242 lines
7.2 KiB
Python
242 lines
7.2 KiB
Python
from typing import List
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import cv2
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import numpy as np
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def projection_by_bboxes(boxes: np.array, axis: int) -> np.ndarray:
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"""
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通过一组 bbox 获得投影直方图，最后以 per-pixel 形式输出
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Args:
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boxes: [N, 4]
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axis: 0-x坐标向水平方向投影， 1-y坐标向垂直方向投影
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Returns:
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1D 投影直方图，长度为投影方向坐标的最大值(我们不需要图片的实际边长，因为只是要找文本框的间隔)
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"""
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assert axis in [0, 1]
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length = np.max(boxes[:, axis::2])
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res = np.zeros(length, dtype=int)
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# TODO: how to remove for loop?
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for start, end in boxes[:, axis::2]:
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res[start:end] += 1
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return res
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# from: https://dothinking.github.io/2021-06-19-%E9%80%92%E5%BD%92%E6%8A%95%E5%BD%B1%E5%88%86%E5%89%B2%E7%AE%97%E6%B3%95/#:~:text=%E9%80%92%E5%BD%92%E6%8A%95%E5%BD%B1%E5%88%86%E5%89%B2%EF%BC%88Recursive%20XY,%EF%BC%8C%E5%8F%AF%E4%BB%A5%E5%88%92%E5%88%86%E6%AE%B5%E8%90%BD%E3%80%81%E8%A1%8C%E3%80%82
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def split_projection_profile(arr_values: np.array, min_value: float, min_gap: float):
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"""Split projection profile:
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```
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┌──┐
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arr_values │ │ ┌─┐───
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┌──┐ │ │ │ │ |
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│ │ │ │ ┌───┐ │ │min_value
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│ │<- min_gap ->│ │ │ │ │ │ |
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────┴──┴─────────────┴──┴─┴───┴─┴─┴─┴───
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0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
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```
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Args:
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arr_values (np.array): 1-d array representing the projection profile.
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min_value (float): Ignore the profile if `arr_value` is less than `min_value`.
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min_gap (float): Ignore the gap if less than this value.
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Returns:
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tuple: Start indexes and end indexes of split groups.
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"""
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# all indexes with projection height exceeding the threshold
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arr_index = np.where(arr_values > min_value)[0]
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if not len(arr_index):
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return
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# find zero intervals between adjacent projections
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# | | ||
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# ||||<- zero-interval -> |||||
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arr_diff = arr_index[1:] - arr_index[0:-1]
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arr_diff_index = np.where(arr_diff > min_gap)[0]
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arr_zero_intvl_start = arr_index[arr_diff_index]
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arr_zero_intvl_end = arr_index[arr_diff_index + 1]
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# convert to index of projection range:
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# the start index of zero interval is the end index of projection
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arr_start = np.insert(arr_zero_intvl_end, 0, arr_index[0])
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arr_end = np.append(arr_zero_intvl_start, arr_index[-1])
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arr_end += 1 # end index will be excluded as index slice
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return arr_start, arr_end
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def recursive_xy_cut(boxes: np.ndarray, indices: List[int], res: List[int]):
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"""
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Args:
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boxes: (N, 4)
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indices: 递归过程中始终表示 box 在原始数据中的索引
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res: 保存输出结果
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"""
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# 向 y 轴投影
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assert len(boxes) == len(indices)
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_indices = boxes[:, 1].argsort()
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y_sorted_boxes = boxes[_indices]
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y_sorted_indices = indices[_indices]
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# debug_vis(y_sorted_boxes, y_sorted_indices)
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y_projection = projection_by_bboxes(boxes=y_sorted_boxes, axis=1)
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pos_y = split_projection_profile(y_projection, 0, 1)
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if not pos_y:
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return
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arr_y0, arr_y1 = pos_y
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for r0, r1 in zip(arr_y0, arr_y1):
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# [r0, r1] 表示按照水平切分，有 bbox 的区域，对这些区域会再进行垂直切分
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_indices = (r0 <= y_sorted_boxes[:, 1]) & (y_sorted_boxes[:, 1] < r1)
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y_sorted_boxes_chunk = y_sorted_boxes[_indices]
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y_sorted_indices_chunk = y_sorted_indices[_indices]
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_indices = y_sorted_boxes_chunk[:, 0].argsort()
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x_sorted_boxes_chunk = y_sorted_boxes_chunk[_indices]
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x_sorted_indices_chunk = y_sorted_indices_chunk[_indices]
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# 往 x 方向投影
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x_projection = projection_by_bboxes(boxes=x_sorted_boxes_chunk, axis=0)
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pos_x = split_projection_profile(x_projection, 0, 1)
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if not pos_x:
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continue
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arr_x0, arr_x1 = pos_x
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if len(arr_x0) == 1:
