Coaxial Single-Pixel Imaging for Shadow Reduction Without Image Post-Processing

Single-pixel imaging (SPI), generally based on computational imaging, has the advantages of a wide bandwidth and imaging objects beyond the visual field. However, for general SPI, to obtain a picture with few shadows by one photodetector is a great challenge. To reduce shadows in SPI, this paper proposes a coaxial SPI to reduce shadows in reconstructed images effectively with a simple structure. Unlike the general shadow reduction method in SPI based on image post-processing, the method proposed in this paper is without the need of additional image post-processing. Shadows can be reduced effectively by single view of only one photodetector. The experiments show that the reconstructed image in the coaxial structure is free from shadows, while the picture reconstructed by the non-coaxial structure contains lots of shadows. Moreover, the coaxial structure shows good applicability for the imaging of the end face in a deep hole. The proposed coaxial SPI has provided a potential direction for the applications of the SPI in information extraction and image quality improvement since the shadows in the reconstructed images have been reduced effectively.