SortNode

SortNode is a JS binding for SORT: Simple, online, and real-time tracking of multiple objects in a video sequence.

This package is maintained by Techainer

Install

To install this package, make sure you have the following dependencies installed:

• NodeJS 12+
• cmake 3.9+
• OpenCV 3.x.x (Build from source recommened)
• Eigen 3.x.x (sudo apt-get install -y libeigen3-dev)

Noted that we have provide a Dockerfile contain all 3rd dependencies. To use it, build and run the image:

docker build -t sort .
./docker_run.sh

Or you can reference our github actions CI flow to install dependencies for your own OS.

Then you can install the package from npm:

yarn add sort-node@npm:@techainer1t/sort-node

Example

The sort-node package contain the object SortNode that can be use to track object detected from a single video or camera.

The SortNode object can be initialize with 4 arguments in the following order:

• kMinHits: (int) Minimum number of hits before a bounding box was assigned a new track ID (should be 3)
• kMaxAge: (int) Maximum number of frames to keep alive a track without associated detections
• kIoUThreshold: (float between 0 and 1) Minimum IOU for match (should be 0.3)
• kMinConfidence: (float between 0 and 1) Bouding boxes with confidence score less than this value will be ignored

With each frame, you will need to call update method.

This method expect a single arguments that had a the format List[List[float]], which means a list of detected object in that frame. Each object will have the format: [x_top, y_top, width, height, confidence] or [x_top, y_top, width, height, confidence, landmark_x1, landmark_y1, ...] for additional landmark associated with each bounding box

The update method will return a list of tracked object in the format List[Object], each object will have the following structure:

{
    bbox: List[(int) x_top, y_top, width, height],
    track_id: int,
    landmarks: List[(float) x1, y1, x2, y2, ..., x_n, y_n],
}

Please noted that the number of returned object might not be the same as the number of inputed object.

const sortnode = require("@techainer1t/sort-node");
const kMinHits = 3;
const kMaxAge = 1;
const kIoUThreshold = 0.3;
const kMinConfidence = 0.3;
const tracker = sortnode.SortNode(kMinHits, kMaxAge, kIoUThreshold, kMinConfidence);
while (true){
    // Call the object detector
    ...

    // Update the tracker
    tracked = tracker.update(detections);
}

References

The C++ implementation of SORT was written by yasenh from the repo yasenh/sort-cpp