Analysis of Task Success Rate for Classifying 2D-Touch and 3D-Touch through Threshold

Since input interfaces using a touchscreen device appeared, some of 2D-Touch methods have been available such as Single Tap, Long Press, and Pinch Zoom, etc. Later, a technology called Force Touch or 3D-Touch was introduced that receives inputs for 2D-touch and touch force. In other words, 3D-touch is an interface that has Z coordinates as strength of touch force in addition to the X and Y coordinates on a screen used in 2D-Touch. Apple has manufactured iPhone 6S and later models which are 3D-Touch interface in use and it implemented force separation with two levels: peek and pop. The forces intensity for pick and pop interactions are divided into 200g and 400g respectively based on the maximum input of 400g that the 3D-Touch screen can measure the pressure.In order to define the range of both touch and peek in two levels provided by Apple, we first should specify an area where touch and peek areas can be distinguished. Previous researches show that the criterion for separating two areas is 200ms. In addition, when the strength is up to 66g, we may identify an action as touch and as force when the strength is more implying that 66g is a boundary for two areas. We need to perform experiments to make sure whether a task can be succeeded with the defined threshold. Then, we may be able to define new ranges for peek and touch and for peek and pop. Furthermore, we will search those ranges as large as possible and provide a basis for how to apply them.