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/*
 * To change this template, choose Tools | Templates
 * and open the template in the editor.
 */

package com.github.ojil.algorithm;

import com.github.ojil.core.Error;
import com.github.ojil.core.Gray8Image;
import com.github.ojil.core.Image;
import com.github.ojil.core.PipelineStage;
import com.github.ojil.core.RgbImage;
import com.github.ojil.core.RgbVal;

/**
 * Thresholds an RgbImage against a number of input colors.
 * @author webb
 */
public class RgbMultiVecThresh extends PipelineStage {
    /**
     * Simplify lookup of color values in array.
     */
    private final int R = 0;
    private final int G = 1;
    private final int B = 2;
    
    private Integer[][] nRgbVals;
    /**
     * Input color values, unpacked.
     */
    private Integer[][] nRgbVecs;
    /**
     * Input threshold value.
     */
    private int nThreshold;
    /**
     * Thresholds an RgbImage against a number of input colors.
     * Each color is described using a target value (rgbVal) and
     * a vector (rgbVec). The idea is that a pixel matches a target
     * value if its difference from the target value, projected
     * on the vector, is less than the threshold. One threshold
     * is used for all colors and the minimum absolute value of
     * all color distances is compared with the threshold. Since
     * the vectors can be unnormalized the relative importance of
     * each target color value can be adjusted. 

     * One way to use this is to set the target color to the mean
     * Rgb value of a region and the target vector to the standard
     * deviation. The threshold would then be the standard deviation
     * squared. Pixels further away than one standard deviation would
     * be rejected.
     * @param rgbVals packed arry of target Rgb values
     * @param rgbVecs packed array of target Rgb vectors
     * @param nThreshold threshold value
     * @throws Error if the input Rgb vectors are not the same
     * length.
     */
    public RgbMultiVecThresh(Integer[] rgbVals, Integer[] rgbVecs, int nThreshold) 
            throws Error
    {
        if (rgbVals.length != rgbVecs.length) {
            throw new Error(
                            Error.PACKAGE.ALGORITHM,
                            ErrorCodes.PARAMETER_SIZES_DIFFER,
                            rgbVals.toString(),
                            rgbVals.toString(),
                            null);
}
        this.nRgbVecs = new Integer[rgbVecs.length][3];
        this.nRgbVals = new Integer[rgbVecs.length][3];
        for (int i=0; i