Add RROIAlign

src/operator/rroi_align-inl.h

@@ -0,0 +1,68 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*!
+ * Copyright (c) 2015 by Contributors
+ * \file rroi_align-inl.h
+ * \brief rroi align operator and symbol
+ * \author Yixin Bao
+ * Adapted from Caffe2
+*/
+#ifndef MXNET_OPERATOR_RROI_ALIGN_INL_H_
+#define MXNET_OPERATOR_RROI_ALIGN_INL_H_
+
+#include <dmlc/logging.h>
+#include <dmlc/parameter.h>
+#include <mxnet/operator.h>
+#include <map>
+#include <vector>
+#include <string>
+#include <utility>
+#include "./mshadow_op.h"
+#include "./operator_common.h"
+
+namespace mxnet {
+namespace op {
+
+// Declare enumeration of input order to make code more intuitive.
+// These enums are only visible within this header
+namespace rroialign {
+enum RROIAlignOpInputs{kData, kBox};
+enum RROIAlignOpOutputs {kOut};
+}  // rroialign
+
+struct RROIAlignParam : public dmlc::Parameter<RROIAlignParam> {
+  mxnet::TShape pooled_size;
+  float spatial_scale;
+  int sampling_ratio;
+  DMLC_DECLARE_PARAMETER(RROIAlignParam) {
+    DMLC_DECLARE_FIELD(pooled_size)
+    .set_expect_ndim(2).enforce_nonzero()
+    .describe("RROI align output shape (h,w) ");
+    DMLC_DECLARE_FIELD(spatial_scale).set_range(0.0, 1.0)
+    .describe("Ratio of input feature map height (or w) to raw image height (or w). "
+    "Equals the reciprocal of total stride in convolutional layers");
+    DMLC_DECLARE_FIELD(sampling_ratio).set_default(-1)
+    .describe("Optional sampling ratio of RROI align, using adaptive size by default.");
+  }
+};
+
+}  // namespace op
+}  // namespace mxnet
+#endif  // MXNET_OPERATOR_RROI_ALIGN_INL_H_

src/operator/rroi_align.cc

@@ -0,0 +1,313 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+/*!
+ * Copyright (c) 2015 by Contributors
+ * \file rroi_align.cc
+ * \brief rroi align operator
+ * \author Yixin Bao
+ * Adapted from Caffe2
+*/
+#include "./rroi_align-inl.h"
+#include <mshadow/tensor.h>
+#include "math.h"
+
+using std::max;
+using std::min;
+using std::floor;
+using std::ceil;
+
+namespace mxnet {
+namespace op {
+
+template <typename DType>
+struct position_for_bilinear_interpolate {
+  // 4 positions and corresponding weights for
+  // computing bilinear interpolation
+  int pos1, pos2, pos3, pos4;
+  DType w1, w2, w3, w4;
+};
+
+template <typename DType>
+void pre_calc_for_bilinear_interpolate(
+    const int height, const int width, const int pooled_height, const int pooled_width,
+    const int iy_upper, const int ix_upper, DType roi_start_h, DType roi_start_w,
+    DType bin_size_h, DType bin_size_w, int roi_bin_grid_h, int roi_bin_grid_w,
+    DType roi_center_h, DType roi_center_w, DType theta,
+    std::vector<position_for_bilinear_interpolate<DType>> *pre_calc) {
+  int pre_calc_index = 0;
+  DType cosTheta = cos(theta);
+  DType sinTheta = sin(theta);
+  for (int ph = 0; ph < pooled_height; ph++) {
+    for (int pw = 0; pw < pooled_width; pw++) {
+      // calc bin grid position (xx,yy)
+      for (int iy = 0; iy < iy_upper; iy++) {
+        const DType yy = roi_start_h + ph * bin_size_h +
+            static_cast<DType>(iy + .5f) * bin_size_h /
+                static_cast<DType>(roi_bin_grid_h);  // e.g., 0.5, 1.5
+        for (int ix = 0; ix < ix_upper; ix++) {
+          const DType xx = roi_start_w + pw * bin_size_w +
+              static_cast<DType>(ix + .5f) * bin_size_w /
+                  static_cast<DType>(roi_bin_grid_w);
+
+          // Rotate by theta around the center and translate
+          DType x = xx * cosTheta + yy * sinTheta + roi_center_w;
+          DType y = yy * cosTheta - xx * sinTheta + roi_center_h;
+
+          // deal with: inverse elements are out of feature map boundary
+          if (y < -1.0 || y > height || x < -1.0 || x > width) {
