两张白色图像的 pHash 互相关为 0

Question

我正在使用 Shipwreck.Phash 进行图像比较。我刚刚认识到两个相同的白色图像 return 互相关为 0，尽管它应该 return 1.

哈希 1：0x0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000

哈希 2：0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000

互相关：0

我的代码：

static void Main(string[] args)
    {


        var firstImage = new Bitmap(@"Bilder\hash1.JPG");
        var secondImage = new Bitmap(@"Bilder\hash1.JPG");


        var hash = ImagePhash.ComputeDigest(firstImage.ToLuminanceImage());
        var hash2 = ImagePhash.ComputeDigest(secondImage.ToLuminanceImage());

        var score = ImagePhash.GetCrossCorrelation(hash, hash2);

        Console.WriteLine(hash);
        Console.WriteLine(hash2);

        Console.WriteLine(score);


    }

有人可以解释一下我的结果吗？提前致谢。

给出的图片：whiteImage

Answer 1

我直接问了 Shipwreck 开发者，他们的回答是：

As the cross-correlation calculation is based on a kind of division, it doesn't support zero vectors. So the pHash doesn't support single-color-image.

实现来自@Bagus Tesa 的 fiddle 它正在运行，尽管它是来自 Shipwreck.Phash 的副本。因此，我将 CrossCorrelation 方法从 NuGet 更改为他的。

两张白色图像的 pHash 互相关为 0

pHash cross correlation of two white images is 0

c#

image-comparison

phash