Analysis and Optimization of Aperture Design in Computational Imaging

There is growing interest in the use of coded aperture imaging systems for a variety of applications. Using an analysis framework based on mutual information, we examine the fundamental limits of such systems---and the associated optimum aperture coding---under simple but meaningful propagation and sensor models. Among other results, we show that when thermal noise dominates, spectrally-flat masks, which have 50% transmissivity, are optimal, but that when shot noise dominates, randomly generated masks with lower transmissivity offer greater performance. We also provide comparisons to classical pinhole cameras

Fortnight

Fortnight is a two-week long, fully immersive, experience based in the interactions and communications of daily life. Up to 200 participants sign up to receive messages that are sent to their mobile phones, email, and home address; these messages contain a series of poetic nudges that encourage those participating to question their sense of place. Participants also receive daily invitations to visit locations throughout their city where they can pause to reflect on what it means to be here now. Fortnight enables the experience of “theatre” to penetrate beneath a seemingly brittle aesthetic surface of performance, deep into the consciousnesses of our participants as they begin to interact with and perceive world around us as the performance itself; the place where we act out our own daily lives. In Fortnight, the spectator becomes participant; the journey becomes narrative. Fortnight therefore subverts the notion of an audience, in which each spectator’s perspective is forced to examine not the situation and setting of performers on a stage, but rather the situation and setting of our own sense of place and the meaning we apportion to our everyday lives. Fortnight uses various forms of ubiquitous technology such as: Radio Frequency Identification (aka, RFID tags of the type contained in key fobs), which are used in badges sent to each participant that allow them to interact with real-world “portals” to trigger certain effects in their surroundings; QR technology (in the form of barcodes on posters that reveal additional hidden messages, should the participant choose to delve further; SMS messages; email; and, Twitter. Alongside this, older modes of communication such as handwritten letters, give Fortnight a decidedly low-fi aesthetic. Throughout Fortnight, participants are encouraged to explore the creative possibilities of pervasive and communicative media without reverting to mere technological fetishism. In Fortnight, each mode of communication is used not only for its functionality but also as symbols that bind the project and the participant together, rooting them to the here and now with the everyday tools of modern society. The mediated messages within Fortnight lead participants down a living, breathing rabbit hole where the familiar becomes unfamiliar and reality distorts. The project becomes an experience for the participant that is as immersive as their own life; creating an alternative reality, that not only co-exists alongside their own everyday realities, but also merges with them.This is a performance with shared responsibilities, reflecting the actions and consequences of our daily lives: what we put in, we get out

Bird's Eye View - A 3-D Situational Awareness Tool for the Space Station

Even as space-qualified computer hardware lags well behind the latest home computers, the possibility of using high-fidelity interactive 3-D graphics for displaying important on board information has finally arrived, and is being used on board the International Space Station (ISS). With the quantity and complexity of space-flight telemetry, 3-D displays can greatly enhance the ability of users, both onboard and on the ground, to interpret data quickly and accurately. This is particularly true for data related to vehicle attitude, position, configuration, and relation to other objects on the ground or in-orbit Bird's Eye View (BEV) is a 3-D real-time application that provides a high degree of Situational Awareness for the crew. Its purpose is to instantly convey important motion-related parameters to the crew and mission controllers by presenting 3-D simulated camera views of the International Space Station (ISS) in its actual environment Driven by actual telemetry, and running on board, as well as on the ground, the user can visualize the Space Station relative to the Earth, Sun, stars, various reference frames, and selected targets, such as ground-sites or communication satellites. Since the actual ISS configuration (geometry) is also modeled accurately, everything from the alignment of the solar panels to the expected view from a selected window can be visualized accurately. A virtual representation of the Space Station in real time has many useful applications. By selecting different cameras, the crew or mission control can monitor the station's orientation in space, position over the Earth, transition from day to night, direction to the Sun, the view from a particular window, or the motion of the robotic arm. By viewing the vehicle attitude and solar panel orientations relative to the Sun, the power status of the ISS can be easily visualized and understood. Similarly, the thermal impacts of vehicle attitude can be analyzed and visually confirmed. Communication opportunities can be displayed, and line-of-sight blockage due to interference by the vehicle structure (or the Earth) can be seen easily. Additional features in BEV display targets on the ground and in-orbit, including cities, communication sites, landmarks, satellites, and special sites of scientific interest for Earth observation and photography. Any target can be selected and tracked. This gives the user a continual line-of-sight to the target of current interest, and real-time knowledge about its visibility. Similarly, the vehicle ground-track, and an option to show "visibility circles" around displayed ground sites, provide continuous insight regarding current and future visibility to any target BEV was designed with inputs from many disciplines in the flight control and operations community both at NASA and from the International Partners. As such, BEV is setting the standards for interactive 3-D graphics for spacecraft applications. One important contribution of BEV is a generic graphical interface for camera control that can be used for any 3-D applications. This interface has become part of the International Display and Graphics Standards for the 16-nation ISS partnership. Many other standards related to camera properties, and the display of 3-D data, also have been defined by BEV. Future enhancements to BEV will include capabilities related to simulating ahead of the current time. This will give the user tools for analyzing off-nominal and future scenarios, as well as for planning future operations