private byte[,] LinqBinarize(byte[,] grayImage)
{
var integral = from g in grayImage
from ri in Result.InitWith(0)
from rq in Result.InitWith(0L)
select ValueTuple.Create(
ri[-1, 0] + ri[0, -1] - ri[-1, -1] + g,
rq[-1, 0] + rq[0, -1] - rq[-1, -1] + g *g);
var(integral_image, integral_sqimg) = integral.ToArrays();
var whalf = W / 2;
var t = from g in grayImage
from i in integral_image.With(OutOfBoundsStrategy.Integral(0))
from q in integral_sqimg.With(OutOfBoundsStrategy.Integral(0L))
let tl = i.Offset(-whalf - 1, -whalf - 1) let tr = i.Offset(-whalf - 1, whalf)
let bl = i.Offset(whalf, -whalf - 1) let br = i.Offset(whalf, whalf)
let tlq = q.Offset(-whalf - 1, -whalf - 1) let trq = q.Offset(-whalf - 1, whalf)
let blq = q.Offset(whalf, -whalf - 1) let brq = q.Offset(whalf, whalf)
let area = (br.X - tl.X) * (br.Y - tl.Y)
let diff = br + tl - tr - bl
let sqdiff = brq.Value + tlq.Value - trq.Value - blq.Value
let mean = (double)diff / area
let std = Math.Sqrt((sqdiff - diff * mean) / (area - 1))
let threshold = mean * (1 + K * ((std / 128) - 1))
select g > threshold ? (byte)255 : (byte)0;
return(t.ToArray());
}
static void Main(string[] args)
{
var WHalf = 6;
var K = 0.3;
var integrateQuery = from d in new byte[0, 0]
from rl in Result.InitWith(0)
from rq in Result.InitWith(0L)
select ValueTuple.Create(
rl[-1, 0] + rl[0, -1] - rl[-1, -1] + d,
rq[-1, 0] + rq[0, -1] - rq[-1, -1] + d *d);
var thresholdQuery = from i in new int[0, 0].With(OutOfBoundsStrategy.Integral(0))
from q in new long[0, 0].With(OutOfBoundsStrategy.Integral(0L))
let itl = i.Offset(-WHalf - 1, -WHalf - 1)
let itr = i.Offset(-WHalf - 1, WHalf)
let ibl = i.Offset(WHalf, -WHalf - 1)
let ibr = i.Offset(WHalf, WHalf)
let sum = ibr + itl - itr - ibl
let qtl = q.Offset(-WHalf - 1, -WHalf - 1)
let qtr = q.Offset(-WHalf - 1, WHalf)
let qbl = q.Offset(WHalf, -WHalf - 1)
let qbr = q.Offset(WHalf, WHalf)
let sumsq = qbr + qtl - qtr - qbl
let area = (ibr.X - itl.X) * (ibr.Y - itl.Y)
let mean = (double)sum / area
let std = Math.Sqrt((sumsq - sum * mean) / (area - 1))
select(byte)(mean * (1 + K * ((std / 128) - 1)));
var detectQuery = from d in new byte[0, 0]
from t in new byte[0, 0]
select d > t ? byte.MaxValue : byte.MinValue;
var integrate = integrateQuery.Transform;
var getThreshold = thresholdQuery.Transform;
var detect = detectQuery.Transform;
foreach (var fileName in args)
{
var(data, palette) = IO.ReadImage(fileName);
data = (from d in data
select palette[d]).ToArray();
Array2d.TryVectorize = true;
var(s, sq) = integrate(data);
var t = getThreshold(s, sq);
var r = detect(data, t);
IO.WriteImage(Path.ChangeExtension(fileName, ".threshold.bmp"), t);
IO.WriteImage(Path.ChangeExtension(fileName, ".linq.bmp"), r);
}
}
public Field(OutOfBoundsStrategy outOfBoundsStrategy)
{
OutOfBoundsStrategy = outOfBoundsStrategy;
}
public void TestSteps(int h, int w, byte seed)
{
var grayImage = ArrayHelper.InitAllRand(h, w, seed);
var integral = from g in grayImage
from ri in Result.InitWith(0)
from rq in Result.InitWith((square)0)
select ValueTuple.Create(
ri[-1, 0] + ri[0, -1] - ri[-1, -1] + g,
rq[-1, 0] + rq[0, -1] - rq[-1, -1] + g *g);
var(integral_image_linq, integral_sqimg_linq) = integral.ToArrays();
var(integral_image, integral_sqimg) = DoubleIntegrateSlow(h, w, grayImage);
TestHelper.AssertEqual(integral_image, integral_image_linq);
TestHelper.AssertEqual(integral_sqimg, integral_sqimg_linq);
var whalf = W / 2;
var area = from i in integral_image_linq.With(OutOfBoundsStrategy.Integral(0))
let tl = i.Offset(-whalf - 1, -whalf - 1)
let br = i.Offset(whalf, whalf)
select(br.X - tl.X) * (br.Y - tl.Y);
var areaA = area.ToArray();
TestHelper.AssertEqual(CalculateArea(grayImage, whalf), area.ToArray());
var diff = from i in integral_image_linq.With(OutOfBoundsStrategy.Integral(0))
let tl = i.Offset(-whalf - 1, -whalf - 1)
let tr = i.Offset(-whalf - 1, whalf)
let bl = i.Offset(whalf, -whalf - 1)
let br = i.Offset(whalf, whalf)
select br.Value + tl.Value - tr.Value - bl.Value;
var diffA = diff.ToArray();
TestHelper.AssertEqual(CalculateDiff(integral_image_linq, whalf), diff.ToArray());
var sqdiff = from i in integral_sqimg_linq.With(OutOfBoundsStrategy.Integral(0L))
let tl = i.Offset(-whalf - 1, -whalf - 1)
let tr = i.Offset(-whalf - 1, whalf)
let bl = i.Offset(whalf, -whalf - 1)
let br = i.Offset(whalf, whalf)
select br.Value + tl.Value - tr.Value - bl.Value;
TestHelper.AssertEqual(CalculateDiff(integral_sqimg_linq, whalf), sqdiff.ToArray());
var mean = from d in diffA
from a in areaA
select(double) d / a;
TestHelper.AssertEqual(CalculateMean(diffA, areaA), mean.ToArray());
var std = from sqd in sqdiff.ToArray()
from d in diffA
from a in areaA
from m in mean.ToArray()
select Math.Sqrt((sqd - d *m) / (a - 1));
TestHelper.AssertEqual(CalculateStd(sqdiff.ToArray(), diffA, areaA, mean.ToArray()), std.ToArray());
var thresh = from m in mean.ToArray()
from s in std.ToArray()
select m *(1 + K * ((s / 128) - 1));
TestHelper.AssertEqual(CalculateThreshold(mean.ToArray(), std.ToArray()), thresh.ToArray());
}
