Beispiel #1
0
        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));
                    }
                }
            }
        }
Beispiel #2
0
        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);
                        }
                    }
                }
            }
        }