public override IObservable <Contours> Process(IObservable <IplImage> source)
{
return(Observable.Defer(() =>
{
IplImage temp = null;
return source.Select(input =>
{
Seq currentContour;
temp = IplImageHelper.EnsureImageFormat(temp, input.Size, IplDepth.U8, 1);
CV.Copy(input, temp);
var storage = new MemStorage();
var scanner = CV.StartFindContours(temp, storage, Contour.HeaderSize, Mode, Method, Offset);
while ((currentContour = scanner.FindNextContour()) != null)
{
if (MinArea.HasValue || MaxArea.HasValue)
{
var contourArea = CV.ContourArea(currentContour, SeqSlice.WholeSeq);
if (contourArea < MinArea || contourArea > MaxArea)
{
scanner.SubstituteContour(null);
}
}
}
return new Contours(scanner.EndFindContours(), input.Size);
});
}));
}
//tracking routine
public float[] GetParams(IplImage input)
{
//subtract mask from frame
CV.Sub(Mask, input, output);
//threshold to remove any small background noise
CV.Threshold(output, output, thr, 255, ThresholdTypes.Binary);
//find countours of the rest of the pixels
Seq currentContour;
using (var storage = new MemStorage())
using (var scanner = CV.StartFindContours(output, storage, Contour.HeaderSize, ContourRetrieval.External, ContourApproximation.ChainApproxNone, new Point(0, 0)))
{
bfArea = 0;
while ((currentContour = scanner.FindNextContour()) != null)
{
//calculate the number of pixels inside the contour
contourArea = CV.ContourArea(currentContour, SeqSlice.WholeSeq);
//if number of pixels fit the expected for the fly, calculate the distribution moments
if (contourArea > bfArea && (contourArea > MinArea && contourArea < MaxArea))
{
scanner.SubstituteContour(null);
//calculate the pixel distribution moments
moments = new Moments(currentContour);
if (moments.M00 > 0)
{
//transform moments into X,Y and orentation
param[0] = Convert.ToSingle(moments.M10 / moments.M00);
param[1] = Convert.ToSingle(moments.M01 / moments.M00);
param[2] = 180f * Convert.ToSingle(0.5 * Math.Atan2(2 * (moments.M11 / moments.M00 - param[0] * param[1]), (moments.M20 / moments.M00 - param[0] * param[0]) - (moments.M02 / moments.M00 - param[1] * param[1]))) / Convert.ToSingle(Math.PI);
}
}
bfArea = contourArea;
}
}
//return position and orientation
return(param);
}