RTcam

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It is a common misconception that artists want to draw and paint “in perspective”. Although it is true that artists and mathematicians of the southern renaissance invented perspective drawing, and that it remains in important foundation, it is a fact that most artists over the rest of the world and the rest of history have not followed suit. Indeed, many have deliberately broken the rules. Moreover, in his influential book “Art and Representation”, John Willats classifies art schools by the projective system they use.


Our RTcam (arty camera, Rational-Tensor camera) allows users to combine stereo pairs to produce the different kinds of projective system commonly used by artists. The visual effect is to have more than one vanishing point in a picture so that objects appear to bend. Even “inverse” perspective is allowed in which objects get bigger as they recede - an effect used in Byzantine art and Cubism, amongst others.


Our RTcam is not the first non-linear camera, but it is the most general of those so far published - in fact all other non-linear cameras are special case  RTcams. An identical formulation to RTcams has appeared in the vision community.

    P.Hall, J. Collomosse, Y-Z Song, P. Shen, and C. Li,  “RTcams: a new perspective on
    nonphotorealistic rendering from photographs”. IEEE Transactions on Visualization and
    Computer Graphics 13(5) 2007, 966-979.


See also the extension to ARTcams (attributed rational tensor camera).

Still-life in the Northern school style.

A pair of images make a montage which is looks more natural than the standard panoramic view, above. Yet careful inspection left shows the image bends (place a ruler against the long book’s right edge).

mother reading: after Matisse

Byzantium vase.

Photographs combined similarly to the still-life,

but with a mosaic effect added.

Child’s house

the walls are in “plan view”, the roof is stretched to fit.
See Willats “Art and Representation” for a real example showing exactly this projection.