We present a new method for recording off-axis digital Fourier holograms of three-dimensional objects under spatially incoherent illumination. The method is implemented by modifying the optical configuration of triangular interferometer. The recording properties and 3D reconstruction ability of the proposed method are investigated theoretically and experimentally. Multicolor holographic recording and reconstruction of spatially incoherent illuminated object are achieved by using the proposed off-axis Fourier triangular interferometer and monochromatic digital camera. Only three holograms are sufficient to rebuild a color image without zero-order and twin image disturbing effect. Combining with some image fusion skills during reconstruction, the reconstructed color images with satisfied quality are demonstrated.

A modified nonlinear reconstruction technique with a noise modulation parameter is proposed for interferenceless coded aperture correlation holography (I-COACH), and thus the signal-to-noise ratio of a reconstructed image is improved without sacrifice of the field of view and temporal resolution of the system. In order to obtain the optimal reconstructed image, no-reference structural sharpness (NRSS) is introduced as the evaluation metric of reconstructed image quality during nonlinear reconstruction. On the other hand, the noise modulation function is built in order to analyze the effect of phase on noise when the amplitude of the point spread hologram and object hologram is unity of 1. Both the NRSS and noise modulation functions are combined with nonlinear reconstruction in I-COACH for improving imaging performance. The validities of the proposed method under different experimental conditions have been demonstrated by experiments.

We present a new self-interference digital holographic approach that allows single-shot capturing threedimensional intensity distribution of the spatially incoherent objects. The Fresnel incoherent correlation holographic microscopy is combined with parallel phaseshifting technique to instantaneously obtain spatially multiplexed phase-shifting holograms. The compressivesensing-based reconstruction algorithm is implemented to reconstruct the original object from the under sampled demultiplexed holograms. The scheme is verified with simulations. The validity of the proposed method is experimentally demonstrated in an indirectly way by simulating the use of specific parallel phaseshifting recording device.

Fresnel incoherent correlation holography (FINCH) was proposed to break the barrier of spatial incoherent digital holographic imaging and show the potential of super-resolution imaging preferences. We developed FINCH as a compressive sensing modality and reconstruction procedure as an inverse problem in order to realize 3D tomographic imaging. Improved axial resolution is obtained via compressive reconstruction. Reconstruction guarantees and accuracy of the proposed method are discussed. Compared with the real-valued signal operation, the signal-to-noise ratio of the results is increased when reconstructing from the complex-valued hologram obtained from the FINCH system.

Motivated by the key role of point spread function in an imaging system, we propose an interferenceless coded aperture correlation holographic (I-COACH) technology with low speckle and high energy efficiency annular sparse coded phase mask (CPM) as system pupil to improve imaging performance. In the proposed method, a modified Gerchberg–Saxton (GS) algorithm is proposed to obtain a low speckle and high energy efficiency annular sparse CPM and to suppress speckle and increase the intensity of the holograms. Therefore, the randomly distributed amplitude in the bandwidth of the GS algorithm is replaced by the annular amplitude to determine the spatial position, and the band-limited random phase and quadratic phase are used as the initial phase to approximately meet band-limited conditions; meanwhile, in the iterative process of the algorithm, appropriate constraints are imposed on the information within and outside the band limit. All are used for obtaining the CPM with low speckle and high energy efficiency. Therefore, the proposed technique here is coined as low speckle I-COACH owing to the characteristics of CPM and imaging performances. The experimental results show that, under the same experimental conditions, the proposed method can obtain holograms with low speckle and intensity enhancement of about 8%, and further improve the quality of reconstructed images due to the improvement signal-to-noise ratio (SNR) of the holograms. The proposed method provides a powerful reference method for further expanding the I-COACH system to the field of low-intensity optical signals detection and imaging.