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# x 方向无法切分
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res.extend(x_sorted_indices_chunk)
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continue
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# x 方向上能分开，继续递归调用
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for c0, c1 in zip(arr_x0, arr_x1):
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_indices = (c0 <= x_sorted_boxes_chunk[:, 0]) & (
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x_sorted_boxes_chunk[:, 0] < c1
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)
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recursive_xy_cut(
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x_sorted_boxes_chunk[_indices], x_sorted_indices_chunk[_indices], res
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)
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def points_to_bbox(points):
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assert len(points) == 8
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# [x1,y1,x2,y2,x3,y3,x4,y4]
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left = min(points[::2])
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right = max(points[::2])
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top = min(points[1::2])
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bottom = max(points[1::2])
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left = max(left, 0)
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top = max(top, 0)
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right = max(right, 0)
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bottom = max(bottom, 0)
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return [left, top, right, bottom]
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def bbox2points(bbox):
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left, top, right, bottom = bbox
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return [left, top, right, top, right, bottom, left, bottom]
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def vis_polygon(img, points, thickness=2, color=None):
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br2bl_color = color
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tl2tr_color = color
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tr2br_color = color
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bl2tl_color = color
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cv2.line(
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img,
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(points[0][0], points[0][1]),
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(points[1][0], points[1][1]),
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color=tl2tr_color,
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thickness=thickness,
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)
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cv2.line(
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img,
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(points[1][0], points[1][1]),
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(points[2][0], points[2][1]),
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color=tr2br_color,
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thickness=thickness,
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)
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cv2.line(
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img,
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(points[2][0], points[2][1]),
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(points[3][0], points[3][1]),
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color=br2bl_color,
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thickness=thickness,
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)
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cv2.line(
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img,
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(points[3][0], points[3][1]),
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(points[0][0], points[0][1]),
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color=bl2tl_color,
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thickness=thickness,
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)
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return img
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def vis_points(
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img: np.ndarray, points, texts: List[str] = None, color=(0, 200, 0)
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) -> np.ndarray:
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"""
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Args:
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img:
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points: [N, 8] 8: x1,y1,x2,y2,x3,y3,x3,y4
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texts:
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color:
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Returns:
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"""
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points = np.array(points)
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if texts is not None:
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assert len(texts) == points.shape[0]
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for i, _points in enumerate(points):
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vis_polygon(img, _points.reshape(-1, 2), thickness=2, color=color)
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bbox = points_to_bbox(_points)
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left, top, right, bottom = bbox
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cx = (left + right) // 2
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cy = (top + bottom) // 2
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txt = texts[i]
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font = cv2.FONT_HERSHEY_SIMPLEX
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cat_size = cv2.getTextSize(txt, font, 0.5, 2)[0]
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img = cv2.rectangle(
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img,
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(cx - 5 * len(txt), cy - cat_size[1] - 5),
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(cx - 5 * len(txt) + cat_size[0], cy - 5),
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color,
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-1,
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)
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img = cv2.putText(
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img,
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txt,
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(cx - 5 * len(txt), cy - 5),
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font,
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0.5,
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(255, 255, 255),
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thickness=1,
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lineType=cv2.LINE_AA,
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)
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return img
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def vis_polygons_with_index(image, points):
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texts = [str(i) for i in range(len(points))]
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res_img = vis_points(image.copy(), points, texts)
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return res_img |