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System Sensor EyeControl calibration

Two calibration levels, Tobii Fine-tuning and results analysis in the "My gaze" tab.

🧭 What this page is about

Calibration is the most important moment when working with System Sensor EyeControl - it determines whether the cursor lands exactly where you look. This guide explains the two independent calibration levels (the Tobii driver and EyeControl Fine-tuning), shows how to read the charts in the "My gaze" tab and how to interpret the quality score 0-100% with its comment.

📥 Just installing EyeControl? Go through the installation first - then come back here to run your first calibration and learn how to analyze it.
➡ EyeControl and Tobii installation step by step

🎯 Two calibration levels - don't confuse them

When working with EyeControl there are two different calibrations. They work independently and are done in different situations. Telling them apart matters - when talking to someone it's always worth clarifying which one you mean.

1️⃣ Tobii driver calibration (system level)

Where: the Tobii Experience / EyeX Settings app (Tobii 5 / Tobii 4C) - not our application.

What it does: teaches Tobii's internal model your eye anatomy, distance from the screen and lighting. 9 colored circles on a dimmed screen, with a "catching" animation as you look.

Scope: the settings affect all applications that use Tobii (EyeControl, Windows Eye Control, Tobii games...).

When to do it: once for each Windows user. Again when you change the monitor position, the distance from Tobii, or when someone else sits down at the computer.

2️⃣ EyeControl Fine-tuning (correction layer)

Where: the "Fine-tuning" button in the System Sensor EyeControl window.

What it does: adds a gentle correction on top of the ready Tobii signal. 13 blue dots on a black screen: the centre, four corners, four dots on the sides and four intermediate ones - between the centre and the corners. The program itself decides whether the reading only needs shifting or also straightening - it measures both ways and keeps the better one.

Scope: only for the EyeControl application - Windows Eye Control and other applications don't see it.

When to do it: when the cursor still "sits" a few cm beside the target after Tobii calibration. A quick fix without redoing the driver calibration.

⚠️ Order matters. First level 1 (Tobii), then level 2 (Fine-tuning). Fine-tuning on top of a badly calibrated Tobii won't fix the problem - no correction, not even the bending one, will straighten out a signal that jumps by many centimeters.

📅 When to do which calibration

🔵 Level 1 - Tobii calibration

🟡 Level 2 - EyeControl Fine-tuning

💡 Pro tip: as soon as you feel the cursor starting to "drift" - don't fight it. Do a Fine-tuning (30 s) before you tire your eyes with imprecise control.

🧍 Position your head before calibration - the eye window

As of the new EyeControl version, right after you click Calibration, before the actual tuning starts, a full-screen window appears asking "Do you want to proceed to calibration?" (large YES / NO buttons). In this same window you now see live whether Tobii sees your eyes and whether your head is well positioned relative to the monitor. It's the simplest way to quickly correct the screen position after each time the computer is moved (a different table, bed, wheelchair), before you start calibration.

💡 What it's for. A good calibration starts with a good head position. If the eyes are outside Tobii's field of view or too close / too far, the calibration won't hold. This window shows everything at once - there's no need to open a separate Tobii program.

Position yourself so both eyes land in the green frame R L Distance farther closer ✔ Position is good
For illustration: dots L (left eye) and R (right eye) in the green frame = head well positioned. The bar on the right shows the distance from the tracker (green area = "good"). The image works like a mirror.

🟩 The green frame and two dots (left-right, up-down)

In the middle of the window there's a dark rectangle with a green dashed frame in the center - that's the target. Your eyes are shown as two dots with letters:

Goal: both dots (L and R) should land inside the green frame in the center. Then the head is centered relative to the tracker.

📏 Distance scale (farther / closer)

To the right of the rectangle there's a vertical "Distance" bar labeled farther (top) and closer (bottom). The green area on the bar is the "good" zone, and the moving marker shows your current distance from Tobii. Aim for the marker to settle in the green zone.

⚠️ The distance indicator is inherently more "jittery" than the horizontal-vertical frame (Tobii measures depth less accurately). Don't chase every twitch - it's enough that the marker stays around the green zone. The most important thing is centering the dots in the frame.

💬 The text below - live status

Below the rectangle there's a short message that changes in real time:

✅ Simple recipe: 1) click Calibration, 2) position your head so both dots (L and R) enter the green frame, 3) check that it says "Position is good" below, 4) only now click YES. A few seconds, and the calibration comes out much better.

