/// <summary>
/// Estimates the pen position on a certain time.
/// </summary>
/// <param name="timestamp"></param>
/// <returns></returns>
public Point GetPenPoint(long timestamp)
{
PointFrame previousFrame = null;
List <PointFrame> .Enumerator enumerator;
lock (this._penPoints)
{
enumerator = this._penPoints.ToList().GetEnumerator();
// Search a predecessor and a successor
while (enumerator.MoveNext() && timestamp < enumerator.Current.Timestamp)
{
if (timestamp == enumerator.Current.Timestamp)
{
return(enumerator.Current.Point);
}
previousFrame = enumerator.Current;
}
// Calculate interpolation
if (previousFrame != null && enumerator.Current != null)
{
long ratio = previousFrame.Timestamp / enumerator.Current.Timestamp;
return(PointTools.CalculateIntermediatePoint(previousFrame.Point, enumerator.Current.Point, ratio));
}
}
return(Point.Empty);
}
/// <summary>
/// Delivers a concrete interpretation of the algorithms resulting candidates.
/// </summary>
/// <param name="candidates">Zero or multiple found pen candidates</param>
/// <returns>This is our final result: A pen position</returns>
private Point FindPen(List <PenCandidate> candidates)
{
// Return intermediate point
switch (candidates.Count())
{
case 0:
// No pen found or pen is not moving
// TODO (0,0) is actually a valid position!
return(Point.Empty);
case 1:
// Take center of the only found rectangle
return(candidates.First().WeightedCenter);
case 2:
var candidateOne = candidates.ElementAt(0);
var candidateTwo = candidates.ElementAt(1);
return(PointTools.CalculateCenterPoint(
candidateOne.WeightedCenter,
candidateTwo.WeightedCenter));
default:
throw new NotImplementedException("TODO Error Handling: more than two points are bad! Wrong Camera adjustment?");
}
}
/// <summary>
/// This is the time consuming part. We try to find pen candidates in two pictures
/// by their filtered difference in a specified area.
/// </summary>
/// <param name="previous">Previous video picture</param>
/// <param name="current">Current video picture</param>
/// <returns>Candidates</returns>
private IEnumerable <PenCandidate> findPenCandidatesInArea(Bitmap previous, Bitmap current, Rectangle searchArea)
{
if (!searchArea.IsEmpty)
{
Crop cropFilter = new Crop(searchArea);
previous = cropFilter.Apply(previous);
current = cropFilter.Apply(current);
}
// calculate difference image
this.Strategy.DifferenceFilter.OverlayImage = previous;
Bitmap diffImage = current; //this.Strategy.DifferenceFilter.Apply(current);
//diffImage.Save(@"c:\temp\images\diff-"+CurrentMillis.Millis+".png");
// translate red parts to gray image
Bitmap grayImage = this.Strategy.GrayFilter.Apply(diffImage);
//a.Save(@"c:\temp\images\r2_grey16.bmp");
// treshold the gray image
Bitmap tresholdImage = this.Strategy.ThresholdFilter.Apply(grayImage);
//tresholdImage.Save(@"c:\temp\images\blobs-" + CurrentMillis.Millis + ".png");
#if DEBUG
if (DebugPicture != null)
{
DebugPicture(this, new DebugPictureEventArgs(new List <Bitmap>()
{
diffImage, grayImage, tresholdImage
}));
}
#endif
// count white blobs (TODO ev. kann man den thresholdFilter wegschmeissen, siehe ctr parameter von BlobCounter)
this.Strategy.BlobCounter.ProcessImage(tresholdImage);
// frame found blobs and add information
Rectangle[] rawCandidates = this.Strategy.BlobCounter.GetObjectsRectangles();
List <PenCandidate> candidates = new List <PenCandidate>();
foreach (Rectangle r in rawCandidates)
{
r.Offset(searchArea.Location); // Adjust Blob Location to search area
candidates.Add(new PenCandidate()
{
Rectangle = r,
WeightedCenter = PointTools.CalculateCenterPoint(r) // TODO more precise weightening
});
}
return(candidates);
}
/// <summary>
/// Delivers a concrete interpretation of the algorithms resulting candidates.
/// </summary>
/// <param name="candidates">Zero or multiple found pen candidates</param>
/// <returns>This is our final result: A pen position</returns>
private Point findPen(IEnumerable <PenCandidate> candidates)
{
// Return intermediate point
switch (candidates.Count())
{
case 0:
// No pen found or pen is not moving
// TODO (0,0) is actually a valid position!
return(Point.Empty);
case 1:
// Take center of the only found rectangle
return(candidates.First().WeightedCenter);
case 2:
PenCandidate candidateOne = candidates.ElementAt(0);
PenCandidate candidateTwo = candidates.ElementAt(1);
//PointFrame previousPointFrame = this.GetLastFrame();
//if (previousPointFrame == null)
//{
// // If we don't have a previous point, then we can't say in which direction
// // the pen is moving. We just interpolate.
// return PointTools.CalculateCenterPoint(
// candidateOne.WeightedCenter,
// candidateTwo.WeightedCenter);
//}
//// We search the candidates for the previously recognized pen point
//// and return just the new one.
//if (candidateOne.Rectangle.Contains(previousPointFrame.Point))
//{
// return candidateTwo.WeightedCenter;
//}
//if (candidateTwo.Rectangle.Contains(previousPointFrame.Point))
//{
// return candidateOne.WeightedCenter;
//}
//// Both points are unknown!
//throw new NotImplementedException("TODO Invalid State. What to do?");
return(PointTools.CalculateCenterPoint(
candidateOne.WeightedCenter,
candidateTwo.WeightedCenter));
default:
throw new NotImplementedException("TODO Error Handling: more than two points are bad! Wrong Camera adjustment?");
}
}
/// <summary>
/// This is the time consuming part. We try to find pen candidates in two pictures
/// by their filtered difference in a specified area.
/// </summary>
/// <param name="previous">Previous video picture</param>
/// <param name="current">Current video picture</param>
/// <param name="searchArea"></param>
/// <returns>Candidates</returns>
private IEnumerable <PenCandidate> FindPenCandidatesInArea(Bitmap previous, Bitmap current, Rectangle searchArea)
{
if (!searchArea.IsEmpty)
{
var cropFilter = new Crop(searchArea);
previous = cropFilter.Apply(previous);
current = cropFilter.Apply(current);
}
// calculate difference image
Strategy.DifferenceFilter.OverlayImage = previous;
var diffImage = current;
// translate red parts to gray image
var grayImage = Strategy.GrayFilter.Apply(diffImage);
// treshold the gray image
var tresholdImage = Strategy.ThresholdFilter.Apply(grayImage);
// count white blobs (TODO ev. kann man den thresholdFilter wegschmeissen, siehe ctr parameter von BlobCounter)
Strategy.BlobCounter.ProcessImage(tresholdImage);
// frame found blobs and add information
var rawCandidates = Strategy.BlobCounter.GetObjectsRectangles();
var candidates = new List <PenCandidate>();
foreach (var r in rawCandidates)
{
r.Offset(searchArea.Location); // Adjust Blob Location to search area
candidates.Add(new PenCandidate
{
Rectangle = r,
WeightedCenter = PointTools.CalculateCenterPoint(r) // TODO more precise weightening
});
}
return(candidates);
}