public static byte[] LoadLabel(string labelFile)
{
/*
* TRAINING SET LABEL FILE (train-labels-idx1-ubyte):
* [offset] [type] [value] [description]
* 0000 32 bit integer 0x00000801(2049) magic number (MSB first)
* 0004 32 bit integer 60000 number of items
* 0008 unsigned byte ?? label
* 0009 unsigned byte ?? label
* ........
* xxxx unsigned byte ?? label
* The labels values are 0 to 9.
*/
using (var raw = File.OpenRead(labelFile))
{
using (var gz = new GZipStream(raw, CompressionMode.Decompress))
{
using (var reader = new BinaryReaderMSB(gz))
{
// Check Header / Magic Number
var header = reader.ReadInt32MSB();
if (header != 0x801)
{
throw new InvalidDataException(header.ToString("x"));
}
var itemCount = reader.ReadInt32MSB();
return(reader.ReadBytes(itemCount));
}
}
}
}
public static IEnumerable <byte[, ]> LoadImages(string imageFile)
{
/*
* TRAINING SET IMAGE FILE (train-images-idx3-ubyte):
* [offset] [type] [value] [description]
* 0000 32 bit integer 0x00000803(2051) magic number
* 0004 32 bit integer 60000 number of images
* 0008 32 bit integer 28 number of rows
* 0012 32 bit integer 28 number of columns
* 0016 unsigned byte ?? pixel
* 0017 unsigned byte ?? pixel
* ........
* xxxx unsigned byte ?? pixel
* Pixels are organized row-wise. Pixel values are 0 to 255. 0 means background (white), 255 means foreground (black).
*/
using (var raw = File.OpenRead(imageFile))
{
using (var gz = new GZipStream(raw, CompressionMode.Decompress))
{
using (var reader = new BinaryReaderMSB(gz))
{
var header = reader.ReadInt32MSB();
if (header != 0x803)
{
throw new InvalidDataException(header.ToString("x"));
}
var itemCount = reader.ReadInt32MSB();
var rowCount = reader.ReadInt32MSB();
var colCount = reader.ReadInt32MSB();
for (var i = 0; i < itemCount; i++)
{
var image = new byte[rowCount, colCount];
for (var r = 0; r < rowCount; r++)
{
for (var c = 0; c < colCount; c++)
{
image[r, c] = reader.ReadByte();
}
}
yield return(image);
}
}
}
}
}
