My main research interests are computational imaging and microscopy. Although modern cameras and microscopes are digital, image processing and analysis is typically only considered as an afterthought. By lifting the border between the hardware and the software, artificial constraints are often removed, and seemingly ‘fundamental’ limits can be overcome.
Novel Hybrid Optics-Digital Imaging Systems
Conventional imaging systems have a limited depth-of-field and digital image-restoration techniques is not effective for such systems. When digital imaging systems are designed without the requirement of producing a sharp intermediate image, the optical-digital hybrid can be focal-distance agnostic.
Spokes at different distances are cannot all be in focus in a conventional imaging system. The optical image of a hybrid imaging system shows all the spokes equally blurry; however, digital deconvolution enables a sharp image. Source:
Computational imaging methods have so far mostly focused on the detection optics, e.g. to extend the depth-of-field of the imaging system of a digital camera. Microscopy also gives us the ability to directly engineering the illumination optics.
In a light-sheet microscope, a single plane of the sample is illuminated at one time. Limiting the illumination to a thin plane limits the sample exposure and improves the axial resolution; however, diffraction limits the field-of-view over which the light-sheet can remain thin. Instead, the light-sheet can be patterned in an Airy-function shape. Although the raw (3D) image would appear blurred, digital deconvolution can obtain diffraction-limited axial resolution over a ten-fold larger field-of-view.
Complex Scattering of Light Waves
Although Maxwell’s equations very precisely define how light waves propagate, solving these equations can be extremely challenging for heterogeneous materials such a biological tissue. Developing efficient algorithms to solve this type of problem is essential to investigate such phenomena numerically. Recently we published a new method to efficiently calculate the electromagnetic field in general (an)isotropic dielectric and magnetic materials. This was work I did with Jacopo Bertolotti and Simon Horsley. Download our paper and the software: Arxiv, Optics Express, GitHub, Python.