Calculates peak signal-to-noise ratio

Introduction

The PSNR is most commonly used as a measure of quality of reconstruction of compression codecs (e.g., for image compression).

Demo Code


import java.util.HashMap;
import java.util.Map;

public class Main{
    /**//from w  w  w. jav a 2s .c om
     * Calculates peak signal-to-noise ratio The PSNR is most commonly used as a
     * measure of quality of reconstruction of lossy compression codecs (e.g.,
     * for image compression). The signal in this case is the original data, and
     * the noise is the error introduced by compression.
     * 
     * <p>
     * PSNR = (max^2 * width * heigth) / summ(|x-y|^2)
     * 
     * <p>
     * expected to be Infinity if original and actual are the same
     * 
     * @param max
     * @param original
     * @param actual
     * @return
     */
    public static double calculatePSNR(double[][] original,
            double[][] actual, int max) {
        int heigth = original.length;
        Assert.argNotNull(original, actual);
        Assert.argCondition(heigth == actual.length, "Sizes must be same");
        Assert.argCondition(heigth > 0, "original data must be non empty");

        int width = original[0].length;
        Assert.argCondition(width == actual[0].length, "Sizes must be same");

        long numerator = max * max * width * heigth;

        double denominator = 0;
        double absDifference = 0;
        for (int row = 0; row < heigth; ++row) {
            for (int col = 0; col < width; ++col) {
                absDifference = Math.abs(original[row][col]
                        - actual[row][col]);
                denominator += (absDifference * absDifference);
            }
        }

        double result = 10 * Math.log10(numerator / denominator);

        return result;
    }
}

Calculates peak signal-to-noise ratio - Java java.lang

Introduction

Demo Code

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