By Gege Li
AI can detect odours in a two step process that mimics the way our noses smell
An AI can sniff out certain odours, giving a glimpse into how our nose might work in detecting them.
Thomas Cleland at Cornell University, New York and Nabil Imam at Intel created an AI based on the mammalian olfactory bulb (MOB), the part of the brain that is responsible for processing odours. The algorithm mimics a part of the MOB that distinguishes between different smells that are usually present as a mixture of compounds in the air.
This part of the MOB contains two key types of neuron: mitral cells, which are activated when a smell is present but dont identify it, and granule cells that learn to become specialised and pick out chemicals in the odour. The algorithm mimics these processes, says Imam.
Cleland and Imam trained the AI to detect 10 different odours, including those of ammonia and carbon monoxide. They used data from previous work that recorded the activity of chemical sensors in a wind tunnel in response to these smells.
When fed that data, the AI learns to detect that a smell is present based on the sensors responses to the chemicals and then goes on to identify it based on the patterns in that data. As it does so, the AI has a spike of activity analogous to the spikes of electrical activity in the human brain, says Imam.
The AI refined its learning over five cycles of exposure, eventually showing activity spikes specific to each odour. The team then tested the AIs ability to sniff out unidentified odours. They considered a smell successfully identified when the AIs fifth spike pattern matched or was similar to the pattern produced by the sensors.
The AI got it almost 100 per cent correct for eight of the odours and about 90 per cent correct for the remaining two. To test how the AI might identify odorous contaminants in the environment, the team blocked 80 per cent of the odour signal to mimic more realistic scenarios. In these tests, the AIs accuracy dipped to less than 30 per cent.
I think the link [to the MOB] is quite strong this algorithm might be an explanation to how it works in the human nose, to some abstraction, says Thomas Nowotny at the University of Sussex, UK. But the AIs ability for solving real life problems such as detecting bombs by picking out hazardous smells associated with them is still some way off, he says.
Journal reference: Nature Machine Intelligence, DOI: 10.1038/s42256-020-0159-4
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By Gege Li