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Temporal Superresolution for Fluorescence Biomicroscopy

When imaging in low light conditions such as fluorescence microscopy, the camera's exposure time must be sufficiently long to detect enough photons for an acceptable signal-to-noise ratio. This imposes a limit on temporal resolution, and a long exposure time results in motion blur when imaging rapid, dynamic processes. By combining information from multiple low frame rate acquisitions, I reconstruct a video with a higher effective frame rate and reduced motion blur. As part of this work, I design novel computational imaging systems, I write Matlab and Java software for image reconstruction, and I apply my techniques with in-vivo fluorescence imaging of embryonic zebrafish.




PSF-Aware Filtered Backprojection for Optical Projection Tomography

In optical projection tomography, filtered backprojection is commonly used to reconstruct a 3D image from multiple 2D projections acquired from different angles. However, standard filtered backprojection fails to account for the optical distortion (which can be described by the point spread function) of the lens. By integrating deconvolution into traditional filtered backprojection, I reduce the blurring effect of the point spread function and increase the spatial resolution of the reconstructed 3D volume. As part of this work, I use optical projection tomographic imaging, in which I rotate the sample and acquire multiple projections from different angles, in combination with a custom filtered backprojection algorithm.




Measuring 3D Blood Flow Using Multiview Microscopy

In this project, I measure 3-dimensional blood flow velocities using a standard 2-dimensional camera. I use multi-view imaging, in which I rotate the sample and acquire multiple rotated image sequences, in combination with an optical flow image processing algorithm, to recover information about the out-of-plane blood flow velocity that is normally lost with single-view imaging. I apply this technique to measure 3D blood flow in the developing heart in embryonic zebrafish.


 

  Contact: kevin@kchan.me