static BooleanMatrix FilterRelativeContrast(DoubleMatrix contrast, BlockMap blocks)
{
var sortedContrast = new List <double>();
foreach (var block in contrast.Size.Iterate())
{
sortedContrast.Add(contrast[block]);
}
sortedContrast.Sort();
sortedContrast.Reverse();
int pixelsPerBlock = blocks.Pixels.Area / blocks.Primary.Blocks.Area;
int sampleCount = Math.Min(sortedContrast.Count, Parameters.RelativeContrastSample / pixelsPerBlock);
int consideredBlocks = Math.Max(Doubles.RoundToInt(sampleCount * Parameters.RelativeContrastPercentile), 1);
double averageContrast = 0;
for (int i = 0; i < consideredBlocks; ++i)
{
averageContrast += sortedContrast[i];
}
averageContrast /= consideredBlocks;
var limit = averageContrast * Parameters.MinRelativeContrast;
var result = new BooleanMatrix(blocks.Primary.Blocks);
foreach (var block in blocks.Primary.Blocks.Iterate())
{
if (contrast[block] < limit)
{
result[block] = true;
}
}
// https://sourceafis.machinezoo.com/transparency/relative-contrast-mask
FingerprintTransparency.Current.Log("relative-contrast-mask", result);
return(result);
}
public IntPoint[] LineTo(IntPoint to)
{
IntPoint[] result;
var relative = to - this;
if (Math.Abs(relative.X) >= Math.Abs(relative.Y))
{
result = new IntPoint[Math.Abs(relative.X) + 1];
if (relative.X > 0)
{
for (int i = 0; i <= relative.X; ++i)
{
result[i] = new IntPoint(X + i, Y + Doubles.RoundToInt(i * (relative.Y / (double)relative.X)));
}
}
else if (relative.X < 0)
{
for (int i = 0; i <= -relative.X; ++i)
{
result[i] = new IntPoint(X - i, Y - Doubles.RoundToInt(i * (relative.Y / (double)relative.X)));
}
}
else
{
result[0] = this;
}
}
else
{
result = new IntPoint[Math.Abs(relative.Y) + 1];
if (relative.Y > 0)
{
for (int i = 0; i <= relative.Y; ++i)
{
result[i] = new IntPoint(X + Doubles.RoundToInt(i * (relative.X / (double)relative.Y)), Y + i);
}
}
else if (relative.Y < 0)
{
for (int i = 0; i <= -relative.Y; ++i)
{
result[i] = new IntPoint(X - Doubles.RoundToInt(i * (relative.X / (double)relative.Y)), Y - i);
}
}
else
{
result[0] = this;
}
}
return(result);
}
static EdgeShape()
{
for (int y = 0; y < PolarCacheRadius; ++y)
{
for (int x = 0; x < PolarCacheRadius; ++x)
{
PolarDistanceCache[y * PolarCacheRadius + x] = Doubles.RoundToInt(Math.Sqrt(Doubles.Sq(x) + Doubles.Sq(y)));
if (y > 0 || x > 0)
{
PolarAngleCache[y * PolarCacheRadius + x] = DoubleAngle.Atan(x, y);
}
else
{
PolarAngleCache[y * PolarCacheRadius + x] = 0;
}
}
}
}
static ConsideredOrientation[][] PlanOrientations()
{
var random = new OrientationRandom();
var splits = new ConsideredOrientation[Parameters.OrientationSplit][];
for (int i = 0; i < Parameters.OrientationSplit; ++i)
{
var orientations = splits[i] = new ConsideredOrientation[Parameters.OrientationsChecked];
for (int j = 0; j < Parameters.OrientationsChecked; ++j)
{
var sample = orientations[j] = new ConsideredOrientation();
while (true)
{
double angle = random.Next() * Math.PI;
double distance = Doubles.InterpolateExponential(Parameters.MinOrientationRadius, Parameters.MaxOrientationRadius, random.Next());
sample.Offset = (distance * DoubleAngle.ToVector(angle)).Round();
if (sample.Offset == IntPoint.Zero)
{
continue;
}
if (sample.Offset.Y < 0)
{
continue;
}
bool duplicate = false;
for (int jj = 0; jj < j; ++jj)
{
if (orientations[jj].Offset == sample.Offset)
{
duplicate = true;
}
}
if (duplicate)
{
continue;
}
break;
}
sample.Orientation = DoubleAngle.ToVector(DoubleAngle.Add(DoubleAngle.ToOrientation(DoubleAngle.Atan((DoublePoint)sample.Offset)), Math.PI));
}
}
return(splits);
}
static DoubleMatrix ClipContrast(BlockMap blocks, HistogramCube histogram)
{
var result = new DoubleMatrix(blocks.Primary.Blocks);
foreach (var block in blocks.Primary.Blocks.Iterate())
{
int volume = histogram.Sum(block);
