ALVINN: a neural network steers the van
At the NIPS conference of 1988 Dean Pomerleau of Carnegie Mellon described ALVINN, a three-layer back-propagation network that takes a 30 by 32 camera image and an 8 by 32 laser range-finder image (1217 inputs in all) and, through 29 hidden units, outputs one of 45 travel directions. The network was trained on 1200 simulated road images for 40 epochs; on new simulated images it picks the curvature within two units about 90 percent of the time. On the Navlab van it drove the vehicle along a 400 metre path through a wooded part of the campus at half a metre per second.
Why it matters
For the first time the steering of a real vehicle was in the hands of a neural network trained on examples rather than an algorithm a person had written: the processing depends on what the network was trained on, and the weights of the hidden units read as road-edge filters. It is the direct ancestor of driving by camera and learning.
The input is split into two retinas and one feedback unit that says whether the road is lighter than the non-road; the blue band of the image is used as the most contrasting; the desired output is a hill of activation around the curvature that would bring the vehicle to the road centre 7 metres ahead. The simulated images come from the group's own road generator with varied positions, lighting and noise, because collecting real ones under every condition was hard. Navlab is a modified Chevy van with three Sun computers, a Warp processor, a video camera and a laser range finder. Under the same conditions on the same course the ALV group at CMU reached the same accuracy at 1 m/s by running its algorithm on the Warp; ALVINN was then simulated on one on-board Sun, and the author expected speed-ups on the Warp. The proceedings are Advances in Neural Information Processing Systems 1 (NIPS 1988), pages 305-313. What the record does not claim: the month of the conference; kilometres (the paper gives 400 metres); that the network was trained on real images (the paper says simulated ones).