private int GetOptimizedThreshold(int count, Bitmap image, int minSize, int maxSize)
{
var blobCounter = new AForge.Imaging.BlobCounter();
AForge.Imaging.Blob[] blobs;
int thresholdMax = 255;
int thresholdMin = 0;
blobCounter.FilterBlobs = true;
blobCounter.MaxHeight = maxSize;
blobCounter.MaxWidth = maxSize;
blobCounter.MinHeight = minSize;
blobCounter.MinWidth = minSize;
for (var i = 255; i >= 0; i--)
{
if (i % 10 == 0)
{
DetectShapesProgress?.Invoke(0.5f / 255f * (255 - i));
}
blobCounter.BackgroundThreshold = Color.FromArgb(255, i, i, i);
blobCounter.ProcessImage(image);
blobs = blobCounter.GetObjectsInformation();
if (blobs.Length == count)
{
thresholdMax = i;
break;
}
}
DetectShapesProgress?.Invoke(0.5f);
for (var i = 0; i <= 255; i++)
{
if (i % 10 == 0)
{
DetectShapesProgress?.Invoke(0.5f + 0.5f / 255f * i);
}
blobCounter.BackgroundThreshold = Color.FromArgb(255, i, i, i);
blobCounter.ProcessImage(image);
blobs = blobCounter.GetObjectsInformation();
if (blobs.Length == count)
{
thresholdMin = i;
break;
}
}
DetectShapesProgress?.Invoke(1f);
var thr = (thresholdMax + thresholdMin) / 2;
return(thr);
}
private List <Shape> DetectShapes(int count, Bitmap image, int minSize, int maxSize)
{
var blobCounter = new AForge.Imaging.BlobCounter();
AForge.Imaging.Blob[] blobs;
blobCounter.FilterBlobs = true;
blobCounter.MaxHeight = maxSize;
blobCounter.MaxWidth = maxSize;
blobCounter.MinHeight = minSize;
blobCounter.MinWidth = minSize;
var threshold = Recognition.GetThreshold(image);
blobCounter.BackgroundThreshold = Color.FromArgb(255, threshold, threshold, threshold);
blobCounter.ProcessImage(image);
blobs = blobCounter.GetObjectsInformation();
if (blobs.Length == count)
{
DetectShapesProgress?.Invoke(1f);
}
else
{
threshold = GetOptimizedThreshold(count, image, minSize, maxSize);
blobCounter.BackgroundThreshold = Color.FromArgb(255, threshold, threshold, threshold);
blobCounter.ProcessImage(image);
blobs = blobCounter.GetObjectsInformation();
}
var shapes = new List <Shape>();
foreach (var blob in blobs)
{
var edgePoints = blobCounter.GetBlobsEdgePoints(blob);
// FindQuadrilateralCorners:
// The first point in the list is the point with lowest X coordinate
// (and with lowest Y if there are several points with the same X value).
// The corners are provided in counter clockwise order
var corners = PointsCloud.FindQuadrilateralCorners(edgePoints);
shapes.Add(new Shape(corners.ToArray(), blob));
}
return(shapes);
}