PaddleX/paddlex/modules/text_detection/predictor/transforms.py

# copyright (c) 2024 PaddlePaddle Authors. All Rights Reserve.
# 
# 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.


import os
import sys
import cv2
import copy
import math
import pyclipper
import numpy as np
from PIL import Image
from shapely.geometry import Polygon

from ....utils import logging
from ...base.predictor.io.writers import ImageWriter
from ...base.predictor.io.readers import ImageReader
from ...base.predictor import BaseTransform
from .keys import TextDetKeys as K

__all__ = [
    'DetResizeForTest', 'NormalizeImage', 'DBPostProcess', 'SaveTextDetResults'
]


class DetResizeForTest(BaseTransform):
    """ DetResizeForTest """

    def __init__(self, **kwargs):
        super(DetResizeForTest, self).__init__()
        self.resize_type = 0
        self.keep_ratio = False
        if 'image_shape' in kwargs:
            self.image_shape = kwargs['image_shape']
            self.resize_type = 1
            if 'keep_ratio' in kwargs:
                self.keep_ratio = kwargs['keep_ratio']
        elif 'limit_side_len' in kwargs:
            self.limit_side_len = kwargs['limit_side_len']
            self.limit_type = kwargs.get('limit_type', 'min')
        elif 'resize_long' in kwargs:
            self.resize_type = 2
            self.resize_long = kwargs.get('resize_long', 960)
        else:
            self.limit_side_len = 736
            self.limit_type = 'min'

    def apply(self, data):
        """ apply """
        img = data[K.IMAGE]
        src_h, src_w, _ = img.shape
        if sum([src_h, src_w]) < 64:
            img = self.image_padding(img)

        if self.resize_type == 0:
            # img, shape = self.resize_image_type0(img)
            img, [ratio_h, ratio_w] = self.resize_image_type0(img)
        elif self.resize_type == 2:
            img, [ratio_h, ratio_w] = self.resize_image_type2(img)
        else:
            # img, shape = self.resize_image_type1(img)
            img, [ratio_h, ratio_w] = self.resize_image_type1(img)
        data[K.IMAGE] = img
        data[K.SHAPE] = np.array([src_h, src_w, ratio_h, ratio_w])
        return data

    @classmethod
    def get_input_keys(cls):
        """ get input keys """

        return [K.IMAGE]

    @classmethod
    def get_output_keys(cls):
        """ get output keys """

        return [K.IMAGE, K.SHAPE]

    def image_padding(self, im, value=0):
        """ padding image """
        h, w, c = im.shape
        im_pad = np.zeros((max(32, h), max(32, w), c), np.uint8) + value
        im_pad[:h, :w, :] = im
        return im_pad

    def resize_image_type1(self, img):
        """ resize the image """
        resize_h, resize_w = self.image_shape
        ori_h, ori_w = img.shape[:2]  # (h, w, c)
        if self.keep_ratio is True:
            resize_w = ori_w * resize_h / ori_h
            N = math.ceil(resize_w / 32)
            resize_w = N * 32
        ratio_h = float(resize_h) / ori_h
        ratio_w = float(resize_w) / ori_w
        img = cv2.resize(img, (int(resize_w), int(resize_h)))
        # return img, np.array([ori_h, ori_w])
        return img, [ratio_h, ratio_w]

    def resize_image_type0(self, img):
        """
        resize image to a size multiple of 32 which is required by the network
        args:
            img(array): array with shape [h, w, c]
        return(tuple):
            img, (ratio_h, ratio_w)
        """
        limit_side_len = self.limit_side_len
        h, w, c = img.shape