int clipLimit = Doubles.RoundToInt(volume * Parameters.ClippedContrast);
int accumulator = 0;
int lowerBound = histogram.Bins - 1;
for (int i = 0; i < histogram.Bins; ++i)
{
accumulator += histogram[block, i];
if (accumulator > clipLimit)
{
lowerBound = i;
break;
}
}
accumulator = 0;
int upperBound = 0;
for (int i = histogram.Bins - 1; i >= 0; --i)
{
accumulator += histogram[block, i];
if (accumulator > clipLimit)
{
upperBound = i;
break;
}
}
result[block] = (upperBound - lowerBound) * (1.0 / (histogram.Bins - 1));
}
// https://sourceafis.machinezoo.com/transparency/contrast
FingerprintTransparency.Current.Log("contrast", result);
return(result);
}
public IntPoint Round()
{
return(new IntPoint(Doubles.RoundToInt(X), Doubles.RoundToInt(Y)));
}
public void Compute(MatcherThread thread)
{
MinutiaCount = thread.Count;
MinutiaScore = Parameters.MinutiaScore * MinutiaCount;
MinutiaFractionInProbe = thread.Count / (double)thread.Probe.Minutiae.Length;
MinutiaFractionInCandidate = thread.Count / (double)thread.Candidate.Minutiae.Length;
MinutiaFraction = 0.5 * (MinutiaFractionInProbe + MinutiaFractionInCandidate);
MinutiaFractionScore = Parameters.MinutiaFractionScore * MinutiaFraction;
SupportingEdgeSum = 0;
SupportedMinutiaCount = 0;
MinutiaTypeHits = 0;
for (int i = 0; i < thread.Count; ++i)
{
var pair = thread.Tree[i];
SupportingEdgeSum += pair.SupportingEdges;
if (pair.SupportingEdges >= Parameters.MinSupportingEdges)
{
++SupportedMinutiaCount;
}
if (thread.Probe.Minutiae[pair.Probe].Type == thread.Candidate.Minutiae[pair.Candidate].Type)
{
++MinutiaTypeHits;
}
}
EdgeCount = thread.Count + SupportingEdgeSum;
EdgeScore = Parameters.EdgeScore * EdgeCount;
SupportedMinutiaScore = Parameters.SupportedMinutiaScore * SupportedMinutiaCount;
MinutiaTypeScore = Parameters.MinutiaTypeScore * MinutiaTypeHits;
int innerDistanceRadius = Doubles.RoundToInt(Parameters.DistanceErrorFlatness * Parameters.MaxDistanceError);
double innerAngleRadius = Parameters.AngleErrorFlatness * Parameters.MaxAngleError;
DistanceErrorSum = 0;
AngleErrorSum = 0;
for (int i = 1; i < thread.Count; ++i)
{
var pair = thread.Tree[i];
var probeEdge = new EdgeShape(thread.Probe.Minutiae[pair.ProbeRef], thread.Probe.Minutiae[pair.Probe]);
var candidateEdge = new EdgeShape(thread.Candidate.Minutiae[pair.CandidateRef], thread.Candidate.Minutiae[pair.Candidate]);
DistanceErrorSum += Math.Max(innerDistanceRadius, Math.Abs(probeEdge.Length - candidateEdge.Length));
AngleErrorSum += Math.Max(innerAngleRadius, DoubleAngle.Distance(probeEdge.ReferenceAngle, candidateEdge.ReferenceAngle));
AngleErrorSum += Math.Max(innerAngleRadius, DoubleAngle.Distance(probeEdge.NeighborAngle, candidateEdge.NeighborAngle));
}
DistanceAccuracyScore = 0;
AngleAccuracyScore = 0;
int distanceErrorPotential = Parameters.MaxDistanceError * Math.Max(0, thread.Count - 1);
DistanceAccuracySum = distanceErrorPotential - DistanceErrorSum;
DistanceAccuracyScore = Parameters.DistanceAccuracyScore * (distanceErrorPotential > 0 ? DistanceAccuracySum / (double)distanceErrorPotential : 0);
double angleErrorPotential = Parameters.MaxAngleError * Math.Max(0, thread.Count - 1) * 2;
AngleAccuracySum = angleErrorPotential - AngleErrorSum;
AngleAccuracyScore = Parameters.AngleAccuracyScore * (angleErrorPotential > 0 ? AngleAccuracySum / angleErrorPotential : 0);
TotalScore = MinutiaScore
+ MinutiaFractionScore
+ SupportedMinutiaScore
+ EdgeScore
+ MinutiaTypeScore
+ DistanceAccuracyScore
+ AngleAccuracyScore;
ShapedScore = Shape(TotalScore);
}
static DoubleMatrix ScaleImage(DoubleMatrix input, double dpi)
{
return(ScaleImage(input, Doubles.RoundToInt(500.0 / dpi * input.Width), Doubles.RoundToInt(500.0 / dpi * input.Height)));
}
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);
}