[OpenCV] cv2로 bounding box/ polygon 그리기 / Drawing polygon by cv2 (cv2.polylines)

file("gt_%d.txt") : GT bounding box 정보를 담고 있음, 각 polygon 좌표값은 tab('\t')으로 구분했다고 가정

[x1    y1    x2    y2    x3    y3    x4    y4    label] 

 

import cv2;
import numpy as np

input_id = 1

# Reading polygon txt file
file = './gt_%d.txt'%input_id
f = open(file,'r')
lines = f.readlines()

# Reading Image
image_file = './images/0/%d.jpg'%input_id
image = cv2.imread(image_file)

# Draw
for line in lines:
    polygon = line.split('\t')[:-1]
    polygon = [int(point) for point in polygon]
    points = []
    for idx in range(0, len(polygon), 2):
        points.append([polygon[idx], polygon[idx+1]])
    points = np.array(points)
    image = cv2.polylines(image, [points], True, (255,0,0),2)

# Save Image
cv2.imwrite('./after_poly_%d.jpg'%input_id, image)