        # limit the max side
        if self.limit_type == 'max':
            if max(h, w) > limit_side_len:
                if h > w:
                    ratio = float(limit_side_len) / h
                else:
                    ratio = float(limit_side_len) / w
            else:
                ratio = 1.
        elif self.limit_type == 'min':
            if min(h, w) < limit_side_len:
                if h < w:
                    ratio = float(limit_side_len) / h
                else:
                    ratio = float(limit_side_len) / w
            else:
                ratio = 1.
        elif self.limit_type == 'resize_long':
            ratio = float(limit_side_len) / max(h, w)
        else:
            raise Exception('not support limit type, image ')
        resize_h = int(h * ratio)
        resize_w = int(w * ratio)

        resize_h = max(int(round(resize_h / 32) * 32), 32)
        resize_w = max(int(round(resize_w / 32) * 32), 32)

        try:
            if int(resize_w) <= 0 or int(resize_h) <= 0:
                return None, (None, None)
            img = cv2.resize(img, (int(resize_w), int(resize_h)))
        except:
            logging.info(img.shape, resize_w, resize_h)
            sys.exit(0)
        ratio_h = resize_h / float(h)
        ratio_w = resize_w / float(w)
        return img, [ratio_h, ratio_w]

    def resize_image_type2(self, img):
        """ resize image size """
        h, w, _ = img.shape

        resize_w = w
        resize_h = h

        if resize_h > resize_w:
            ratio = float(self.resize_long) / resize_h
        else:
            ratio = float(self.resize_long) / resize_w

        resize_h = int(resize_h * ratio)
        resize_w = int(resize_w * ratio)

        max_stride = 128
        resize_h = (resize_h + max_stride - 1) // max_stride * max_stride
        resize_w = (resize_w + max_stride - 1) // max_stride * max_stride
        img = cv2.resize(img, (int(resize_w), int(resize_h)))
        ratio_h = resize_h / float(h)
        ratio_w = resize_w / float(w)

        return img, [ratio_h, ratio_w]


class NormalizeImage(BaseTransform):
    """ normalize image such as substract mean, divide std
    """

    def __init__(self, scale=None, mean=None, std=None, order='chw', **kwargs):
        if isinstance(scale, str):
            scale = eval(scale)
        self.scale = np.float32(scale if scale is not None else 1.0 / 255.0)
        mean = mean if mean is not None else [0.485, 0.456, 0.406]
        std = std if std is not None else [0.229, 0.224, 0.225]

        shape = (3, 1, 1) if order == 'chw' else (1, 1, 3)
        self.mean = np.array(mean).reshape(shape).astype('float32')
        self.std = np.array(std).reshape(shape).astype('float32')

    def apply(self, data):
        """ apply """
        img = data[K.IMAGE]
        from PIL import Image
        if isinstance(img, Image.Image):
            img = np.array(img)
        assert isinstance(img,
                          np.ndarray), "invalid input 'img' in NormalizeImage"
        data[K.IMAGE] = (
            img.astype('float32') * self.scale - self.mean) / self.std
        return data

    @classmethod
    def get_input_keys(cls):
        """ get input keys """
        return [K.IMAGE]

    @classmethod
    def get_output_keys(cls):
        """ get output keys """
        return [K.IMAGE]


class DBPostProcess(BaseTransform):
    """
    The post process for Differentiable Binarization (DB).
    """

    def __init__(self,
                 thresh=0.3,
                 box_thresh=0.7,
                 max_candidates=1000,
                 unclip_ratio=2.0,
                 use_dilation=False,
                 score_mode="fast",
                 box_type='quad',
                 **kwargs):
        self.thresh = thresh
        self.box_thresh = box_thresh
        self.max_candidates = max_candidates
        self.unclip_ratio = unclip_ratio
        self.min_size = 3
        self.score_mode = score_mode
        self.box_type = box_type
        assert score_mode in [
            "slow", "fast"
        ], "Score mode must be in [slow, fast] but got: {}".format(score_mode)

        self.dilation_kernel = None if not use_dilation else np.array([[1, 1],
                                                                       [1, 1]])

    def polygons_from_bitmap(self, pred, _bitmap, dest_width, dest_height):
        """ _bitmap: single map with shape (1, H, W), whose values are binarized as {0, 1} """

        bitmap = _bitmap
        height, width = bitmap.shape

        boxes = []
        scores = []

        contours, _ = cv2.findContours((bitmap * 255).astype(np.uint8),
                                       cv2.RETR_LIST, cv2.CHAIN_APPROX_SIMPLE)

        for contour in contours[:self.max_candidates]:
            epsilon = 0.002 * cv2.arcLength(contour, True)
            approx = cv2.approxPolyDP(contour, epsilon, True)
            points = approx.reshape((-1, 2))
            if points.shape[0] < 4:
                continue

            score = self.box_score_fast(pred, points.reshape(-1, 2))
            if self.box_thresh > score:
                continue

            if points.shape[0] > 2:
                box = self.unclip(points, self.unclip_ratio)
                if len(box) > 1:
                    continue
            else:
                continue
            box = box.reshape(-1, 2)

