How to make more than 1 binary mask in an image?

[BabakRG]

@maftouni Hi,
Hope you be well, I have got a question. The code you scripted, just make binary mask from first region in each image. How can I convert all regions in images to binary masks?
Thanks a lot.

[phsilvafct]

@BabakRG I have made some modifications to the code as to represent all the regions(polygons) into the binary mask, I also made the change of storing the masks with the same filename as the original images. @maftouni Maybe you can add this code the repository as there are several questions on the subject online.

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


with open("annotation.json", "r") as read_file:
    data = json.load(read_file)

all_file_names=list(data.keys())

Files_in_directory = []
for root, dirs, files in os.walk("sample_frames"):
    for filename in files:
        Files_in_directory.append(filename)
        
for j in range(len(all_file_names)): 
    image_name=data[all_file_names[j]]['filename']
    if image_name in Files_in_directory: 
         img = np.asarray(PIL.Image.open('sample_frames/'+image_name))    
    else:
        continue
    
    if data[all_file_names[j]]['regions'] != {}:
        x = 0
        mask = np.zeros((img.shape[0],img.shape[1]))
        while x < len(data[all_file_names[j]]['regions']):
            try: 
                shape1_x=data[all_file_names[j]]['regions'][str(x)]['shape_attributes']['all_points_x']
                shape1_y=data[all_file_names[j]]['regions'][str(x)]['shape_attributes']['all_points_y']
            except : 
                shape1_x=data[all_file_names[j]]['regions'][x]['shape_attributes']['all_points_x']
                shape1_y=data[all_file_names[j]]['regions'][x]['shape_attributes']['all_points_y']
            

            ab=np.stack((shape1_x, shape1_y), axis=1)
            img2=cv2.drawContours(img, [ab], -1, (255,255,255), -1)
            img3=cv2.drawContours(mask, [ab], -1, 255, -1)
            x+=1

        tempTuple = os.path.splitext(data[all_file_names[j]]['filename'])
        cv2.imwrite('binary_masks/' + tempTuple[0] + '.png',mask.astype(np.uint8))