Multi-object parallel optical encryption for single-pixel imaging security

Multi-object optical encryption has emerged as a promising field for enhancing encryption performance and reducing communication overhead, which can ensure the security of single-pixel imaging. However, it faces some critical challenges like low efficiency, reliance on complex system design, high hardware costs, and the difficulty of parallel encryption with independent decryption, hindering practical deployment. In this work, an illumination pattern construction algorithm is proposed to generate projected basis patterns for parallel optical encryption, while a decoupling algorithm is developed to demodulate coupled measurements to recover Hadamard spectrum for each object. Independent decryption is then performed using a random-order Hadamard matrix assigned to each object. The proposed method achieves multi-object parallel encryption and independent decryption using a lightweight optical system, with improved efficiency, lower hardware costs, and smaller ciphertext size compared to conventional methods. In addition, it also exhibits robustness against both cropping and noise attacks. These results indicate potential for practical applications and may contribute to future developments in multi-object optical encryption for single-pixel imaging security.