public override async IAsyncEnumerable <AlgorithmResultElement> AddWatermark([EnumeratorCancellation] CancellationToken ct)
{
int size = 0;
if (Math.Max(parameters.Original.Width, parameters.Original.Height) > 512)
{
size = Math.Max(parameters.Original.Width, parameters.Original.Height) / 2;
}
complexImage = ComplexImage.FromBitmap(parameters.Original, size);
complexWatermark = ComplexImage.FromBitmap(parameters.Watermark, complexImage.Width);
ct.ThrowIfCancellationRequested();
complexImage.DCT();
var cosineTransform = complexImage.ToEffectiveBitmapCosine();
yield return(new AlgorithmResultElement("Cosine transform (DCT)", cosineTransform.ToBitmap(parameters.Original.Size), new ResultDescription(ToString())));
ct.ThrowIfCancellationRequested();
complexWatermark.DCT();
ct.ThrowIfCancellationRequested();
complexImage.EmbedImageCosine(complexWatermark, parameters.Key, parameters.Alpha);
var cosineWatermarked = complexImage.ToEffectiveBitmapCosine();
yield return(new AlgorithmResultElement("DCT + watermark", cosineWatermarked.ToBitmap(parameters.Original.Size), new ResultDescription(ToString())));
ct.ThrowIfCancellationRequested();
complexImage.IDCT();
var watermarked = complexImage.ToEffectiveBitmapCosine();
yield return(new AlgorithmResultElement("Watermarked", watermarked.ToBitmap(parameters.Original.Size), new ResultDescription(ToString())));
}
public override async IAsyncEnumerable <AlgorithmResultElement> RemoveWatermark([EnumeratorCancellation] CancellationToken ct)
{
int size = 0;
if (Math.Max(parameters.Watermarked.Width, parameters.Watermarked.Height) > 512)
{
size = Math.Max(parameters.Watermarked.Width, parameters.Watermarked.Height) / 2;
}
ComplexImage complexWatermarked = ComplexImage.FromBitmap(parameters.Watermarked, size);
ct.ThrowIfCancellationRequested();
complexWatermarked.DCT();
ct.ThrowIfCancellationRequested();
ComplexImage complexOriginal = ComplexImage.FromBitmap(parameters.Original, complexWatermarked.Width);
complexOriginal.DCT();
ct.ThrowIfCancellationRequested();
int[] v = new int[complexWatermarked.Width];
double[] vAlpha = new double[complexWatermarked.Width];
Random random = new Random(parameters.Key);
ct.ThrowIfCancellationRequested();
for (int i = 0; i < complexWatermarked.Width; i++)
{
v[i] = random.Next(0, 2);
vAlpha[i] = v[i] * parameters.Alpha;
}
ct.ThrowIfCancellationRequested();
for (int y = 0; y < complexWatermarked.Height; y++)
{
for (int x = 0; x < complexWatermarked.Width; x++)
{
if (vAlpha[x] == 0)
{
complexWatermarked.DCTData[y, x] = 0;
}
else
{
complexWatermarked.DCTData[y, x] = (complexWatermarked.DCTData[y, x] - complexOriginal.DCTData[y, x]) / vAlpha[x];
}
}
}
ct.ThrowIfCancellationRequested();
yield return(new AlgorithmResultElement("Extracted watermark DCT", complexWatermarked.ToEffectiveBitmapCosine(true).ToBitmap(parameters.Original.Size), new ResultDescription(ToString())));
complexWatermarked.IDCT();
ct.ThrowIfCancellationRequested();
yield return(new AlgorithmResultElement("Extracted watermark", complexWatermarked.ToEffectiveBitmapCosine(true).ToBitmap(parameters.Original.Size), new ResultDescription(ToString())));
}