Forced perspective

Abstract: Males often produce elaborate displays that increase their attractiveness to females, and some species extend their displays to include structures or objects that are not part of their body. Such "extended phenotypes" may communicate information that cannot be transmitted by bodily signals or may provide a more reliable signal than bodily signals. However, it is unclear whether these signals are individually distinct and whether they are consistent over long periods of time. Male bowerbirds construct and decorate bowers that function in mate choice. Bower display courts constructed by male great bowerbirds (Ptilonorhynchus nuchalis) induce a visual illusion known as forced perspective for the female viewing the male's display over the court, and the quality of illusion is associated with mating success. We improved the quality of the forced perspective to determine whether males maintained it at the new higher level, decreased the perspective quality back to its original value, or allowed it to decay at random over time. We found that the original perspective quality was actively recovered to individual original values within 3 d. We measured forced perspective over the course of one breeding season and compared the forced perspective of individual males between two successive breeding seasons. We found that differences in the quality of visual illusion among males were consistent within and between two breeding seasons. This suggests that forced perspective is actively and strongly maintained at a different level by each individual male.

Abstract: The present invention relates to conversion of 2D media to pseudo-3D left and right image pairs. In particular, it relates to imposing forced perspective on left and right versions of a 2D image. The distorted pair of images, when displayed, will be interpreted by a viewer as a 3D image. The pseudo-3D forced perspective image pairs can be produced without depth mapping of objects in scenes and without comparing the position of objects in successive image frames.

Abstract: Many animals build structures to provide shelter, avoid predation, attract mates or house offspring, but the behaviour and potential cognitive processes involved during building are poorly understood. Great bowerbird (Ptilinorhynchus nuchalis) males build and maintain display courts by placing tens to hundreds of objects in a positive size-distance gradient. The visual angles created by the gradient create a forced perspective illusion that females can use to choose a mate. Although the quality of illusion is consistent within males, it varies among males, which may reflect differences in how individuals reconstruct their courts. We moved all objects off display courts to determine how males reconstructed the visual illusion. We found that all individuals rapidly created the positive size-distance gradient required for forced perspective within the first 10 objects placed. Males began court reconstruction by placing objects in the centre of the court and then placing objects further out, a technique commonly used when humans lay mosaics. The number of objects present after 72 h was not related to mating success or the quality of the illusion, indicating that male skill at arranging objects rather than absolute number of objects appears to be important. We conclude that differences arise in the quality of forced perspective illusions despite males using the same technique to reconstruct their courts.

Abstract: Linear perspective is a drawing system that can transform geometry from conceptual form to perceptual, and thus it is an essential tool for designers to predict the spatial perception of proposed construction designs Linear perspective is also identified as an effective pictorial depth cue that can provide the visual information necessary to retrieve the three-dimensional sense of depth from both the two-dimensional retinal images and drawn pictures As a result, linear perspective has been used as an effective design strategy to create forced perspectives that can exaggerate the depth perception of architectural scenes Light has also been observed to influence the perceptual judgment of depth in an architectural scene Luminance contrast has been proven through perceptual studies conducted using the perceptually realistic computer-generated environment to be an effective depth cue that can create illusory depth effects In this study, the interrelationship of the size and tone-related depth cue