PaddleOCR/ppocr/utils/e2e_utils/visual.py

# Copyright (c) 2021 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.
import numpy as np
import cv2
import time


def resize_image(im, max_side_len=512):
    """
    resize image to a size multiple of max_stride which is required by the network
    :param im: the resized image
    :param max_side_len: limit of max image size to avoid out of memory in gpu
    :return: the resized image and the resize ratio
    """
    h, w, _ = im.shape

    resize_w = w
    resize_h = h

    if resize_h > resize_w:
        ratio = float(max_side_len) / resize_h
    else:
        ratio = float(max_side_len) / 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
    im = cv2.resize(im, (int(resize_w), int(resize_h)))
    ratio_h = resize_h / float(h)
    ratio_w = resize_w / float(w)

    return im, (ratio_h, ratio_w)


def resize_image_min(im, max_side_len=512):
    """
    """
    h, w, _ = im.shape

    resize_w = w
    resize_h = h

    if resize_h < resize_w:
        ratio = float(max_side_len) / resize_h
    else:
        ratio = float(max_side_len) / 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
    im = cv2.resize(im, (int(resize_w), int(resize_h)))
    ratio_h = resize_h / float(h)
    ratio_w = resize_w / float(w)
    return im, (ratio_h, ratio_w)


def resize_image_for_totaltext(im, max_side_len=512):
    """
    """
    h, w, _ = im.shape

    resize_w = w
    resize_h = h
    ratio = 1.25
    if h * ratio > max_side_len:
        ratio = float(max_side_len) / resize_h

    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
    im = cv2.resize(im, (int(resize_w), int(resize_h)))
    ratio_h = resize_h / float(h)
    ratio_w = resize_w / float(w)
    return im, (ratio_h, ratio_w)


def point_pair2poly(point_pair_list):
    """
    Transfer vertical point_pairs into poly point in clockwise.
    """
    pair_length_list = []
    for point_pair in point_pair_list:
        pair_length = np.linalg.norm(point_pair[0] - point_pair[1])
        pair_length_list.append(pair_length)
    pair_length_list = np.array(pair_length_list)
    pair_info = (pair_length_list.max(), pair_length_list.min(),
                 pair_length_list.mean())

    point_num = len(point_pair_list) * 2
    point_list = [0] * point_num
    for idx, point_pair in enumerate(point_pair_list):
        point_list[idx] = point_pair[0]
        point_list[point_num - 1 - idx] = point_pair[1]
    return np.array(point_list).reshape(-1, 2), pair_info


def shrink_quad_along_width(quad, begin_width_ratio=0., end_width_ratio=1.):
    """
    Generate shrink_quad_along_width.
    """
    ratio_pair = np.array(
        [[begin_width_ratio], [end_width_ratio]], dtype=np.float32)
    p0_1 = quad[0] + (quad[1] - quad[0]) * ratio_pair
    p3_2 = quad[3] + (quad[2] - quad[3]) * ratio_pair
    return np.array([p0_1[0], p0_1[1], p3_2[1], p3_2[0]])


def expand_poly_along_width(poly, shrink_ratio_of_width=0.3):
    """
    expand poly along width.
    """
    point_num = poly.shape[0]
    left_quad = np.array(
        [poly[0], poly[1], poly[-2], poly[-1]], dtype=np.float32)
    left_ratio = -shrink_ratio_of_width * np.linalg.norm(left_quad[0] - left_quad[3]) / \
                 (np.linalg.norm(left_quad[0] - left_quad[1]) + 1e-6)
    left_quad_expand = shrink_quad_along_width(left_quad, left_ratio, 1.0)
    right_quad = np.array(
        [
            poly[point_num // 2 - 2], poly[point_num // 2 - 1],
            poly[point_num // 2], poly[point_num // 2 + 1]
        ],
        dtype=np.float32)
    right_ratio = 1.0 + \
                  shrink_ratio_of_width * np.linalg.norm(right_quad[0] - right_quad[3]) / \
                  (np.linalg.norm(right_quad[0] - right_quad[1]) + 1e-6)
    right_quad_expand = shrink_quad_along_width(right_quad, 0.0, right_ratio)
    poly[0] = left_quad_expand[0]
    poly[-1] = left_quad_expand[-1]
    poly[point_num // 2 - 1] = right_quad_expand[1]
    poly[point_num // 2] = right_quad_expand[2]
    return poly


def norm2(x, axis=None):
    if axis:
        return np.sqrt(np.sum(x**2, axis=axis))
    return np.sqrt(np.sum(x**2))


def cos(p1, p2):
    return (p1 * p2).sum() / (norm2(p1) * norm2(p2))