Aristotle: Critic or Pioneer of Atomism?

Aristotle is typically construed as a critic of atomism. He was indeed a critic of atomism of the extreme kind formulated by Democritus, according to which bulk matter is made of nothing other than unchangeable pieces of universal matter possessing shape and size and capable of motion in the void. However, there is a weaker kind of atomism involving the assumption that macroscopic substances have least parts which have properties sufficient to account for the properties of the bulk substances that they are least parts of. Insofar as atomism has been vindicated by modern science, it is the weaker version of atomism that has proved to be profitable. The beginnings of the weaker version of atomism are to be found in Aristotle. Far from being an opponent of atomism, there is a sense in which Aristotle was one of its pioneers

Smoothness perception : investigation of beat rate effect on frame rate perception

Despite the complexity of the Human Visual System (HVS), research over the last few decades has highlighted a number of its limitations. These limitations can be exploited in computer graphics to significantly reduce computational cost and thus required rendering time, without a viewer perceiving any difference in resultant image quality. Furthermore, cross-modal interaction between different modalities, such as the influence of audio on visual perception, has also been shown as significant both in psychology and computer graphics. In this paper we investigate the effect of beat rate on temporal visual perception, i.e. frame rate perception. For the visual quality and perception evaluation, a series of psychophysical experiments was conducted and the data analysed. The results indicate that beat rates in some cases do affect temporal visual perception and that certain beat rates can be used in order to reduce the amount of rendering required to achieve a perceptual high quality. This is another step towards a comprehensive understanding of auditory-visual cross-modal interaction and could be potentially used in high-fidelity interactive multi-sensory virtual environments

Selective rendering for efficient ray traced stereoscopic images

Depth-related visual effects are a key feature of many virtual environments. In stereo-based systems, the depth effect can be produced by delivering frames of disparate image pairs, while in monocular environments, the viewer has to extract this depth information from a single image by examining details such as perspective and shadows. This paper investigates via a number of psychophysical experiments, whether we can reduce computational effort and still achieve perceptually high-quality rendering for stereo imagery. We examined selectively rendering the image pairs by exploiting the fusing capability and depth perception underlying human stereo vision. In ray-tracing-based global illumination systems, a higher image resolution introduces more computation to the rendering process since many more rays need to be traced. We first investigated whether we could utilise the human binocular fusing ability and significantly reduce the resolution of one of the image pairs and yet retain a high perceptual quality under stereo viewing condition. Secondly, we evaluated subjects' performance on a specific visual task that required accurate depth perception. We found that subjects required far fewer rendered depth cues in the stereo viewing environment to perform the task well. Avoiding rendering these detailed cues saved significant computational time. In fact it was possible to achieve a better task performance in the stereo viewing condition at a combined rendering time for the image pairs less than that required for the single monocular image. The outcome of this study suggests that we can produce more efficient stereo images for depth-related visual tasks by selective rendering and exploiting inherent features of human stereo vision

Was Aristotle the founder of chemistry?

Aristotle has recently been construed as the founder of chemistry. Aristotle does give a detailed account of combination in Generation and Corruption that can be read as conforming to the kind of combination characteristic of modern chemistry. Nevertheless, to interpret Aristotle’s discussion as constituting the beginnings of, or opening the way to, chemistry is to misunderstand both Aristotle and chemistry

Importance driven environment map sampling

In this paper we present an automatic and efficient method for supporting Image Based Lighting (IBL) for bidirectional methods which improves both the sampling of the environment, and the detection and sampling of important regions of the scene, such as windows and doors. These often have a small area proportional to that of the entire scene, so paths which pass through them are generated with a low probability. The method proposed in this paper improves this by taking into account view importance, and modifies the lighting distribution to use light transport information. This also automatically constructs a sampling distribution in locations which are relevant to the camera position, thereby improving sampling. Results are presented when our method is applied to bidirectional rendering techniques, in particular we show results for Bidirectional Path Tracing, Metropolis Light Transport and Progressive Photon Mapping. Efficiency results demonstrate speed up of orders of magnitude (depending on the rendering method used), when compared to other methods

Aristotle on Atomism

Two kinds of atomism emerged in the philosophy off the Presocratics. One kind was devised as a response to Parmenides and involved indivisible physical atoms. The other kind emerged in response to Zeno’s paradoxes and involved indivisible magnitudes that served as a barrier to the infinite division that led to those paradoxes. I argue, contrary to a range of positions to be found in the literature that Aristotle was aware of the distinction between the two kinds of atomism, did not attribute an atomism involving indivisible magnitudes to Democritus, and countered the two kinds of atomism with distinct kinds of arguments

Aristotle on Homoeomerous Substances

Aristotle’s characterisation of homoeomerous substances in Generation and Corruption is typically interpreted as involving the idea that such substances retain their identity as such however far they are divided. Yet, in Meteorology 4 Aristotle attributes properties of homoeomerous substances to a structure of corpuscles separated by pores. I suggest the clash between these two views is removed once it is appreciated that the position in Generation and Corruption does not involve indefinite division, as is typically supposed. Aristotle’s construal of homoeomerous substances, on my interpretation, is an important part of his attempt to make conceptual sense of the notion that all terrestrial substances are combinations of air, earth, fire and water

Repeatable texture sampling with interchangeable patches

Rendering textures in real-time environments is a key task in computer graphics. This paper presents a new parallel patch-based method which allows repeatable sampling without cache, and does not create visual repetitions. Interchangeable patches of arbitrary shape are prepared in a preprocessing step, such that patches may lie over the boundary of other patches in a repeating tile. This compresses the example texture into an infinite texture map with small memory requirements, suitable for GPU and ray-tracing applications. The quality of textures rendered with this method can be tuned in the offline preprocessing step, and they can then be rendered in times comparable to Wang tiles. Experimental results demonstrate combined benefits in speed, memory requirements, and quality of randomisation when compared to previous methods

A local model of eye adaptation for high dynamic range images

In the real world, the human eye is confronted with a wide range of luminances from bright sunshine to low night light. Our eyes cope with this vast range of intensities by adaptation; changing their sensitivity to be responsive at di erent illumination levels. This adaptation is highly localized, allowing us to see both dark and bright regions of a high dynamic range environment. In this paper we present a new model of eye adaptation based on physiological data. The model, which can be easily integrated into existing renderers, can function either as a static local tone mapping operator for single high dynamic range image, or as a temporal adaptation model taking into account time elapsed and intensity of preadaptation for a dynamic sequence. We nally validate our technique with a high dynamic range display and a psychophysical study.(undefined