125 lines
4.7 KiB
Python
125 lines
4.7 KiB
Python
import cv2
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from nonebot import logger
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import numpy as np
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from shapely.geometry import Polygon
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from shapely.ops import unary_union
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def fix_with_shapely(contours: list) -> np.ndarray:
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"""
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使用Shapely库处理复杂自相交
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"""
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fixed_polygons = []
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for contour in contours:
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# 转换输入为正确的格式
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contour_array = contour.reshape(-1, 2)
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# 转换为Shapely多边形
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polygon = Polygon(contour_array)
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if not polygon.is_valid:
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polygon = polygon.buffer(0)
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fixed_polygons.append(polygon)
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# 接下来把所有轮廓合并为一个
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if len(fixed_polygons) >= 1:
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merged_polygon = unary_union(fixed_polygons)
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if merged_polygon.geom_type == 'Polygon':
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merged_points = np.array(merged_polygon.exterior.coords, dtype=np.int32)
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elif merged_polygon.geom_type == 'MultiPolygon':
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largest = max(merged_polygon.geoms, key=lambda p: p.area)
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merged_points = np.array(largest.exterior.coords, dtype=np.int32)
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return [merged_points.reshape(-1, 1, 2)]
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else:
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logger.warning("No valid contours found after fixing with Shapely.")
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return [np.array([], dtype=np.int32).reshape(0, 1, 2)]
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def expand_contours(contours, stroke_width):
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"""
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将轮廓向外扩展指定宽度
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参数:
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contours: OpenCV轮廓列表
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stroke_width: 扩展宽度（像素）
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返回:
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扩展后的轮廓列表
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"""
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expanded_contours = []
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for cnt in contours:
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# 将轮廓转换为点列表
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points = cnt.reshape(-1, 2).astype(np.float32)
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n = len(points)
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if n < 3:
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continue # 至少需要3个点才能形成多边形
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expanded_points = []
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for i in range(n):
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# 获取当前点、前一个点和后一个点
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p_curr = points[i]
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p_prev = points[(i - 1) % n]
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p_next = points[(i + 1) % n]
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# 计算两条边的向量
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v1 = p_curr - p_prev # 前一条边（从prev到curr）
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v2 = p_next - p_curr # 后一条边（从curr到next）
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# 归一化
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norm1 = np.linalg.norm(v1)
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norm2 = np.linalg.norm(v2)
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if norm1 == 0 or norm2 == 0:
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# 如果有零向量，直接沿着法线方向扩展
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edge_dir = np.array([0, 0])
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if norm1 > 0:
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edge_dir = v1 / norm1
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elif norm2 > 0:
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edge_dir = v2 / norm2
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normal = np.array([-edge_dir[1], edge_dir[0]])
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expanded_point = p_curr + normal * stroke_width
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else:
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# 归一化向量
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v1_norm = v1 / norm1
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v2_norm = v2 / norm2
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# 计算两条边的单位法向量（指向多边形外部）
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n1 = np.array([-v1_norm[1], v1_norm[0]])
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n2 = np.array([-v2_norm[1], v2_norm[0]])
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# 计算角平分线方向（两个法向量的和）
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bisector = n1 + n2
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# 计算平分线的长度
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bisector_norm = np.linalg.norm(bisector)
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if bisector_norm == 0:
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# 如果两条边平行（同向或反向），取任一法线方向
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expanded_point = p_curr + n1 * stroke_width
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else:
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# 归一化平分线
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bisector_normalized = bisector / bisector_norm
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# 计算偏移距离（考虑夹角）
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# 使用余弦定理计算正确的偏移距离
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cos_angle = np.dot(v1_norm, v2_norm)
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angle = np.arccos(np.clip(cos_angle, -1.0, 1.0))
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if abs(np.pi - angle) < 1e-6: # 近似平角
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# 接近直线的情况
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offset_distance = stroke_width
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else:
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# 计算正确的偏移距离
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offset_distance = stroke_width / np.sin(angle / 2)
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# 计算扩展点
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expanded_point = p_curr + bisector_normalized * offset_distance
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expanded_points.append(expanded_point)
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# 将扩展后的点转换为整数坐标
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expanded_cnt = np.array(expanded_points, dtype=np.float32).reshape(-1, 1, 2)
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expanded_contours.append(expanded_cnt.astype(np.int32))
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expanded_contours = fix_with_shapely(expanded_contours)
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return expanded_contours |