Recent advances in ultra-fast imaging have triggered many promising applications in graphics and vision, such as capturing transparent objects, estimating hidden geometry and materials, or visualizing light in motion. There is, however, very little work regarding the effective simulation and analysis of transient light transport, where the speed of light can no longer be considered infinite. We first introduce the transient path integral framework, formally describing light transport in transient state. We then analyze the difficulties arising when considering the light's time-of-flight in the simulation (rendering) of images and videos. We propose a novel density estimation technique that allows reusing sampled paths to reconstruct time-resolved radiance, and devise new sampling strategies that take into account the distribution of radiance along time in participating media. We then efficiently simulate time-resolved phenomena (such as caustic propagation, fluorescence or temporal chromatic dispersion), which can help design future ultra-fast imaging devices using an analysis-by-synthesis approach, as well as to achieve a better understanding of the nature of light transport.

Decomposing an input image into its intrinsic shading and reflectance components is a long-standing ill-posed problem. We present a novel algorithm that requires no user strokes and works on a single image. Based on simple assumptions about its reflectance and luminance, we first find clusters of similar reflectance in the image, and build a linear system describing the connections and relations between them. Our assumptions are less restrictive than widely-adopted Retinex-based approaches, and can be further relaxed in conflicting situations. The resulting system is robust even in the presence of areas where our assumptions do not hold. We show a wide variety of results, including natural images, objects from the MIT dataset and texture images, along with several applications, proving the versatility of our method.

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In this article we present a synthetic overview and preliminary analysis of the data collected by members of the Sierra del Lacandón Regional Archaeology Project (SLRAP) during four field seasons of research from 2003 to 2007. We examine the growth, development, and transformation of the Classic Maya polities of Piedras Negras, Guatemala, and Yaxchilan, Mexico, located in the Middle Usumacinta Basin. This analysis uses a conjunctive approach, incorporating analyses of iconography, epigraphy, settlement patterns, ceramics, mortuary patterns, and architectural styles. During the Late Preclassic period (c. 250 B.C.-A.D. 350) settlement was scattered widely across the study region and Piedras Negras and Yaxchilan were only two of a number of other equally powerful Preclassic communities. In the Early Classic period (c. A.D. 350-600) royal dynasties were established at both Piedras Negras and Yaxchilan and the population of the region became concentrated at these two sites. During the Late Classic period (c. A.D. 600-810) the political frontier between Piedras Negras and Yaxchilan was repopulated and transformed into a contested border zone surrounding a political boundary. This territorial expansion culminated in endemic warfare by the eighth century A.D., which may have ultimately led to the demise of these two Maya polities.

La Virgen is an ephemeral tributary of the Ebro River in northeast Spain with a complex alluvial sequence. We analyzed alluvial stratigraphy to develop a model of Holocene fluvial evolution for La Virgen and infer causes of floodplain dynamics. Three alluvial terraces were mapped and described using a combination of geoarchaeological and geomorphological techniques. Stratigraphic ages were estimated using 14 C dating and archaeological remains. Sedimentation in the valley floor commenced in the Neolithic period ca. 6000 BC and continued during the Bronze and Iron ages (ca. 1800-500 BC), the Iberian and Roman periods (ca. 500 BC-AD 500), and the Middle Ages (ca. AD 500-1500). The main terrace (N3) is 14 m thick and predominantly composed of sand, silt, and clay that we believe are derived from local hillslopes and represent a long period of human-induced soil erosion that intensified during the Bronze and Iron ages until the Late Roman period.