28 Critical Reflections: random 8 to 14

Specular reflection could be called a sort of congruence, insofar as congruences are a type of equality, thus establishing a bi-univocal relation founded on the properties of being reflexive, symmetrical and transitive. In this sense specular reflection is equality and not similitude.[3]

Oh yes, there were birds, but not like the birds you see today. Big as eagles and coloured like kingfishers. They roosted on the ledges of the towers, and under the ramps. Long curving ribbon ramps, with... Obviously these were too heavy to fly, so they had to go on the roads. Very fast. Automated, of course.[2]

This can be explained by the existence of microfacets. We assume that surfaces that are not perfectly smooth are composed of many very tiny facets, each of which is a perfect specular reflector. These microfacets have normals that are distributed about the normal of the approximating smooth surface. The degree to which microfacet normals differ from the smooth surface normal is determined by the roughness of the surface. At points on the object where the smooth normal is close to the half-angle direction, many of the microfacets point in the half-angle direction and so the specular highlight is bright. As one moves away from the center of the highlight, the smooth normal and the half-angle direction get farther apart; the number of microfacets oriented in the half-angle direction falls, and so the intensity of the highlight falls off to zero.[6]

Specular reflection could be called a sort of congruence, insofar as congruences are a type of equality, thus establishing a bi-univocal relation founded on the properties of being reflexive, symmetrical and transitive. In this sense specular reflection is equality and not similitude.[3]

Even admitting that what happens in a camera obscura is something 'similar' to the phenomenon of the specular reflection (which is not questionable), what changes is the fact that an image remains traced somewhere, and any successive discussion about its iconic properties deals with the imprinted image and not with the process itself.[3]

But the first thing to make clear is that a specular reflection cannot be taken as a sign if one follows the definition given in this book. Not only can it not be properly called an image (since it is a virtual image, and therefore not a material expression) but even granted the existence of the image it must be admitted that it does not stand for something else:on the contrary it stands in front of something else, it exists not instead of but because of the presence of that something: when that something disappears the pseudo-image in the mirror disappears too.[3]

Oh yes, there were birds, but not like the birds you see today. Big as eagles and coloured like kingfishers. They roosted on the ledges of the towers, and under the ramps. Long curving ribbon ramps, with... Obviously these were too heavy to fly, so they had to go on the roads. Very fast. Automated, of course.[2]

28 Critical Reflections random 15 to 21
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Sources

[1] http://www.neworleanspast.com/art/id62.html

[2] Ken MacLeod, Reflective Surfaces, New Scientist, 2009.

[3] Umberto Eco, A Theory of Semiotics, Indiana University Press, 1979.

[4] Clive Fencott, Reflections on seeing River Form in Barbra Hepworth's garden in St. Ives.

[5] http://www.flickr.com/photos/nigelhomer/316548379/

[6] http://en.wikipedia.org/wiki/Specular_highlight

[7] http://www.barbarahepworth.org.uk/texts/

[8] tripadvisor.co.uk