An Optical Neuromorphic Sensor with High Uniformity and High Linearity for Indoor Visible Light Localization

The visible light localization system holds great promise as a highly accurate indoor positioning method. However, it still suffers deficiencies including high latency and power consumption, and large area cost. To address these issues, a high energy efficient spiking localization system inspired by the biological spatial representation system is presented. This system utilizes an optical neuromorphic sensor, consisting of a compact NbO_x-based threshold switching memristor and a photoresistor. The key lies in the system's ability to convert analog light information into electrical spikes, resembling the behavior of sensory neurons, which enables the encoding of light illuminance through spiking frequency. Consequently, the system achieves high uniformity, high linearity (≈10%), and high sensitivity (≈1.1 kHz Lux⁻¹ and ≈72.7 kHz cm⁻¹ for light illuminance and distance detection, respectively), indicating its potential suitability for visible light localizations. By leveraging a spiking neural network classifier, the system successfully distinguishes locations with different illuminances. After 150 epochs, it achieves an accuracy of 97%, showcasing the feasibility of using the spiking localization system in real-world applications. The approach of spike-based light positioning is a leap forward toward the development of future compact, highly energy-efficient visible light localization systems.