/// <summary>
/// Construct integral image from source grayscale image.
/// </summary>
///
/// <param name="image">Source unmanaged image.</param>
///
/// <returns>Returns integral image.</returns>
///
/// <exception cref="UnsupportedImageFormatException">The source image has incorrect pixel format.</exception>
///
public static IntegralImage FromBitmap(UnmanagedImage image)
{
// check image format
if (image.PixelFormat != PixelFormat.Format8bppIndexed)
{
throw new ArgumentException("Source image can be graysclae (8 bpp indexed) image only.");
}
// get source image size
int width = image.Width;
int height = image.Height;
int offset = image.Stride - width;
// create integral image
IntegralImage im = new IntegralImage(width, height);
uint[,] integralImage = im.integralImage;
// do the job
unsafe
{
byte *src = (byte *)image.ImageData.ToPointer( );
// for each line
for (int y = 1; y <= height; y++)
{
uint rowSum = 0;
// for each pixel
for (int x = 1; x <= width; x++, src++)
{
rowSum += *src;
integralImage[y, x] = rowSum + integralImage[y - 1, x];
}
src += offset;
}
}
return(im);
}
/// <summary>
/// Construct integral image from source grayscale image.
/// </summary>
///
/// <param name="image">Source grayscale image.</param>
///
/// <returns>Returns integral image.</returns>
///
/// <exception cref="UnsupportedImageFormatException">The source image has incorrect pixel format.</exception>
///
public static IntegralImage FromBitmap(Bitmap image)
{
// check image format
if (image.PixelFormat != PixelFormat.Format8bppIndexed)
{
throw new UnsupportedImageFormatException("Source image can be graysclae (8 bpp indexed) image only.");
}
// lock source image
BitmapData imageData = image.LockBits(
new Rectangle(0, 0, image.Width, image.Height),
ImageLockMode.ReadOnly, PixelFormat.Format8bppIndexed);
// process the image
IntegralImage im = FromBitmap(imageData);
// unlock image
image.UnlockBits(imageData);
return(im);
}