皮尔逊相关系数

Question

我编写了以下 C# 代码来查找两个图像之间的 Pearson 相关系数。完整源码here in the DotNetFiddle.

关联源代码：

public sealed class PearsonCorrelation 
{
    public static double GetSimilarityScore(double[,] p, double[,] q)
    {
        int Width = p.GetLength(0);
        int Height = p.GetLength(1);

        if (Width != q.GetLength(0) || Height != q.GetLength(1))
        {
            throw new ArgumentException("Input vectors must be of the same dimension.");
        }

        double pSum = 0, qSum = 0, pSumSq = 0, qSumSq = 0, productSum = 0;
        double pValue, qValue;

        for (int y = 0; y < Height; y++)
        {
            for (int x = 0; x < Width; x++)
            {
                pValue = p[y, x];
                qValue = q[y, x];

                pSum += pValue;
                qSum += qValue;
                pSumSq += pValue * pValue;
                qSumSq += qValue * qValue;
                productSum += pValue * qValue;
            }
        }

        double numerator = productSum - ((pSum * qSum) / (double)Height);
        double denominator = Math.Sqrt((pSumSq - (pSum * pSum) / (double)Height) * (qSumSq - (qSum * qSum) / (double)Height));

        return (denominator == 0) ? 0 : numerator / denominator;
    }
}

结果：

同一张图片被加载到两个图片框中。

他们的相关系数的值变成了，-1.

这是正确的结果吗？

如果不是，我应该如何纠正？

Answer 1

相同序列的相关性必须是1

看来你在例程的最后有问题；而不是

 double numerator = productSum - ((pSum * qSum) / (double)Height);
 double denominator = Math.Sqrt((pSumSq - (pSum * pSum) / (double)Height) * (qSumSq - (qSum * qSum) / (double)Height));

你应该把

 double n = ((double) Width) * Height;

 double numerator = productSum - ((pSum * qSum) / n);
 double denominator = 
   Math.Sqrt((pSumSq - (pSum * pSum) / n) * (qSumSq - (qSum * qSum) / n));

见

https://en.wikipedia.org/wiki/Pearson_product-moment_correlation_coefficient

皮尔逊相关系数

Pearson correlation coefficient

c#

image-processing

correlation

pearson-correlation