Face Tracking Camera

Face tracking algorithm is not included in DynamiKontrol package. So we use Mediapipe face tracking solution for face tracking and OpenCV for streaming webcam.

Explanation

Let’s define x1, x2 are top left point and bottom right point of face bounding box, then cx would be center point of the face. Mediapipe face tracking solution returns relative coordinates of the input image, so range of cx would be 0.0 to 1.0. For instance, if your face is located in exact center of the image, cx is 0.5.

cx = (x1 + x2) / 2 # center of the face

if cx < 0.4: # left -> clockwise
    angle += ANGLE_STEP
    module.motor.angle(angle)
elif cx > 0.6: # right -> counter clockwise
    angle -= ANGLE_STEP
    module.motor.angle(angle)

If cx < 0.4, face is located in the left of the image, camera should move to left, and it means the motor should move to clockwise(+). Otherwise vice versa.

Source Code

import cv2
import mediapipe as mp
from dynamikontrol import Module

ANGLE_STEP = 1

module = Module()

mp_drawing = mp.solutions.drawing_utils
mp_face_detection = mp.solutions.face_detection

face_detection = mp_face_detection.FaceDetection(
    min_detection_confidence=0.7)

cap = cv2.VideoCapture(0)
angle = 0 # motor current angle

while cap.isOpened():
    ret, img = cap.read()
    if not ret:
        break

    img = cv2.flip(img, 1) # mirror image

    results = face_detection.process(cv2.cvtColor(img, cv2.COLOR_BGR2RGB))

    if results.detections:
        for detection in results.detections:
            mp_drawing.draw_detection(img, detection)

            x1 = detection.location_data.relative_bounding_box.xmin # left side of face bounding box
            x2 = x1 + detection.location_data.relative_bounding_box.width # right side of face bounding box

            cx = (x1 + x2) / 2 # center of the face

            if cx < 0.4: # left -> clockwise
                angle += ANGLE_STEP
                module.motor.angle(angle)
            elif cx > 0.6: # right -> counter clockwise
                angle -= ANGLE_STEP
                module.motor.angle(angle)

            cv2.putText(img, '%d deg' % (angle), org=(10, 30), fontFace=cv2.FONT_HERSHEY_SIMPLEX, fontScale=1, color=255, thickness=2)

            break

    cv2.imshow('Face Cam', img)
    if cv2.waitKey(1) == ord('q'):
        break

cap.release()
face_detection.close()
module.disconnect()