Blink Counter Webcam

How the Blink Counter works

Blink counter webcam: what to know first

People blink around fifteen to twenty times a minute in conversation and around five to seven while reading on a screen. That drop is why eyes feel dry and tired after a long session: each blink respreads the tear film, and at a third of the normal rate the film breaks up between blinks. Optometrists tell you to blink more; the difficulty is that you cannot feel yourself not blinking. This page measures it.

How a blink is detected. The face model running in your browser fits a 478-point mesh to your face each frame and, alongside it, produces 52 "blendshape" scores — the same set Apple uses for animated emoji — each describing one facial action from 0 to 1. Two of them are eye-blink-left and eye-blink-right. The tool averages the pair and counts a blink when the score rises above a half and then falls back below a third. The two thresholds, rather than one, stop a flutter around the boundary being counted twice. A slow squint that never gets above a half is not a blink; a wink counts if the average clears the bar, which with one eye fully closed it usually does not.

The rate figure. For the first minute of a session the rate is the count so far scaled to a minute, which is rough; after a minute it is the number of blinks in the last sixty seconds, which is what you want to watch. Compare the figure while you read something demanding against the figure while you chat with someone next to you. The difference is usually stark.

The stare reminder. Ten seconds without a blink is a long time — at a healthy rate the gap is three to four seconds — so the default threshold catches real staring without nagging. The tint is deliberately mild: enough to notice in the corner of your eye, not enough to interrupt. Adjust the slider if ten seconds fires too often or too rarely for you.

Limits. The model needs your face roughly towards the camera and reasonably lit; looking down at a keyboard, turning to a second monitor, or a very dark room will lose it, and the readout says Face not in view rather than guessing. Glasses are fine. Very fast blinks can fall between frames at low frame rates, which undercounts slightly on old hardware. This is a habit monitor, not a medical instrument; if your eyes are persistently dry, see an optometrist.

Privacy. The face model runs in WebAssembly inside the page. The camera stream, the mesh and the blink scores never leave your browser, and the counts are held in memory only until you press Reset or close the tab.

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