We present a range-gated camera system designed for real-time (10 Hz) 3D estimation underwater. The system uses a fast-shutter CMOS sensor (1280×1024) customized to facilitate gating with 1.67 ns (18.8 cm in water) delay steps relative to the triggering of a solid-state actively Q-switched 532 nm laser. A depth estimation algorithm has been carefully designed to handle the effects of light scattering in water, i.e., forward and backward scattering. The raw range-gated signal is carefully filtered to reduce noise while preserving the signal even in the presence of unwanted backscatter. The resulting signal is proportional to the number of photons that are reflected during a small time unit (range), and objects will show up as peaks in the filtered signal. We present a peak-finding algorithm that is robust to unwanted forward scatter peaks and at the same time can pick out distant peaks that are barely higher than peaks caused by sensor and intensity noise. Super-resolution is achieved by fitting a parabola around the peak, which we show can provide depth precision below 1 cm at high signal levels. We show depth estimation results when scanning a range of 8 m (typically 1-9 m) at 10 Hz. The results are dependent on the water quality. We are capable of estimating depth at distances of over 4.5 attenuation lengths when imaging high albedo targets at low attenuation lengths, and we achieve a depth resolution (σ) ranging from 0.8 to 9 cm, depending on signal level.
From literary canons all the way to the motion picture industry, the artistic and popular cultural experience of marginalized or nonmainstream groups has been one of being represented by the other. In this article, we explore how online fanfiction, as an audience-driven, interactive form of writing, may offer a way for members of nonmainstream groups to push back against and offer alternatives to stereotypical and normative discourses. We focus on how autistic people, family members, teachers, and advocates cast autistic characters in their fanfiction stories, how these stories represent autism and how, given the affordances of an online publishing platform, audience members respond to such representations. Findings suggest that these online narratives diversify available representations of autistic characters; moreover, the interactive nature of the online publishing forum allows readers to respond to and potentially disrupt stereotypical thinking and common fictional tropes surrounding autism.
In this essay, we map out four major approaches to the study of writing experiences: (a) worlds apart, (b) literacy in the wild, (c) ecologies and networks, and (d) transfer. We examine how the primary metaphors used in each approach have contributed to our field’s understanding of writing. In focusing on specific dimensions of writing, each framework privileges a different aspect of the writing process, writing development, and/or writers’ context(s). Building on these approaches, we propose the concept of wayfinding to emphasize how writers navigate their own writing development, skills acquisition, and changing knowledge about writing over time. Wayfinding offers a metaphor that resonates with recent work on lifelong learning and meaningful writing. Among other characteristics, wayfinding emphasizes how writers encounter a continuous potentiality in writing and how they navigate unanticipated challenges and opportunities.
Background/Context Sociocultural research on young people's literate practices with digital media has generally focused on literacy events and practices that are grounded in distinct online locations, such as affinity spaces, specific websites, particular videogames, or virtual worlds. Purpose/Objective/Research Question/Focus of Study Contemporary media landscapes have become networked to such an extent that a transmedial approach is needed to understand the social, cultural, and literate contexts that young people inhabit. Research Design In this article, we use qualitative and literary analyses of products and artifacts from the Hunger Games media franchise to explore young people's literacy practices as embedded in corporate and fan-produced transmedia ecologies. Conclusions/Recommendations Our analysis looks beyond spatial and structural boundaries to understand how flows of corporate and user-produced artifacts can shape, constrain, and expand young people's literate repertoires.
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