Sensorless LED display screen interaction and object recognition

Abstract

AbstractTaking advantage of the photoelectric characteristics of LED other than the light‐emitting function, this paper proposes a light sensing detection method and system without adding additional sensors to the LED screen. A two‐pole detection structure with a function of detecting positive and negative voltage is introduced to the LED drive circuit, which ensures the high‐speed characteristics during detection. What's more, the LED is controlled to work in photoconductive mode to obtain high voltage sensitivity when the intensity of incident light changes. The proposed module can reach an optical signal response rate of 19.1 μs with a detection rate of 23.5 Hz without affecting the original display function. The optical signal detection can reach a voltage sensitivity of 3.02 mV per lx. To verify the photoelectric detection capability of the method presented in this paper, a brand‐new screen object recognition system is built and tested. An 8 × 8 LED display module is used in experiment, and the scale of LED screen can be expanded easily and flexibly. In an ideal environment, a recognition accuracy of 99.25% can be achieved, while the recognition accuracy can still reach over 96.5% in a complex light environment. Therefore, this work has further application possibilities for light interaction and fast object recognition in large screens.