title: Mobility and low contrast trip hazard avoidance using augmented depth.
abstract: OBJECTIVE
  We evaluated a novel visual representation for current and near-term prosthetic vision. Augmented depth emphasizes ground obstacles and floor-wall boundaries in a depth-based visual representation. This is achieved by artificially increasing contrast between obstacles and the ground surface via a novel ground plane extraction algorithm specifically designed to preserve low-contrast ground-surface boundaries.
  
  
  METHODS
  The effectiveness of augmented depth was examined in human mobility trials compared against standard intensity-based (Intensity), depth-based (Depth) and random (Random) visual representations. Eight participants with normal vision used simulated prosthetic vision with 20 phosphenes and eight perceivable brightness levels to traverse a course with randomly placed small and low-contrast obstacles on the ground.
  
  
  RESULTS
  The number of collisions was significantly reduced using augmented depth, compared with intensity, depth and random representations (48%, 44% and 72% less collisions, respectively).
  
  
  CONCLUSIONS
  These results indicate that augmented depth may enable safe mobility in the presence of low-contrast obstacles with current and near-term implants. This is the first demonstration that an augmentation of the scene ensuring key objects are visible may provide better outcomes for prosthetic vision.
authors.affiliation: NICTA Computer Vision Research Group, Building A, 7 London Circuit, Canberra, Australia. Research School of Engineering, Australian National University, Canberra, Australia.
authors.forename: Chris
authors.initials: C
authors.lastname: McCarthy
authors.forename: Janine G
authors.initials: JG
authors.lastname: Walker
authors.forename: Paulette
authors.initials: P
authors.lastname: Lieby
authors.forename: Adele
authors.initials: A
authors.lastname: Scott
authors.forename: Nick
authors.initials: N
authors.lastname: Barnes
mesh_terms: D000058:Accidental Falls / Q000517:prevention & control*; D000328:Adult; D003867:Depth Perception / Q000502:physiology*; D005684:Gait / Q000502:physiology*; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010719:Phosphenes / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology; D057488:Visual Prosthesis