ocr_crnn_process.cpp

// 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 "ocr_crnn_process.h"
#include <cmath>
#include <cstring>
#include <fstream>
#include <iostream>
#include <iostream>
#include <vector>

const std::string CHARACTER_TYPE = "ch";
const int MAX_DICT_LENGTH = 6624;
//ch_PP-OCRv2
//const std::vector<int> REC_IMAGE_SHAPE = {3, 32, 320};
//ch_PP-OCRv3
const std::vector<int> REC_IMAGE_SHAPE = {3, 48, 320};

static cv::Mat crnn_resize_norm_img(cv::Mat img, float wh_ratio) {
  int imgC = REC_IMAGE_SHAPE[0];
  int imgW = REC_IMAGE_SHAPE[2];
  int imgH = REC_IMAGE_SHAPE[1];

  if (CHARACTER_TYPE == "ch")
    //ch_PP-OCRv2
    //imgW = int(32 * wh_ratio);
    //ch_PP-OCRv3
    imgW = int(48 * wh_ratio);

  float ratio = float(img.cols) / float(img.rows);
  int resize_w = 0;
  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_CUBIC);

  resize_img.convertTo(resize_img, CV_32FC3, 1 / 255.f);

  for (int h = 0; h < resize_img.rows; h++) {
    for (int w = 0; w < resize_img.cols; w++) {
      resize_img.at<cv::Vec3f>(h, w)[0] =
          (resize_img.at<cv::Vec3f>(h, w)[0] - 0.5) * 2;
      resize_img.at<cv::Vec3f>(h, w)[1] =
          (resize_img.at<cv::Vec3f>(h, w)[1] - 0.5) * 2;
      resize_img.at<cv::Vec3f>(h, w)[2] =
          (resize_img.at<cv::Vec3f>(h, w)[2] - 0.5) * 2;
    }
  }

  cv::Mat dist;
  cv::copyMakeBorder(resize_img, dist, 0, 0, 0, int(imgW - resize_w),
                     cv::BORDER_CONSTANT, {0, 0, 0});

  return dist;
}

cv::Mat crnn_resize_img(const cv::Mat &img, float wh_ratio) {
  int imgC = REC_IMAGE_SHAPE[0];
  int imgW = REC_IMAGE_SHAPE[2];
  int imgH = REC_IMAGE_SHAPE[1];

  if (CHARACTER_TYPE == "ch") {
    imgW = int(32 * wh_ratio);
  }

  float ratio = float(img.cols) / float(img.rows);
  int resize_w = 0;
  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));
  return resize_img;
}

cv::Mat get_rotate_crop_image(const cv::Mat &srcimage,
                              const std::vector<std::vector<int>> &box) {

  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;
  srcimage(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 = int(sqrt(pow(points[0][0] - points[1][0], 2) +
                                pow(points[0][1] - points[1][1], 2)));
  int img_crop_height = 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);

  if (float(dst_img.rows) >= float(dst_img.cols) * 1.5) {
    /*
    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;
    */
    cv::transpose(dst_img, dst_img);
    cv::flip(dst_img, dst_img, 0);
    return dst_img;
  } else {
    return dst_img;
  }
}