public static CIFARImageBW FromCIFARImage(CIFARImage orig)
{
CIFARImageBW result = new CIFARImageBW(orig.Label, orig.Width, orig.Height);
for (int i = 0; i < result.PixelData.Length; ++i)
{
result.PixelData[i] = (orig.PixelData[i] + orig.PixelData[i + 1024] + orig.PixelData[i + 2048]) / 3.0;
}
return result;
}
public static CIFARImageBW FromCIFARImage(CIFARImage orig, int channel)
{
if (channel < 0 || channel > 2)
throw new Exception("Channel != 1, 2, or 3");
CIFARImageBW result = new CIFARImageBW(orig.Label, orig.Width, orig.Height );
for (int i = 0; i < result.PixelData.Length; ++i)
{
result.PixelData[i] = (orig.PixelData[i + 1024 * channel]);
}
return result;
}
public static void SavePicture(CIFARImageBW image, string path, bool isCentered)
{
Bitmap bm = new Bitmap(image.Width, image.Height);
for (int i = 0; i < image.Height; ++i)
{
for (int j = 0; j < image.Width; ++j)
{
int val = isCentered ? DoubleTo8bppGray(image.PixelData[i*image.Width+j]) : (byte) image.PixelData[i*image.Width+j];
bm.SetPixel(j, i, Color.FromArgb(val, val, val));
}
}
bm.Save(path, System.Drawing.Imaging.ImageFormat.Png);
}
public static CIFARImageBW GetPatch(CIFARImageBW img, int x, int y)
{
CIFARImageBW result = new CIFARImageBW(img.Label, 8, 8);
for (int j = 0; j < 8; ++j)
{
for (int i = 0; i < 8; ++i)
{
result.PixelData[j * 8 + i] = img.PixelData[(y + j) * 32 + x + i];
}
}
return result;
}
public static double[,] ToDoubleMtx(CIFARImageBW image)
{
int sqrtDim = (int) Math.Sqrt(image.PixelData.Length);
double[,] result = new double[sqrtDim, sqrtDim];
for (int i = 0; i < sqrtDim; ++i)
for (int j = 0; j < sqrtDim; ++j)
result[i, j] = image.PixelData[j * sqrtDim + i];
return result;
}
public static CIFARImageBW Normalize_ZeroMean(CIFARImageBW orig)
{
CIFARImageBW result = new CIFARImageBW(orig.Label, orig.Width, orig.Height);
double mean = Mean(orig);
for (int i = 0; i < result.PixelData.Length; ++i)
{
result.PixelData[i] = orig.PixelData[i] - mean;
}
return result;
}
public static double[,] Normalize_Whiten(CIFARImageBW image)
{
image = Normalize_ZeroMean(image);
var img_mtx = ToDoubleMtx(image);
var cov_mtx = Cov_Mtx(img_mtx);
double[] w = new double[cov_mtx.GetLength(1)];
double[,] u = new double[cov_mtx.GetLength(0), cov_mtx.GetLength(1)];
double[,] vt = new double[cov_mtx.GetLength(0), cov_mtx.GetLength(1)];
alglib.svd.rmatrixsvd(cov_mtx, cov_mtx.GetLength(0), cov_mtx.GetLength(1), 2, 2, 2, ref w, ref u, ref vt);
double[,] _1_sqrt_w_mtx = new double[w.Length, w.Length];
for (int i = 0; i < w.Length; ++i)
{
_1_sqrt_w_mtx[i, i] = 1 / Math.Sqrt(w[i] + 0.00000001);
}
double[,] ut = new double[w.Length, w.Length];
alglib.rmatrixtranspose(w.Length, w.Length, u, 0, 0, ref ut, 0, 0);
double[,] result1 = new double[w.Length, w.Length];
double[,] result2 = new double[w.Length, w.Length];
double[,] result3 = new double[w.Length, w.Length];
alglib.rmatrixgemm(w.Length, w.Length, w.Length, 1, u, 0, 0, 0, _1_sqrt_w_mtx, 0, 0, 0, 0, ref result1, 0, 0);
alglib.rmatrixgemm(w.Length, w.Length, w.Length, 1, result1, 0, 0, 0, ut, 0, 0, 0, 0, ref result2, 0, 0);
alglib.rmatrixgemm(w.Length, w.Length, w.Length, 1, result2, 0, 0, 0, img_mtx, 0, 0, 0, 0, ref result3, 0, 0);
return NormalizeMtx(result3);
}
public static double Mean(CIFARImageBW img)
{
double mean = 0;
foreach (var PixelVal in img.PixelData)
{
mean += PixelVal;
}
return mean / img.PixelData.Length;
}
public static List<CIFARImageBW> GetPatches_Seq(CIFARImageBW img)
{
List<CIFARImageBW> result = new List<CIFARImageBW>();
for (int i = 0; i < 24; i += 1)
{
for (int j = 0; j < 24; j += 1)
{
//Console.WriteLine("{0}:{1}", i, j);
result.Add(GetPatch(img, j, i));
}
}
return result;
}
public static List<CIFARImageBW> GetPatches_25(CIFARImageBW img)
{
List<CIFARImageBW> result = new List<CIFARImageBW>();
for (int i = 0; i < 4; ++i)
for (int j = 0; j < 4; ++j)
result.Add(GetPatch(img, j * 8, i * 8));
for (int i = 0; i < 3; ++i)
for (int j = 0; j < 3; ++j)
result.Add(GetPatch(img, j * 8 + 4, i * 8 + 4));
return result;
}