protected Matrix fingerprintEnhance(Matrix image)
{
Matrix result;
const int filterRadius = 8;
const float filterVariance = 4.0f; // std deviation squared
// const int filterRadius = 6;
// const float filterVariance = 4.0f; // std deviation squared
result = filterGaussian(image, filterVariance, filterRadius);
result = ImageUtils.Convolve(result, Laplacian);
// We leave a few levels of grey.
ImageUtils.BoundImage(result, -4.0f, -1.0f);
ImageUtils.AutoScaleLevels(result);
clearBorder(result, filterRadius + 1, 255);
// Uncomment the following three lines to get a pure b&w image.
ImageUtils.InvertImage(result);
ImageUtils.ThresholdImage(result, 1);
ImageUtils.InvertImage(result);
return(result);
}
private Matrix inRelief(Matrix image)
{
Matrix hDiff = new float[, ] {
{ -1, 1, 0 }
};
Matrix vDiff = hDiff.Transpose;
Matrix gradH = new float[, ] {
{ 0, -2, 0 },
{ 0, 0, 0 },
{ 0, 2, 0 }
};
Matrix gradV = gradH.Transpose;
Matrix gX = ImageUtils.Convolve(image, -hDiff);
Matrix gY = ImageUtils.Convolve(image, -vDiff);
Matrix r = (gX + gY) / 2;
// ImageUtils.BoundImage(r, 0, 255);
ImageUtils.AutoScaleLevels(r);
// ImageUtils.PutImage("gx.png", r);
return(r);
}
protected Matrix autoScaleLevels(Matrix image)
{
Matrix r = image.Clone();
ImageUtils.AutoScaleLevels(r);
return(r);
}
