10::to_string(max_decode_error_ratio_));
  }

  // If the context is not CPUContext, we will need to do a copy in the
  // prefetch function as well.
  auto device = at::device(Context::GetDeviceType());
  if (!std::is_same<Context, CPUContext>::value) {
    // do sync copies
    ReinitializeAndCopyFrom(
        &prefetched_image_on_device_, device, prefetched_image_);
    ReinitializeAndCopyFrom(
        &prefetched_label_on_device_, device, prefetched_label_);

    for (const auto i : c10::irange(prefetched_additional_outputs_on_device_.size())) {
      ReinitializeAndCopyFrom(
          &prefetched_additional_outputs_on_device_[i],
          device,
          prefetched_additional_outputs_[i]);
    }
  }

  num_decode_errors_in_batch_ = 0;

  return true;
}

template <class Context>
bool ImageInputOp<Context>::CopyPrefetched() {
  auto type = Device(Context::GetDeviceType());
  auto options = at::device(type);

  // Note(jiayq): The if statement below should be optimized away by the
  // compiler since std::is_same is a constexpr.
  if (std::is_same<Context, CPUContext>::value) {
    OperatorBase::OutputTensorCopyFrom(
        0, options, prefetched_image_, /* async */ true);
    OperatorBase::OutputTensorCopyFrom(
        1, options, prefetched_label_, /* async */ true);

    for (const auto i : c10::irange(2, OutputSize())) {
      OperatorBase::OutputTensorCopyFrom(
          i, options, prefetched_additional_outputs_[i - 2], /* async */ true);
    }
  } else {
    // TODO: support color jitter and color lighting in gpu_transform
    if (gpu_transform_) {
      if (!mean_std_copied_) {
        ReinitializeTensor(
            &mean_gpu_,
            {static_cast<int64_t>(mean_.size())},
            at::dtype<float>().device(Context::GetDeviceType()));
        ReinitializeTensor(
            &std_gpu_,
            {static_cast<int64_t>(std_.size())},
            at::dtype<float>().device(Context::GetDeviceType()));

        context_.template CopyFromCPU<float>(
            mean_.size(),
            mean_.data(),
            mean_gpu_.template mutable_data<float>());
        context_.template CopyFromCPU<float>(
            std_.size(), std_.data(), std_gpu_.template mutable_data<float>());
        mean_std_copied_ = true;
      }
      const auto& X = prefetched_image_on_device_;
      // data comes in as NHWC
      const int N = X.dim32(0), C = X.dim32(3), H = X.dim32(1), W = X.dim32(2);
      // data goes out as NCHW
      auto dims = std::vector<int64_t>{N, C, H, W};
      if (!ApplyTransformOnGPU(dims, type)) {
        return false;
      }

    } else {
      OperatorBase::OutputTensorCopyFrom(
          0, type, prefetched_image_on_device_, /* async */ true);
    }
    OperatorBase::OutputTensorCopyFrom(
        1, type, prefetched_label_on_device_, /* async */ true);

    for (const auto i : c10::irange(2, OutputSize())) {
      OperatorBase::OutputTensorCopyFrom(
          i,
          type,
          prefetched_additional_outputs_on_device_[i - 2],
          /* async */ true);
    }
  }
  return true;
}
} // namespace caffe2

#endif // CAFFE2_IMAGE_IMAGE_INPUT_OP_H_