Touch technology in displays is not very well understood yet. The company Agawi wants to change that so they have developed TouchMarks that can measure the latency of a touch display in a smartphone or tablet. The first test reveals that the iPhone 5 touch display is 2.5 times faster than the flagship Android and Windows smartphones.

Measuring latency of touch displays
Touch displays have become extremely popular in recent years, almost a part of everyday life for most people. They have also become the primary method for humans to interact with machines, but most reviewers put very little effort into examining the subject.  That is a shame, so Agawi has set out to develop a tool.

Agawi kicks off the project by measuring latency of touch displays in high-end smartphones from Apple, Samsung, Nokia, HTC and Motorola (Google). The tests show that the touch display in iPhone 5 is 2.5 times faster than the most powerful Android, Galaxy S4, and the fastest Windows Phone, Lumia 928. Even Apple’s aging iPhone 4 is much faster than the other flagship phones.


Agawi’s TouchMarks tool used to measure response time of the touch display in popular smartphones

Agawi uses a measurement called MART (minimum app response times) as an indicator for latency during very light use. That is a slightly strange approach as response time can vary depending on the intensity of the task, so a measurement of the average or maximum latency level would make more sense. Agawi says that they will continue to do more testing in games and apps, so expect more results to come. They also say that they will include more smartphones and tablets soon.

Touch display latency depends on several factors, including the touch technology used in the display, the touch sensor, and also the operating system in the device. The actual display technology can also have a role (most mobile displays use 60 Hz today). A fast processor can help “translate” touch sequences for the operating system, but the processor in smartphones is far from the decisive factor in this context.

In perspective
To put the measurements into perspective, the best gamer monitors have effectively reached 0 ms “input lag”. The best TVs hover at around 10-20 ms. Depending on who you ask, a dedicated gamer would say that anything above 20-30 is useless, but average people probably need about 40-80 ms to perceive a lag-free experience when using a mouse or game controller on a TV or PC monitor. Touch displays require lower latency.

The iPhone 5 and Sony’s Xperia P were first smartphones to switch to so-called in-cell touch technology. FlatpanelsHD has explained the differences between in-cell and on-cell touch technology here.

Several manufacturers have launch research programs that aim to lower latency of touch displays, including Microsoft. Microsoft has demonstrated their work in the research video below. Paradoxically, the progress in optimizing touch displays has yet to be implemented in Windows Phone devices.




- Source: Agawi