face-detect-usb.py

# MIT License
# Copyright (c) 2019 JetsonHacks
# See LICENSE for OpenCV license and additional information

# https://docs.opencv.org/3.3.1/d7/d8b/tutorial_py_face_detection.html
# On the Jetson Nano, OpenCV comes preinstalled
# Data files are in /usr/sharc/OpenCV

import cv2

window_title = "Face Detect"

def face_detect():
    face_cascade = cv2.CascadeClassifier(
        "/usr/share/opencv4/haarcascades/haarcascade_frontalface_default.xml"
    )
    eye_cascade = cv2.CascadeClassifier(
        "/usr/share/opencv4/haarcascades/haarcascade_eye.xml"
    )
    # ASSIGN CAMERA ADDRESS HERE
    camera_id="/dev/video0"
    # Full list of Video Capture APIs (video backends): https://docs.opencv.org/3.4/d4/d15/group__videoio__flags__base.html
    # For webcams, we use V4L2
    video_capture = cv2.VideoCapture(camera_id, cv2.CAP_V4L2)
    """ 
    # How to set video capture properties using V4L2:
    # Full list of Video Capture Properties for OpenCV: https://docs.opencv.org/3.4/d4/d15/group__videoio__flags__base.html
    #Select Pixel Format:
    # video_capture.set(cv2.CAP_PROP_FOURCC, cv2.VideoWriter_fourcc(*'YUYV'))
    # Two common formats, MJPG and H264
    # video_capture.set(cv2.CAP_PROP_FOURCC, cv2.VideoWriter_fourcc(*'MJPG'))
    # Default libopencv on the Jetson is not linked against libx264, so H.264 is not available
    # video_capture.set(cv2.CAP_PROP_FOURCC, cv2.VideoWriter_fourcc(*'H264'))
    # Select frame size, FPS:
    video_capture.set(cv2.CAP_PROP_FRAME_WIDTH, 640)
    video_capture.set(cv2.CAP_PROP_FRAME_HEIGHT, 480)
    video_capture.set(cv2.CAP_PROP_FPS, 30)
    """

    if video_capture.isOpened():
        try:
            cv2.namedWindow(window_title, cv2.WINDOW_AUTOSIZE)
            # Start counting the number of frames read and displayed
            # left_camera.start_counting_fps()
            while True:
                _, frame = video_capture.read()
                gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
                faces = face_cascade.detectMultiScale(gray, 1.3, 5)

                for (x, y, w, h) in faces:
                    cv2.rectangle(frame, (x, y), (x + w, y + h), (255, 0, 0), 2)
                    roi_gray = gray[y : y + h, x : x + w]
                    roi_color = frame[y : y + h, x : x + w]
                    eyes = eye_cascade.detectMultiScale(roi_gray)
                    for (ex, ey, ew, eh) in eyes:
                        cv2.rectangle(
                            roi_color, (ex, ey), (ex + ew, ey + eh), (0, 255, 0), 2
                        )

                # Check to see if the user closed the window
                # Under GTK+, WND_PROP_VISIBLE does not work correctly. Under Qt it does
                # GTK - Substitute WND_PROP_AUTOSIZE to detect if window has been closed by user
                if cv2.getWindowProperty(window_title, cv2.WND_PROP_AUTOSIZE) >= 0:
                    cv2.imshow(window_title, frame)
                else:
                    break
                
                keyCode = cv2.waitKey(30) & 0xFF
                # Stop the program on the ESC key or 'q'
                if keyCode == 27 or keyCode == ord('q'):
                    break
        finally:
            video_capture.release()
            cv2.destroyAllWindows()
    else:
        print("Unable to open camera")


if __name__ == "__main__":
    face_detect()