+            // empty
+            position_for_bilinear_interpolate<DType> pc;
+            pc.pos1 = 0;
+            pc.pos2 = 0;
+            pc.pos3 = 0;
+            pc.pos4 = 0;
+            pc.w1 = 0;
+            pc.w2 = 0;
+            pc.w3 = 0;
+            pc.w4 = 0;
+            pre_calc->at(pre_calc_index) = pc;
+            pre_calc_index += 1;
+            continue;
+          }
+          if (y <= 0) {
+            y = 0;
+          }
+          if (x <= 0) {
+            x = 0;
+          }
+
+          // calc 4 points for interpolation
+          int y_low = static_cast<int>(y);
+          int x_low = static_cast<int>(x);
+          int y_high;
+          int x_high;
+          if (y_low >= height - 1) {
+            y_high = y_low = height - 1;
+            y = (DType)y_low;
+          } else {
+            y_high = y_low + 1;
+          }
+          if (x_low >= width - 1) {
+            x_high = x_low = width - 1;
+            x = (DType)x_low;
+          } else {
+            x_high = x_low + 1;
+          }
+          DType ly = y - y_low;
+          DType lx = x - x_low;
+          DType hy = 1. - ly, hx = 1. - lx;
+          DType w1 = hy * hx, w2 = hy * lx, w3 = ly * hx, w4 = ly * lx;
+
+          // Save weights and indices
+          position_for_bilinear_interpolate<DType> pc;
+          pc.pos1 = y_low * width + x_low;
+          pc.pos2 = y_low * width + x_high;
+          pc.pos3 = y_high * width + x_low;
+          pc.pos4 = y_high * width + x_high;
+          pc.w1 = w1;
+          pc.w2 = w2;
+          pc.w3 = w3;
+          pc.w4 = w4;
+          pre_calc->at(pre_calc_index) = pc;
+
+          pre_calc_index += 1;
+        }
+      }
+    }
+  }
+}
+
+template <typename DType>
+inline void RROIAlignForward(const OpContext &ctx, const RROIAlignParam &param,
+                             const std::vector<TBlob> &in_data, const std::vector<OpReqType> &req,
+                             const std::vector<TBlob> &out_data) {
+  // data: [batch_size, c, h, w]
+  const TBlob &data = in_data[rroialign::kData];
+  const TBlob &bbox = in_data[rroialign::kBox];
+  const DType *bottom_data = data.dptr<DType>();
+  const int channels_ = data.size(1);
+  const int height_ = data.size(2);
+  const int width_ = data.size(3);
+  const index_t data_size_c = height_ * width_;
+  const index_t data_size = channels_ * data_size_c;
+
+  // bbox: [num_rois, 6] (6: [batch_index, x, y, w, h, theta])
+  const DType *bottom_rois = bbox.dptr<DType>();
+  const int num_rois = bbox.size(0);
+  const float spatial_scale_ = param.spatial_scale;
+  const int sampling_ratio_ = param.sampling_ratio;
+
+  // out: [num_rois, c, pooled_h, pooled_w]
+  const TBlob &out = out_data[rroialign::kOut];
+  DType *top_data = out.dptr<DType>();
+  const int pooled_height_ = out.size(2);
+  const int pooled_width_ = out.size(3);
+  const index_t out_size_c = pooled_height_ * pooled_width_;
+  const index_t out_size = channels_ * out_size_c;
+
+  for (int n = 0; n < num_rois; ++n) {
+    // Increment ROI data pointer
+    const DType *bottom_rois_n = bottom_rois + n * bbox.size(1);
+    DType *top_data_n = top_data + n * out_size;
+    int roi_batch_ind = static_cast<int>(bottom_rois_n[0]);
+    DType roi_center_w = bottom_rois_n[1] * spatial_scale_;
+    DType roi_center_h = bottom_rois_n[2] * spatial_scale_;
+    DType roi_width = bottom_rois_n[3] * spatial_scale_;
+    DType roi_height = bottom_rois_n[4] * spatial_scale_;
+    DType roi_theta = bottom_rois_n[5] * M_PI / 180.0;
+
+    // force malformed ROIs to be 1 * 1
+    roi_width = max(roi_width, (DType) 1.);
+    roi_height = max(roi_height, (DType) 1.);
+    // roi_start_h and roi_start_w are computed wrt the center of RoI (x, y).
