In this work, we describe an original method of solving the shape from shading (SFS) problem, which relies on the marriage of two simple ideas. On the one hand, we propose to modelize the scene by a parametric surface, namely a 3D-spline. The key advantage is that boundary conditions are no longer required to render the problem well-posed. On the other hand, we introduce the concept of ‘‘useful...

In computer vision, convolutional neural networks (CNNs) achieve unprecedented performance for inverse problems where RGB pixel appearance is mapped to attributes such as positions, normals or reflectance. In computer graphics, screen space shading has boosted the quality of real-time rendering, converting the same kind of attributes of a virtual scene back to appearance, enabling effects like ...

RATIONALE It is not clearly evident whether malaria affects the poor more although it has been argued that the poor bear a very high burden of the disease. This study explored the socioeconomic and geographic differences in incidence and burden of malaria as well as ownership of mosquito nets. METHODS Structured questionnaires were used to collect information from 1657 respondents from rural ...

A smooth object depicted in a photographwill often exhibit brightness variation, or shading. Various computational techniques have been developed that perform reasonably well in inferring shape from shading. However, these techniques typically require substantial prerequisite information if they are to evolve an estimate of surface shape. It is therefore interesting to consider how depth might ...

A wide range of software tools have been developed for visualising three-dimensional range data of topographic surfaces. Digital Elevation Models (DEMs), derived from photogrammetric measurements and from digitised contour maps are here used for illustration. To increase our understanding of the information content in DEMs in isolation or in combination with remotelysensed images and to facilit...

This paper introduces a framebuffer level of detail algorithm for controlling the pixel workload in an interactive rendering application. Our basic strategy is to evaluate the shading in a low resolution buffer and, in a second rendering pass, resample this buffer at the desired screen resolution. The size of the lower resolution buffer provides a trade-off between rendering time and the level ...

Quadratic shading has been proposed as a technique giving better results than Gouraud shading, but which is substantially faster than Phong shading. Several techniques for fitting a second order surface to six points have been proposed. We show in this paper how an approximation of the mid-edge samples can be done in a very efficient way. An approximation of the mid-edge vectors are derived. Se...

This contribution presents the formalism of Elementary Object Systems (Eos). Object nets are Petri nets which have Petri nets as tokens – an approach known as the nets-within-nets paradigm. One central aim of this contribution is to compile all our previous works dedicated to certain aspects of Eos together with recent yet unpublished results within one selfcontained presentation. Since object ...

Refinement of Petri nets is well suited for the hierarchical design of system models. It is used to represent a model at different levels of abstraction. Usually, refinement is a static concept. For many scenarios, however, it is desirable to have a more flexible form of refinement. For example in the context of service updates, e.g. version control in distributed systems, a mechanism for dynam...

Shape-from-shading algorithms that use a single image often find incorrect solutions because of ambiguity in the image shading. We describe a robust shape-from-shading algorithm using scale space tracking that can resolve most of these ambiguities by using two images taken from slightly different positions. Further improvements are obtained by combining stereo with shape-fromshading. Results ar...