Selecting a Camera

BlinkEasy works with most cameras out of the box and supports a wide range of recording formats like NV21, NV12, YUV, and various RGB formats. In general, most webcams built in the past couple of years are sufficient, be it external USB devices or built-in laptop cameras.

In case you don't have a webcam yet or want to improve blink detection with a better model, here are some pointers: First of all, the most important factor when picking a camera is the speed at which it can record. This is usually given by the manufacturer as frames per second (fps).

Blinks are very quick events that typically last only 100 to 150 milliseconds (around 1/8 of a second). Recording with a camera capable of capturing at least 30 frames per second is recommended as it allows for multiple frames to record the start, middle and end of a blink for more precise detection and analysis.

Many webcams will reduce the recording frame rate to compensate for low lighting, so higher frame rate cameras will produce a more steady stream even if the software limits itself by default to 30 fps to preserve CPU resources. In case of low recording frame rates, a warning message will be displayed in the histogram window. Below 15 fps blink detection becomes unreliable.

The camera's resolution, on the other hand, is less important. While higher resolutions can improve detection, this comes at an exponential tradeoff in computing power. To avoid slowing down your system unnecessarily, the real-time analysis defaults to a medium resolution, while allowing you to increase it in the settings tab.

In a nutshell, consider getting a high-fps webcam from a reputable brand, as they usually come with better sensors and optics that produce less noisy images.

Adjusting Detection Sensitivity

The histogram next to the video preview visualizes in real time the opening and closing of your eyes. Spikes on this graph signal the rapid closing of the eyelids. Here you can also fine-tune the blink detection sensitivity to suit your setup.

1. Move the slider on the right side of the histogram to adjust the detection level.
2. The yellow bar on the histogram indicates the threshold. Transitions between open and closed eyes that cross this bar will be recognized as a blink.
3. Watch the top left counter to confirm if your blinks are being detected correctly. Blink frequently while adjusting the slider.

After setting the sensitivity, move your head around without blinking to check for over-sensitivity. If the settings are too high, rapid movements might trigger false positives (incorrectly detected blinks).

Good Lighting

In low-light conditions many webcams will compensate by increasing exposure time. This means the shutter remains open longer to let enough light reach the camera's sensor, allowing it to record a brighter image. As a result the frame rate drops, which can hinder blink detection.

For the best results, make sure your workspace is well-lit with even, consistent lighting. Natural daylight or LED lamps work well—avoid harsh overhead lights that cause shadows. If the lighting isn't sufficient for clear camera capture, it's probably not ideal for your eyes either, as dim environments contribute to eye strain and fatigue.

Camera Position

For optimal results, position your camera to capture your face frontally (straight on).

• Center the camera on your screen, and tilt it slightly downward towards your face.

Webcams are usually designed to mount on top of your monitor. However, if you work a lot with physical documents and look down at the table often, you may get better results by mounting the camera below the screen so that the camera has an unobstructed view of your eyes.

If you use a secondary monitor:

• Position the camera on your primary monitor, about three-quarters of the way towards the secondary monitor.
• Angle the camera slightly toward your seating position to keep your face centered in the frame.

Troubleshooting and Known Limitations

The most likely error to encounter is the camera being blocked by another application. Under Windows, only one application can use a specific camera device at a time in most cases. Closing the other application will release the camera. If you frequently use your camera for video conferencing, a secondary webcam is a good investment. BlinkEasy supports switching between multiple camera devices.

You will be asked by Windows or macOS to grant permission to use your camera when BlinkEasy launches for the first time. If you need to grant permissions later, you can do so in your operating system's privacy settings. This is usually done on a per-application basis. After granting access to BlinkEasy, restart the app.

When wearing glasses ensure that your pupils are visible and your eyelids aren't covered by the frame. Increase the detection sensitivity as needed. Minimize glare from reflections with indirect lighting. Slightly tinted glasses like blue light filters are supported, but more opaque glasses like sunglasses are not.

When games are run in Direct X's exclusive fullscreen mode, other applications cannot draw to the screen. This is mostly an issue with older games and most modern games run in windowed mode natively or support it as an option. Select "Windowed Fullscreen" in your game's video settings; otherwise, only audio warnings will be available for the blink reminder.