Exemplo n.º 1
0
 void lineToArea(ImagePlus imp) {
   Roi roi = imp.getRoi();
   if (roi == null || !roi.isLine()) {
     IJ.error("Line to Area", "Line selection required");
     return;
   }
   ImageProcessor ip2 = new ByteProcessor(imp.getWidth(), imp.getHeight());
   ip2.setColor(255);
   if (roi.getType() == Roi.LINE && roi.getStrokeWidth() > 1) ip2.fillPolygon(roi.getPolygon());
   else roi.drawPixels(ip2);
   // new ImagePlus("ip2", ip2.duplicate()).show();
   ip2.setThreshold(255, 255, ImageProcessor.NO_LUT_UPDATE);
   ThresholdToSelection tts = new ThresholdToSelection();
   Roi roi2 = tts.convert(ip2);
   imp.setRoi(roi2);
   Roi.previousRoi = (Roi) roi.clone();
 }
Exemplo n.º 2
0
 void areaToLine(ImagePlus imp) {
   Roi roi = imp.getRoi();
   if (roi == null || !roi.isArea()) {
     IJ.error("Area to Line", "Area selection required");
     return;
   }
   Polygon p = roi.getPolygon();
   if (p == null) return;
   int type1 = roi.getType();
   if (type1 == Roi.COMPOSITE) {
     IJ.error("Area to Line", "Composite selections cannot be converted to lines.");
     return;
   }
   int type2 = Roi.POLYLINE;
   if (type1 == Roi.OVAL
       || type1 == Roi.FREEROI
       || type1 == Roi.TRACED_ROI
       || ((roi instanceof PolygonRoi) && ((PolygonRoi) roi).isSplineFit())) type2 = Roi.FREELINE;
   Roi roi2 = new PolygonRoi(p.xpoints, p.ypoints, p.npoints, type2);
   imp.setRoi(roi2);
 }
Exemplo n.º 3
0
  /*
  if selection is closed shape, create a circle with the same area and centroid, otherwise use<br>
  the Pratt method to fit a circle to the points that define the line or multi-point selection.<br>
  Reference: Pratt V., Direct least-squares fitting of algebraic surfaces", Computer Graphics, Vol. 21, pages 145-152 (1987).<br>
  Original code: Nikolai Chernov's MATLAB script for Newton-based Pratt fit.<br>
  (http://www.math.uab.edu/~chernov/cl/MATLABcircle.html)<br>
  Java version: https://github.com/mdoube/BoneJ/blob/master/src/org/doube/geometry/FitCircle.java<br>
  @authors Nikolai Chernov, Michael Doube, Ved Sharma
  */
  void fitCircle(ImagePlus imp) {
    Roi roi = imp.getRoi();
    if (roi == null) {
      noRoi("Fit Circle");
      return;
    }

    if (roi.isArea()) { // create circle with the same area and centroid
      ImageProcessor ip = imp.getProcessor();
      ip.setRoi(roi);
      ImageStatistics stats =
          ImageStatistics.getStatistics(ip, Measurements.AREA + Measurements.CENTROID, null);
      double r = Math.sqrt(stats.pixelCount / Math.PI);
      imp.killRoi();
      int d = (int) Math.round(2.0 * r);
      IJ.makeOval(
          (int) Math.round(stats.xCentroid - r), (int) Math.round(stats.yCentroid - r), d, d);
      return;
    }

    Polygon poly = roi.getPolygon();
    int n = poly.npoints;
    int[] x = poly.xpoints;
    int[] y = poly.ypoints;
    if (n < 3) {
      IJ.error("Fit Circle", "At least 3 points are required to fit a circle.");
      return;
    }

    // calculate point centroid
    double sumx = 0, sumy = 0;
    for (int i = 0; i < n; i++) {
      sumx = sumx + poly.xpoints[i];
      sumy = sumy + poly.ypoints[i];
    }
    double meanx = sumx / n;
    double meany = sumy / n;

    // calculate moments
    double[] X = new double[n], Y = new double[n];
    double Mxx = 0, Myy = 0, Mxy = 0, Mxz = 0, Myz = 0, Mzz = 0;
    for (int i = 0; i < n; i++) {
      X[i] = x[i] - meanx;
      Y[i] = y[i] - meany;
      double Zi = X[i] * X[i] + Y[i] * Y[i];
      Mxy = Mxy + X[i] * Y[i];
      Mxx = Mxx + X[i] * X[i];
      Myy = Myy + Y[i] * Y[i];
      Mxz = Mxz + X[i] * Zi;
      Myz = Myz + Y[i] * Zi;
      Mzz = Mzz + Zi * Zi;
    }
    Mxx = Mxx / n;
    Myy = Myy / n;
    Mxy = Mxy / n;
    Mxz = Mxz / n;
    Myz = Myz / n;
    Mzz = Mzz / n;

    // calculate the coefficients of the characteristic polynomial
    double Mz = Mxx + Myy;
    double Cov_xy = Mxx * Myy - Mxy * Mxy;
    double Mxz2 = Mxz * Mxz;
    double Myz2 = Myz * Myz;
    double A2 = 4 * Cov_xy - 3 * Mz * Mz - Mzz;
    double A1 = Mzz * Mz + 4 * Cov_xy * Mz - Mxz2 - Myz2 - Mz * Mz * Mz;
    double A0 = Mxz2 * Myy + Myz2 * Mxx - Mzz * Cov_xy - 2 * Mxz * Myz * Mxy + Mz * Mz * Cov_xy;
    double A22 = A2 + A2;
    double epsilon = 1e-12;
    double ynew = 1e+20;
    int IterMax = 20;
    double xnew = 0;
    int iterations = 0;

    // Newton's method starting at x=0
    for (int iter = 1; iter <= IterMax; iter++) {
      iterations = iter;
      double yold = ynew;
      ynew = A0 + xnew * (A1 + xnew * (A2 + 4. * xnew * xnew));
      if (Math.abs(ynew) > Math.abs(yold)) {
        if (IJ.debugMode) IJ.log("Fit Circle: wrong direction: |ynew| > |yold|");
        xnew = 0;
        break;
      }
      double Dy = A1 + xnew * (A22 + 16 * xnew * xnew);
      double xold = xnew;
      xnew = xold - ynew / Dy;
      if (Math.abs((xnew - xold) / xnew) < epsilon) break;
      if (iter >= IterMax) {
        if (IJ.debugMode) IJ.log("Fit Circle: will not converge");
        xnew = 0;
      }
      if (xnew < 0) {
        if (IJ.debugMode) IJ.log("Fit Circle: negative root:  x = " + xnew);
        xnew = 0;
      }
    }
    if (IJ.debugMode)
      IJ.log("Fit Circle: n=" + n + ", xnew=" + IJ.d2s(xnew, 2) + ", iterations=" + iterations);

    // calculate the circle parameters
    double DET = xnew * xnew - xnew * Mz + Cov_xy;
    double CenterX = (Mxz * (Myy - xnew) - Myz * Mxy) / (2 * DET);
    double CenterY = (Myz * (Mxx - xnew) - Mxz * Mxy) / (2 * DET);
    double radius = Math.sqrt(CenterX * CenterX + CenterY * CenterY + Mz + 2 * xnew);
    if (Double.isNaN(radius)) {
      IJ.error("Fit Circle", "Points are collinear.");
      return;
    }
    CenterX = CenterX + meanx;
    CenterY = CenterY + meany;
    imp.killRoi();
    IJ.makeOval(
        (int) Math.round(CenterX - radius),
        (int) Math.round(CenterY - radius),
        (int) Math.round(2 * radius),
        (int) Math.round(2 * radius));
  }