The norfair from rs9000

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This project forked from tryolabs/norfair

Lightweight Python library for adding real-time object tracking to any detector.

License: BSD 3-Clause "New" or "Revised" License

Python 100.00%

norfair's Introduction

Fork of https://github.com/tryolabs/norfair
Customized for Maritime Vessel Tracking.

Features

Detection class support MMSI and message_type (ex. AIS)
The distance function is matrix, for fast computation.

Installation

git clone https://github.com/rs9000/norfair

How it works

Define a matrix euclidean distance metric

def matrix_euclidean(threshold, detections, objects):
    detections_arr = np.array([x.points for x in detections])
    objects_arr = np.array([x.estimate[0] for x in objects])
    same_mmsi = np.array([x.mmsi == y.mmsi for x in detections for y in objects]).reshape(len(detections), len(objects))

    distance_matrix = scipy.spatial.distance_matrix(detections_arr, objects_arr)
    distance_matrix[distance_matrix > threshold] = threshold + 1
    distance_matrix[same_mmsi] = 0

    return distance_matrix

Tracking Example

class Message():
    def __init__(self, timestamp, position, stn, mmsi, type):
        self.timestamp = timestamp
        self.position = position
        self.mmsi = mmsi
        self.type = type


tracker = Tracker(distance_function=matrix_euclidean, distance_threshold=0.5,
                  initialization_delay=3)

messages_t0 = [Message("987298479", np.array([44, 22]), "873624", "AIS"),
            Message("987298479", np.array([44, 22]), "873624", "AIS")]

messages_t1 = [Message("987298479", np.array([44, 22]), "873624", "AIS"),
            Message("987298479", np.array([44, 22]), "873624", "AIS")]

messages_t2 = [Message("987298479", np.array([44, 22]), "873624", "AIS"),
            Message("987298479", np.array([44, 22]), "873624", "AIS")]


messages = [messages_t0, messages_t1, messages_t2]

for t in messages:
    detections = [Detection(points=np.array([x.position for x in t]),
                            mmsi=[x.mmsi for x in t],
                            message_type=[x.message_type for x in t])]

    tracked_objects = tracker.update(detections=detections)