ℹ️ Note. This eye window works when controlling with a Tobii tracker (4C / 5). When controlling with a regular webcam, the window only asks YES / NO without an eye preview - a webcam doesn't provide the position of the eyeballs in space.

🖥️ What the calibration itself and its result look like

Once your head is positioned and you click YES, the actual calibration in the EyeControl program begins. Below are two illustrative images: the calibration screen (you look at the dots) and the result window (the program shows how well it went).

1) The calibration screen - look at the dots

1 2 3 4 5 6 7 8 9 10 11 12 13 ESC = cancel
The screen is black. There are thirteen dots and they appear one after another: the centre first, then the top row, then the intermediate dots and the sides, and the bottom row last. Look at the centre of each dot - head still, move only your eyes. The dot turns from blue to red over 2 seconds - that is how long one point is measured. The whole thing takes about 40 seconds. To cancel: the ESC key.

2) The check screen - five dots at the end

Passed 3 of 5 ESC = cancel
Right after Fine-tuning the program shows five dots - four corners and the centre. Look at each of them; once your gaze rests on a dot for one second, the dot turns green. It usually takes 7-8 seconds.

🔑 Why this screen is here. The Fine-tuning score is calculated from the very dots you have just been looking at. This screen checks something different and more important: whether the cursor actually lands where you look - it tests the whole path, from the reading, through the correction, to the place the cursor will go. The gaze cursor is still switched off at this point, so you are looking "blind" and cannot help yourself by correcting.

If any dot fails to turn green within 30 seconds, the program asks whether to repeat the Fine-tuning. This is a safeguard in case the correction came out completely wrong - somebody using gaze alone would have no way of fixing it, because the cursor would be landing in the wrong places.

3) The result window - how it went

Wynik kalibracji 82 na 100 Świetna kalibracja Tryb: oba oczy Kursor powinien trafiać dokładnie tam, gdzie patrzysz. Wzrok był stabilny, oczy dobrze widoczne. Możesz zaczynać. Powtórz kalibrację OK, zaczynajmy!
After calibration the program shows a score of 0-100 with a short description. Click "OK, zaczynajmy!" (OK, let's start) when the result is good, or "Powtórz kalibrację" (Repeat calibration) when you want to improve it. ⚠️ This window is in Polish in the program itself, so the picture above shows exactly what you will see on screen.

💡 How to read the score: 80-100 - great (green), 60-79 - good, 40-59 - acceptable (yellow), below 40 - poor (red, worth repeating). The color of the frame and the number tell you right away whether to start or to redo it.

ℹ️ These are screens of calibration within the EyeControl program itself (Fine-tuning / webcam calibration). The Tobii driver calibration (level 1) looks different - it's 9 colored circles in the Tobii Experience app. Both levels are described in the "Two calibration levels" section above.

👁️ The "My gaze" tab - calibration analysis

After each Fine-tuning (and webcam Calibration) EyeControl automatically saves the raw gaze samples for each of the 13 (or 5, with webcam calibration) points. You can review them later in Settings → "My gaze". This is your history: you can see whether your calibration is getting more stable over time or needs more frequent repeats.

🔓 How to open it

  1. In the EyeControl window click "Settings" - the button with a wrench and screwdriver (not a gear; that is what the icon looks like in the program).
  2. Choose the "My gaze" tab.
  3. From the "Session" drop-down list choose a specific calibration date and time.
  4. You'll see thumbnails of each point (13 for Fine-tuning, 5 for webcam calibration) - click a thumbnail to open the detailed view.

📁 Where the data is stored:

C:\Users\Public\Documents\System Sensor EyeControl\Kalibracja\telemetria\

Each session is a separate XML file. We keep the last 20 sessions - older ones are deleted automatically. If you want to keep a particular session longer, copy the file somewhere else.

🎨 How to read a calibration point chart

Each detailed chart (after clicking a thumbnail) shows ~270 gaze samples collected over 3 seconds of looking at one circle. Here's what you see:

cloud of dots - your gaze samples
cross - the median (center of the cloud)
yellow square - the target (the dot you looked at)
median → target arrow (offset)

In the bottom right corner - a small "Point map" showing which of the 13 (or 5) points you're viewing. The current one is yellow with a number, the rest gray.

In the top right corner - a large quality score 0-100% with a one-sentence comment.

The gray grid in the background (Tobii only) - every 50 actual px, giving you a reference: "my cloud is roughly 1 cell wide = 50 px, that's very stable".

📊 Four examples - recognize your gaze

Below are four typical images you'll see in the "My gaze" tab. Each shows a different scenario - compare with your own result to know what to do next.

