A wavefront coded light field microscope
- Light field microscopy is a high-speed computational imaging method, which enables reconstruction of a 3-dimensional volume from a light field image. Unlike standard imaging systems, the light field microscope uses a microlens array to capture both spatial and angular information about the incoming light in a single image, from which a volume can be reconstructed computationally. Among volumetric imaging methods in microscopy, light field microscopy is unique in that it allows imaging large volumes, spanning hundreds of microns in depth, at a speed limited only by the camera frame rate. Due to this unique advantage it has recently been adapted to in vivo imaging of neural activity, enabling biologists a glimpse into an organism's brain while in action. Despite its advantages, the light field microscope still suffers from a major limitation - its lateral spatial resolution is not uniform across depth. Some depths, particularly at the center of the imaged volume, where the microscope is focused at, show very low resolution which hinders its use in applications. This non-uniform resolution stems from the way the light field microscope samples the volume: at the center of the volume samples are angularly discriminative but spatially redundant, hence for isotropically absorptive or emissive volumes, they cannot support high resolution reconstructions. We present a method that, for such isotropic volumes, significantly improves the resolution profile of the light field microscope across depth and enables accurate control over it, thereby overcoming the limitations of traditional light field design. The key to our approach is using a technique called wavefront coding to control properties of the point spread function of the microscope. By including phase masks in the optical path we a create a wavefront coded light field microscope that samples the 3-dimensional volume more uniformly than the standard light field microscope, solving the low resolution problem at the center of the imaged volume and improving the resolution at its borders. We derive an extended optical model for the wavefront coded light field microscope and propose design guidelines and a performance metric which we use to choose adequate parameters for good phase masks. To validate our approach, we show simulated data and experimental resolution measurements, and demonstrate the wavefront coded light field microscope's utility for biological applications.
|Type of resource
|electronic; electronic resource; remote
|1 online resource.
|Stanford University, Department of Electrical Engineering.
|Dror, Ron, 1975-
|Dror, Ron, 1975-
|Statement of responsibility
|Submitted to the Department of Electrical Engineering.
|Thesis (Ph.D.)--Stanford University, 2015.
- © 2015 by Noy Cohen
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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