Denoising time series of fluorescent imaging data
报告人: Denis Spelic
报告时间：2016年6月1日 下午1:30-2:30
报告地点：金石滩校区综合楼F113
摘要：
Pancreatic islets of Langerhans include beta cells, which are precise biological sensors for glucose and play a central role in balancing the organism between catabolic and anabolic needs. While analysing the beta cells the main challenge is how to effectively measure cell’s membrane potential and calcium changes at the same time with high spatial and temporal resolution, and also in as many cells as possible. With highly sensitive membrane potential reporter dyes in combination with high temporal and spatial confocal calcium imaging we can simultaneously detecting membrane potential and calcium changes in many cells at a time. Since the signals are noisy, we have developed complex methods of data denoising. This allow as visualization and pixel-wise analysis of signals.
Algorithm for denoising consists of three main steps. First, detection of changes in fluorescence signal is achieved by decomposing individual images in the time-series into a series of high-frequency differences HFD and a low-frequency mean LFM image. Second, a noise removal filter is then applied on each HFD image, such that the meaningful signal containing information about oscillations is preserved. In the filter, alpha trimming and Gaussian smoothing are used through the temporal and spatial resolution. Finally, output images are constructed by adding denoised HFD and LFM images. This produces a reconstructed image with cell structure and edges stemming from LFD and the overlaid filtered signal from denoised HFD. In the final step, the signal can be amplified by multiplying denoised HFD with a selected factor and overlay signal images with different colours to visualize the spatio-temporal dynamics of beta cells more clearly.
个人简介：
Denis Špeli? was born 09.07, 1980 in Maribor. His work career started in 2004 when he joined the laboratory for Geometric Modelling and Multimedia Algorithms (GeMMA) on FERI of Maribor University. He was the leader of several industrial R&D projects while his research interests are data compression, signal and image processing, parallel processing, scientific visualization, and GIS. He is a promoter of ImagineCup competition on FERI and has been a mentor of teams that achieve two 2nd places in Slovenia finals and a team that win Slovenian finals and placed 4th place in world finals in St. Petersburg. Since 2010, he is a member of ACM competition for development of web application for high schools in Slovenia. He published 5 SCI-indexed journal papers, more than 10 conference papers, and has more than 35 other bibliographic entries. He is collaborating on international and national research and industrial projects.
