node-moving-things-tracker

Realtime tracker by detections wrote in javascript for node.js / browsers

Introduction

node-moving-things-tracker is a javascript implementation of the "tracker by detections" for realtime multiple object tracking (MOT).

It takes in input a txt file (TODO change to json) generated by node-yolo and outputs a tracker.json file that assigns unique IDs to the YOLO detections bbox.

_The detections entry file could be generated by object detection algorithm than YOLO, it just needs to respects the same format.

Detections input:

Tracker output:

Installation and usage

Requires node.js , available as a npm module: http://npmjs.com/node-moving-things-tracker

# Install globaly to use as command line tool
npm install -g node-moving-things-tracker 

# Install localy your node.js / javascript project
npm install --save node-moving-things-tracker 

Command line usage

NOTE : usage is customized for the use case of lab-beat-the-traffic

node-moving-things-tracker --input PATH_TO_YOLO_DETECTIONS.txt
# This will output a tracker.json file in the same folder containing the tracker data

As an external module

See usage in lab-traffic-cam

const Tracker = require('node-moving-things-tracker').Tracker;

Tracker.updateTrackedItemsWithNewFrame(detectionScaledOfThisFrame, currentFrame);

const trackerDataForThisFrame = Tracker.getJSONOfTrackedItems();

Detections Input and tracker output format

See example here:

Coordinate space:

Detections Input

rawdetections.txt

{"frame":0,"detections":[{"x":699,"y":99,"w":32,"h":19,"prob":34,"name":"car"},{"x":285,"y":170,"w":40,"h":32,"prob":26,"name":"car"},{"x":259,"y":178,"w":75,"h":46,"prob":42,"name":"car"},{"x":39,"y":222,"w":91,"h":52,"prob":61,"name":"car"},{"x":148,"y":199,"w":123,"h":55,"prob":53,"name":"car"}]}
{"frame":1,"detections":[{"x":699,"y":99,"w":32,"h":19,"prob":31,"name":"car"},{"x":694,"y":116,"w":34,"h":23,"prob":25,"name":"car"},{"x":285,"y":170,"w":40,"h":32,"prob":27,"name":"car"},{"x":259,"y":178,"w":75,"h":46,"prob":42,"name":"car"},{"x":39,"y":222,"w":91,"h":52,"prob":61,"name":"car"},{"x":148,"y":199,"w":123,"h":55,"prob":52,"name":"car"}]}

Tracker Output

Normal mode:

{
  // Tracker data for each frame
  "43": [
    {      
      "id": 0,
      "x": 628,
      "y": 144,
      "w": 48,
      "h": 29,
      "name": "car",
    },
    {
      "id": 1,
      "x": 620,
      "y": 154,
      "w": 50,
      "h": 35,
      "name": "car",
    }
  ]
}

Debug mode:

#Run with ---debug flag at the end
node-moving-things-tracker --debug --input PATH_TO_YOLO_DETECTIONS.txt

{
  // Tracker data for each frame
  "43": [
    {
      "id": "900e36a2-cbc7-427c-83a9-819d072391f0",
      "idDisplay": 0,
      "x": 628,
      "y": 144,
      "w": 48,
      "h": 29,
      "name": "car",
      "isZombie": false,
      "zombieOpacity": 1,
      "appearFrame": 35,
      "disappearFrame": null
    },
    {
      "id": "38939c38-c977-40a9-ad6a-3bb916c37fa1",
      "idDisplay": 1,
      "x": 620,
      "y": 154,
      "w": 50,
      "h": 35,
      "name": "car",
      "isZombie": false,
      "zombieOpacity": 1,
      "appearFrame": 43,
      "disappearFrame": null
    }
  ]
}

Limitations

No params tweaking is possible via command-line for now, it is currently optimized for car tracking.