“…Sensor-based systems have been developed to recognize color blocks [ 57 ], benches [ 58 ], tables [ 59 ], staircases [ 60 , 61 , 62 , 63 ], and elevators [ 64 ], using laser range sensors [ 62 , 63 ], laser pointers combined with a CCD camera [ 61 ], or Kinect sensors [ 57 , 58 , 59 , 64 ]. These systems allow visually impaired users to find and use target objects.…”