/*
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 * Image processing operations for SciJava Ops.
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package org.scijava.ops.image.features.tamura2d;

import java.util.function.Function;

import net.imglib2.IterableInterval;
import net.imglib2.type.numeric.RealType;

import org.scijava.function.Computers;
import org.scijava.ops.spi.OpDependency;

/**
 * Default implementation of tamura feature contrast.
 *
 * @author Andreas Graumann (University of Konstanz)
 * @implNote op names='features.tamura.contrast'
 */
public class DefaultContrastFeature<I extends RealType<I>, O extends RealType<O>>
	implements Computers.Arity1<IterableInterval<I>, O>
{

	@OpDependency(name = "stats.moment4AboutMean")
	private Function<Iterable<I>, O> m4Op;
	@OpDependency(name = "stats.variance")
	private Function<Iterable<I>, O> varOp;
	@OpDependency(name = "stats.stdDev")
	private Function<Iterable<I>, O> stdOp;

	/**
	 * TODO
	 *
	 * @param input
	 * @param output
	 */
	@Override
	public void compute(final IterableInterval<I> input, final O output) {
		if (input.numDimensions() != 2) throw new IllegalArgumentException(
			"Only 2 dimensional images allowed!");

		// Get fourth moment about mean
        var m4 = m4Op.apply(input).getRealDouble();
        var var = varOp.apply(input).getRealDouble();
        var std = stdOp.apply(input).getRealDouble();

        var l4 = m4 / (var * var);

		// contrast
        var fCon = std / Math.pow(l4, 0.25);
		output.setReal(fCon);
	}

}
