Prof. Colin Sheppard

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Prof. Colin Sheppard, a world wide reference in microscopy, will give a seminar on "Image scanning microscopy (ISM)" on May 24th, at 11:00 a.m., Institut Fresnel, Pierre Cotton room.

Abstract :

In a microscope, if a scanning illumination spot is combined with a detector array, we acquire a 4 dimensional signal. Unlike confocal microscopy with a small pinhole, we detect almost all the light from the object, which is particularly important for fluorescence microscopy, when the signal is weak. The image signal is basically a cross-correlation, and is highly redundant. It has more than sufficient information to reconstruct an improved resolution image. A 2D image can be generated from the measured signal by pixel reassignment. The result is improved resolution and signal strength, the system being called image scanning microscopy. A variety of different signal processing techniques can be used to predict the reassignment and deconvolve the partial images. We use an innovative single-photon avalanche diode (SPAD) array detector of 25 detectors (arranged into a 5x5 matrix). We can simultaneously acquire 25 partial images and process to calculate the final reconstruction online.

Biography : Colin Sheppard is Senior Scientist at the Italian Institute of Technology, Genoa, Italy. Previously, he was Professor in the Department of Bioengineering and Faculty of Engineering for National University of Singapore (2003-2012). He has held joint appointments with the NUS Departments of Biological Sciences (Faculty of Science) and Diagnostic Radiology (School of Medicine). He was SMART (Singapore/MIT Alliance for Research & Technology) Faculty Fellow, and Adjunct Research Staff at SERI (Singapore Eye Research Institute).
His areas of research are in optics, microscopy and imaging, including confocal and multiphoton microscopy, diffraction, 3D imaging and reconstruction, superresolution, beam propagation, and pulse propagation.

See his profile on ResearchGate

Invitation : Sophie Brasselet, MOSAIC Group