/// <summary>
/// Actual detection function for trailless light sources.
/// </summary>
/// <param name="Input">Input image data.</param>
/// <param name="Position">Data position in the image.</param>
/// <param name="Instance">DotDetector instance in which this is called.</param>
static void DetectSources(double[,] Input, ImageSegmentPosition Position, DotDetector Instance)
{
int OW = Input.GetLength(1);
int OH = Input.GetLength(0);
int i, j;
bool[,] Mask = new bool[OH, OW];
List <DotDetection> ldot = new List <DotDetection>();
/* Local mean & variance computation */
double Mean = 0, Var = 0;
double NThSq = Instance.NonrepresentativeThreshold * Instance.NonrepresentativeThreshold;
int cnt = 0;
for (i = 0; i < OH; i++)
{
for (j = 0; j < OW; j++)
{
if (Input[i, j] * Input[i, j] < NThSq)
{
Mean += Input[i, j]; Var += Input[i, j] * Input[i, j]; cnt++;
}
}
}
Mean /= cnt;
Var /= cnt;
Var -= Mean * Mean;
double StDev = Sqrt(Var);
double HighThreshold = Instance.HighThresholdMultiplier * StDev + Mean;
double LowThreshold = Instance.LowThresholdMultiplier * StDev + Mean;
/* Hysteresis-based detection */
for (i = 0; i < OH; i++)
{
for (j = 0; j < OW; j++)
{
if (Mask[i, j])
{
continue;
}
if (Input[i, j] > HighThreshold)
{
ldot.Add(BitmapFill(Input, new IntPoint()
{
X = j, Y = i
}, Mask, LowThreshold, (int)Position.Alignment.X, (int)Position.Alignment.Y));
}
}
}
ldot.RemoveAll((x) => x.Pixels.Count < Instance.MinPix);
lock (Instance.Detections)
Instance.Detections.AddRange(ldot);
}
/// <summary>
/// Attempts to recover a detection on an image.
/// </summary>
/// <returns>The recovered object.</returns>
/// <param name="Location">Location which to check.</param>
/// <param name="Radius">Maximum radius of the detection.</param>
/// <param name="RecoveryImage">Image on which to perform the recovery.</param>
private DotDetector.DotDetection Recover(PixelPoint Location, double Radius, Image RecoveryImage)
{
/* Area in the image to retrieve */
System.Drawing.Rectangle r = new System.Drawing.Rectangle((int)Math.Round(Location.X) - HalfLength, (int)Math.Round(Location.Y) - HalfLength,
2 * HalfLength, 2 * HalfLength);
bool[,] Mask = new bool[2 * HalfLength, 2 * HalfLength];
/* Mask areas outside Radius */
for (int i = 0; i < 2 * HalfLength; i++)
{
for (int j = 0; j < 2 * HalfLength; j++)
{
if (!InDisk(i, j, Radius))
{
Mask[i, j] = true;
}
}
}
ImageData dt = RecoveryImage.LockData(r, true);
/* Compute background level of the area */
var sts = RecoveryImage.GetProperty <ImageStatistics>();
ComputeSmartStats(dt.Data, 10 * sts.StDev, out double Median, out double MedSigma);
/* Perform recovery */
DotDetector.IntPoint Position = new DotDetector.IntPoint()
{
X = HalfLength, Y = HalfLength
};
var det = DotDetector.BitmapFill(dt.Data, Position, Mask, ThresholdMultiplier * MedSigma, r.X, r.Y);
RecoveryImage.ExitLock(dt);
return(det);
}
