public static IntField BackgroundFilterSmall(IntField image, int areaThresh)
{
image = image.Clone();
IntField processed = image.Clone();
// 0..3 - original unprocessed colors
// -1 - accepted as background
// -2 - trial fill / kept for later elimination
for (int y = 0; y < image.Height; y++)
{
for (int x = 0; x < image.Width; x++)
{
if (processed[x, y] >= 0)
{
// Do trial fill
processed.Floodfill(x, y, -2);
// Accept as background?
if (processed.Counter_Floodfill_TotalPixels > areaThresh)
{
processed.Floodfill(x, y, -1);
}
}
}
}
for (int p = 0; p < image.Data.Length; p++)
{
if (processed.Data[p] == -2)
{
image.Data[p] = -2;
}
}
for (int y = 0; y < image.Height; y++)
{
for (int x = 0; x < image.Width; x++)
{
if (processed[x, y] == -2)
{
if (x > 0 && processed[x - 1, y] == -1)
{
image.Floodfill(x, y, image[x - 1, y]);
processed.Floodfill(x, y, -3);
}
else if (y > 0 && processed[x, y - 1] == -1)
{
image.Floodfill(x, y, image[x, y - 1]);
processed.Floodfill(x, y, -3);
}
else if (x < image.Width - 1 && processed[x + 1, y] == -1)
{
image.Floodfill(x, y, image[x + 1, y]);
processed.Floodfill(x, y, -3);
}
else if (y < image.Height - 1 && processed[x, y + 1] == -1)
{
image.Floodfill(x, y, image[x, y + 1]);
processed.Floodfill(x, y, -3);
}
}
}
}
return(image);
}
private void backgroundSplit(IntField image, out IntField backgr, out IntField foregr)
{
IntField largeBackgrMap;
// First pass: all large areas are always backgrounds
{
IntField vis_hitpoints = image.Clone();
largeBackgrMap = image.Clone();
int x = 0, y = 0, xfr = 0;
double yd = 0;
double ystep = _backgrLargeStepSize * 0.866 / ((double)image.Width / _backgrLargeStepSize);
int curfill = -2;
while (true)
{
y = (int)yd;
if (y >= image.Height)
{
break;
}
vis_hitpoints[x, y] = 10;
if (largeBackgrMap[x, y] >= 0)
{
largeBackgrMap.Floodfill(x, y, curfill);
curfill--;
if (largeBackgrMap.Counter_Floodfill_TotalPixels > _backgrLargeAreaThresh)
{
largeBackgrMap.Floodfill(x, y, -1);
}
}
yd += ystep;
x += _backgrLargeStepSize;
if (x >= image.Width)
{
xfr += _backgrLargeStepSize / 3;
if (xfr > _backgrLargeStepSize)
{
xfr -= _backgrLargeStepSize;
}
x = xfr;
}
}
largeBackgrMap.Map(pix => pix == -1 ? 1 : 0);
AddImageGrayscale(vis_hitpoints, "10-bkg-large-hitpoints");
AddImageGrayscale(largeBackgrMap, "11-bkg-large-map");
}
// TODO: also background if perfectly rectangular and larger than 4 area
// Second pass - background continuation
{
// Prepare image
backgr = image.Clone();
for (int p = 0; p < image.Data.Length; p++)
{
if (largeBackgrMap.Data[p] == 0)
{
backgr.Data[p] = -1;
}
}
AddImageGrayscale(backgr, -1, 3, "12-bkg-cont-before");
// Horizontal continuation
for (int y = 0; y < backgr.Height; y++)
{
int lastbg = -1;
int lastfgstart = -1; // -1 means not in a foreground run
int x = 0;
while (true)
{
if (lastfgstart != -1 && (x == backgr.Width || backgr[x, y] != -1))
{ // in a fg run and either end of image or end of run (no longer foreground)
if (lastbg == -1 || x == backgr.Width || lastbg == backgr[x, y])
{
int clr = x == backgr.Width ? lastbg : backgr[x, y];
for (int fx = lastfgstart; fx < x; fx++)
{
backgr[fx, y] = clr;
}
}
lastfgstart = -1;
}
if (x == backgr.Width)
{
break;
}
if (lastfgstart == -1 && backgr[x, y] == -1)
{
lastfgstart = x;
lastbg = x == 0 ? -1 : backgr[x - 1, y];
}
x++;
}
}
AddImageGrayscale(backgr, -1, 3, "13-bkg-cont-horz");
// Vertical continuation
for (int x = 0; x < backgr.Width; x++)
{
int lastbg = -1;
int lastfgstart = -1; // -1 means not in a foreground run
int y = 0;
while (true)
{
if (lastfgstart != -1 && (y == backgr.Height || backgr[x, y] != -1))
{ // in a fg run and either end of image or end of run (no longer foreground)
if (lastbg == -1 || y == backgr.Height || lastbg == backgr[x, y])
{
int clr = y == backgr.Height ? lastbg : backgr[x, y];
for (int fy = lastfgstart; fy < y; fy++)
{
backgr[x, fy] = clr;
}
}
lastfgstart = -1;
}
if (y == backgr.Height)
{
break;
}
if (lastfgstart == -1 && backgr[x, y] == -1)
{
lastfgstart = y;
lastbg = y == 0 ? -1 : backgr[x, y - 1];
}
y++;
}
}
AddImageGrayscale(backgr, -1, 3, "14-bkg-cont-vert");
// Continuation of leftover areas
int lastc = -1;
for (int p = 0; p < backgr.Data.Length; p++)
{
if (backgr.Data[p] == -1 && lastc != -1)
{
backgr.Floodfill(p % backgr.Width, p / backgr.Width, lastc);
}
else if (p > 0 && backgr.Data[p - 1] == -1 && backgr.Data[p] != -1)
{
backgr.Floodfill((p - 1) % backgr.Width, (p - 1) / backgr.Width, backgr.Data[p]);
}
if (backgr.Data[p] != -1)
{
lastc = backgr.Data[p];
}
}
// TODO: remove anything that's highly non-rect
AddImageGrayscale(backgr, 0, 3, "15-final-bkg");
}
// Final pass - extract foreground
{
foregr = image.Clone();
for (int p = 0; p < image.Data.Length; p++)
{
foregr.Data[p] ^= backgr.Data[p];
}
AddImageGrayscale(foregr, 0, 3, "16-final-fgr");
}
}