protected override void BuildObjectsMap(UnmanagedImage image)
{
this.stride = image.Stride;
// check pixel format
if ((image.PixelFormat != PixelFormat.Format8bppIndexed) &&
(image.PixelFormat != PixelFormat.Format24bppRgb) &&
(image.PixelFormat != PixelFormat.Format32bppRgb) &&
(image.PixelFormat != PixelFormat.Format32bppArgb) &&
(image.PixelFormat != PixelFormat.Format32bppPArgb))
{
throw new UnsupportedImageFormatException("Unsupported pixel format of the source image.");
}
// allocate temporary labels array
tempLabels = new int[(ImageWidth + 2) * (ImageHeight + 2)];
// fill boundaries with reserved value
for (int x = 0, mx = ImageWidth + 2; x < mx; x++)
{
tempLabels[x] = -1;
tempLabels[x + (ImageHeight + 1) * (ImageWidth + 2)] = -1;
}
for (int y = 0, my = ImageHeight + 2; y < my; y++)
{
tempLabels[y * (ImageWidth + 2)] = -1;
tempLabels[y * (ImageWidth + 2) + ImageWidth + 1] = -1;
}
// initial objects count
ObjectsCount = 0;
// do the job
unsafe
{
byte* src = (byte*)image.ImageData.ToPointer();
int p = ImageWidth + 2 + 1;
if (image.PixelFormat == PixelFormat.Format8bppIndexed)
{
int offset = stride - ImageWidth;
// for each line
for (int y = 0; y < ImageHeight; y++)
{
// for each pixel
for (int x = 0; x < ImageWidth; x++, src++, p++)
{
// check for non-labeled pixel
if ((*src > backgroundThresholdG) && (tempLabels[p] == 0))
{
ObjectsCount++;
LabelPixel(src, p);
}
}
src += offset;
p += 2;
}
}
else
{
pixelSize = Bitmap.GetPixelFormatSize(image.PixelFormat) / 8;
int offset = stride - ImageWidth * pixelSize;
// for each line
for (int y = 0; y < ImageHeight; y++)
{
// for each pixel
for (int x = 0; x < ImageWidth; x++, src += pixelSize, p++)
{
// check for non-labeled pixel
if ((
(src[RGB.R] > backgroundThresholdR) ||
(src[RGB.G] > backgroundThresholdG) ||
(src[RGB.B] > backgroundThresholdB)
) &&
(tempLabels[p] == 0))
{
ObjectsCount++;
LabelColorPixel(src, p);
}
}
src += offset;
p += 2;
}
}
}
// allocate labels array
ObjectLabels = new int[ImageWidth * ImageHeight];
for (int y = 0; y < ImageHeight; y++)
Array.Copy(tempLabels, (y + 1) * (ImageWidth + 2) + 1, ObjectLabels, y * ImageWidth, ImageWidth);
}
