/// <summary>
/// Computes the weighted variance of a box.
/// </summary>
/// <param name="cube">The cube.</param>
/// <returns>The result.</returns>
private double Variance(Box cube)
{
double dr = WuAlphaColorQuantizer.Volume(cube, this.vmr);
double dg = WuAlphaColorQuantizer.Volume(cube, this.vmg);
double db = WuAlphaColorQuantizer.Volume(cube, this.vmb);
double da = WuAlphaColorQuantizer.Volume(cube, this.vma);
double xx =
this.m2[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G1, cube.B1, cube.A1)]
- this.m2[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G1, cube.B1, cube.A0)]
- this.m2[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G1, cube.B0, cube.A1)]
+ this.m2[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G1, cube.B0, cube.A0)]
- this.m2[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G0, cube.B1, cube.A1)]
+ this.m2[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G0, cube.B1, cube.A0)]
+ this.m2[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G0, cube.B0, cube.A1)]
- this.m2[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G0, cube.B0, cube.A0)]
- this.m2[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G1, cube.B1, cube.A1)]
+ this.m2[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G1, cube.B1, cube.A0)]
+ this.m2[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G1, cube.B0, cube.A1)]
- this.m2[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G1, cube.B0, cube.A0)]
+ this.m2[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B1, cube.A1)]
- this.m2[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B1, cube.A0)]
- this.m2[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B0, cube.A1)]
+ this.m2[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B0, cube.A0)];
return(xx - (((dr * dr) + (dg * dg) + (db * db) + (da * da)) / WuAlphaColorQuantizer.Volume(cube, this.vwt)));
}
/// <summary>
/// Computes remainder of Volume(cube, moment), substituting position for r1, g1, or b1 (depending on direction).
/// </summary>
/// <param name="cube">The cube.</param>
/// <param name="direction">The direction.</param>
/// <param name="position">The position.</param>
/// <param name="moment">The moment.</param>
/// <returns>The result.</returns>
private static long Top(Box cube, int direction, int position, long[] moment)
{
switch (direction)
{
// Red
case 3:
return(moment[WuAlphaColorQuantizer.GetIndex(position, cube.G1, cube.B1, cube.A1)]
- moment[WuAlphaColorQuantizer.GetIndex(position, cube.G1, cube.B1, cube.A0)]
- moment[WuAlphaColorQuantizer.GetIndex(position, cube.G1, cube.B0, cube.A1)]
+ moment[WuAlphaColorQuantizer.GetIndex(position, cube.G1, cube.B0, cube.A0)]
- moment[WuAlphaColorQuantizer.GetIndex(position, cube.G0, cube.B1, cube.A1)]
+ moment[WuAlphaColorQuantizer.GetIndex(position, cube.G0, cube.B1, cube.A0)]
+ moment[WuAlphaColorQuantizer.GetIndex(position, cube.G0, cube.B0, cube.A1)]
- moment[WuAlphaColorQuantizer.GetIndex(position, cube.G0, cube.B0, cube.A0)]);
// Green
case 2:
return(moment[WuAlphaColorQuantizer.GetIndex(cube.R1, position, cube.B1, cube.A1)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R1, position, cube.B1, cube.A0)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R1, position, cube.B0, cube.A1)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R1, position, cube.B0, cube.A0)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R0, position, cube.B1, cube.A1)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R0, position, cube.B1, cube.A0)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R0, position, cube.B0, cube.A1)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R0, position, cube.B0, cube.A0)]);
// Blue
case 1:
return(moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G1, position, cube.A1)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G1, position, cube.A0)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G0, position, cube.A1)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G0, position, cube.A0)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G1, position, cube.A1)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G1, position, cube.A0)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, position, cube.A1)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, position, cube.A0)]);
// Alpha
case 0:
return(moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G1, cube.B1, position)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G1, cube.B0, position)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G0, cube.B1, position)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G0, cube.B0, position)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G1, cube.B1, position)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G1, cube.B0, position)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B1, position)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B0, position)]);
default:
throw new ArgumentOutOfRangeException(nameof(direction));
}
}
/// <summary>
/// Marks a color space tag.
/// </summary>
/// <param name="cube">The cube.</param>
/// <param name="label">A label.</param>
private void Mark(Box cube, byte label)
{
for (int r = cube.R0 + 1; r <= cube.R1; r++)
{
for (int g = cube.G0 + 1; g <= cube.G1; g++)
{
for (int b = cube.B0 + 1; b <= cube.B1; b++)
{
for (int a = cube.A0 + 1; a <= cube.A1; a++)
{
this.tag[WuAlphaColorQuantizer.GetIndex(r, g, b, a)] = label;
}
}
}
}
}
/// <summary>
/// Computes sum over a box of any given statistic.
/// </summary>
/// <param name="cube">The cube.</param>
/// <param name="moment">The moment.</param>
/// <returns>The result.</returns>
private static double Volume(Box cube, long[] moment)
{
return(moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G1, cube.B1, cube.A1)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G1, cube.B1, cube.A0)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G1, cube.B0, cube.A1)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G1, cube.B0, cube.A0)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G0, cube.B1, cube.A1)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G0, cube.B1, cube.A0)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G0, cube.B0, cube.A1)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R1, cube.G0, cube.B0, cube.A0)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G1, cube.B1, cube.A1)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G1, cube.B1, cube.A0)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G1, cube.B0, cube.A1)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G1, cube.B0, cube.A0)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B1, cube.A1)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B1, cube.A0)]
- moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B0, cube.A1)]
+ moment[WuAlphaColorQuantizer.GetIndex(cube.R0, cube.G0, cube.B0, cube.A0)]);
}
/// <summary>
/// Builds a 3-D color histogram of <c>counts, r/g/b, c^2</c>.
