High Dynamic Range Imaging and Analysis in Radio Interferometry

2019-09-23

Title	High Dynamic Range Imaging and Analysis in Radio Interferometry

Speaker:	Dr. YE Haoyang

Affiliation:	(University of Cambridge)

Time：	Monday morning, Sept. 23, 10:00 a.m.

Location:	Room 212, Astronomy Building
	Welcome to Attend

	( PMO Academic Committee & Academic Circulating committee)

Abstract: High-dynamic-range images are highly demanded when the target view contains sources with a large contrast. In this talk, I will focus on the work we have done to improve the dynamic range in radio interferometric images.

Followed by a brief introduction of the imaging process in radio interferometry, a Bayesian source extraction method will be presented to show how two nearby sources with a high contract can be well distinguished using intermediate image products such as dirty images and dirty beams. A software called “BaSC” based on this Bayesian approach will be demonstrated. We will see that BaSC can better distinguish sources than widely used software SExtractor, whose resolution is limited by the size of the restoring beam. (See paper https://arxiv.org/abs/1807.01719)

The “Least-misfit gridding function” will then be introduced which improves the dynamic range on dirty images. It was proposed under the criteria of minimising the upper bound of the difference between the DFT and FFT dirty images. With the same gridding width and image cropping ratio, it achieves a dynamic range at least 100 times higher than the widely used spheroidal function. In addition, it is shown to have a stronger aliasing suppression performance by at least 100 times compared to the spheroidal function. (See paper https://arxiv.org/abs/1906.07102)

Haoyang Ye just obtained her PhD degree from the Astrophysics Group, Department of Physics, University of Cambridge, UK. Her PhD focused on accurate image reconstruction in radio interferometry. Her work on gridding and wide-field imaging algorithms enhances the accuracy of FFT dirty images by at least 100 times compared to their corresponding DFT dirty images. She received her Bachelor’s degree in Electronic Engineering from the National University of Defense Technology in Changsha, China.

Apart from research, she is passionate about outreach activities: she volunteered for various outreach events at Cambridge and deliver outreach talks at local schools to inspire the younger generation to study STEM subjects.

Contact: haoyang.ye@cantab.net

Website: https://haoyangye.com/Home/

ORCID: https://orcid.org/0000-0002-3586-0786

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High Dynamic Range Imaging and Analysis in Radio Interferometry