Bug in the motion detector cause false positives

[sarxos]

Motion detector should trigger the motion event and stay in "motion" state for the time when motion is in progress and the intertia time defined as one of the parameters. Due to bug in the implementation it caused false positive events about new motion started when previous motion was already in progress.

import java.io.IOException;

import com.github.sarxos.webcam.Webcam;
import com.github.sarxos.webcam.WebcamMotionDetector;
import com.github.sarxos.webcam.WebcamResolution;


/**
 * The goal of this example is to demonstrate the idea behind detecting that
 * motion has stopped.
 * 
 * @author Bartosz Firyn (sarxos)
 */
public class DetectMotionEventsExample {

    Webcam webcam;
    WebcamMotionDetector detector;

    public DetectMotionEventsExample() {

        webcam = Webcam.getDefault();
        webcam.setViewSize(WebcamResolution.VGA.getSize());

        detector = new WebcamMotionDetector(webcam);
        detector.setInterval(200); // one check per 200 ms
        detector.setInertia(2000); // keep "motion" state for 2 seconds
        detector.start();

        Thread t = new Thread("motion-printer") {

            @Override
            public void run() {

                boolean motion = false;
                long now = 0;

                while (true) {
                    now = System.currentTimeMillis();
                    if (detector.isMotion()) {
                        if (!motion) {
                            motion = true;
                            System.out.println(now + " MOTION STARTED");
                        }
                    } else {
                        if (motion) {
                            motion = false;
                            System.out.println(now + " MOTION STOPPED");
                        }
                    }
                    try {
                        Thread.sleep(50); // must be smaller than interval
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        };

        t.setDaemon(true);
        t.start();
    }

    public static void main(String[] args) throws IOException {
        new DetectMotionEventsExample();
        System.in.read(); // keep program open
    }
}