A Curvature-Based Multidirectional Local Contrast Method for Star Detection of a Star Sensor

Stray light, such as sunlight, moonlight, and earth-atmosphere light, can bring about light spots in backgrounds, and it affects the star detection of star sensors. To overcome this problem, this paper proposes a star detection algorithm (CMLCM) with multidirectional local contrast based on curvature. It regards the star image as a spatial surface and analyzes the difference in the curvature between the star and the background. It uses a facet model to represent the curvature and calculate the second-order derivatives in four directions. According to the characteristic of the star and the complex background, it enhances the target and suppresses the complex background by a new calculation method of a local contrast map. Finally, it divides the local contrast map into multiple 256 × 256 sub-regions for a more effective threshold segmentation. The experimental results indicated that the CMLCM algorithm could effectively detect a large number of accurate stars under stray light interference, and the detection rate was higher than other compared algorithms with a lower false alarm rate.

An End-to-End Identification Algorithm for Smearing Star Image

In the previous study, there were a few direct star identification (star-ID) algorithms for smearing star image. An end-to-end star-ID algorithm is proposed in this article, to directly identify the smearing image from star sensors with fast attitude maneuvering. Combined with convolutional neural networks and the self-attention mechanism of transformer encoder, the algorithm can effectively classify the smearing image and identify the star. Through feature extraction and position encoding, neural networks learn the position of stars to generate semantic information and realize the end-to-end identification for the smearing star image. The algorithm can also solve the problem of low identification rate due to smearing of long exposure time for images. A dataset of dynamic stars is analyzed and constructed based on multiple angular velocities. Experiment results show that, compared with representative algorithms, the identification rate of the proposed algorithm is improved at high angular velocities. When the three-axis angular velocity is 10°/s, the rate is still 60.4%. At the same time, the proposed algorithm has good robustness to position noise and magnitude noise.

A SLIC-DBSCAN Based Algorithm for Extracting Effective Sky Region from a Single Star Image

The star tracker is widely used for high-accuracy missions due to its high accuracy position high autonomy and low power consumption. On the other hand, the ability of interference suppression of the star tracker has always been a hot issue of concern. A SLIC-DBSCAN-based algorithm for extracting effective information from a single image with strong interference has been developed in this paper to remove interferences. Firstly, the restricted LC (luminance-based contrast) transformation is utilized to enhance the contrast between background noise and the large-area interference. Then, SLIC (the simple linear iterative clustering) algorithm is adopted to segment the saliency map and in this process, optimized parameters are harnessed. Finally, from these segments, features are extracted and superpixels with similar features are combined by using DBSCAN (density-based spatial clustering of applications with noise). The proposed algorithm is proved effective by successfully removing large-area interference and extracting star spots from the sky region of the real star image.

Star Sensor Denoising Algorithm Based on Edge Protection

Single-pixel noise commonly appearing in a star sensor can cause an unexpected error in centroid extraction. To overcome this problem, this paper proposes a star image denoising algorithm, named Improved Gaussian Side Window Filtering (IGSWF). Firstly, the IGSWF algorithm uses four special triangular Gaussian subtemplates for edge protection. Secondly, it exploits a reconstruction function based on the characteristic of stars and noise. The proposed IGSWF algorithm was successfully verified through simulations and evaluated in a star sensor. The experimental results indicated that the IGSWF algorithm performed better in preserving the shape of stars and eliminating the single-pixel noise and the centroid estimation error (CEE) value after using the IGSWF algorithm was eight times smaller than the original value, six times smaller than that after traditional window filtering, and three times smaller than that after the side window filtering.

Risk in the digital age: Comedian-activists and Trump’s cancel culture

This article contributes to the study of comedians as activists by examining the campaigns by some of America’s most influential figures – Seth Rogan, Jim Carrey, Dave Chapelle, Amy Schumer, Roseanne Barr and Kathy Griffin. To varying degrees, these comedians all use their star images and personal stories to influence public debates through their stand-up, television work, and content on YouTube, Instagram and Twitter. By studying their activities in the media, their press coverage, and public reactions online, this article also presents an original examination of the way ‘Cancel Culture’ manifests, often hindering their activism. This includes identifying the polarizing influence of the ‘Canceller-in-Chief’ former president Donald J. Trump, and the risks suffered by comedian-activists in terms of their reputation, commercial prospects, and even their legality. Specifically, this article suggests that ‘Cancel Culture’ manifests as a spectrum of varying risk which can be shaped by the comedian’s star image and the degree of social transgression in their comedy.

‘Battleship Femininity’ deconstructed: Unmasking the myth of Eva Dahlbeck and Ingmar Bergman

The Swedish film star Eva Dahlbeck (1920–2008) is now remembered mainly for her contributions to Ingmar Bergman’s comedies in the 1950s. The epithet ‘Pansarskeppet kvinnligheten’ (‘Battleship Femininity’), allegedly given to her by the director, has integrated her stardom into the myth-making process driven by Bergman and the press. This can erroneously give him sole credit for Dahlbeck’s fame despite her already established star status. To reconsider such an auteurist misconception, this article examines Dahlbeck’s stardom from 1946 to 1956, drawing on Richard Dyer’s seminal theorization of a film star as a media construction. By analysing Dahlbeck’s star image and its relationship to three characters she plays in Bergman’s films, the article situates these films in the dynamics formed by diverse media texts and elucidates their historical and cultural context while also providing a case study of film stardom in post-war Sweden.

Performed realities and intertextualities: the commodification of everyday life and the celebrification of everyday people in modern televisual and digital cultures

This paper, while firmly rooted in Dyer's star image system, will also incorporate several narrative (of course, non-fiction) "scenes," based on my own experiences working with a Toronto-based documentary crew. The documentary, Peep Me, which has been produced by Chocolate Box entertainment for CBC Television, focuses, primarily, on peep culture and reality programming. Peep Me also features The Peep Diaries' author and public intellectual Hal Niedzviecki, documenting, among other events, his attempt at creating a "lifecast," and his three-day reality TV boot camp adventure in Simi Valley, California. Needless to say, my six-month internship provided me with invaluable insights into all things "peep," including reality programming, reality performers, and the Internet's answer to the reality star.

Performed realities and intertextualities: the commodification of everyday life and the celebrification of everyday people in modern televisual and digital cultures

This paper, while firmly rooted in Dyer's star image system, will also incorporate several narrative (of course, non-fiction) "scenes," based on my own experiences working with a Toronto-based documentary crew. The documentary, Peep Me, which has been produced by Chocolate Box entertainment for CBC Television, focuses, primarily, on peep culture and reality programming. Peep Me also features The Peep Diaries' author and public intellectual Hal Niedzviecki, documenting, among other events, his attempt at creating a "lifecast," and his three-day reality TV boot camp adventure in Simi Valley, California. Needless to say, my six-month internship provided me with invaluable insights into all things "peep," including reality programming, reality performers, and the Internet's answer to the reality star.