101 lines
3.1 KiB
Python
101 lines
3.1 KiB
Python
import cv2
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import numpy as np
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def get_bounding_box(image_input):
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"""
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从阈值化图像中提取最小外接矩形，返回四个角点坐标（顺时针）
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参数
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----
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image_input : 图像文件路径或图像数组
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"""
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if isinstance(image_input, str):
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# 如果是文件路径
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image = cv2.imread(image_input, cv2.IMREAD_GRAYSCALE)
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if image is None:
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raise FileNotFoundError(f"图像文件 {image_input} 未找到")
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else:
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# 如果是图像数组
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image = cv2.cvtColor(image_input, cv2.COLOR_BGR2GRAY) if image_input.ndim == 3 else image_input.copy()
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coords = np.argwhere(image > 0)
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if coords.size == 0:
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raise ValueError("图像中没有非零像素，无法计算外接矩形")
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ymin, xmin = coords.min(axis=0)
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ymax, xmax = coords.max(axis=0)
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# 返回四个角点（顺时针）
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return (xmin, ymin), (xmax, ymin), (xmax, ymax), (xmin, ymax)
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def get_line_equation(p1, p2):
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"""
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给定两点 (p1, p2)，返回直线方程：
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- 垂直线: (None, x_const, y1, y2)
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- 水平线: (0, y_const, x1, x2)
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- 斜率线: (a, b, x1, x2) 对应 y = ax + b，范围 [x1, x2]
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"""
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if p2[0] == p1[0]: # 垂直线
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return None, p1[0], p1[1], p2[1]
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elif p2[1] == p1[1]: # 水平线
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return 0, p1[1], p1[0], p2[0]
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else:
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a = (p2[1] - p1[1]) / (p2[0] - p1[0])
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b = p1[1] - a * p1[0]
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return a, b, p1[0], p2[0]
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def calculate_lines(top_left, top_right, bottom_right, bottom_left):
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"""
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返回外接矩形四条边的线性表达式
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"""
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top_line = get_line_equation(top_left, top_right)
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right_line = get_line_equation(top_right, bottom_right)
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bottom_line = get_line_equation(bottom_right, bottom_left)
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left_line = get_line_equation(bottom_left, top_left)
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return top_line, right_line, bottom_line, left_line
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def apply_morphology(gray,
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kernel_size=(5, 5),
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erode_iter=3,
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dilate_iter=3):
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"""
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对灰度图执行"腐蚀 → 膨胀"去噪声并返回处理后的结果。
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参数
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----
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gray : np.ndarray，灰度图 (H, W)
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kernel_size : structuring element 尺寸
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erode_iter : 腐蚀迭代次数
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dilate_iter : 膨胀迭代次数
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"""
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kernel = cv2.getStructuringElement(cv2.MORPH_RECT, kernel_size)
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out = cv2.erode(gray, kernel, iterations=erode_iter)
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out = cv2.dilate(out, kernel, iterations=dilate_iter)
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return out
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def perpendicular_foot(pt, line_info):
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"""
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计算点 pt 到指定直线 line_info 的垂足坐标。
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pt : (x0, y0)
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line_info : get_line_equation() 的返回值
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"""
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x0, y0 = pt
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if line_info[0] is None: # 垂直线 x = const
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return int(line_info[1]), int(y0)
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if line_info[0] == 0: # 水平线 y = const
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return int(x0), int(line_info[1])
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a, b, *_ = line_info # 斜率线 y = ax + b
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xf = (x0 + a * (y0 - b)) / (1 + a**2)
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yf = a * xf + b
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return int(round(xf)), int(round(yf))
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