            _, sside = self.get_mini_boxes(box.reshape((-1, 1, 2)))
            if sside < self.min_size + 2:
                continue

            box = np.array(box)
            box[:, 0] = np.clip(
                np.round(box[:, 0] / width * dest_width), 0, dest_width)
            box[:, 1] = np.clip(
                np.round(box[:, 1] / height * dest_height), 0, dest_height)
            boxes.append(box.tolist())
            scores.append(score)
        return boxes, scores

    def boxes_from_bitmap(self, pred, _bitmap, dest_width, dest_height):
        """ _bitmap: single map with shape (1, H, W), whose values are binarized as {0, 1} """

        bitmap = _bitmap
        height, width = bitmap.shape

        outs = cv2.findContours((bitmap * 255).astype(np.uint8), cv2.RETR_LIST,
                                cv2.CHAIN_APPROX_SIMPLE)
        if len(outs) == 3:
            img, contours, _ = outs[0], outs[1], outs[2]
        elif len(outs) == 2:
            contours, _ = outs[0], outs[1]

        num_contours = min(len(contours), self.max_candidates)

        boxes = []
        scores = []
        for index in range(num_contours):
            contour = contours[index]
            points, sside = self.get_mini_boxes(contour)
            if sside < self.min_size:
                continue
            points = np.array(points)
            if self.score_mode == "fast":
                score = self.box_score_fast(pred, points.reshape(-1, 2))
            else:
                score = self.box_score_slow(pred, contour)
            if self.box_thresh > score:
                continue

            box = self.unclip(points, self.unclip_ratio).reshape(-1, 1, 2)
            box, sside = self.get_mini_boxes(box)
            if sside < self.min_size + 2:
                continue
            box = np.array(box)

            box[:, 0] = np.clip(
                np.round(box[:, 0] / width * dest_width), 0, dest_width)
            box[:, 1] = np.clip(
                np.round(box[:, 1] / height * dest_height), 0, dest_height)
            boxes.append(box.astype(np.int16))
            scores.append(score)
        return np.array(boxes, dtype=np.int16), scores

    def unclip(self, box, unclip_ratio):
        """ unclip """
        poly = Polygon(box)
        distance = poly.area * unclip_ratio / poly.length
        offset = pyclipper.PyclipperOffset()
        offset.AddPath(box, pyclipper.JT_ROUND, pyclipper.ET_CLOSEDPOLYGON)
        expanded = np.array(offset.Execute(distance))
        return expanded

    def get_mini_boxes(self, contour):
        """ get mini boxes """
        bounding_box = cv2.minAreaRect(contour)
        points = sorted(list(cv2.boxPoints(bounding_box)), key=lambda x: x[0])

        index_1, index_2, index_3, index_4 = 0, 1, 2, 3
        if points[1][1] > points[0][1]:
            index_1 = 0
            index_4 = 1
        else:
            index_1 = 1
            index_4 = 0
        if points[3][1] > points[2][1]:
            index_2 = 2
            index_3 = 3
        else:
            index_2 = 3
            index_3 = 2

        box = [
            points[index_1], points[index_2], points[index_3], points[index_4]
        ]
        return box, min(bounding_box[1])

    def box_score_fast(self, bitmap, _box):
        """ box_score_fast: use bbox mean score as the mean score """
        h, w = bitmap.shape[:2]
        box = _box.copy()
        xmin = np.clip(np.floor(box[:, 0].min()).astype("int"), 0, w - 1)
        xmax = np.clip(np.ceil(box[:, 0].max()).astype("int"), 0, w - 1)
        ymin = np.clip(np.floor(box[:, 1].min()).astype("int"), 0, h - 1)
        ymax = np.clip(np.ceil(box[:, 1].max()).astype("int"), 0, h - 1)

