Understanding back-to-front pinching for eyes-free mobile touch input

Using a smartphone touchscreen to control apps mirrored to a distant display is hard, since the user cannot see where she is touching while looking at the distant screen. Tactile landmarks at the back of the phone can mitigate this problem, especially in landscape mode [3]: By moving a finger across these landmarks, the user can haptically estimate the finger position in proportion to the touchscreen. Upon pinching the thumb resting above the touchscreen towards that finger at the back, the finger position is transferred to the front and registered as a touch. However, despite proprioception, this technique leads to a shift between back and front position, denoted as pinch error. We investigated this error using different target locations, device thicknesses, and tilt angles to derive target sizes that can be acquired at a 96% success rate.

[1]  Jan O. Borchers,et al.  HaptiCase: Back-of-Device Tactile Landmarks for Eyes-Free Absolute Indirect Touch , 2015, CHI.

[2]  I. Scott MacKenzie,et al.  Towards a standard for pointing device evaluation, perspectives on 27 years of Fitts' law research in HCI , 2004, Int. J. Hum. Comput. Stud..

[3]  Michael Rohs,et al.  Ergonomic characteristics of gestures for front- and back-of-tablets interaction with grasping hands , 2014, MobileHCI '14.

[4]  Nicolas Roussel,et al.  Impact of form factors and input conditions on absolute indirect-touch pointing tasks , 2014, CHI.

[5]  D. Wolpert,et al.  When Feeling Is More Important Than Seeing in Sensorimotor Adaptation , 2002, Current Biology.

[6]  Niels Henze,et al.  Comparing pointing techniques for grasping hands on tablets , 2014, MobileHCI '14.

[7]  Christina T Fuentes,et al.  Where is your arm? Variations in proprioception across space and tasks. , 2010, Journal of neurophysiology.

[8]  R. J. van Beers,et al.  Integration of proprioceptive and visual position-information: An experimentally supported model. , 1999, Journal of neurophysiology.

[9]  Victor Horsley,et al.  UPON THE ORIENTATION OF POINTS IN SPACE BY THE MUSCULAR, ARTHRODIAL, AND TACTILE SENSES OF THE UPPER LIMBS IN NORMAL INDIVIDUALS AND IN BLIND PERSONS , 1906 .

[10]  Brad A. Myers,et al.  The performance of hand postures in front- and back-of-device interaction for mobile computing , 2008, Int. J. Hum. Comput. Stud..

[11]  A. Crowe,et al.  Proprioceptive Accuracy in Two Dimensions , 1987, Perceptual and motor skills.

[12]  J Paillard,et al.  A proprioceptive contribution to the spatial encoding of position cues for ballistic movements. , 1974, Brain research.

[13]  Robert J. van Beers,et al.  How humans combine simultaneous proprioceptive and visual position information , 1996, Experimental Brain Research.

[14]  M. Björklund Effects of Repetitive Work on Proprioception and of Stretching on Sensory Mechanisms : Implications for Work-related Neuromuscular Disorders , 2004 .

[15]  Katrin Wolf,et al.  PinchPad: performance of touch-based gestures while grasping devices , 2012, TEI.