/// </summary>
/// <param name="image">The image.</param>
private void Build3DHistogram(Color[] image)
{
foreach (var color in image)
{
int a = color.A;
int r = color.R;
int g = color.G;
int b = color.B;
int inr = r >> (8 - IndexBits);
int ing = g >> (8 - IndexBits);
int inb = b >> (8 - IndexBits);
int ina = a >> (8 - IndexAlphaBits);
int ind = WuAlphaColorQuantizer.GetIndex(inr + 1, ing + 1, inb + 1, ina + 1);
this.vwt[ind]++;
this.vmr[ind] += r;
this.vmg[ind] += g;
this.vmb[ind] += b;
this.vma[ind] += a;
this.m2[ind] += (r * r) + (g * g) + (b * b) + (a * a);
}
}
/// <summary>
/// Converts the histogram into moments so that we can rapidly calculate
/// the sums of the above quantities over any desired box.
/// </summary>
private void Get3DMoments()
{
long[] volume = new long[WuAlphaColorQuantizer.IndexCount * WuAlphaColorQuantizer.IndexAlphaCount];
long[] volumeR = new long[WuAlphaColorQuantizer.IndexCount * WuAlphaColorQuantizer.IndexAlphaCount];
long[] volumeG = new long[WuAlphaColorQuantizer.IndexCount * WuAlphaColorQuantizer.IndexAlphaCount];
long[] volumeB = new long[WuAlphaColorQuantizer.IndexCount * WuAlphaColorQuantizer.IndexAlphaCount];
long[] volumeA = new long[WuAlphaColorQuantizer.IndexCount * WuAlphaColorQuantizer.IndexAlphaCount];
double[] volume2 = new double[WuAlphaColorQuantizer.IndexCount * WuAlphaColorQuantizer.IndexAlphaCount];
long[] area = new long[WuAlphaColorQuantizer.IndexAlphaCount];
long[] areaR = new long[WuAlphaColorQuantizer.IndexAlphaCount];
long[] areaG = new long[WuAlphaColorQuantizer.IndexAlphaCount];
long[] areaB = new long[WuAlphaColorQuantizer.IndexAlphaCount];
long[] areaA = new long[WuAlphaColorQuantizer.IndexAlphaCount];
double[] area2 = new double[WuAlphaColorQuantizer.IndexAlphaCount];
for (int r = 1; r < WuAlphaColorQuantizer.IndexCount; r++)
{
Array.Clear(volume, 0, WuAlphaColorQuantizer.IndexCount * WuAlphaColorQuantizer.IndexAlphaCount);
Array.Clear(volumeR, 0, WuAlphaColorQuantizer.IndexCount * WuAlphaColorQuantizer.IndexAlphaCount);
Array.Clear(volumeG, 0, WuAlphaColorQuantizer.IndexCount * WuAlphaColorQuantizer.IndexAlphaCount);
Array.Clear(volumeB, 0, WuAlphaColorQuantizer.IndexCount * WuAlphaColorQuantizer.IndexAlphaCount);
Array.Clear(volumeA, 0, WuAlphaColorQuantizer.IndexCount * WuAlphaColorQuantizer.IndexAlphaCount);
Array.Clear(volume2, 0, WuAlphaColorQuantizer.IndexCount * WuAlphaColorQuantizer.IndexAlphaCount);
for (int g = 1; g < WuAlphaColorQuantizer.IndexCount; g++)
{
Array.Clear(area, 0, WuAlphaColorQuantizer.IndexAlphaCount);
Array.Clear(areaR, 0, WuAlphaColorQuantizer.IndexAlphaCount);
Array.Clear(areaG, 0, WuAlphaColorQuantizer.IndexAlphaCount);
Array.Clear(areaB, 0, WuAlphaColorQuantizer.IndexAlphaCount);
Array.Clear(areaA, 0, WuAlphaColorQuantizer.IndexAlphaCount);
Array.Clear(area2, 0, WuAlphaColorQuantizer.IndexAlphaCount);
for (int b = 1; b < WuAlphaColorQuantizer.IndexCount; b++)
{
long line = 0;
long lineR = 0;
long lineG = 0;
long lineB = 0;
long lineA = 0;
double line2 = 0;
for (int a = 1; a < WuAlphaColorQuantizer.IndexAlphaCount; a++)
{
int ind1 = WuAlphaColorQuantizer.GetIndex(r, g, b, a);
line += this.vwt[ind1];
lineR += this.vmr[ind1];
lineG += this.vmg[ind1];
lineB += this.vmb[ind1];
lineA += this.vma[ind1];
line2 += this.m2[ind1];
area[a] += line;
areaR[a] += lineR;
areaG[a] += lineG;
areaB[a] += lineB;
areaA[a] += lineA;
area2[a] += line2;
int inv = (b * WuAlphaColorQuantizer.IndexAlphaCount) + a;
volume[inv] += area[a];
volumeR[inv] += areaR[a];
volumeG[inv] += areaG[a];
volumeB[inv] += areaB[a];
volumeA[inv] += areaA[a];
volume2[inv] += area2[a];
int ind2 = ind1 - WuAlphaColorQuantizer.GetIndex(1, 0, 0, 0);
this.vwt[ind1] = this.vwt[ind2] + volume[inv];
this.vmr[ind1] = this.vmr[ind2] + volumeR[inv];
this.vmg[ind1] = this.vmg[ind2] + volumeG[inv];
this.vmb[ind1] = this.vmb[ind2] + volumeB[inv];
this.vma[ind1] = this.vma[ind2] + volumeA[inv];
this.m2[ind1] = this.m2[ind2] + volume2[inv];
}
}
}
}
}