Quasi-non-diffraction single-pixel imaging enabled by spatial multiplexing holography

Single-pixel imaging (SPI) has emerged as an effective computational technique for sensing unknown targets in free space. However, conventional SPI detection schemes rely on multi-scale scanning and auxiliary sensors, incurring high time complexity and increased cost. Here, we propose and experimentally demonstrate a spatial-multiplexing holography (SMH)-based SPI detection scheme that projects non-diffractive patterns and achieves accurate reconstruction over a fixed distance range using a single spatial-multiplexing device and one pattern sequence. In our experiments, we project 16 × 16 Hadamard patterns within a 0.4-0.5 m range; SMH-SPI extends the range of clearly projected patterns (SSIM ≥ 0.755) from a single point to 0.1 m. Moreover, by applying the Hadamard matrix pseudo-inverse for reconstruction, the average SSIM of three reconstructed images increases by up to 200% at 0.5 m, with an average gain of 177% across the 0.4-0.5 m range.