147 lines
4.0 KiB
Python
147 lines
4.0 KiB
Python
# copyright (c) 2022 PaddlePaddle Authors. All Rights Reserve.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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import numpy as np
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from shapely.geometry import Polygon
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def points2polygon(points):
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"""Convert k points to 1 polygon.
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Args:
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points (ndarray or list): A ndarray or a list of shape (2k)
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that indicates k points.
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Returns:
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polygon (Polygon): A polygon object.
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"""
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if isinstance(points, list):
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points = np.array(points)
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assert isinstance(points, np.ndarray)
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assert (points.size % 2 == 0) and (points.size >= 8)
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point_mat = points.reshape([-1, 2])
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return Polygon(point_mat)
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def poly_intersection(poly_det, poly_gt, buffer=0.0001):
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"""Calculate the intersection area between two polygon.
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Args:
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poly_det (Polygon): A polygon predicted by detector.
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poly_gt (Polygon): A gt polygon.
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Returns:
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intersection_area (float): The intersection area between two polygons.
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"""
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assert isinstance(poly_det, Polygon)
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assert isinstance(poly_gt, Polygon)
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if buffer == 0:
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poly_inter = poly_det & poly_gt
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else:
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poly_inter = poly_det.buffer(buffer) & poly_gt.buffer(buffer)
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return poly_inter.area, poly_inter
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def poly_union(poly_det, poly_gt):
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"""Calculate the union area between two polygon.
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Args:
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poly_det (Polygon): A polygon predicted by detector.
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poly_gt (Polygon): A gt polygon.
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Returns:
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union_area (float): The union area between two polygons.
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"""
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assert isinstance(poly_det, Polygon)
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assert isinstance(poly_gt, Polygon)
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area_det = poly_det.area
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area_gt = poly_gt.area
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area_inters, _ = poly_intersection(poly_det, poly_gt)
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return area_det + area_gt - area_inters
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def valid_boundary(x, with_score=True):
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num = len(x)
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if num < 8:
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return False
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if num % 2 == 0 and (not with_score):
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return True
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if num % 2 == 1 and with_score:
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return True
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return False
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def boundary_iou(src, target):
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"""Calculate the IOU between two boundaries.
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Args:
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src (list): Source boundary.
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target (list): Target boundary.
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Returns:
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iou (float): The iou between two boundaries.
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"""
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assert valid_boundary(src, False)
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assert valid_boundary(target, False)
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src_poly = points2polygon(src)
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target_poly = points2polygon(target)
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return poly_iou(src_poly, target_poly)
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def poly_iou(poly_det, poly_gt):
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"""Calculate the IOU between two polygons.
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Args:
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poly_det (Polygon): A polygon predicted by detector.
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poly_gt (Polygon): A gt polygon.
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Returns:
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iou (float): The IOU between two polygons.
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"""
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assert isinstance(poly_det, Polygon)
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assert isinstance(poly_gt, Polygon)
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area_inters, _ = poly_intersection(poly_det, poly_gt)
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area_union = poly_union(poly_det, poly_gt)
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if area_union == 0:
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return 0.0
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return area_inters / area_union
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def poly_nms(polygons, threshold):
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assert isinstance(polygons, list)
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polygons = np.array(sorted(polygons, key=lambda x: x[-1]))
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keep_poly = []
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index = [i for i in range(polygons.shape[0])]
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while len(index) > 0:
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keep_poly.append(polygons[index[-1]].tolist())
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A = polygons[index[-1]][:-1]
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index = np.delete(index, -1)
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iou_list = np.zeros((len(index), ))
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for i in range(len(index)):
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B = polygons[index[i]][:-1]
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iou_list[i] = boundary_iou(A, B)
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remove_index = np.where(iou_list > threshold)
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index = np.delete(index, remove_index)
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return keep_poly
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