Strange timing bug

gistfile1.java

import hypermedia.video.*;
import java.awt.Rectangle;

int MAXFACES = 500;
int DX, DY, DW, DH;
int TX, TY, TW, TH;
int numberOfFacesCaptured = 0;
int faceLengthFlag = 0;
int cueFlag = 0;
int sleepCount = 5000;

OpenCV opencv;



public void setup() {

  size(640, 480);
  // THESE ARE THE OFFSETS CAUSED BY THE ROI
  // CHANGE THESE ACCORDING TO THE PARAMS
  // YOU WANT FOR THE ROI CALL
  DX = width / 4;
  DY = 50;
  DW = 300;
  DH = 300;
  // coordinates for the text box
  TX = 150;
  TY = 400;
  TW = 300;
  TH = 100;
  cueFlag = 0;
  background(0, 0, 0);
  /*
		opencv = new OpenCV(this);
   		opencv.capture(width, height); // open video stream
   		// may need to change this depending on where you have OpenCV installed
   		opencv.cascade("/usr/local/share/OpenCV/haarcascades/haarcascade_frontalface_alt.xml");
   		*/
}

public void placeSquare() {
  stroke(100, 100, 100);
  fill(100, 100, 100);
  rect(TX, TY, TW, TH);
}


public void draw() {
  if (cueFlag == 0) {
    opencv = new OpenCV(this);
    opencv.capture(width, height); // open video stream
    // may need to change this depending on where you have OpenCV installed
    opencv.cascade("/usr/local/share/OpenCV/haarcascades/haarcascade_frontalface_alt.xml");
  }
  cueFlag = 1;
  opencv.read();
  opencv.ROI(DX, DY, DW, DH);

  //initialScreen();
  // rect(TX, TY, TW, TH);

  // countdownScreen();
  rect(DX, DY, DW, DH);

  Rectangle[] faces = opencv.detect((float) (1.2), 6, 
  OpenCV.HAAR_DO_CANNY_PRUNING, 100, 100);

  if (faces.length == 0) {
    faceLengthFlag = 0;
  }

  image(opencv.image().get(DX, DY, DW, DH), DX, DY);

  if (faces.length > 0) {
    placeSquare();
    long start = System.currentTimeMillis();
    while (abs (start - System.currentTimeMillis ()) < 3000) {
      // wait so the person can get their face centered
    }

    opencv.stop();
    
    cueFlag = 0;
  }

  noFill();
  stroke(0, 0, 0);
}