The core of the machine-learning process was the simulated steering by the CNN using Torch 7. The steering commands the CNN executed in a simulated response to the 10 fps images taken from a car driven by a human were compared to the human steering angles. The analysis of the difference between the human steering angles and the CNN-simulated steering commands taught the system to see and steer. The test data used in simulation was based on the video recording of three hours of driving over test routes, amounting to a total distance of 100 miles.
When the CNN driving simulation performed well, further machine learning and testing was stepped up to test vehicles on the road. On-road testing improved the system, with a human driver supervising the autonomous car and intervening when the autonomous system erred. Each correction was fed to the machine-learning system to improve the accuracy of the steering process. In the first 10 miles of driving on the New Jersey Turnpike, the vehicle operated 100 percent autonomously. Overall in early testing, the vehicle operated 98 percent autonomously.
Nvidia demonstrated that CNNs can learn the entire task of lane detection and road following without manually and explicitly decomposing and classifying road or lane markings, semantic abstractions, path planning and control. This was learned using Torch 7 to render fewer than 100 hours of training data to create the internal process to operate a vehicle autonomously in diverse weather and lighting conditions, on highways and side roads. Nvidia released a video with its paper that shows examples of the system autonomously steering the test vehicles.
The Nvidia team indicated that the system is not yet ready for production by stating in its paper:
“More work is needed to improve the robustness of the network, to find methods to verify the robustness, and to improve visualization of the network-internal processing steps.”
Based on the video, it’s fairly certain that the engineering team at every company building or planning to build an autonomous vehicle is reading this paper right now and discussing the results. Building this autonomous vehicle prototype could put Nvidia in the position to be a leading supplier of massively parallel GPU systems to all of the autonomous car manufacturers.
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