private bool isBlackWhite(Color[,] image, CIELAB[,] imageLAB)
{
double nonGray = 0;
double thresh = 0.001;
CIELAB white = new CIELAB(100, 0, 0);
CIELAB black = new CIELAB(0, 0, 0);
int width = image.GetLength(0);
int height = image.GetLength(1);
for (int i = 0; i < width; i++)
{
for (int j = 0; j < height; j++)
{
Color color = image[i, j];
CIELAB lab = imageLAB[i, j];//Util.RGBtoLAB(color);
bool gray = color.GetSaturation() <= 0.2 || lab.SqDist(white) <= 5 || lab.SqDist(black) <= 5;
if (!gray)
{
nonGray++;
}
}
}
return(nonGray / (width * height) < thresh);
}
private CIELAB ClosestColor(CIELAB color, List <CIELAB> palette)
{
int bestc = 0;
Double bestDist = Double.PositiveInfinity;
for (int c = 0; c < palette.Count(); c++)
{
double dist = color.SqDist(palette[c]);
if (dist < bestDist)
{
bestDist = dist;
bestc = c;
}
}
return(palette[bestc]);
}
private void RemoveBackground(Color[,] image, CIELAB[,] imageLAB)
{
//check perimeter to see if it's mostly black or white
//RGB to LAB
CIELAB black = new CIELAB(0, 0, 0);
CIELAB white = new CIELAB(100, 0, 0);
int width = image.GetLength(0);
int height = image.GetLength(1);
CIELAB[,] labs = imageLAB;//Util.Map<Color, CIELAB>(image, (c) => Util.RGBtoLAB(c));
int numBlack = 0;
int numWhite = 0;
int thresh = 3 * 3;
List <Point> perimeterIdx = new List <Point>();
double totalPerimeter = 4 * width + 4 * height;
double bgThresh = totalPerimeter * 0.75;
for (int i = 0; i < width; i++)
{
//top
for (int j = 0; j < 2; j++)
{
if (black.SqDist(labs[i, j]) < thresh)
{
numBlack++;
}
if (white.SqDist(labs[i, j]) < thresh)
{
numWhite++;
}
perimeterIdx.Add(new Point(i, j));
}
//bottom
for (int j = height - 2; j < height; j++)
{
perimeterIdx.Add(new Point(i, j));
if (black.SqDist(labs[i, j]) < thresh)
{
numBlack++;
}
if (white.SqDist(labs[i, j]) < thresh)
{
numWhite++;
}
}
}
for (int j = 0; j < height; j++)
{
//left
for (int i = 0; i < 2; i++)
{
perimeterIdx.Add(new Point(i, j));
if (black.SqDist(labs[i, j]) < thresh)
{
numBlack++;
}
if (white.SqDist(labs[i, j]) < thresh)
{
numWhite++;
}
}
//right
for (int i = width - 2; i < width; i++)
{
perimeterIdx.Add(new Point(i, j));
if (black.SqDist(labs[i, j]) < thresh)
{
numBlack++;
}
if (white.SqDist(labs[i, j]) < thresh)
{
numWhite++;
}
}
}
if (numBlack >= bgThresh || numWhite >= bgThresh)
{
//connected components
UnionFind <CIELAB> uf = new UnionFind <CIELAB>((a, b) => a.SqDist(b) < thresh);
int[,] cc = uf.ConnectedComponents(labs);
SortedSet <int> ids = new SortedSet <int>();
//go around the perimeter to collect the right ids
foreach (Point p in perimeterIdx)
{
if (numWhite > numBlack)
{
if (labs[p.X, p.Y].SqDist(white) < thresh)
{
ids.Add(cc[p.X, p.Y]);
}
}
else
{
if (labs[p.X, p.Y].SqDist(black) < thresh)
{
ids.Add(cc[p.X, p.Y]);
}
}
}
//fill the bitmap with transparency
for (int i = 0; i < width; i++)
{
for (int j = 0; j < height; j++)
{
if (ids.Contains(cc[i, j]))
{
image[i, j] = Color.FromArgb(0, 0, 0, 0);
}
}
}
}
}
private double[] GetProbabilities(String query, Func <CIELAB, CIELAB, double> distFunc, Kernel kernel, double whiteThresh = 20)
{
CIELAB white = new CIELAB(100, 0, 0);
//load the histogram
double[, ,] hist = new double[Lbins, Abins, Bbins];
String histFile = Path.Combine(cacheDir, query) + ".txt";
String[] hlines = File.ReadAllLines(histFile);
for (int i = 0; i < hlines.Count(); i++)
{
int L = i / (Abins * Bbins);
int plane = (i % (Abins * Bbins));
int A = plane / Bbins;
int B = plane % Bbins;
hist[L, A, B] = Double.Parse(hlines[i]);
}
int ncolors = paletteLAB.Count();
double[] freq = new double[20];
Parallel.For(0, ncolors, l =>
{
double count = 0;
for (int i = 0; i < Lbins; i++)
{
for (int j = 0; j < Abins; j++)
{
for (int k = 0; k < Bbins; k++)
{
double val = hist[i, j, k];
System.Diagnostics.Debug.Assert(!double.IsNaN(val));
CIELAB lab = new CIELAB(i * binSize, j * binSize - 100, k * binSize - 100);
if (white.SqDist(lab) < whiteThresh * whiteThresh)
{
continue;
}
if (val <= 0)
{
continue;
}
count += val;
freq[l] += val * kernel.Eval(distFunc(paletteLAB[l], lab));
}
}
}
if (count > 0)
{
freq[l] /= count;
}
});
//now renormalize
double totalFreq = 0;
for (int i = 0; i < freq.Count(); i++)
{
totalFreq += freq[i];
}
//this should only happen if the histogram is empty or has no valid bins
if (totalFreq == 0)
{
totalFreq = 1;
}
for (int i = 0; i < freq.Count(); i++)
{
freq[i] /= totalFreq;
}
return(freq);
}