python 灰度抠图

提示：个人笔记

• 前言
• 一、取目标轮廓坐标
• 二、代码处理

提示：笔记背景

在写专利的时候，需要附录一些图，画轮廓图又太难看了，所以就把实物的目标抠出来后再放到白板上

提示：以下是本篇文章正文内容，下面案例可供参考

用的是labelme把对象都标注出来，保存成json

代码如下（示例）：

import os
import cv2
import json
import numpy as np
import matplotlib.pyplot as plt

def read_json(josn_path):
    obj = json.load(open(josn_path))
    shapes = obj['shapes']
    return shapes

def draw(image_path,shapes):
     #灰度化
    image = cv2.imread(image_path, cv2.IMREAD_GRAYSCALE)
    # 创建白板背景图
    background = np.zeros_like(image)
    background[:] = 255
    temp = []
    # 将轮廓都取出来
    for shape in shapes:
        points = shape['points']
        np_points = np.array(points, np.int32)
        temp.append(np_points)
    #在白板上填充目标
    cv2.fillPoly(background,temp,0)
    # 将灰度化的目标取出来，粘贴到白板上
    background[background==0] = image[background==0]
    #name = os.path.basename(image_path)
    #path = ''
    #保存
    cv2.imwrite(os.path.join(path,name),background)

def fillploy():
  '''  fillploy测试例
  '''  
    a = np.array([[[10,10],[100,10],[100,100],[10,100]]],dtype=np.int32)
    b = np.array([[[100, 100], [200, 230], [150, 200], [100, 220]]], dtype=np.int32)
    print(a.shape)
    im = np.zeros([240,320],dtype=np.uint8)
    cv2.polylines(im,a,1,255)
    cv2.fillPoly(im,b,255)
    plt.imshow(im)
    plt.show()

if __name__=='__main__':
    root_path = ''
    for file in os.listdir(root_path):
        file_path = os.path.join(root_path,file)
        if file.endswith('json'):
            image_path = file_path.replace('json','jpg')
            shapes = read_json(file_path)
            draw(image_path,shapes)