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 * ImageJ software for multidimensional image processing and analysis.
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package net.imagej.ops.imagemoments.centralmoments;

import net.imagej.ops.Op;
import net.imagej.ops.Ops;
import net.imagej.ops.imagemoments.AbstractImageMomentOp;
import net.imagej.ops.special.chain.RTs;
import net.imagej.ops.special.function.UnaryFunctionOp;
import net.imglib2.Cursor;
import net.imglib2.IterableInterval;
import net.imglib2.type.numeric.RealType;

import org.scijava.plugin.Plugin;

/**
 * {@link Op} to calculate the {@code imageMoments.centralMoment03} using
 * 
 * @author Daniel Seebacher (University of Konstanz)
 * @author Christian Dietz (University of Konstanz)
 * @param <I> input type
 * @param <O> output type
 */
@Plugin(type = Ops.ImageMoments.CentralMoment03.class, label = "Image Moment: CentralMoment03")
public class DefaultCentralMoment03<I extends RealType<I>, O extends RealType<O>>
	extends AbstractImageMomentOp<I, O> implements Ops.ImageMoments.CentralMoment03
{
	
	private UnaryFunctionOp<IterableInterval<I>, O> moment00Func;
	private UnaryFunctionOp<IterableInterval<I>, O> moment01Func;

	@Override
	public void initialize() {
		moment00Func = RTs.function(ops(), Ops.ImageMoments.Moment00.class, in());
		moment01Func = RTs.function(ops(), Ops.ImageMoments.Moment01.class, in());
	}

	@Override
	public void compute(final IterableInterval<I> input, final O output) {
		final double moment00 = moment00Func.calculate(input).getRealDouble();
		final double moment01 = moment01Func.calculate(input).getRealDouble();
		
		final double centerY = moment01 / moment00;

		double centralmoment03 = 0;

		final Cursor<I> it = input.localizingCursor();
		while (it.hasNext()) {
			it.fwd();
			final double y = it.getDoublePosition(1) - centerY;
			final double val = it.get().getRealDouble();

			centralmoment03 += val * y * y * y;
		}

		output.setReal(centralmoment03);
	}
}