Esempio n. 1
0
        public override ulong Create(BitmapData image)
        {
            var data = new DenseMatrix(32, 32);

            using (var unmanaged = new UnmanagedImage(image))
            {
                using (var filtered = ExtractChannel.Apply(unmanaged))
                {
                    Filter.ApplyInPlace(filtered);

                    using (var imgdata = Resize.Apply(filtered))
                    {
                        unsafe
                        {
                            var src    = (byte *)imgdata.ImageData.ToPointer();
                            var offset = imgdata.Stride - imgdata.Width;
                            var width  = imgdata.Width;
                            var height = imgdata.Height;
                            for (var y = 0; y < height; y++)
                            {
                                for (var x = 0; x < width; x++, src++)
                                {
                                    data.At(y, x, (float)*src / 255);
                                }
                                src += offset;
                            }
                        }
                    }
                }
            }

            var dct = DctMatrix.FastDCT(data);

            var vals      = new double[dctsize * dctsize];
            var valscount = 0;

            for (var r = 1; r <= dctsize; r++)
            {
                for (var c = 1; c <= dctsize; c++)
                {
                    vals[valscount] = dct.At(r, c);
                    ++valscount;
                }
            }

            var sorted = new double[dctsize * dctsize];

            Array.Copy(vals, sorted, vals.Length);
            Array.Sort(sorted);

            var mid    = dctsize * dctsize / 2;
            var median = (sorted[mid - 1] + sorted[mid]) / 2d;

            ulong index  = 1;
            ulong result = 0;

            for (var i = 0; i < dctsize * dctsize; i++)
            {
                if (vals[i] > median)
                {
                    result |= index;
                }

                index = index << 1;
            }

            return(result);
        }
        public override ulong Create(BitmapData image)
        {
            var data = new DenseMatrix(32, 32);

            using (var unmanaged = UnmanagedImage.FromManagedImage(image))
                using (var filtered = ExtractChannel.Apply(unmanaged))
                {
                    new Convolution(Filter, 9).ApplyInPlace(filtered);
                    using (var imgdata = new ResizeNearestNeighbor(32, 32).Apply(filtered))
                    {
                        unsafe
                        {
                            byte *src    = (byte *)imgdata.ImageData.ToPointer();
                            int   offset = imgdata.Stride - imgdata.Width;
                            int   width  = imgdata.Width;
                            int   height = imgdata.Height;
                            for (int y = 0; y < height; y++)
                            {
                                for (int x = 0; x < width; x++, src++)
                                {
                                    data.At(y, x, (float)*src / 255);
                                }
                                src += offset;
                            }
                        }
                    }
                }

            var dct = DctMatrix.FastDCT(data);

            int dctsize = 8;
            var vals    = new List <double>();

            for (int r = 1; r <= dctsize; r++)
            {
                for (int c = 1; c <= dctsize; c++)
                {
                    vals.Add(dct[r, c]);
                }
            }

            var sorted = new List <double>(vals);

            sorted.Sort();
            var    mid    = dctsize * dctsize / 2;
            double median = (sorted[mid - 1] + sorted[mid]) / 2d;

            ulong index  = 1;
            ulong result = 0;

            for (int i = 0; i < dctsize * dctsize; i++)
            {
                if (vals[i] > median)
                {
                    result |= index;
                }

                index = index << 1;
            }

            return(result);
        }