title: Psychophysical evaluation of haptic perception under augmentation by a handheld device.
abstract: OBJECTIVE
  This study investigated the effectiveness of force augmentation in haptic perception tasks.
  
  
  BACKGROUND
  Considerable engineering effort has been devoted to developing force augmented reality (AR) systems to assist users in delicate procedures like microsurgery. In contrast, far less has been done to characterize the behavioral outcomes of these systems, and no research has systematically examined the impact of sensory and perceptual processes on force augmentation effectiveness.
  
  
  METHODS
  Using a handheld force magnifier as an exemplar haptic AR, we conducted three experiments to characterize its utility in the perception of force and stiffness. Experiments 1 and 2 measured, respectively, the user's ability to detect and differentiate weak force (<0.5 N) with or without the assistance of the device and compared it to direct perception. Experiment 3 examined the perception of stiffness through the force augmentation.
  
  
  RESULTS
  The user's ability to detect and differentiate small forces was significantly improved by augmentation at both threshold and suprathreshold levels. The augmentation also enhanced stiffness perception. However, although perception of augmented forces matches that of the physical equivalent for weak forces, it falls off with increasing intensity.
  
  
  CONCLUSIONS
  The loss in the effectiveness reflects the nature of sensory and perceptual processing. Such perceptual limitations should be taken into consideration in the design and development of haptic AR systems to maximize utility.
  
  
  CONCLUSIONS
  The findings provide useful information for building effective haptic AR systems, particularly for use in microsurgery.
authors: Arizona State University, Mesa, Arizona Bing.Wu@asu.edu.
authors: Bing
authors: B
authors: Wu
authors: Carnegie Mellon University, Pittsburgh, Pennsylvania.
authors: Roberta
authors: R
authors: Klatzky
authors: University of Pittsburgh, Pennsylvania.
authors: Randy
authors: R
authors: Lee
authors: University of Pittsburgh, Pennsylvania.
authors: Vikas
authors: V
authors: Shivaprabhu
authors: Carnegie Mellon University, Pittsburgh, Pennsylvania.
authors: John
authors: J
authors: Galeotti
authors: Carnegie Mellon University, Pittsburgh, Pennsylvania.
authors: Mel
authors: M
authors: Siegel
authors: University of Pittsburgh, Pennsylvania.
authors: Joel S
authors: JS
authors: Schuman
authors: Carnegie Mellon University, Pittsburgh, Pennsylvania.
authors: Ralph
authors: R
authors: Hollis
authors: University of Pittsburgh, Pennsylvania.
authors: George
authors: G
authors: Stetten
mesh_terms: D000328:Adult; D004867:Equipment Design; D005260:Female; D006801:Humans; D008297:Male; D011601:Psychophysics / Q000295:instrumentation* / Q000379:methods*; D014110:Touch / Q000502:physiology*; D055698:Touch Perception / Q000502:physiology*; D014584:User-Computer Interface; D055815:Young Adult
keywords: augmented reality; force perception; haptic interfaces; perceptual effectiveness; stiffness perception