In plain words: A reconstruction rebuilds the handwritten-digit set from its original source, matching each digit to its writer and other details, and restores the full 60,000-image test set. Testing on the 50,000 never-released digits, classifier rankings and model choices held up despite slightly shifted error rates.
Abstract · Cold Case: The Lost MNIST Digits
Although the popular MNIST dataset [LeCun et al., 1994] is derived from the NIST database [Grother and Hanaoka, 1995], the precise processing steps for this derivation have been lost to time. We propose a reconstruction that is accurate enough to serve as a replacement for the MNIST dataset, with insignificant changes in accuracy. We trace each MNIST digit to its NIST source and its rich metadata such as writer identifier, partition identifier, etc. We also reconstruct the complete MNIST test set with 60,000 samples instead of the usual 10,000. Since the balance 50,000 were never distributed, they enable us to investigate the impact of twenty-five years of MNIST experiments on the reported testing performances. Our results unambiguously confirm the trends observed by Recht et al. [2018, 2019]: although the misclassification rates are slightly off, classifier ordering and model selection remain broadly reliable. We attribute this phenomenon to the pairing benefits of comparing classifiers on the same digits.
Chhavi Yadav, Léon Bottou
arXiv:1905.10498 · cs.LG, cs.CV, stat.ML · submitted May 25, 2019 · updated Nov 4, 2019
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