mnist.tools
Class MnistManager

java.lang.Object
  mnist.tools.MnistManager

public class MnistManager
extends java.lang.Object

Utility class for working with the MNIST database.

Provides methods for traversing the images and labels data files separately, as well as simultaneously.

Provides also method for exporting an image by writing it as a PPM file.

Example usage:

  MnistManager m = new MnistManager("t10k-images.idx3-ubyte", "t10k-labels.idx1-ubyte");
  m.setCurrent(10); //index of the image that we are interested in
  int[][] image = m.readImage();
  System.out.println("Label:" + m.readLabel());
  MnistManager.writeImageToPpm(image, "10.ppm");
 

Constructor Summary

MnistManager(java.lang.String imagesFile, java.lang.String labelsFile)
Constructs an instance managing the two given data files.

Method Summary

MnistImageFile	getImages() Get the underlying images file as MnistImageFile.
MnistLabelFile	getLabels() Get the underlying labels file as MnistLabelFile.
int[][]	readImage() Reads the current image.
int	readLabel() Reads the current label.
void	setCurrent(int index) Set the position to be read.
static void	writeImageToPpm(int[][] image, java.lang.String ppmFileName) Writes the given image in the given file using the PPM data format.

Methods inherited from class java.lang.Object

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

Constructor Detail

MnistManager

public MnistManager(java.lang.String imagesFile,
                    java.lang.String labelsFile)
             throws java.io.IOException

Constructs an instance managing the two given data files. Supports NULL value for one of the arguments in case reading only one of the files (images and labels) is required.

Parameters:

imagesFile - Can be NULL. In that case all future operations using that file will fail.

labelsFile - Can be NULL. In that case all future operations using that file will fail.

Throws:

java.io.IOException

Method Detail

writeImageToPpm

public static void writeImageToPpm(int[][] image,
                                   java.lang.String ppmFileName)
                            throws java.io.IOException

Writes the given image in the given file using the PPM data format.

Parameters:

image -

ppmFileName -

Throws:

java.io.IOException

readImage

public int[][] readImage()
                  throws java.io.IOException

Reads the current image.

Returns:

matrix

Throws:

java.io.IOException

setCurrent

public void setCurrent(int index)

Set the position to be read.

Parameters:

index -

readLabel

public int readLabel()
              throws java.io.IOException

Reads the current label.

Returns:

int

Throws:

java.io.IOException

getImages

public MnistImageFile getImages()

Get the underlying images file as MnistImageFile.

Returns:

MnistImageFile.

getLabels

public MnistLabelFile getLabels()

Get the underlying labels file as MnistLabelFile.

Returns:

MnistLabelFile.