source/PaddleOCR/deploy/lite/crnn_process.cc

// Copyright (c) 2020 PaddlePaddle Authors. All Rights Reserved.
//
// Licensed 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.

#include "crnn_process.h" //NOLINT
#include <algorithm>
#include <memory>
#include <string>

const std::vector<int> rec_image_shape{3, 32, 320};

cv::Mat CrnnResizeImg(cv::Mat img, float wh_ratio, int rec_image_height) {
  int imgC, imgH, imgW;
  imgC = rec_image_shape[0];
  imgH = rec_image_height;
  imgW = rec_image_shape[2];

  imgW = int(imgH * wh_ratio);

  float ratio = float(img.cols) / float(img.rows);
  int resize_w, resize_h;

  if (ceilf(imgH * ratio) > imgW)
    resize_w = imgW;
  else
    resize_w = int(ceilf(imgH * ratio));
  cv::Mat resize_img;
  cv::resize(img, resize_img, cv::Size(resize_w, imgH), 0.f, 0.f,
             cv::INTER_LINEAR);
  cv::copyMakeBorder(resize_img, resize_img, 0, 0, 0,
                     int(imgW - resize_img.cols), cv::BORDER_CONSTANT,
                     {127, 127, 127});
  return resize_img;
}

std::vector<std::string> ReadDict(std::string path) {
  std::ifstream in(path);
  std::string filename;
  std::string line;
  std::vector<std::string> m_vec;
  if (in) {
    while (getline(in, line)) {
      m_vec.push_back(line);
    }
  } else {
    std::cout << "no such file" << std::endl;
  }
  return m_vec;
}

cv::Mat GetRotateCropImage(cv::Mat srcimage,
                           std::vector<std::vector<int>> box) {
  cv::Mat image;
  srcimage.copyTo(image);
  std::vector<std::vector<int>> points = box;

  int x_collect[4] = {box[0][0], box[1][0], box[2][0], box[3][0]};
  int y_collect[4] = {box[0][1], box[1][1], box[2][1], box[3][1]};
  int left = int(*std::min_element(x_collect, x_collect + 4));
  int right = int(*std::max_element(x_collect, x_collect + 4));
  int top = int(*std::min_element(y_collect, y_collect + 4));
  int bottom = int(*std::max_element(y_collect, y_collect + 4));

  cv::Mat img_crop;
  image(cv::Rect(left, top, right - left, bottom - top)).copyTo(img_crop);

  for (int i = 0; i < points.size(); i++) {
    points[i][0] -= left;
    points[i][1] -= top;
  }

  int img_crop_width =
      static_cast<int>(sqrt(pow(points[0][0] - points[1][0], 2) +
                            pow(points[0][1] - points[1][1], 2)));
  int img_crop_height =
      static_cast<int>(sqrt(pow(points[0][0] - points[3][0], 2) +
                            pow(points[0][1] - points[3][1], 2)));

  cv::Point2f pts_std[4];
  pts_std[0] = cv::Point2f(0., 0.);
  pts_std[1] = cv::Point2f(img_crop_width, 0.);
  pts_std[2] = cv::Point2f(img_crop_width, img_crop_height);
  pts_std[3] = cv::Point2f(0.f, img_crop_height);

  cv::Point2f pointsf[4];
  pointsf[0] = cv::Point2f(points[0][0], points[0][1]);
  pointsf[1] = cv::Point2f(points[1][0], points[1][1]);
  pointsf[2] = cv::Point2f(points[2][0], points[2][1]);
  pointsf[3] = cv::Point2f(points[3][0], points[3][1]);

  cv::Mat M = cv::getPerspectiveTransform(pointsf, pts_std);

  cv::Mat dst_img;
  cv::warpPerspective(img_crop, dst_img, M,
                      cv::Size(img_crop_width, img_crop_height),
                      cv::BORDER_REPLICATE);

  const float ratio = 1.5;
  if (static_cast<float>(dst_img.rows) >=
      static_cast<float>(dst_img.cols) * ratio) {
    cv::Mat srcCopy = cv::Mat(dst_img.rows, dst_img.cols, dst_img.depth());
    cv::transpose(dst_img, srcCopy);
    cv::flip(srcCopy, srcCopy, 0);
    return srcCopy;
  } else {
    return dst_img;
  }
}