org.deeplearning4j.datasets.mnist

Class MnistImageFile

java.lang.Object

java.io.RandomAccessFile

org.deeplearning4j.datasets.mnist.MnistDbFile

org.deeplearning4j.datasets.mnist.MnistImageFile

All Implemented Interfaces:

Closeable, DataInput, DataOutput, AutoCloseable

public class MnistImageFile
extends MnistDbFile

MNIST database image file. Contains additional header information for the number of rows and columns per each entry.

Constructor Summary

Constructors

Constructor and Description
MnistImageFile(String name, String mode) Creates new MNIST database image file ready for reading.

Method Summary

Modifier and Type	Method and Description
int	getCols() Number of columns per image.
int	getEntryLength() Number of bytes for each entry.
int	getHeaderSize()
protected int	getMagicNumber() MNIST DB files start with unique integer number.
int	getRows() Number of rows per image.
void	nextImage() Move the cursor to the next image.
void	prevImage() Move the cursor to the previous image.
int[][]	readImage() Reads the image at the current position.
byte[][]	readImagesUnsafe(int nImages) Read the specified number of images from the current position, to a byte[nImages][rows*cols] Note that MNIST data set is stored as unsigned bytes; this method returns signed bytes without conversion (i.e., same bits, but requires conversion before use)

Methods inherited from class org.deeplearning4j.datasets.mnist.MnistDbFile

getCount, getCurrentIndex, next, prev, setCurrentIndex

Methods inherited from class java.io.RandomAccessFile

close, getChannel, getFD, getFilePointer, length, read, read, read, readBoolean, readByte, readChar, readDouble, readFloat, readFully, readFully, readInt, readLine, readLong, readShort, readUnsignedByte, readUnsignedShort, readUTF, seek, setLength, skipBytes, write, write, write, writeBoolean, writeByte, writeBytes, writeChar, writeChars, writeDouble, writeFloat, writeInt, writeLong, writeShort, writeUTF

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

MnistImageFile

public MnistImageFile(String name,
                      String mode)
               throws IOException

Creates new MNIST database image file ready for reading.

Parameters:

name - the system-dependent filename

mode - the access mode

Throws:

IOException

FileNotFoundException

Method Detail

readImage

public int[][] readImage()
                  throws IOException

Reads the image at the current position.

Returns:

matrix representing the image

Throws:

IOException

readImagesUnsafe

public byte[][] readImagesUnsafe(int nImages)
                          throws IOException

Read the specified number of images from the current position, to a byte[nImages][rows*cols] Note that MNIST data set is stored as unsigned bytes; this method returns signed bytes without conversion (i.e., same bits, but requires conversion before use)

Parameters:

nImages - Number of images

Throws:

IOException

nextImage

public void nextImage()
               throws IOException

Move the cursor to the next image.

Throws:

IOException

prevImage

public void prevImage()
               throws IOException

Move the cursor to the previous image.

Throws:

IOException

getMagicNumber

protected int getMagicNumber()

Description copied from class: MnistDbFile

MNIST DB files start with unique integer number.

Specified by:

getMagicNumber in class MnistDbFile

Returns:

integer number that should be found in the beginning of the file.

getRows

public int getRows()

Number of rows per image.

Returns:

int

getCols

public int getCols()

Number of columns per image.

Returns:

int

getEntryLength

public int getEntryLength()

Description copied from class: MnistDbFile

Number of bytes for each entry. Defaults to 1.

Overrides:

getEntryLength in class MnistDbFile

Returns:

int

getHeaderSize

public int getHeaderSize()

Overrides:

getHeaderSize in class MnistDbFile