Single-pixel imaging is an emerging computational imaging technology that, in contrast to traditional array detector imaging, utilizes a single point detector without spatial resolution capability to record image information. The single-point detector offers significant advantages, including low dark noise, high sensitivity, rapid response, and lower cost, while exhibiting excellent performance across nearly the entire spectral range. Due to its unique imaging mechanism, single-pixel imaging has found widespread applications in various fields,including terahertz imaging, remote sensing, three-dimensional imaging, multispectral imaging, and optical information encryption.
Furthermore, the combination of single-pixel imaging with digital holography has led to the development of a novel technique known as single-pixel holography. Computational ghost holography, as a realization of single-pixel holography, has attracted considerable attention due to its capability to simultaneously acquire both amplitude and phase information of an object. However, computational ghost holography typically requires a large number of measurements to gather sufficient spatial information to reconstruct images with fine details. Consequently, researchers often utilize real-valued orthogonal bases such as Hadamard, Fourier, and wavelet bases, which are sparse for natural images, allowing for the reconstruction of clear images under undersampling conditions to reduce the number of measurements. Nevertheless, pure amplitude modulation based on real values struggles to differentiate the uncertainty introduced by the target's complex conjugate.
Recently, Professor Yuan Ren and his team from the Space Engineering University proposed a novel computational ghost holography scheme using Laguerre-Gaussian (LG) modes as complex orthogonal bases. By sequentially projecting 4,128 different orders of LG modes and employing second-order correlation (SOC) and TVAL3 compressed sensing (CS) algorithms, they successfully reconstructed both the amplitude and phase images of complex amplitude objects. Due to the symmetry of LG modes, objects with rotational symmetry can be identified and imaged using fewer modes. Additionally, the research team theoretically analyzed the differences between bucket detection (correlation detection) and zero-frequency detection (coherent detection),which was validated through experiment. Zero-frequency detection enables the simultaneous acquisition of both amplitude and phase information of an object, while bucket detection is limited to amplitude information but demonstrates greater robustness under interference conditions. During the image reconstruction process, preprocessing of LG modes also enabled direct edge extraction of images. This research offers new possibilities for the application of single-pixel imaging in fields such as target recognition and microscopic imaging.
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The relevant research has been published in Chinese Optics Letters, Volume 23, Issue 1, 2025, and selected as the cover article for this issue. Professors Yuan Ren and Associate Professor Tong Liu from the Space Engineering University are the corresponding authors, while Ph.D. student Liyuan Xu is the first author.
