We’ve seen how hardware, software, and graphics constraints can all work to produce latency. Now it’s time to put them all together, and ask what we can take away from this analysis.
The best way to illustrate the impacts of these different factors is to look at their respective contributions under different scenarios. These measurements are averages across a few different machines, so performance on your machine in particular can be better or worse than these numbers.
Latency is an important factor in making any human interface feel right. The Leap Motion Controller has lower latency than other similar products on the market, but exactly how low is it? The honest answer is that it depends on quite a few different variables, some of which are often overlooked.
We’ve learned from empirical evidence in building and testing motion control systems that there is some amount of latency that is tolerable by the human visual and nervous system, in that the delay is still imperceptible. This line is fuzzy and changes from person to person, but we’ve found that a good threshold is around 30 milliseconds on average.
An analogy for this threshold is the pixel density needed for a display to be of “Retina” resolution - any better, and you might not even be able to tell. You could say that being under this 30-millisecond threshold might refer to a “Nervous” controller.
Reducing latency has been a strong motivator for us here at Leap Motion since day one, and our success depends on how the latency is measured. In the first part of this article, we’ll examine various sources of delay between the time when you make a movement until that movement is fully processed and the result is visible to you. In the second part, we’ll see what happens when these factors come together, and what that means for our technology.