+    // Appropriate translation needs to be applied after.
+    DType roi_start_h = -roi_height / 2.0;
+    DType roi_start_w = -roi_width / 2.0;
+
+    const DType bin_size_h = static_cast<DType>(roi_height) / static_cast<DType>(pooled_height_);
+    const DType bin_size_w = static_cast<DType>(roi_width) / static_cast<DType>(pooled_width_);
+    // We use roi_bin_grid to sample the grid and mimic integral,
+    // e.g. roi_bin_grid = 2, means sample 2*2=4 points in each bin
+    int roi_bin_grid_h =
+        (sampling_ratio_ > 0) ? sampling_ratio_ : ceil(roi_height / pooled_height_);
+    int roi_bin_grid_w = (sampling_ratio_ > 0) ? sampling_ratio_ : ceil(roi_width / pooled_width_);
+    const DType bin_points_count = roi_bin_grid_h * roi_bin_grid_w;  // e.g. = 4
+
+    // We want to precalculate indices and weights shared by all channels,
+    // this is the key point of optimization.
+    std::vector<position_for_bilinear_interpolate<DType>> pre_calc(roi_bin_grid_h * roi_bin_grid_w *
+                                                                   pooled_width_ * pooled_height_);
+
+    pre_calc_for_bilinear_interpolate(height_, width_, pooled_height_, pooled_width_,
+                                      roi_bin_grid_h, roi_bin_grid_w, roi_start_h, roi_start_w,
+                                      bin_size_h, bin_size_w, roi_bin_grid_h, roi_bin_grid_w,
+                                      roi_center_h, roi_center_w, roi_theta, &pre_calc);
+
+#pragma omp parallel for
+    for (int c = 0; c < channels_; ++c) {
+      const DType *offset_bottom_data = bottom_data + roi_batch_ind * data_size + c * data_size_c;
+      int pre_calc_index = 0;
+
+      for (int ph = 0; ph < pooled_height_; ph++) {
+        for (int pw = 0; pw < pooled_width_; pw++) {
+          DType output_val = 0.;
+          for (int iy = 0; iy < roi_bin_grid_h; iy++) {
+            for (int ix = 0; ix < roi_bin_grid_w; ix++) {
+              position_for_bilinear_interpolate<DType> pc = pre_calc[pre_calc_index];
+              output_val +=
+                  pc.w1 * offset_bottom_data[pc.pos1] + pc.w2 * offset_bottom_data[pc.pos2] +
+                  pc.w3 * offset_bottom_data[pc.pos3] + pc.w4 * offset_bottom_data[pc.pos4];
+
+              pre_calc_index += 1;
+            }
+          }
+          output_val /= bin_points_count;  // avg pooling for bin grid
+          int index = c * pooled_height_ * pooled_width_ + ph * pooled_width_ + pw;
+          top_data_n[index] = output_val;
+        }   // for pw
+      }   // for ph
+    }   // for c
+  }   // for n
+}
+
+template<typename xpu>
+void RROIAlignForwardCompute(const nnvm::NodeAttrs& attrs,
+                      const OpContext& ctx, const std::vector<TBlob>& in_data,
+                      const std::vector<OpReqType>& req,
+                      const std::vector<TBlob>& out_data) {
+  const RROIAlignParam& param = nnvm::get<RROIAlignParam>(attrs.parsed);
+  CHECK_EQ(in_data.size(), 2);
+  CHECK_EQ(out_data.size(), 1);
+  CHECK_EQ(out_data[rroialign::kOut].shape_[0], in_data[rroialign::kBox].shape_[0]);
+
+  MSHADOW_REAL_TYPE_SWITCH(in_data[0].type_flag_, DType, {
+    RROIAlignForward<DType>(ctx, param, in_data, req, out_data);
+  })
+}
+
+DMLC_REGISTER_PARAMETER(RROIAlignParam);
+
+NNVM_REGISTER_OP(_contrib_RROIAlign)
+.describe(R"code(Performs Rotated ROI Align on the input array.