        mask = np.zeros((ymax - ymin + 1, xmax - xmin + 1), dtype=np.uint8)
        box[:, 0] = box[:, 0] - xmin
        box[:, 1] = box[:, 1] - ymin
        cv2.fillPoly(mask, box.reshape(1, -1, 2).astype(np.int32), 1)
        return cv2.mean(bitmap[ymin:ymax + 1, xmin:xmax + 1], mask)[0]

    def box_score_slow(self, bitmap, contour):
        """ box_score_slow: use polyon mean score as the mean score """
        h, w = bitmap.shape[:2]
        contour = contour.copy()
        contour = np.reshape(contour, (-1, 2))

        xmin = np.clip(np.min(contour[:, 0]), 0, w - 1)
        xmax = np.clip(np.max(contour[:, 0]), 0, w - 1)
        ymin = np.clip(np.min(contour[:, 1]), 0, h - 1)
        ymax = np.clip(np.max(contour[:, 1]), 0, h - 1)

        mask = np.zeros((ymax - ymin + 1, xmax - xmin + 1), dtype=np.uint8)

        contour[:, 0] = contour[:, 0] - xmin
        contour[:, 1] = contour[:, 1] - ymin

        cv2.fillPoly(mask, contour.reshape(1, -1, 2).astype(np.int32), 1)
        return cv2.mean(bitmap[ymin:ymax + 1, xmin:xmax + 1], mask)[0]

    def apply(self, data):
        """ apply """
        pred = data[K.PROB_MAP]
        shape_list = [data[K.SHAPE]]
        pred = pred[0][:, 0, :, :]
        segmentation = pred > self.thresh

        boxes_batch = []
        for batch_index in range(pred.shape[0]):
            src_h, src_w, ratio_h, ratio_w = shape_list[batch_index]
            if self.dilation_kernel is not None:
                mask = cv2.dilate(
                    np.array(segmentation[batch_index]).astype(np.uint8),
                    self.dilation_kernel)
            else:
                mask = segmentation[batch_index]
            if self.box_type == 'poly':
                boxes, scores = self.polygons_from_bitmap(pred[batch_index],
                                                          mask, src_w, src_h)
            elif self.box_type == 'quad':
                boxes, scores = self.boxes_from_bitmap(pred[batch_index], mask,
                                                       src_w, src_h)
            else:
                raise ValueError("box_type can only be one of ['quad', 'poly']")

            data[K.DT_POLYS] = boxes
            data[K.DT_SCORES] = scores

        return data

    @classmethod
    def get_input_keys(cls):
        """ get input keys """
        return [K.PROB_MAP]

    @classmethod
    def get_output_keys(cls):
        """ get output keys """
        return [K.DT_POLYS, K.DT_SCORES]


class CropByPolys(BaseTransform):
    """Crop Image by Polys
    """

    def __init__(self, det_box_type='quad'):
        super().__init__()
        self.det_box_type = det_box_type

    def apply(self, data):
        """ apply """
        ori_im = data[K.ORI_IM]
        # TODO
        # dt_boxes = self.sorted_boxes(data[K.DT_POLYS])
        dt_boxes = np.array(data[K.DT_POLYS])
        img_crop_list = []
        for bno in range(len(dt_boxes)):
            tmp_box = copy.deepcopy(dt_boxes[bno])
            if self.det_box_type == "quad":
                img_crop = self.get_rotate_crop_image(ori_im, tmp_box)
            else:
                img_crop = self.get_minarea_rect_crop(ori_im, tmp_box)
            img_crop_list.append(img_crop)
        data[K.SUB_IMGS] = img_crop_list
        return data

    @classmethod
    def get_input_keys(cls):
        """ get input keys """
        return [K.IM_PATH, K.DT_POLYS]

