Navigation methods and apparatus for the visually impaired

Abstract

According to some aspects, a wearable device for estimating a location of the device within a space is provided, the device comprising a plurality of cameras mounted to a structure, at least a portion of the structure being adapted to facilitate a user wearing the device, the plurality of cameras having substantially fixed positions and orientations on the structure relative to each other, and at least one processor configured to receive image data from the plurality of cameras, perform feature detection on the image data to obtain a first plurality of features from the image data, and determine an estimate of the location of the device in the space based, at least in part, on a location associated with a second plurality of features obtained from image data previously captured of the space that matches the first plurality of features.

What is claimed is: 
     
         1 .- 20 . (canceled) 
     
     
         21 . A system for guiding a visually impaired user, the system comprising:
 an image acquisition device configured to capture image data;   a plurality of path data stored in a database, the path data identifying traversable paths to and from selectable locations, wherein the path data is derived from previously captured images of the locations and the identified traversable paths include a map containing graph nodes representing defined locations, captured images, and annotations;   at least one processor executing computer readable instructions stored in at least one non-transitory computer readable storage medium to perform operations comprising:
 performing feature detection on the image data to obtain a plurality of features from the image data, wherein feature detection includes identifying curves, edges, and evaluating metadata of the image data; 
 comparing the plurality of features from the image data and the plurality of stored path data to determine a user's location; and 
 automatically selecting the traversable path from the stored path data corresponding to the user's location and a user-selected destination location. 
   
     
     
         22 . The system of  claim 21  wherein the at least one processor guides the user along the traversable path to the user-selected destination. 
     
     
         23 . The system of  claim 21  further comprising a haptic device configured to receive input from the at least one processor and render haptic gestures as nonaudible guidance to the user on the traversable path to the destination. 
     
     
         24 . The system of  claim 21  further comprising an audio interface configured to receive spoken input from the user and produce audio feedback to the user. 
     
     
         25 . The system of  claim 21  wherein the image acquisition device captures image data of objects in multiple directions in synchronization with one another from the multiple cameras. 
     
     
         26 . The system of  claim 25  wherein the at least one processor generates an N-best list of closest matches between previously acquired image data and newly acquired image data, along with the corresponding match scores, a closest matching image data used to estimate the location and/or orientation of the user. 
     
     
         27 . The system of  claim 21  wherein the at least one processor receives image data of the user's environment from the image data to determine incremental motion of the user. 
     
     
         28 . The system of  claim 21  further comprising an inertial odometry sensor for identifying motion based on inertial measurements and providing inertial data pertaining to a location and a trajectory of a user being tracked. 
     
     
         29 . The system of  claim 28  wherein the inertial odometry sensor comprises any one or combination of accelerometers, magnetometers and/or gyroscopes that detect motion. 
     
     
         30 . The system of  claim 21  wherein the map comprises an undirected graph containing nodes that represent known locations, wherein each node includes any one or combination of location, references to neighboring or adjacent nodes, annotations, image data associated with the node, a timestamp indicating when the node was created, and/or a list of connecting links. 
     
     
         31 . The system of  claim 21  wherein the map further comprises edges indicating a walkable path between two nodes. 
     
     
         32 . The system of  claim 31  wherein the at least one processor presents a sequence of commands indicating which direction the user needs to move to reach a next node in the walkable path from an origin node to a destination node, where the commands are dynamically updated based on the user's progress as the user follows the directions. 
     
     
         33 . A method comprising:
 in a wearable navigation system comprising the system of  claim 21 ;   determining a navigation instruction to be conveyed to a user, the navigation instruction comprising a direction to a target location identified by a vector in a direction of the target location from the user's current location and a difference in the direction between the vector and the user's current heading;   identifying a haptic gesture adapted to convey the navigation instruction; and   rendering the haptic gesture by activating one or more haptic feedback components of a haptic device according to the haptic gesture.   
     
     
         34 . The method of  claim 33  wherein the target location is one of a series of incremental target locations along a sequence of nodes forming a path to a destination. 
     
     
         35 . The method of  claim 33  wherein the target location is a destination location. 
     
     
         36 . The method of  claim 33  wherein the navigation system is a wearable device. 
     
     
         37 . The method of  claim 33  wherein the user's current location is determined by the navigation system. 
     
     
         38 . The method of  claim 33  wherein the navigation system receives image data from one or more image acquisition devices and matches features detected in the image data with features detected in previously acquired image data to facilitate tracking movements of the user in an environment. 
     
     
         39 . At least one computer readable medium having instructions stored thereon that, when executed by at least one computer, cause the at least one computer to perform a method of estimating a location of a device within a space, the device comprising the system of  claim 21 , the method comprising:
 determining a navigation instruction to be conveyed to a user, the navigation instruction comprising a direction to a target location identified by a vector in a direction of the target location from the user's current location and a difference in the direction between the vector and the user's current heading;   identifying a haptic gesture adapted to convey the navigation instruction; and   rendering the haptic gesture by activating one or more haptic feedback components of a haptic device according to the haptic gesture.   
     
     
         40 . The at least one computer readable medium of  claim 39  wherein the device is wearable.