[bravura]

LeCun et al (1989) had backprop working for digit recognition.

LeCun, Bottou, et al (2002) in "Efficient Backprop" described techniques for improving backprop algorithms.

[sigmoid10]

Rosenblatt had a working perceptron for classifying images in the 1950s (!). And yet it took 60 years before the theory and compute power had developed enough for all of this to be interesting outside of small, purely academic experiments.

[bravura]

Handwriting recognition on checks (LeCun et al 1989) wasn't really a small, purely academic experiment

[sigmoid10]

And yet classical OCR techniques continued to dominate. Nothing happened in the industry on that front for over 20 years. That's as academic as it gets.