    @classmethod
    def get_output_keys(cls):
        """ get output keys """
        return [K.SUB_IMGS]

    def sorted_boxes(self, dt_boxes):
        """
        Sort text boxes in order from top to bottom, left to right
        args:
            dt_boxes(array):detected text boxes with shape [4, 2]
        return:
            sorted boxes(array) with shape [4, 2]
        """
        dt_boxes = np.array(dt_boxes)
        num_boxes = dt_boxes.shape[0]
        sorted_boxes = sorted(dt_boxes, key=lambda x: (x[0][1], x[0][0]))
        _boxes = list(sorted_boxes)

        for i in range(num_boxes - 1):
            for j in range(i, -1, -1):
                if abs(_boxes[j + 1][0][1] - _boxes[j][0][1]) < 10 and (
                        _boxes[j + 1][0][0] < _boxes[j][0][0]):
                    tmp = _boxes[j]
                    _boxes[j] = _boxes[j + 1]
                    _boxes[j + 1] = tmp
                else:
                    break
        return _boxes

    def get_minarea_rect_crop(self, img, points):
        """get_minarea_rect_crop
        """
        bounding_box = cv2.minAreaRect(np.array(points).astype(np.int32))
        points = sorted(list(cv2.boxPoints(bounding_box)), key=lambda x: x[0])

        index_a, index_b, index_c, index_d = 0, 1, 2, 3
        if points[1][1] > points[0][1]:
            index_a = 0
            index_d = 1
        else:
            index_a = 1
            index_d = 0
        if points[3][1] > points[2][1]:
            index_b = 2
            index_c = 3
        else:
            index_b = 3
            index_c = 2

        box = [
            points[index_a], points[index_b], points[index_c], points[index_d]
        ]
        crop_img = self.get_rotate_crop_image(img, np.array(box))
        return crop_img

    def get_rotate_crop_image(self, img, points):
        """
        img_height, img_width = img.shape[0:2]
        left = int(np.min(points[:, 0]))
        right = int(np.max(points[:, 0]))
        top = int(np.min(points[:, 1]))
        bottom = int(np.max(points[:, 1]))
        img_crop = img[top:bottom, left:right, :].copy()
        points[:, 0] = points[:, 0] - left
        points[:, 1] = points[:, 1] - top
        """
        assert len(points) == 4, "shape of points must be 4*2"
        img_crop_width = int(
            max(
                np.linalg.norm(points[0] - points[1]),
                np.linalg.norm(points[2] - points[3])))
        img_crop_height = int(
            max(
                np.linalg.norm(points[0] - points[3]),
                np.linalg.norm(points[1] - points[2])))
        pts_std = np.float32([
            [0, 0],
            [img_crop_width, 0],
            [img_crop_width, img_crop_height],
            [0, img_crop_height],
        ])
        M = cv2.getPerspectiveTransform(points, pts_std)
        dst_img = cv2.warpPerspective(
            img,
            M,
            (img_crop_width, img_crop_height),
            borderMode=cv2.BORDER_REPLICATE,
            flags=cv2.INTER_CUBIC, )
        dst_img_height, dst_img_width = dst_img.shape[0:2]
        if dst_img_height * 1.0 / dst_img_width >= 1.5:
            dst_img = np.rot90(dst_img)
        return dst_img


class SaveTextDetResults(BaseTransform):
    """ Save Text Det Results """
    _DEFAULT_FILE_NAME = 'text_det_out.png'

    def __init__(self, save_dir, file_name=None):
        super().__init__()
        self.save_dir = save_dir
        if file_name is None:
            file_name = self._DEFAULT_FILE_NAME
        self.file_name = file_name
        # We use pillow backend to save both numpy arrays and PIL Image objects
        self._writer = ImageWriter(backend='opencv')

    def apply(self, data):
        """ apply """
        if self.save_dir is None:
            logging.warning(
                "The `save_dir` has been set to None, so the text detection result won't to be saved."
            )
            return data
        save_path = os.path.join(self.save_dir, self.file_name)
        bbox_res = data[K.DT_POLYS]
        vis_img = self.draw_rectangle(data[K.IM_PATH], bbox_res)
        self._writer.write(save_path, vis_img)
        return data

    @classmethod
    def get_input_keys(cls):
        """ get input keys """
        return [K.IM_PATH, K.DT_POLYS, K.DT_SCORES]

    @classmethod
    def get_output_keys(cls):
        """ get output keys """
        return []

    def draw_rectangle(self, img_path, boxes):
        """ draw rectangle """
        boxes = np.array(boxes)
        img = cv2.imread(img_path)
        img_show = img.copy()
        for box in boxes.astype(int):
            box = np.reshape(np.array(box), [-1, 1, 2]).astype(np.int64)
            cv2.polylines(img_show, [box], True, (0, 0, 255), 2)
        return img_show