@inproceedings{huy:2020:imprint, abstract = {Touchscreens translate touches of all kinds into 2D coordinates. This limits the input vocabulary and constrains effective interaction to touches by the fingertip. Previous tabletop research extended the input vocabulary with a myriad of promising input techniques using the shape of fingers and hands. However, these techniques are not applicable to mobile devices due to differences in size, ergonomics, and technology. We conducted ideation sessions (N=17) to explore novel input techniques and use cases for imprint-based touch sensing on mobile devices. As a case study, we present FlexionTouch, a novel input technique that recognizes the finger flexion on a touchscreen. Using the finger flexion as an additional input dimension, FlexionTouch provides an always-available shortcut and can be used for value inputs, document previews, and gestures. We propose five example use cases for FlexionTouch input which we evaluated in a second user study (N=20). While the low resolution of the capacitive images leads to a less accurate input compared to tabletops, participants still find the presented use cases helpful. As our input technique is purely software-based, it can be readily deployed to every mobile device with a capacitive touchscreen.}, author = {Huy Viet Le and Sven Mayer and Niels Henze}, booktitle = {19th International Conference on Mobile and Ubiquitous Multimedia}, date = {2020-11-22}, doi = {10.1145/3428361.3428393}, keywords = {capacitive sensing, mobile device}, pubstate = {forthcoming}, series = {MUM 2020}, title = {Imprint-Based Input Techniques for Touch-Based Mobile Devices}, tppubtype = {inproceedings}, url = {https://sven-mayer.com/wp-content/uploads/2020/10/le2020imprint.pdf}, year = {2020} }