static void MaskMinutiae(List <MutableMinutia> minutiae, BooleanMatrix mask)
{
minutiae.RemoveAll(minutia =>
{
var arrow = (-Parameters.MaskDisplacement * DoubleAngle.ToVector(minutia.Direction)).Round();
return(!mask.Get(minutia.Position + arrow, false));
});
}
static void TraceRidges(BooleanMatrix thinned, Dictionary <IntPoint, SkeletonMinutia> minutiaePoints)
{
var leads = new Dictionary <IntPoint, SkeletonRidge>();
foreach (var minutiaPoint in minutiaePoints.Keys)
{
foreach (var startRelative in IntPoint.CornerNeighbors)
{
var start = minutiaPoint + startRelative;
if (thinned.Get(start, false) && !minutiaePoints.ContainsKey(start) && !leads.ContainsKey(start))
{
var ridge = new SkeletonRidge();
ridge.Points.Add(minutiaPoint);
ridge.Points.Add(start);
var previous = minutiaPoint;
var current = start;
do
{
var next = IntPoint.Zero;
foreach (var nextRelative in IntPoint.CornerNeighbors)
{
next = current + nextRelative;
if (thinned.Get(next, false) && next != previous)
{
break;
}
}
previous = current;
current = next;
ridge.Points.Add(current);
} while (!minutiaePoints.ContainsKey(current));
var end = current;
ridge.Start = minutiaePoints[minutiaPoint];
ridge.End = minutiaePoints[end];
leads[ridge.Points[1]] = ridge;
leads[ridge.Reversed.Points[1]] = ridge;
}
}
}
}
static bool IsFalseEnding(BooleanMatrix binary, IntPoint ending)
{
foreach (var relativeNeighbor in IntPoint.CornerNeighbors)
{
var neighbor = ending + relativeNeighbor;
if (binary[neighbor])
{
int count = 0;
foreach (var relative2 in IntPoint.CornerNeighbors)
{
if (binary.Get(neighbor + relative2, false))
{
++count;
}
}
return(count > 2);
}
}
return(false);
}
List <IntPoint> FindMinutiae(BooleanMatrix thinned)
{
var result = new List <IntPoint>();
foreach (var at in Size.Iterate())
{
if (thinned[at])
{
int count = 0;
foreach (var relative in IntPoint.CornerNeighbors)
{
if (thinned.Get(at + relative, false))
{
++count;
}
}
if (count == 1 || count > 2)
{
result.Add(at);
}
}
}
return(result);
}
static DoubleMatrix Equalize(BlockMap blocks, DoubleMatrix image, HistogramCube histogram, BooleanMatrix blockMask)
{
const double rangeMin = -1;
const double rangeMax = 1;
const double rangeSize = rangeMax - rangeMin;
double widthMax = rangeSize / histogram.Bins * Parameters.MaxEqualizationScaling;
double widthMin = rangeSize / histogram.Bins * Parameters.MinEqualizationScaling;
var limitedMin = new double[histogram.Bins];
var limitedMax = new double[histogram.Bins];
var dequantized = new double[histogram.Bins];
for (int i = 0; i < histogram.Bins; ++i)
{
limitedMin[i] = Math.Max(i * widthMin + rangeMin, rangeMax - (histogram.Bins - 1 - i) * widthMax);
limitedMax[i] = Math.Min(i * widthMax + rangeMin, rangeMax - (histogram.Bins - 1 - i) * widthMin);
dequantized[i] = i / (double)(histogram.Bins - 1);
}
var mappings = new Dictionary <IntPoint, double[]>();
foreach (var corner in blocks.Secondary.Blocks.Iterate())
{
double[] mapping = new double[histogram.Bins];
mappings[corner] = mapping;
if (blockMask.Get(corner, false) ||
blockMask.Get(corner.X - 1, corner.Y, false) ||
blockMask.Get(corner.X, corner.Y - 1, false) ||
blockMask.Get(corner.X - 1, corner.Y - 1, false))
{
double step = rangeSize / histogram.Sum(corner);
double top = rangeMin;
for (int i = 0; i < histogram.Bins; ++i)
{
double band = histogram[corner, i] * step;
double equalized = top + dequantized[i] * band;
top += band;
if (equalized < limitedMin[i])
{
equalized = limitedMin[i];
}
if (equalized > limitedMax[i])
{
equalized = limitedMax[i];
}
mapping[i] = equalized;
}
}
}
var result = new DoubleMatrix(blocks.Pixels);
foreach (var block in blocks.Primary.Blocks.Iterate())
{
var area = blocks.Primary.Block(block);
if (blockMask[block])
{
var topleft = mappings[block];
var topright = mappings[new IntPoint(block.X + 1, block.Y)];
var bottomleft = mappings[new IntPoint(block.X, block.Y + 1)];
var bottomright = mappings[new IntPoint(block.X + 1, block.Y + 1)];
for (int y = area.Top; y < area.Bottom; ++y)
{
for (int x = area.Left; x < area.Right; ++x)
{
int depth = histogram.Constrain((int)(image[x, y] * histogram.Bins));
double rx = (x - area.X + 0.5) / area.Width;
double ry = (y - area.Y + 0.5) / area.Height;
result[x, y] = Doubles.Interpolate(bottomleft[depth], bottomright[depth], topleft[depth], topright[depth], rx, ry);
}
}
}
else
{
for (int y = area.Top; y < area.Bottom; ++y)
{
for (int x = area.Left; x < area.Right; ++x)
{
result[x, y] = -1;
}
}
}
}
// https://sourceafis.machinezoo.com/transparency/equalized-image
FingerprintTransparency.Current.Log("equalized-image", result);
return(result);
}