imagejで一定範囲のmin, maxを求めるplugin

Custom_Min_Max.java

import ij.*;
import ij.gui.*;
import ij.measure.*;
import ij.plugin.*;
import ij.plugin.filter.*;
import ij.process.*;
import java.awt.*;
import java.util.Arrays;

public class Custom_Min_Max implements PlugIn {

  public void run(String arg) {
    ResultsTable rt = Analyzer.getResultsTable();
    if (rt == null) {
      rt = new ResultsTable();
      Analyzer.setResultsTable(rt);
    }

    ImagePlus imp = IJ.getImage();
    if (imp == null) {
      IJ.showMessage("Required to Select Image Window!");
      return;
    }
    ImageProcessor ip = imp.getProcessor();
    int width = ip.getWidth();
    int height = ip.getHeight();
    Rectangle rect = imp.getRoi().getBoundingRect();
    if (rect == null) {
      IJ.showMessage("Roi not select!");
      return;
    }
    int type = imp.getType();
    int area = rect.height * rect.width;

    int[] grayArr = new int[area];

    for (int i = 0; i < rect.height; i++) {
      for (int j = 0; j < rect.width; j++) {
        int val = 0;
        if (type == ImagePlus.COLOR_RGB) {
          int[] pixels = (int[])ip.getPixels();
          val = (int)pixels[(j + rect.x) + (i + rect.y) * width];
          int r = (val >> 16) & 0xff;
          int g = (val >> 8) & 0xff;
          int b = (val >> 0) & 0xff;
          val = (r + g + b) / 3;
        } else if (type == ImagePlus.GRAY16){
          short[] pixels = (short[])ip.getPixels();
          val = pixels[(j + rect.x) + (i + rect.y) * width] & 0xffff;
        }
        grayArr[i * rect.width + j] = val;
      }
    }
    Arrays.sort(grayArr);
    rt.incrementCounter();
    // raw min_max
    rt.addValue("min_raw", grayArr[0]);
    rt.addValue("max_raw", grayArr[area - 1]);

    double ratio = 0.95;
    int half_ex = (int)(((1.0 - ratio) / 2.0) * area);
    rt.addValue("min_95", grayArr[half_ex]);
    rt.addValue("max_95", grayArr[(area - 1) - half_ex]);

    ratio = 0.9;
    half_ex = (int)(((1.0 - ratio) / 2.0) * area);
    rt.addValue("min_90", grayArr[half_ex]);
    rt.addValue("max_90", grayArr[(area - 1) - half_ex]);

    ratio = 0.8;
    half_ex = (int)(((1.0 - ratio) / 2.0) * area);
    rt.addValue("min_80", grayArr[half_ex]);
    rt.addValue("max_80", grayArr[(area - 1) - half_ex]);

    rt.show("Results");
  }
};