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- This topic has 5 replies, 3 voices, and was last updated 5 years, 6 months ago by Grant [Tobii].
- 24/10/2017 at 04:02 #7501Carl HilinskiParticipant
I would like a better explanation of how eye tracking calibration works for the 4C.
Let’s say I start from scratch. The first thing I have to do is align the screen with the lines on the 4C. This is how it determines the left and right borders for the monitor in use? Now I get presented with the exploding dots. That seems simple enough, but is it using both head tracking and eye tracking while it’s doing this? Now I can go back and recalibrate where I get six circles on the screen and as I look at each, the “viewer” shifts to show where I’m looking. Okay, so it’s nominal. It doesn’t seem to matter how long I look at a circle or if I shift vision or if I look at all of them or not. Is this screen just for my benefit so I can see how accurate it is? I’ve seen some videos where it looks like it leaves marker dots on the screen, but I don’t get anything like that. I’m just not sure what I should be doing here. If I think it can be better, I can improve the accuracy and it takes me back to the exploding dot screen. Am I really accomplishing anything by going through this again? Did it remember the last time I was here and is actually improving? I’m just not sure what it’s doing.
Maybe it would be helpful if you could point me to a document that explains how one should use the tools to actually improve things. Just for additional info, I’m running Win10 Fall Creator on an AMD RX480 graphics card.24/10/2017 at 18:27 #7503
Hi @chilinski, please let me try to deal with your queries as they appear in your original post:
>> This is how it determines the left and right borders for the monitor in use?
That’s correct, we use this to determine the screen dimensions and scale relative to the eye tracerk.
>> that seems simple enough, but is it using both head tracking and eye tracking while it’s doing this?
No, this stage is using eye tracking for the calibration component as head tracking operates under seperate
>> Is this screen just for my benefit so I can see how accurate it is?
Yes, In a sense.. this is for you to verify that the accuracy of calibration is sufficient to detect the dots at all
the extremities of the monitor.
>> I’ve seen some videos where it looks like it leaves marker dots on the screen
This is the ‘gaze trace’ feature which you can enable via the Tobii Interaction Software from the system tray icon.
>> Am I really accomplishing anything by going through this again?
Yes, sometimes by a number of a factors such as ambient light, or not looking focusedly enough at one point, this may result
in a poor overall calibration. By choosing recalibration you provide the software the chance to redo and hopefully improve
>> Did it remember the last time I was here and is actually improving?
No, the recalibration is performed from scratch each time.
Certainly by using the ‘gaze trace’ feature you should get a good impression of overall accuracy. If you find this to be consistently poor, even after recalibration, there are a few things you can try such as adjusting environmental light levels, ensuring proper positioning, cleaning of the eye tracker screen, etc.
If problems persist, please get in touch and we will see how we can be of further assistance.24/10/2017 at 19:27 #7504Carl HilinskiParticipant
Thank you. I have a couple of additional calibration questions. When the calibration first starts, you get the screen where it shows two dots/circles for your eyes. I’ve noticed that as I move closer/further from the 4C that the size of the dots gets larger. I assume that the point at which they are the largest is the ideal distance. Is that correct?
I also have a question about ambient light. Is it better to be brighter or dimmer? As I understand it, the tracker uses IR to bounce a beam off the back of your eye and this is detected by a standard vga camera (the same one used by Windows Hello)? When I’m gaming I light to keep the ambient light reduced, but I notice when I try to use the Windows Hello stuff that the image of my fat face that it shows me is very dark and needs more light. I’ve only gotten Hello to work sporadically, and I think the ambient lighting is the issue. Do you have any better guidelines for ambient light and where it is best to be located? Would a light background on the monitor work better for illumination in Hello than one of the darker ones?
One final thing, I promise. I play F1 2017 and can’t have the monitor as close to my eyes as the Tobii requires. So I built a stand to which the 4C is attached, and that sits about eight inches in front of the monitor. It seems that I can get a reasonably accurate setup if I use the setup screen where you adjust the bar to match the lines on the Tobii and vary that alignment. Basically, it’s trying to fool the 4C about the size of the screen. This may actually not work, but it SEEMS to work because in a driving game you’re focused primarily on the center of the screen anyway and the range isn’t that great (there’s usually not much to see at the edges of the screen). This may all fall apart with a FPS where accuracy is more critical.
Okay, that’s enough. I’ve taken enough of your time. Thank you in advance for the previous info; that was very helpful and it might merit a write-up on your website that describes the calibration process. Just the fact that it’s not learning from trial to trial could save someone a lot of time and frustration.25/10/2017 at 20:27 #7509
>> I assume that the point at which they are the largest is the ideal distance. Is that correct?
No, in fact the nominal distance is around 30cm from the screen (About half way between the extremties) but so long as both eyes are found and within the tracking area, you should not notice any difference in calibration quality.
>> Is it better to be brighter or dimmer?
Well, generally we would recommend a dim environment, but this very much depends on the *type* of light in your area. Natural light (containing IR) can interfere with ideal trackability to try not to have the tracker particularly close to large windows or in fact facing electric spotlights. With regard to background, yes a darker background has been found to improve those in problematic cases. Overall, try to keep ambient visible and IR light to low levels if possible.
>> So I built a stand to which the 4C is attached, and that sits about eight inches in front of the monitor.
Yes, a few other customers have experiemented (With mixed results) on this kind of setup
This post @ http://developer.tobii.com/community/forums/topic/ultrawide-monitors/ might help you out in optimising your setup.
>> Thank you in advance for the previous info; that was very helpful and it might merit a write-up on your website that describes the calibration process.
You are quite welcome! Please don’t hesitate to let us know if we can be of any further assistance 🙂17/11/2017 at 03:06 #7603ChristopherParticipant
No, in fact the nominal distance is around 30cm from the screen (About half way between the extremties
30cm is ridiculously close. I’ve had the best results on my 27 inch screen at 70cm. Are you sure you don’t mean 30 inches?17/11/2017 at 13:28 #7604
Hi @tenghuang, 30cm is just a guideline for nominal positions under testing conditions. The Tobii trackers are designed to provide idealised accuracy throughout the entire range of movement within the tracking box of the Eye Tracker.
This includes the distances you alluded to in your post of around 70cm.
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