Control-display ratio enhancements for mobile interaction

Mobile devices pose new design challenges, prompting the development of indirect interaction techniques that improve performance by reducing the occlusion caused by touch input. Direct touch interaction (e.g., tap to select) is imprecise, due to occlusion and the finger's surface area. Many cursor-based interaction techniques have been proposed to address this issue; however, these techniques do not dynamically adjust the control-to-display movement ratio (CDratio) to improve accuracy and interaction times. This paper analyzes the performance benefits of applying adaptive CDratio enhancements to mobile device interaction for selecting targets placed among distractors. Existing desktop computer enhancement methods were compared to a new enhancement method, Magnetic Targets and a method that combines CDratio enhancements based on a greater context of the interactions. Magnetic Targets and the combined method both resulted in significantly better objective performance compared to the existing enhancements. The combined method performed similarly to Magnetic Targets or significantly better across the objective metrics. It is noted that an optimization process was not used to set the CDratio enhancement parameters; however, optimization of the parameters is expected to improve the interaction performance.