Unknown Radial Distortion Centers in Multiple View Geometry Problems

The radial undistortion model proposed by Fitzgibbon and the radial fundamental matrix were early steps to extend classical epipolar geometry to distorted cameras. Later minimal solvers have been proposed to find relative pose and radial distortion, given point correspondences between images. However, a big drawback of all these approaches is that they require the distortion center to be exactly known. In this paper we show how the distortion center can be absorbed into a new radial fundamental matrix. This new formulation is much more practical in reality as it allows also digital zoom, cropped images and camera-lens systems where the distortion center does not exactly coincide with the image center. In particular we start from the setting where only one of the two images contains radial distortion, analyze the structure of the particular radial fundamental matrix and show that the technique also generalizes to other linear multi-view relationships like trifocal tensor and homography. For the new radial fundamental matrix we propose different estimation algorithms from 9,10 and 11 points. We show how to extract the epipoles and prove the practical applicability on several epipolar geometry image pairs with strong distortion that - to the best of our knowledge - no other existing algorithm can handle properly.

Animação Viral, Vanguarda Trash e o Capital Simbólico dos nossos Piores Defeitos: a Ideologia de Bruno Aleixo

"Bruno Aleixo" is a viral animation character, created by the Portuguese collective GANA, that surfaced online in 2008. Their animation works have meanwhile crossed onto the most diverse media, and have been branching out in multiple webs of narratives, constantly referring to each other, as well as constantly quoting disparate references such as film classics, chatrooms and TV ads for detergents. This paper attempts a triple analysis of this object of study: the ways in which technology has been fostering non-linear narratives while widening the available aesthetic spectrum, the ways in which processes of cultural consumerism are being reinvented in light of the web 2.0, and the use of "pseudo-nonsense" as a process of oblique cultural psychoanalysis. We will further attempt to demonstrate how new media and web networks have been contributing to a fragmentation of audiences, as well as a blurring between dominant cultures and sub-cultural phenomena; and we will end by positing that the structural principles behind the "Bruno Aleixo" series can be applied in social and cultural contexts situated at the opposite end of the spectrum of traditional expectations regarding Animation.