To enhance imaging performance of hybrid imaging systems by using two asymmetrical phase masks

Abstract

We propose the use of two asymmetrical phase masks combined with the subtracted imaging method to enhance the signal-to-noise ratio in wavefront coding systems. This subtracted imaging technique is similar to the variable pinhole diameter in confocal microscopy. Two different phase modulations of same phase masks are employed to promote the magnitude of the optical transfer function (OTF). The ratio factor is used to control the phase variation between two phase masks. The noise of decoded images is suppressed owing to the higher magnitude of the OTF than the wavefront coding systems with a phase mask. A tangent phase mask as an example is used to demonstrate our concept. Simulated results show that the performance promotion controls noise amplification of decoded images while maintaining a depth-of-field extension.

Resolution Enhancement and Background Suppression in Optical Super‐Resolution Imaging for Biological Applications

“…In order to extend the depth of field (DOF) in a hybrid imaging system, symmetrical and asymmetrical phase masks are applied and the two widefield biological images are therefore subtracted. [ 78,79 ] In our perspective, the subtraction of the different backfocal plane intensities can be used to reconstruct unknown wavefronts without the reference wave. [ 80 ] Apart from far‐field modalities, phase‐mask‐based subtraction also works well in a near‐field setup ( Figure b).…”

Improved extension of depth-of-field performance by apodized wavefront coding

“…It has been pointed out that the original phase mask, i.e., a cubic phase mask (CPM) proposed by Dowski and Cathey, produces a significant number of artifacts in the reconstructed image and various new types of phase masks have been proposed so far to overcome the artifact problem. [23][24][25][26][27][28][29][30][31][32][33][34] We previously proposed an apodized WFC system with a Gaussian aperture that extends the DOF while suppressing artifacts in the reconstructed image. [35][36][37] In this study, the influence of aberrations on the proposed WFC system was examined in detail by computer simulation.…”