+
+This operator takes a 4D feature map as an input array and region proposals as `rois`,
+then align the feature map over sub-regions of input and produces a fixed-sized output array.
+
+Different from ROI Align, RROI Align uses rotated rois, which is suitable for text detection.
+RRoIAlign computes the value of each sampling point by bilinear interpolation from the nearby
+grid points on the rotated feature map. No quantization is performed on any coordinates
+involved in the RoI, its bins, or the sampling points. Bilinear interpolation is used to
+compute the exact values of the input features at four regularly sampled locations in
+each RoI bin. Then the feature map can be aggregated by avgpooling.
+
+References
+----------
+
+Ma, Jianqi, et al. "Arbitrary-Oriented Scene Text Detection via Rotation Proposals."
+IEEE Transactions on Multimedia, 2018.
+
+)code" ADD_FILELINE)
+.set_num_inputs(2)
+.set_num_outputs(1)
+.set_attr<nnvm::FListInputNames>("FListInputNames",
+    [](const NodeAttrs& attrs) {
+  return std::vector<std::string>{"data", "rois"};
+})
+.set_attr<nnvm::FListOutputNames>("FListOutputNames",
+    [](const NodeAttrs& attrs) {
+  return std::vector<std::string>{"output"};
+})
+.set_attr_parser(ParamParser<RROIAlignParam>)
+.set_attr<mxnet::FInferShape>("FInferShape", [](const nnvm::NodeAttrs& attrs,
+      mxnet::ShapeVector *in_shape, mxnet::ShapeVector *out_shape){
+  using namespace mshadow;
+  const RROIAlignParam& param = nnvm::get<RROIAlignParam>(attrs.parsed);
+  CHECK_EQ(in_shape->size(), 2U) << "Input:[data, rois]";
+  // data: [batch_size, c, h, w]
+  mxnet::TShape dshape = in_shape->at(rroialign::kData);
+  CHECK_EQ(dshape.ndim(), 4U) << "data should be a 4D tensor";
+  // bbox: [num_rois, 6]
+  mxnet::TShape bshape = in_shape->at(rroialign::kBox);
+  CHECK_EQ(bshape.ndim(), 2U) << "bbox should be a 2D tensor of shape [batch, 6]";
+  CHECK_EQ(bshape[1], 6U) << "bbox should be a 2D tensor of shape [batch, 6]";
+  // out: [num_rois, c, pooled_h, pooled_w]
+  out_shape->clear();
+  out_shape->push_back(Shape4(bshape[0], dshape[1], param.pooled_size[0], param.pooled_size[1]));
+  return true;
+})
+.set_attr<nnvm::FInferType>("FInferType", [](const nnvm::NodeAttrs& attrs,
+      std::vector<int> *in_type, std::vector<int> *out_type) {
+  CHECK_EQ(in_type->size(), 2U);
+  int dtype = (*in_type)[0];
+  CHECK_EQ(dtype, (*in_type)[1]);
+  CHECK_NE(dtype, -1) << "Input must have specified type";
+
+  out_type->clear();
+  out_type->push_back(dtype);
+  return true;
+})
+.set_attr<FCompute>("FCompute<cpu>", RROIAlignForwardCompute<cpu>)
+.set_attr<nnvm::FGradient>("FGradient", MakeZeroGradNodes)
+.add_argument("data", "NDArray-or-Symbol", "Input data to the pooling operator, a 4D Feature maps")
+.add_argument("rois", "NDArray-or-Symbol", "Bounding box coordinates, a 2D array")
+.add_arguments(RROIAlignParam::__FIELDS__());
+
+}  // namespace op
+}  // namespace mxnet