Detecting Traffic Signs in OpenStreetCam

OpenStreetCam’s mission is to help you improve OSM with street-view imagery. Photos taken with regular smartphones seem to be good enough for capturing map features like traffic signs, lanes or crosswalks. However, browsing the 120 million+ photos in OSC to find relevant things to map will take a while. The human factor is fundamental to OSM’s culture and we don’t see that changing, but we want to make editing street related attributes more efficient with automation.

We’re happy to announce a beta release of the traffic signs recognition on OpenStreetCam photos, made possible with machine learning. We processed a few million photos and detected around 500.000 traffic signs so far, currently available for tracks in several areas in United States and Canada. We’re working on extending the training sets and optimize the processing so that the area’s soon expanded.

What’s new from a user perspective: the track page on openstreetcam.org will now show detected traffic signs when available:

There’s a preview list of all detections in the track, detection overlays on photos and, of course, filters. Filters might now get a rep as something really exciting, but we’re excited about one of ours: the OSM status. Here’s why: after detecting a sign we compare it to the corresponding OSM feature and check if they’re consistent. Based on that, filtering is available.

For a practical example, let’s take speed limits: Instead of manually cross checking every detection with the maxspeed tag in OSM, one can only review detections where presumably maxspeed is not set or the value’s different in OSM. Just tick the Need review in OSM box.

Here are a few more examples of trips that have already been processed with our sign detections.

What’s next?

We’re busy working on a few things:

  • Scale the training sets and pipeline to extend the supported areas.
  • Traffic signs integration in the JOSM plugin.
  • Tagging new traffic signs support in the webpage.

If you like what we do and want to help:

  • First and foremost, you can use detections to improve OSM. If you’re seeing detections on tracks check them out, see what needs reviewing in OSM and edit. You can open iD or JOSM to photo’s location straight from the webpage.
  • Help us improve the traffic signs recognition. There’s a chance you will find some bad detections. You can review them and flag whether they’re good or bad, see the two buttons above the photo. We’re adding those reviews to training sets to improve recognitions, so please play nice.
  • Help us add these detections to the iD editor as well.

Tip: you can navigate between detections with Ctrl/Cmd + right/left arrows and confirm/invalidate with Ctrl/Cmd + up/down arrows. Goes pretty fast.

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