hog_person_detection.py

import cv2
import time

hog = cv2.HOGDescriptor()
hog.setSVMDetector(cv2.HOGDescriptor_getDefaultPeopleDetector())
cap = cv2.VideoCapture("/path/to/test/video")
while True:
    r, frame = cap.read()
    if r:
        start_time = time.time()
        frame = cv2.resize(frame,(1280, 720)) # Downscale to improve frame rate
        gray_frame = cv2.cvtColor(frame, cv2.COLOR_RGB2GRAY) # HOG needs a grayscale image

        rects, weights = hog.detectMultiScale(gray_frame)
        
        # Measure elapsed time for detections
        end_time = time.time()
        print("Elapsed time:", end_time-start_time)
        
        for i, (x, y, w, h) in enumerate(rects):
            if weights[i] < 0.7:
                continue
            cv2.rectangle(frame, (x,y), (x+w,y+h),(0,255,0),2)

        cv2.imshow("preview", frame)
    k = cv2.waitKey(1)
    if k & 0xFF == ord("q"): # Exit condition
        break