scholarly journals The Effects of Mirror Reflections and Planar Rotations of Pictures on the Shape Percept of the Depicted Object

Perception ◽  
10.1068/p6101 ◽  
2009 ◽  
Vol 38 (10) ◽  
pp. 1439-1466 ◽  
Author(s):  
Els V K Cornelis ◽  
Andrea J van Doorn ◽  
Johan Wagemans
Keyword(s):  
Planar Rotations

The Role of Edges in Object Recognition by Pigeons

Perception ◽  
10.1068/p5427 ◽  
2005 ◽  
Vol 34 (11) ◽  
pp. 1353-1374 ◽  
Author(s):  
Jessie J Peissig ◽  
Michael E Young ◽  
Edward A Wasserman ◽  
Irving Biederman
Keyword(s):  
Object Recognition ◽  
Visual Recognition ◽  
Line Drawing ◽  
Human Recognition ◽  
Single View ◽  
Line Drawings ◽  
Consistent Condition ◽  
Depth Discontinuities ◽  
Planar Rotations

In three experiments, we explored how pigeons use edges, corresponding to orientation and depth discontinuities, in visual recognition tasks. In experiment 1, we compared the pigeon's ability to recognize line drawings of four different geons when trained with shaded images. The birds were trained with either a single view or five different views of each object. Because the five training views had markedly different appearances and locations of shaded surfaces, reflectance edges, etc, the pigeons might have been expected to rely more on the orientation and depth discontinuities that were preserved over rotation and in the line drawings. In neither condition, however, was there any transfer from the rendered images to the outline drawings. In experiment 2, some pigeons were trained with line drawings and shaded images of the same objects associated with the same response (consistent condition), whereas other pigeons were trained with a line drawing and a shaded image of two different objects associated with the same response (inconsistent condition). If the pigeons perceived any correspondence between the stimulus types, then birds in the consistent condition should have learned the discrimination more quickly than birds in the inconsistent condition. But, there was no difference in performance between birds in the consistent and inconsistent conditions. In experiment 3, we explored pigeons' processing of edges by comparing their discrimination of shaded images or line drawings of four objects. Once trained, the pigeons were tested with planar rotations of those objects. The pigeons exhibited different patterns of generalization depending on whether they were trained with line drawings or shaded images. The results of these three experiments suggest that pigeons may place greater importance on surface features indicating materials, such as food or water. Such substances do not have definite boundaries—cued by edges—which are thought to be central to human recognition.

scholarly journals Approximating Planar Rotations

1999 ◽  
Vol 21 (1) ◽  
pp. 45-56
Author(s):  
I. Sterling ◽  
T. Sterling
Keyword(s):  
Planar Rotations
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