94% excellent

A) Very good calibration - a small cloud exactly on the target, the median coincides with the square. Offset ≈ 0, spread ≈ 0. Green badge 90-100%.

68% Fine-tuning fixes the offset

B) Systematic offset - a small, tight cloud, but shifted ~50 px beside the target. This is the ideal situation for Fine-tuning - the correction layer will move the cursor back onto the target.

52% gaze was shaky

C) Shaky gaze - a large, spread-out cloud; the median is OK, but individual samples run off. Cause: fatigue, head movements, an unstable position. Repeat the calibration calmly, head still.

28% Tobii lost the eyes

D) Few samples / scatter - under the thumbnail you see "N:8 inv:42 off:15" instead of "N:270". Tobii didn't see the eyes (bad lighting, face outside the trackbox) or you looked beside the dot. Fix your position / lighting and repeat.

📸 Screenshots: the charts above are illustrative diagrams. Once you run your first Tobii calibration on your installation, your "My gaze" tab will show real data - compare it with the A-D patterns above.

📈 The quality score 0-100% - how we calculate it

Each point in the detailed view has a percentage badge and a one-sentence comment. The badge color ranges from green (very good) to red (poor). For Tobii Fine-tuning the score is composed of three metrics:

For webcam Calibration (5 points with separate channels for the left and right eye) the formula is different - 40% for the number of samples + 60% for the spread of the left and right eye.

Thresholds and interpretation

Score Color Interpretation What to do
90-100% green Very stable fixation, excellent result. Nothing. The cursor will be precise.
75-89% green Good result, minor deviations within norm. Nothing. Work will be comfortable.
60-74% yellow Acceptable. If the offset is large but the spread small - it's waiting for Fine-tuning. Consider repeating Fine-tuning calmly.
40-59% orange Unstable calibration - the gaze was shaky or many samples off-target. Repeat Fine-tuning, head still, look calmly at the dots.
0-39% red Poor result. Tobii may not have seen the eyes, or the driver calibration needs repeating. First fix your position/lighting, then redo the Tobii calibration (level 1).

✅ Note: a single weak point (e.g. a screen corner) while the other 8 are high quality is normal - the extreme points are the hardest. Only when most of the points glow yellow or orange is it worth running another calibration.

🧪 Common scenarios and what to do about them

🎭 Scenario 1: no binocular vision (strabismus, ptosis, diplopia)

Symptom: the cursor jumps by 5-15 cm, especially when looking at a corner. In "My gaze" the extreme points glow red, the central ones green.

Solution: in Tobii Experience, during calibration choose the "Left eye only" or "Right eye only" option (usually the dominant one). Tobii will stop trying to combine the eyes and the cursor will settle down. Then Fine-tuning.

📐 Scenario 2: systematic offset (e.g. everything 20 px to the right)

Symptom: the cursor always sits beside the target by the same distance. In "My gaze" all the clouds are small and tight, but the offset arrows point in the same direction.

Solution: Fine-tuning - this is exactly the situation where the affine correction layer works perfectly. One Fine-tuning and the problem's gone.

😵 Scenario 3: shaky gaze, large sample clouds

Symptom: 40-60% quality, large and spread-out clouds, the median close to the target. During work the cursor "shakes" / "is noisy".

Solution: most often fatigue or an unstable head position. Take a break, make sure the head is supported, repeat Fine-tuning calmly. If the problem persists - check that Tobii is well mounted (not vibrating).

🌑 Scenario 4: Tobii loses the eyes (lots of "inv")

Symptom: under the charts you see "N:50 inv:120" instead of "N:270". Tobii failed to see the eyes more often than it saw them.

Solution: (1) improve the lighting - the face should be evenly lit, without harsh shadows; (2) check the distance - Tobii works best 50-80 cm from the face; (3) make sure there are no strong reflections on the glasses. After each change → a new Tobii calibration (level 1).

🎯 Scenario 5: lots of "off-target" samples

Symptom: under the charts "N:150 off:100". Tobii saw the eyes, but you looked beside the dot.

Solution: during Fine-tuning/Calibration deliberately look at the very center of the dot, not somewhere beside it. The dot darkens from blue to red as it collects samples - hold your gaze until the end of that animation. If you can't keep up - nothing happens. EyeControl repeats the dot also when your gaze wandered during the measurement or when Tobii lost the eye; a caption next to the dot then says that the same dot is being shown a second time. Every dot is repeated at most once.

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