Blink Counter¶

Counts your blinks by measuring how open your eyes are.

Run it¶

python examples/blink_counter.py

Code¶

examples/blink_counter.py

"""Count eye blinks from how open the eyes are.

An eye's openness is its height divided by its width. Press q to quit.
"""

import math

import cv2 as cv

from detectors_world import create_detector

# Two corners of the eye, then its upper and lower lid.
RIGHT_EYE = (33, 133, 159, 145)
LEFT_EYE = (362, 263, 386, 374)
CLOSED = 0.2


def openness(face, eye):
    corner_a, corner_b, upper, lower = eye
    return math.dist(face[upper], face[lower]) / math.dist(face[corner_a], face[corner_b])


blinks = 0
eyes_closed = False

cap = cv.VideoCapture(0)
with create_detector("face_mesh", max_faces=1) as face_mesh:
    while cap.isOpened():
        ok, frame = cap.read()
        if not ok:
            break
        faces = face_mesh.detect(frame, draw=False)
        if faces:
            average = (openness(faces[0], RIGHT_EYE) + openness(faces[0], LEFT_EYE)) / 2
            closed_now = average < CLOSED
            if closed_now and not eyes_closed:
                blinks += 1
            eyes_closed = closed_now
        cv.putText(frame, f"Blinks: {blinks}", (10, 50), cv.FONT_HERSHEY_SIMPLEX, 1.4, (0, 255, 0), 3)
        cv.imshow("Blink Counter", frame)
        if cv.waitKey(1) & 0xFF == ord("q"):
            break
cap.release()
cv.destroyAllWindows()

How it works¶

Each eye has two corner landmarks and two eyelid landmarks, listed on the face mesh page.
openness() divides the eye's height by its width. Using a ratio means the result stays the same as you move closer or farther.
eyes_closed makes sure one blink counts once, however many frames it lasts.

Try next¶

CLOSED works for most people, but adjust it if blinks are missed or counted by mistake.
Print the average value while you blink to see the range for your eyes.