MNIST Dataset

Overview

  • Training Set: 60,000 training images & labels
  • Test Set: 10,000 test images & labels
  • Handwritten single digits ranging 0-9

Data Format

  • Each 28 x 28 pixel single digit image is represented as a 28 x 28 array, with grayscale (single color channel) values ranging from 0 (white) to 255 (black).
    • It can be normalized to a range of 0-1.
  • With 60,000 images, each with a single channel sized 28 x 28 x 1 results in a 4D array:
    • (60,000, 28, 28, 1)
    • The '1' denotes a single color channel: grayscale. Color images would have a value of '3'.
  • When the 28 x 28 array is flattened it is a 1D vector measuring 784 units. Note that the flattening of this array removes the information about the pixel relationships with adjacent pixels, but this can otherwise be accounted for in a CNN. This results in an overall training tensor of a 784 x 60,000 array.
  • Labels
    • Labels are one-hot encoded into a single array for each image and identified by the index position in the array.
      • Example label for a digit of 4: [0, 0, 0, 0, 1, 0, 0, 0, 0, 0]
    • With labels identifying 1 of the 10 available values, the training labels are a (60,000, 10) 2D array.

Sample Image

The following is a sample of the data for a single image depicting a handwritten number '5'.

array([
       [  0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,  0,  0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,  0,   0],
       [  0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,  0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 0,   0],
       [  0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,  0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,  0,   0],
       [  0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,  0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,  0,   0],
       [  0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,  0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,  0,   0],
       [  0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   3, 18,  18,  18, 126, 136, 175,  26, 166, 255, 247, 127,   0,   0,  0,   0],
       [  0,   0,   0,   0,   0,   0,   0,   0,  30,  36,  94, 154, 170,  253, 253, 253, 253, 253, 225, 172, 253, 242, 195,  64,   0,   0,   0,   0],
       [  0,   0,   0,   0,   0,   0,   0,  49, 238, 253, 253, 253, 253,  253, 253, 253, 253, 251,  93,  82,  82,  56,  39,   0,   0,   0,  0,   0],
       [  0,   0,   0,   0,   0,   0,   0,  18, 219, 253, 253, 253, 253,  253, 198, 182, 247, 241,   0,   0,   0,   0,   0,   0,   0,   0,  0,   0],
       [  0,   0,   0,   0,   0,   0,   0,   0,  80, 156, 107, 253, 253,  205,  11,   0,  43, 154,   0,   0,   0,   0,   0,   0,   0,   0,  0,   0],
       [  0,   0,   0,   0,   0,   0,   0,   0,   0,  14,   1, 154, 253,   90,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0],
       [  0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 139, 253,  190,   2,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,  0,   0],
       [  0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,  11, 190,  253,  70,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0],
       [  0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,  35,   241, 225, 160, 108,   1,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0],
       [  0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   81, 240, 253, 253, 119,  25,   0,   0,   0,   0,   0,   0,   0,   0,   0],
       [  0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,    0,  45, 186, 253, 253, 150,  27,   0,   0,   0,   0,   0,   0,   0,   0],
       [  0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,  16,  93, 252, 253, 187,   0,   0,   0,   0,   0,   0,  0,   0],
       [  0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0, 249, 253, 249,  64,   0,   0,   0,   0,   0,  0,   0],
       [  0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,  0,  46, 130, 183, 253, 253, 207,   2,   0,   0,   0,   0,   0,  0,   0],
       [  0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,  39,   148, 229, 253, 253, 253, 250, 182,   0,   0,   0,   0,   0,   0,  0,   0],
       [  0,   0,   0,   0,   0,   0,   0,   0,   0,   0,  24, 114, 221, 253, 253, 253, 253, 201,  78,   0,   0,   0,   0,   0,   0,   0,   0,   0],
       [  0,   0,   0,   0,   0,   0,   0,   0,  23,  66, 213, 253, 253,  253, 253, 198,  81,   2,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0],
       [  0,   0,   0,   0,   0,   0,  18, 171, 219, 253, 253, 253, 253,  195,  80,   9,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0],
       [  0,   0,   0,   0,  55, 172, 226, 253, 253, 253, 253, 244, 133,  11,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0],
       [  0,   0,   0,   0, 136, 253, 253, 253, 212, 135, 132,  16,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0],
       [  0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0],
       [  0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0],
       [  0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0,   0]
       ], dtype=uint8)

Documentation

TensorFlow

TF MNIST Dataset

Distributed Training with MNIST Dataset

Documentation