The Crosswatch Traffic IntersectionAnalyzer: a Roadmap for the Future       James Coughlan, Ph.D.
Traffic intersections: difficult    for many visually impaired              travelersHow to align oneself properly to cros...
Past work“Crosswatch” system (Ivanchenko et al.,ICCHP 2010; etc.) – computer visionsmartphone app that performs thefollowi...
Crosswatch (past work)Two kinds of misalignment relative tocrosswalk corridor: (1) translated to theleft; (2) direction er...
Crosswatch (past work)How Crosswatch finds crosswalk andcalculates alignment                 5
Crosswatch (past work)Crosswalk scene   Zoomed-in                  region showing                  Walk light       6
Advantages of   Crosswatch approachInformation provided to user in real timeSystem requires no new infrastructuresince it ...
Related workAranda & Mares, ICCHP 2004: computervision for Walk light detectionZebralocalizer (Ahmetovic, Bernareggi &Masc...
Next stepsTravelers need a broad range ofinformation about intersections:•What type of intersection, features in it•Where ...
“What” informationWhat is the intersectionlayout? Four-way, three-way, etc.?Are there stop signs?Signal lights? Walk light...
“Where” informationWhere are all the crosswalks? How am Ioriented relative to the one I want?Where is the pedestrian walk ...
“When” informationWhen is it time to cross, according to Walk light(or traffic lights if there is no Walk light)?Note: thi...
How to get What, Where,     When information?Realization: it is impractical to expect computervision to figure out all thi...
Walk buttons come inmany shapes and sizes                        14
Find the walk button!                        15
Median stripsWithout high-resolution depthinformation to showthe elevated medianstrip, it is hard tofind reliably         ...
Complicated intersectionsWhere a visually impaired traveler mayneed the most guidance… computervision may have the most di...
Solution: GISUse computer vision where it isnecessary:(b)find user’s location and orientationrelative to intersection feat...
How this worksGPS tells you which intersection you’re atSmartphone compass and accelerometerindicate direction you’re poin...
How this works (continued)GIS has data foreach intersection,including layout ofall crosswalks, listof importantfeatures an...
Much to doWhere to find this GIS information?Some available through municipal/transitagencies, Google MapsBut much of it m...
Much to do (continued)Develop Crosswatch algorithms forestimating high-resolution GPScoordinatesAppropriate Crosswatch use...
ConclusionCrosswatch needs to expand itsfunctionality to provide extensive “what”,“where” and “when” informationUse comput...
Thanks to…Second author: Dr. Huiying Shen (Smith-  Kettlewell)Collaborators: Dr. Megan Lawrence  (Smith-Kettlewell), Dr. V...
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The Crosswatch Traffic Intersection Analyzer: A Roadmap for the Future - Coughlan, James (s)

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Portable and Mobile Systems in Assistive Technology - The Crosswatch Traffic Intersection Analyzer: A Roadmap for the Future - Coughlan, James (s)

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The Crosswatch Traffic Intersection Analyzer: A Roadmap for the Future - Coughlan, James (s)

