ImageJ plugin which calculates the average value in each slice

AverageSliceValue.java

import ij.*;
import ij.process.*;
import ij.gui.*;
import java.awt.*;
import ij.plugin.*;
import ij.plugin.frame.*;

public class AverageSliceValue implements PlugIn {

	public void run(String arg) {
		ImagePlus imp = IJ.getImage();
		ImageStack is = imp.getStack();
		int n_slices = is.getSize();
		for(int sliceIndex=1;sliceIndex<=n_slices;sliceIndex++) {
			double sumVal=0;
			long countPixel=0;
			ImageProcessor curSlice=is.getProcessor(sliceIndex);
			float[][] sliceArray=curSlice.getFloatArray();
			for(int x=0;x<sliceArray.length;x++) {
				for(int y=0;y<sliceArray[x].length;y++) {
					sumVal+=sliceArray[x][y];
					countPixel+=1;
				}
				
			}
			IJ.log("Slice:"+sliceIndex+", Mean:"+sumVal/countPixel);
		}
	}

}