模仿maskrcnn，在图片中画一个多边形掩膜，提供可视化效果

code

'''
author:chenjun
date:2020-01-16
use:draw the mask on image
'''
import cv2
import numpy as np
from PIL import Image
import matplotlib.pyplot as plt
import pycocotools.mask as mask_util

mask_threth = 50

img = cv2.imread('./test_imgs/test_0.jpg')

# binary mask
coordinates = [[[40, 135], [168,132], [164,330], [2,328]]]
coordinates = np.array(coordinates)
mask = np.zeros(img.shape[:2], dtype=np.int8)
mask = cv2.fillPoly(mask, coordinates, 255)
bbox_mask = (mask > mask_threth).astype(np.uint8)

# draw the masked image
color_mask = np.random.randint(0, 256, (1, 3), dtype=np.uint8)
color_mask = np.array([0, 215, 255], dtype=np.uint8)
bbox_mask = bbox_mask.astype(np.bool)
img[bbox_mask] = img[bbox_mask] * 0.5 + color_mask * 0.5
img = img[:,:,::-1]
plt.imshow(img)
plt.savefig('./result.png')
plt.show()

结果