Visualisation of Parallel Data Streams with Temporal Mosaics

Despite its popularity and widespread use, timeline visualisation suffers from shortcomings which limit its use for displaying multiple data streams when the number of streams increases to more than a handful. This paper presents the TemporalMosaic technique for visualisation of parallel time-based streams which addresses some of these shortcomings. Temporal mosaics provide a compact way of representing parallel streams of events by allocating a fixed drawing area to time intervals and partitioning that area according to the number of concurrent events. A user study is presented which compares this technique to a standard timeline representation technique in which events are depicted as horizontal bars and multiple streams are drawn in parallel along a vertical axis. Results of this user study show that users of the temporal mosaic visualisation perform significantly better at detecting concurrency, interval overlaps and inactivity than users of standard timelines

Inhibition decorrelates visual feature representations in the inner retina

The retina extracts visual features for transmission to the brain. Different types of bipolar cell split the photoreceptor input into parallel channels and provide the excitatory drive for downstream visual circuits. Mouse bipolar cell types have been described at great anatomical and genetic detail, but a similarly deep understanding of their functional diversity is lacking. Here, by imaging light-driven glutamate release from more than 13,000 bipolar cell axon terminals in the intact retina, we show that bipolar cell functional diversity is generated by the interplay of dendritic excitatory inputs and axonal inhibitory inputs. The resulting centre and surround components of bipolar cell receptive fields interact to decorrelate bipolar cell output in the spatial and temporal domains. Our findings highlight the importance of inhibitory circuits in generating functionally diverse excitatory pathways and suggest that decorrelation of parallel visual pathways begins as early as the second synapse of the mouse visual system

On Multi-Resolution 3D Orbital Imagery and Visualisation for Mars Geological Analysis

Mars Science Laboratory has revealed a dynamic history of water as the rover has ascended the mysterious Mount Sharp in Gale crater. Because rovers only “see” their local environment, planetary scientists rely on satellite-based orbital imagery to understand the regional geology of Gale crater. However, orbital imagery is map-view—viewed from above, lacking perspective—which presents challenges to interpretation of stratigraphy. 3D visualisation is an emerging opportunity to study orbital images in more intuitive, field-like environments, but has had limited application to Mars. In this work, I formulate and analyse 3D orbital imagery over Gale crater, Mars to investigate the stratigraphy of Mount Sharp 700 m above and 40 km away from MSL. First, I process orbital imagery from the HRSC, CTX, and HiRISE cameras into 3D digital terrain models (DTMs). I then co-register and evaluate these DTMs using statistical tools and existing products to build a new, validated, multi-resolution basemap tied down to MOLA. Sakarya Vallis, a 400-m deep canyon on Mount Sharp, was then analysed in a 3D environment at 1 m/px. From measurements of exposed rock layers, I construct cross-sections, stratigraphic logs, and a geological unit map to capture this geology. Seven geological units are interpreted across 1 km of exposure, varying in thicknesses (10–174 m) and dips (3–12º). These units may reveal a cyclic depositional environment; a progradational sequence and channel; and unconformities. This work therefore suggests two periods of sub-aqueous deposition in this region during the Late Noachian to Early Hesperian. These results further provide geological context of Gale crater as MSL ascends Mount Sharp, and future inputs for palaeoenvironmental models of Gale crater

An exploratory investigation of low-altitude aerial image acquisition for land surface studies

In the context of environmental monitoring and sustainable land management this thesis seeks to evaluate the application of low-altitude remote sensing from a DIY perspective in the lower Ashburton River catchment. It seeks to demonstrate that the innovative synergistic use of airborne digital videography and CIR (colour infrared) 35mm photography can provide near real-time photomapping at local levels. These technologies are relatively inexpensive, easy-to-use and have proven successful in other countries. Used together with Desktop software systems for image processing, measurement and spatial calibration one can fulfil many community based environmental monitoring and sustainable land use management tasks. The concept of sustainable land use also implies we have an understanding of the landscape processes past and present that have occurred in the region. This is assessed using historical documents so that we may better appreciate the pace of rapid transformation. The role of GPS technology for the georeferencing of selected images into a GIS system is evaluated. The potential adoption of environmental monitoring index systems developed in Australia and Canada is investigated which would rely partly on the proposals recommended in this study