Learning OpenCV 4 Computer Vision with Python 3 - Third Edition

Understanding the MNIST database of handwritten digits

The MNIST database (or Modified National Institute of Standards and Technology database) is publicly available at http://yann.lecun.com/exdb/mnist/. The database includes a training set of 60,000 images of handwritten digits. Half of these were written by employees of the United States Census Bureau, while the other half were written by high school students in the United States.

The database also includes a test set of 10,000 images, gathered from the same writers. All the training and test images are in grayscale format, with dimensions of 28 x 28 pixels. The digits are white (or shades of gray) on a black background. For example, here are three of the MNIST training samples:

As an ...