public override async IAsyncEnumerable <AlgorithmResultElement> AddWatermark([EnumeratorCancellation] CancellationToken ct) { complexImage = ComplexImage.FromBitmap(parameters.Original); complexWatermark = ComplexImage.FromBitmap(parameters.Watermark, complexImage.Width); ct.ThrowIfCancellationRequested(); complexImage.ForwardFourierTransform(); var fourierDomain = complexImage.ToEffectiveBitmapFourier(); yield return(new AlgorithmResultElement("Fourier domain (DFT)", fourierDomain.ToBitmap(parameters.Original.Size), new ResultDescription(ToString()))); ct.ThrowIfCancellationRequested(); complexWatermark.ForwardFourierTransform(); complexImage.EmbedImageFourier(complexWatermark, parameters.Key, parameters.Alpha); var fourierDomainWatermarked = complexImage.ToEffectiveBitmapFourier(); yield return(new AlgorithmResultElement("DFT + watermark", fourierDomainWatermarked.ToBitmap(parameters.Original.Size), new ResultDescription(ToString()))); ct.ThrowIfCancellationRequested(); complexImage.BackwardFourierTransform(); var watermarked = complexImage.ToEffectiveBitmapFourier(); yield return(new AlgorithmResultElement("Watermarked", watermarked.ToBitmap(parameters.Original.Size), new ResultDescription(ToString()))); }
public override async IAsyncEnumerable <AlgorithmResultElement> RemoveWatermark([EnumeratorCancellation] CancellationToken ct) { ct.ThrowIfCancellationRequested(); ComplexImage complexWatermarked = ComplexImage.FromBitmap(parameters.Watermarked); complexWatermarked.ForwardFourierTransform(); ct.ThrowIfCancellationRequested(); ComplexImage complexOriginal = ComplexImage.FromBitmap(parameters.Original); complexOriginal.ForwardFourierTransform(); 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++) { double watermarkedReal = complexWatermarked.Data[y, x].Real; double watermarkedImaginary = complexWatermarked.Data[y, x].Imaginary; double originalReal = complexOriginal.Data[y, x].Real; double originalImaginary = complexOriginal.Data[y, x].Imaginary; if (vAlpha[x] == 0) { complexWatermarked.Data[y, x] = new System.Numerics.Complex(0, 0); } else { complexWatermarked.Data[y, x] = new System.Numerics.Complex((watermarkedReal - originalReal) / vAlpha[x], (watermarkedImaginary - originalImaginary) / vAlpha[x]); } } } ct.ThrowIfCancellationRequested(); yield return(new AlgorithmResultElement("Extracted watermark DFT", complexWatermarked.ToEffectiveBitmapFourier(true).ToBitmap(parameters.Original.Size), new ResultDescription(ToString()))); complexWatermarked.BackwardFourierTransform(); ct.ThrowIfCancellationRequested(); yield return(new AlgorithmResultElement("Extracted watermark", complexWatermarked.ToEffectiveBitmapFourier(true).ToBitmap(parameters.Original.Size), new ResultDescription(ToString()))); }