模糊而不是锐化

我正在使用以下内核，

  double[,] kernel = new double[,]  { { -1, -1, -1, }, 
                                        { -1,  9, -1, }, 
                                        { -1, -1, -1, }, };

以下代码似乎使输入图像模糊，而不是锐化。

这里的问题可能是什么？

这是整个VS2013解决方案。

原始图片，

产生的模糊图像，

我编写了以下代码以锐化图像，

    public static Bitmap FftSharpen(Bitmap image, double [,] mask)
    {
        if (image.PixelFormat == PixelFormat.Format8bppIndexed)
        {
            Bitmap imageClone = (Bitmap)image.Clone();
            double[,] maskClone = (double[,])mask.Clone();

            Complex[,] cPaddedImage = ImageDataConverter.ToComplex(imageClone);
            Complex[,] cPaddedMask = ImageDataConverter.ToComplex(maskClone);
            Complex[,] cConvolved = Convolution.Convolve(cPaddedImage, cPaddedMask);

            return ImageDataConverter.ToBitmap(cConvolved);
        }
        else
        {
            throw new Exception("not a grascale");
        }
    }

。

。

聚苯乙烯

以下是我的卷积代码，

public static class Convolution
{
    public static Complex[,] Convolve(Complex[,] image, Complex[,] mask)
    {
        Complex[,] convolve = null;

        int imageWidth = image.GetLength(0);
        int imageHeight = image.GetLength(1);

        int maskWidth = mask.GetLength(0);
        int maskeHeight = mask.GetLength(1);

        if (imageWidth == maskWidth && imageHeight == maskeHeight)
        {
            FourierTransform ftForImage = new FourierTransform(image); ftForImage.ForwardFFT();
            FourierTransform ftForMask = new FourierTransform(mask); ftForMask.ForwardFFT();

            Complex[,] fftImage = ftForImage.FourierImageComplex;
            Complex[,] fftKernel = ftForMask.FourierImageComplex;

            Complex[,] fftConvolved = new Complex[imageWidth, imageHeight];


            for (int j = 0; j < imageHeight; j++)
            {
                for (int i = 0; i < imageWidth; i++)
                {
                    fftConvolved[i, j] = fftImage[i, j] * fftKernel[i, j];
                }
            }

            FourierTransform ftForConv = new FourierTransform();

            ftForConv.InverseFFT(fftConvolved);

            convolve = ftForConv.GrayscaleImageComplex;

            Rescale(convolve);

            convolve = FourierShifter.FFTShift(convolve);
        }
        else
        {
            throw new Exception("padding needed");
        }

        return convolve;
    }

    //Rescale values between 0 and 255.
    private static void Rescale(Complex[,] convolve)
    {
        int imageWidth = convolve.GetLength(0);
        int imageHeight = convolve.GetLength(1);

        double maxAmp = 0.0;
        for (int j = 0; j < imageHeight; j++)
        {
            for (int i = 0; i < imageWidth; i++)
            {
                maxAmp = Math.Max(maxAmp, convolve[i, j].Magnitude);
            }
        }
        double scale = 255.0 / maxAmp;

        for (int j = 0; j < imageHeight; j++)
        {
            for (int i = 0; i < imageWidth; i++)
            {
                convolve[i, j] = new Complex(convolve[i, j].Real * scale, convolve[i, j].Imaginary * scale);
                maxAmp = Math.Max(maxAmp, convolve[i, j].Magnitude);
            }
        }
    }
}