Target rotation parameter estimation for ISAR imaging via frame processing

Frame processing method offers a model-based approach to Inverse Synthetic Aperture Radar(ISAR) imaging. It also provides a way to estimate the rotation rate of a non-cooperative target from radar returns via the frame operator properties. In this paper, the relationship between the best achievable ISAR image and the reconstructed image from radar returns was derived in the framework of Finite Frame Processing theory. We show that image defocusing caused by the use of an incorrect target rotation rate is interpreted under the FP method as a frame operator mismatch problem which causes energy dispersion. The unknown target rotation rate may be computed by optimizing the frame operator via a prominent point. Consequently, a prominent intensity maximization method in FP framework was proposed to estimate the underlying target rotation rate from radar returns. In addition, an image filtering technique was implemented to assist searching for a prominent point in practice. The proposed method is justified via a simulation analysis on the performance of FP imaging versus target rotation rate error.Effectiveness of the proposed method is also confirmed from real ISAR data experiments.

The Impact of the News Frames on Report of the 2020 Pandemic in China’s National Media

News frames is a general application of the Frame Theory in journalistic practice,and the setting of the Frame Theory in news media,to some extent,may make the news agency have more choices of the topics,more channels of the report,and more impacts on readers and audiences.It is for this reason that news media are very interested in setting up their news frame to guide their reportage.It won’t be surprised that when important affairs took place,the media set a theme for their coverage;while at the same time,audiences recognized that they are allowed to know the facts as well to evaluate the events properly.The coverage of disaster news is one of the concrete examples.However,when reading the reportage framework of the news in China,it can be seen that media would be likely to set similar frames for the focus of the report,and this potentially created complexity and difficulty in analyzing disaster news events in terms of content classification,reporting form,and news-making on effectiveness.The outbreak of the 2020 COVID-19 gathered media to work on a centralized proposal–anti-epidemic,so that textual,audio-visual contents and other forms of reporting show a diversified perspective for disaster news.This reporting form is a new challenge for Chinese news media,reflected in their practice on how Chinese government and people fought against the virus,how Chinese medical community dispatched their team to assist COVID-19 fight,and how Chinese media responded to the vilification of foreign media during that period.This paper takes three established media Hubei Daily,CCTV and China Daily as examples for an in-depth analysis.