It is shown that the set of all paraperspective images with arbitrary reference point and the set of aane images of a 3-D object are identical. Consequently, all uncalibrated paraper-spective images of an object can be constructed from a 3-D model of the object by applying an aane transformation to the model and every aane image of the object represents some uncalibrated paraperspective image o...

The Hyers–Ulam–Rassias stability of the conditional quadratic functional equation of Pexider type f (x+y)+f (x−y) = 2g(x)+2h(y), x ⊥ y is proved where ⊥ is the orthogonality in the sense of Rätz.