50k fps computational ghost imaging with an ultrafast LED array

Abstract

Computational ghost imaging is a new photoelectric imaging technique mainly characterized by spatial light modulation and single-pixel detection. It provides advantages in multi-wavelength imaging, three-dimensional imaging, and other applications. Improving the image frame rate is always the focus of computational ghost imaging technology, but the image frame rate is mainly limited by the modulation speed of spatial light modulator. In this work, we developed a low-cost LED array module suitable for computational ghost imaging, which can provide high-speed structured illumination at a speed of 25 MHz. With a special scan display scheme, the 32×32 resolution LED array module can display Hadamard sub-patterns at a rate of 12.5 MHz, which is approximately 500 times faster than commercial DMD modulator. Combined with evolutionary compressive sensing algorithm, we obtained the image frame rate of 50k fps in the dynamic imaging experiment. Furthermore, we analyzed the light intensity error caused by the designed LED module and proposed a targeted algorithm to improve the imaging quality in this work. The proposed scheme greatly improves the real-time performance of computational ghost imaging technology and makes it more suitable for dynamic imaging applications. Besides, the LED array presented in this work can also potentially be applied to other technologies requiring high-speed structured illumination, such as LIFI and fringe projection profilometry.