Computational multifocal microscopy

Abstract

Despite recent advances, high performance single-shot 3D microscopy remains an elusive task. By introducing designed diffractive optical elements (DOEs), one is capable of converting a microscope into a 3D "kaleidoscope", in which case the snapshot image consists of an array of tiles and each tile focuses on different depths. However, the acquired multifocal microscopic (MFM) image suffers from multiple sources of degradation, which prevents MFM from further applications. We propose a unifying computational framework which simplifies the imaging system and achieves 3D reconstruction via computation. Our optical configuration omits chromatic correction grating and redesigns the multifocal grating to enlarge the tracking area. Our proposed setup features only one single grating in addition to a regular microscope. The aberration correction, along with Poisson and background denoising, are incorporated in our deconvolution-based fully-automated algorithm, which requires no empirical parameter-tuning. In experiments, we achieve the spatial resolutions of 0.35um (lateral) and 0.5um (axial), which are comparable to the resolution that can be achieved with confocal deconvolution microscopy. We demonstrate a 3D video of moving bacteria recorded at 25 frames per second using our proposed computational multifocal microscopy technique.

High-contrast multifocus microscopy with a single camera and z-splitter prism

“…Our multifocus imaging strategy offers several notable advantages over alternative strategies. Compared to techniques using a DOE [29][30][31] , our z-splitter prism is low cost, easy to design and assemble, does not require the addition of a chromatic corrector, and can be adapted to a variety of imaging modalities. Compared to techniques that also involve the use of beamsplitting optics 24,25,27,28 , our system requires only a single camera and enables significantly larger FOV while offering the flexibility of swapping in different z-splitters to accommodate different imaging speed or volume requirements.…”

“…To date, examples of such devices include specially fabricated beam splitters (using two cameras 27,28 ) or diffractive optical elements (DOEs) [29][30][31][32] . These usually involve significant design and manufacturing challenges.…”

Advances in 3D single particle localization microscopy

“…This technique, termed "multifocus microscopy" (MFM), allows for a simpler optical configuration, employing just a single camera, but the MFG introduces chromatic aberration, which degrades performance and/or restricts spectral bandwidth, 42 although this can be mitigated using computational techniques. 43 A key benefit of MUM is that it can also be used to image extended objects, 41,44 whereas the emphasis for PSF-engineering has been on localization of PSFs that are the images of pointlike objects. 45,46 There is also the opportunity to use MUM/MFM in combination with engineered PSFs for even better localization precision, as has been done using an astigmatic PSF [47][48][49] and an Airy-beam-based PSF.…”

Event-Driven Video Frame Synthesis

“…Our paper investigates the temporal upsampling problem. While previous approaches investigate in the framework of compressive sensing [1,14,17,26,35,38,41], we formulate our work as fusing event streams with intensity images to obtain a temporally dense video. Compared to existing literature [36] which integrates event counts per pixel across time, our differentiable model utilizes "tanh" functions as event activation units and imposes sparsity constraints on both spatial and temporal domain.…”