  1. 1. The Crosswatch Traffic IntersectionAnalyzer: a Roadmap for the Future James Coughlan, Ph.D.
  2. 2. Traffic intersections: difficult for many visually impaired travelersHow to align oneself properly to crosswalk?What is the layout of the intersection?How to remain inside crosswalk while walking?When is it safe to cross?How to avoid moving 2 vehicles?
  3. 3. Past work“Crosswatch” system (Ivanchenko et al.,ICCHP 2010; etc.) – computer visionsmartphone app that performs thefollowing functions in real time for visuallyimpaired user:•find crosswalk markings (e.g., zebrastripes), determine user’s orientationrelative to crosswalk “corridor”•find Walk light and announce if it’s on 3
  4. 4. Crosswatch (past work)Two kinds of misalignment relative tocrosswalk corridor: (1) translated to theleft; (2) direction error.Crosswatch can calculate both kinds ofmisalignment. 4
  5. 5. Crosswatch (past work)How Crosswatch finds crosswalk andcalculates alignment 5
  6. 6. Crosswatch (past work)Crosswalk scene Zoomed-in region showing Walk light 6
  7. 7. Advantages of Crosswatch approachInformation provided to user in real timeSystem requires no new infrastructuresince it analyzes the visual features thatare already there 7
  8. 8. Related workAranda & Mares, ICCHP 2004: computervision for Walk light detectionZebralocalizer (Ahmetovic, Bernareggi &Mascetti, 2011): smartphone computervision systemBohonos et al., ICCHP 2008: Bluetoothbeaconing at traffic intersections 8
  9. 9. Next stepsTravelers need a broad range ofinformation about intersections:•What type of intersection, features in it•Where are the crosswalk and otherimportant features•When is it time to cross? 9
  10. 10. “What” informationWhat is the intersectionlayout? Four-way, three-way, etc.?Are there stop signs?Signal lights? Walk light?Is there a pedestrianwalk button?Is there a median stripsomewhere in thecrosswalk? 10
  11. 11. “Where” informationWhere are all the crosswalks? How am Ioriented relative to the one I want?Where is the pedestrian walk button relative towhere I am standing?How long is the crosswalk? How far is it to themedian strip? 11
  12. 12. “When” informationWhen is it time to cross, according to Walk light(or traffic lights if there is no Walk light)?Note: this is not necessarily the same as whenit is safe to cross! 12
  13. 13. How to get What, Where, When information?Realization: it is impractical to expect computervision to figure out all this information on itsown!Intersections, and the features in them, areextremely variable, and not always easy to see(even for people with normal vision) 13
  14. 14. Walk buttons come inmany shapes and sizes 14
  15. 15. Find the walk button! 15
  16. 16. Median stripsWithout high-resolution depthinformation to showthe elevated medianstrip, it is hard tofind reliably 16
  17. 17. Complicated intersectionsWhere a visually impaired traveler mayneed the most guidance… computervision may have the most difficulties! 17
  18. 18. Solution: GISUse computer vision where it isnecessary:(b)find user’s location and orientationrelative to intersection features(b) detect signal lights in real time (e.g.,Walk light)Augment with GIS (GeographicInformation Systems) 18
  19. 19. How this worksGPS tells you which intersection you’re atSmartphone compass and accelerometerindicate direction you’re pointing inComputer vision analyzes visible featuresin scene and determines (x,y) GPScoordinates (to within about 1 meter)Use GIS to find information relevant tocurrent location (look up online, ordownload all information for a city orregion onto smartphone) 19
  20. 20. How this works (continued)GIS has data foreach intersection,including layout ofall crosswalks, listof importantfeatures andlandmarks and theirlocations 20
  21. 21. Much to doWhere to find this GIS information?Some available through municipal/transitagencies, Google MapsBut much of it may require crowd-sourcing:volunteers will contribute information aboutintersections in their neighborhood toonline GIS database 21
  22. 22. Much to do (continued)Develop Crosswatch algorithms forestimating high-resolution GPScoordinatesAppropriate Crosswatch user interface: forinstance, how to help user pan left to rightto capture entire intersection sceneUser surveys (what should Crosswatch do 22and not do?) and testing
  23. 23. ConclusionCrosswatch needs to expand itsfunctionality to provide extensive “what”,“where” and “when” informationUse computer vision where it is neededand rely on GIS to provide otherinformation (data infrastructure)Future idea: use GIS to help with routeplanning that is tailored to needs of traveler 23
  24. 24. Thanks to…Second author: Dr. Huiying Shen (Smith- Kettlewell)Collaborators: Dr. Megan Lawrence (Smith-Kettlewell), Dr. Volodymyr Ivanchenko (Amazon Lab 126)Funding from NIH and NIDRR 24

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