/// <summary>
/// Encapsulates the entire parking lot state
/// change, triggerd by Camera changes
/// </summary>
public void Update()
{
if (Baseline != null && Baseline.SameSize(Camera.CurrentImage))
{
lock (this)
{
// Reset percentDifferences to zero
Annotations.ForEach(a => a.PercentDifference = 0);
// Maps annotations to their area in pixels
Dictionary <Annotation, int> annotationPixelAreas = Annotations.ToDictionary(a => a, a => 0);
// Get the raw pixel difference (color sensitive)
Bitmap baseline = Baseline;
Bitmap current = Camera.CurrentImage;
Bitmap difference = baseline.Difference(
current.Add(
// Adjust the current image by the average light difference
// between the baseline and current image
AverageDifference(
baseline,
current,
Annotations.Where(a =>
a.Type == Annotation.AnnotationType.Constant
)
)
)
);
// Sum up difference percentage contained by each annotation
for (int x = 0; x < difference.Width; x++)
{
for (int y = 0; y < difference.Height; y++)
{
Vector2 pixelPoint = new Vector2((double)x / difference.Width, (double)y / difference.Height);
foreach (Annotation annotation in Annotations.Where(a => a.Contains(pixelPoint)))
{
annotationPixelAreas[annotation]++;
annotation.PercentDifference += difference.GetPixel(x, y).Value();
}
}
}
// Normalize the difference percentages by dividing out the total pixel area
foreach (var pixelArea in annotationPixelAreas.Where(p => p.Value > 0))
{
pixelArea.Key.PercentDifference /= pixelArea.Value;
}
}
}
}