public void water_test()
{
Bitmap water = Accord.Imaging.Image.Clone(Resources.water);
var dt = new DistanceTransform();
Bitmap result = dt.Apply(water);
Assert.AreEqual(111.364265, dt.MaximumDistance, 1e-5);
Assert.AreEqual(new IntPoint(436, 310), dt.UltimateErodedPoint);
Assert.IsNotNull(result);
float[] distance1D;
new ImageToArray().Convert(result, out distance1D);
float[][] distance;
new ImageToMatrix().Convert(result, out distance);
Assert.AreEqual(distance1D.Sum(), distance.Sum());
float[][] distances2 = Jagged.Reshape(dt.Pixels, result.Height, result.Width);
float actual = distances2[84][533];
float expected = 1.4142135f;
Assert.AreEqual(expected, actual);
}
/// <summary>
/// Processes the filter.
/// </summary>
/// <param name="image">The image.</param>
protected override void ProcessFilter(UnmanagedImage image)
{
if (image.PixelFormat != PixelFormat.Format8bppIndexed)
{
throw new UnsupportedImageFormatException("Binary Watershed only works in grayscale (binary) images");
}
int width = image.Width;
int height = image.Height;
DistanceTransform dt = new DistanceTransform(this.distance);
UnmanagedImage d = dt.Apply(image);
// Convert 2D to 1D - ImageJ Compatibility
float[] distance1D = dt.Pixels;
float[][] distance = Jagged.Reshape(distance1D, height, width);
Debug.Assert(distance1D.Length == d.Size);
Debug.Assert(distance.GetTotalLength() == d.Size);
// Make directions offsets
makeDirectionOffsets(width);
byte[] back = new byte[width * height];
// Find the maxima
long[] maxPoints = getSortedMaxPoints(distance, distance1D, back, 0, dt.MaximumDistance, -808080.0);
// Mark the maxima locations
float maxSortingError = 1.1f * SQRT2 / 2f;
this.maxPoints = analyseAndMarkMaxima(distance1D, back, maxPoints, tolerance, maxSortingError, width, height);
// Transform em 8bit 0..255
byte[] outImage = make8Bit(distance, back, dt.MaximumDistance, -808080.0, width, height);
cleanupMaxima(outImage, back, maxPoints, width, height);
watershedSegment(outImage, width, height);
watershedPostProcess(outImage);
unsafe
{
int offset = image.Offset;
byte *dst = (byte *)image.ImageData;
for (int y = 0, k = 0; y < height; y++)
{
for (int x = 0; x < width; x++, dst++, k++)
{
*dst = outImage[k];
}
dst += offset;
}
}
}
