Neuromorphic device mimics human brain

Team leader Professor Sumeet Walia at the Royal Melbourne Institute of Technology (RMIT) said the development marked a step towards instant visual processing in autonomous vehicles, advanced robotics and other next-generation applications for improved human interaction.

“Neuromorphic vision systems are designed to use similar analogue processing to our brains, which can greatly reduce the amount of energy needed to perform complex visual tasks compared with digital technologies used today,” Walia said in a statement.

The work brings together neuromorphic materials and advanced signal processing led by Professor Akram Al-Hourani, who is deputy director of COMAS.

The device contains molybdenum disulfide (MoS2). In their latest study, the team showed how atomic-scale defects in this compound can be harnessed to capture light and process it as electrical signals.

“This proof-of-concept device mimics the human eye’s ability to capture light and the brain’s ability to process that visual information, enabling it to sense a change in the environment instantly and make memories without the need for using huge amounts of data and energy,” said Walia, director of the RMIT Centre for Opto-electronic Materials and Sensors (COMAS).

“Current digital systems, by contrast, are very power hungry and unable to keep up as data volume and complexity increases, which limits their ability to make ‘true’ real-time decisions.”

Waving hand experiment

During experiments, the device detected changes in a waving hand’s movement, without the need to capture the events frame by frame. According to the team, this edge detection process requires significantly less data processing and power.  

Once the changes were detected, the device stored these events as memories like a brain.

The researchers conducted experiments in the spectrum visible to the human eye, which built upon the team’s previous neuromorphic research in the ultraviolet domain.

“We demonstrated that atomically thin molybdenum disulfide can accurately replicate the leaky integrate-and-fire [LIF] neuron behaviour, a fundamental building block of spiking neural networks,” said RMIT PhD student Thiha Aung.

The past UV work involved the detection, memory making and processing of still images. In the visible-spectrum and UV devices, memories could be reset so that devices were ready to perform the next task.

Real world uses

The team’s innovation could one day improve response times of automated vehicles and advanced robotic systems to visual information, which could be crucial particularly in dangerous and unpredictable environments.

“Neuromorphic vision in these applications, which is still many years away, could detect changes in a scene almost instantly, without the need to process lots of data, enabling a much faster response that could save lives,” said Walia.

Moving forward

The team is now scaling up the proof-of-concept single-pixel device to a larger pixel array of MoS2-based devices.

“While our system mimics certain aspects of the brain’s neural processing, particularly in vision, it's still a simplified model,” said Walia. “We will optimise the devices to perform specific real-world applications with more complex vision tasks, and further reduce power consumption.”

The team is also investigating materials other than MoS2 that might extend capabilities into infrared, which could enable real-time tracking of global emissions and intelligent sensing of contaminants such as toxic gases, pathogens and chemicals.

The research is published in Advanced Materials Technologies. RMIT has filed a provisional patent for the work.