去除分叉轮廓

去除分叉轮廓

思路来源于https://blog.youkuaiyun.com/weixin_39639550/article/details/111624935，但是使用不同的方法进行实现，实际测试发现仅对特定轮廓有效，不具有通用性，仅供参考。

示例代码

import numpy as np
import cv2
from copy import deepcopy

def get_contour_remove_fork(mask_path):
    mask = cv2.imread(mask_path, 0)
    # 找到轮廓
    contours, _ = cv2.findContours(mask, cv2.RETR_TREE, cv2.CHAIN_APPROX_SIMPLE)
    mask_convex = deepcopy(mask)
    # 遍历所有轮廓
    for contour in contours:
        # 计算轮廓的凸包
        hull = cv2.convexHull(contour)

        # 可以选择绘制凸包
        mask_convex = cv2.drawContours(
            mask_convex, [hull], -1, 
            255, -1
        )
    
    mask_convex_remove_raw_contour = deepcopy(mask_convex)
    mask_convex_remove_raw_contour[mask == 255] = 0
    # 腐蚀
    kernel = cv2.getStructuringElement(cv2.MORPH_RECT, (3, 3))
    mask_convex_remove_raw_contour = cv2.erode(
        mask_convex_remove_raw_contour, 
        kernel, iterations=1
    )
    # # 获取最大的轮廓
    contours, _ = cv2.findContours(
        mask_convex_remove_raw_contour, 
        cv2.RETR_EXTERNAL, 
        cv2.CHAIN_APPROX_SIMPLE
    )
    # print(len(contours))
    
    max_contour = max(contours, key=cv2.contourArea)
    # 获取最大轮廓

    # 绘制最大的轮廓
    mask_convex_remove_raw_contour_max_contour = cv2.drawContours(
        np.zeros_like(mask_convex_remove_raw_contour), 
        [max_contour], 
        -1, 
        255, 
        -1
    )

    # 膨胀
    kernel_size = 20
    kernel = cv2.getStructuringElement(
        cv2.MORPH_RECT, (kernel_size, kernel_size)
    )
    mask_convex_remove_raw_contour_dilate = cv2.dilate(
        mask_convex_remove_raw_contour_max_contour, 
        kernel, iterations=1
    )

    # 与原图取交集
    mask_dst = cv2.bitwise_and(mask, mask_convex_remove_raw_contour_dilate)
    return mask_dst
if __name__ == '__main__':
    mask_path = "./test.png"
    mask_remove_fork = get_contour_remove_fork(mask_path)
    mask_remove_fork_path = ".test_remove_fork.png"
    cv2.imwrite(mask_remove_fork_path, mask_remove_fork)

相关图示例

原图

凸包后对原图非零像素对应位置取0

最终效果图