Optical encoding and multiplexing based regional single-pixel imaging via TD-SCDMA

Different from traditional imaging methods that rely on plane array detectors, single-pixel imaging (SPI) utilizes a single detector without spatial resolution to acquire images. However, achieving high-resolution reconstruction with SPI typically requires a large number of measurements, which limits the development of SPI. To achieve a balance between high resolution and frame rate, an SPI method based on optical encoding and multiplexing is proposed and demonstrated. In this method, the beam modulated by illumination patterns is subjected to orthogonal space-time encoding to achieve the redistribution of sampling density across different sub-regions of the target. After optical multiplexing, the combined light intensity is collected by a single-pixel detector and decoded to reconstruct each sub-region. Consequently, sub-regions assigned higher sampling densities exhibit improved detail resolution, more closely matching human visual perception compared to those with lower sampling. This work overcomes the limitation of traditional SPI approaches that impose uniform resolution across the entire field of view. With the introduction of space-time encoding, sampling density can be flexibly allocated among various regions. This enables the reconstruction of large-scale scenes at a low overall sampling rate while still achieving higher resolution in selected regions of interest. Moreover, the proposed method can be integrated with various reconstruction algorithms to further reduce computational costs and acquisition time.