Michael J Fu1, Andrew D Hershberger2, Kumiko Sano2, M Cenk Cavuşoğlu2. 1. Cleveland FES Center of Excellence, Louis Stokes Cleveland Dept. of Veterans Affairs Medical Center, Cleveland, OH, USA. 2. Dept. of Electrical Engineering and Computer Science, Case Western Reserve University, Cleveland, OH, USA.
Abstract
Given the ease that humans have with using a keyboard and mouse in typical, non-colocated computer interaction, many studies have investigated the value of co-locating the visual field and motor workspaces using immersive display modalities. Significant understanding has been gained by previous work comparing physical tasks against virtual tasks, visuo-motor co-location versus non-colocation, and even visuo-motor rotational misalignments in virtual environments (VEs). However, few studies have explored all of these paradigms in context with each other and it is difficult to perform inter-study comparisons because of the variation in tested motor tasks. Therefore, using a stereoscopic fish tank display setup, the goal for the current study was to characterize human performance of a 3D Fitts' point-to-point reaching task using a stylus-based haptic interface in the physical, co-located/non-colocated, and rotated VE visualization conditions.Five performance measures - throughput, initial movement error, corrective movements, and peak velocity - were measured and used to evaluate task performance. These measures were studied in 22 subjects (11 male, 11 female, ages 20-32) performing a 3D variant of Fitts' serial task under 10 task conditions: physical, co-located VE, non-colocated VE, and rotated VEs from 45-315° in 45° increments. HYPOTHESES: All performance measures in the co-located VE were expected to reflect significantly reduced task performance over the real condition, but also reflect increased performance over the non-colocated VE condition. For rotational misalignments, all performance measures were expected to reflect highest performance at 0°, reduce to lowest performance at 90° and rise again to a local maximum at 180° (symmetric about 0°). RESULTS: All performance measures showed that the co-located VE condition resulted in significantly lower task performance than the physical condition and higher mean performance than the non-colocated VE condition, but the difference was not statistically significant. Also, rotation misalignments showed that task performance were mostly reduced to minimums at 90°, 135°, and 225°. We conclude that co-located VEs may not significantly improve point-to-point reaching performance over non-colocated VEs. Also, visual rotations of ±45° affected throughput, efficiency, peak velocity, and initial movement error, but the number of corrective movements were not affected until ±90°.
Given the ease that humans have with using a keyboard and mouse in typical, non-colocated computer interaction, many studies have investigated the value of co-locating the visual field and motor workspaces using immersive display modalities. Significant understanding has been gained by previous work comparing physical tasks against virtual tasks, visuo-motor co-location versus non-colocation, and even visuo-motor rotational misalignments in virtual environments (VEs). However, few studies have explored all of these paradigms in context with each other and it is difficult to perform inter-study comparisons because of the variation in tested motor tasks. Therefore, using a stereoscopic fish tank display setup, the goal for the current study was to characterize human performance of a 3D Fitts' point-to-point reaching task using a stylus-based haptic interface in the physical, co-located/non-colocated, and rotated VE visualization conditions.Five performance measures - throughput, initial movement error, corrective movements, and peak velocity - were measured and used to evaluate task performance. These measures were studied in 22 subjects (11 male, 11 female, ages 20-32) performing a 3D variant of Fitts' serial task under 10 task conditions: physical, co-located VE, non-colocated VE, and rotated VEs from 45-315° in 45° increments. HYPOTHESES: All performance measures in the co-located VE were expected to reflect significantly reduced task performance over the real condition, but also reflect increased performance over the non-colocated VE condition. For rotational misalignments, all performance measures were expected to reflect highest performance at 0°, reduce to lowest performance at 90° and rise again to a local maximum at 180° (symmetric about 0°). RESULTS: All performance measures showed that the co-located VE condition resulted in significantly lower task performance than the physical condition and higher mean performance than the non-colocated VE condition, but the difference was not statistically significant. Also, rotation misalignments showed that task performance were mostly reduced to minimums at 90°, 135°, and 225°. We conclude that co-located VEs may not significantly improve point-to-point reaching performance over non-colocated VEs. Also, visual rotations of ±45° affected throughput, efficiency, peak velocity, and initial movement error, but the number of corrective movements were not affected until ±90°.