Compare and contrast Marr and Nishihara’s and Biederman’s theories of object recognition. How well do they explain how we are able to recognize three dimensional objects despite changes in viewing angle?
Humphreys and Bruce (1989) proposed a model of object recognition that fits a wider context of cognition. According to them, the recognition of objects occurs in a series of stages. First, sensory input is generated, leading to perceptual classification, where the information is compared with previously stored descriptions of objects. Then, the object is recognized and can be semantically classified and subsequently named. This approach is, however, over-simplified. Other theories like Marr and Nishihara’s and Biederman’s explain in more detail the processes involved in the stages of perceptual and semantic classification. This essay will compare and contrast these two latter theories and evaluate their contribution to 3D object recognition. In doing so, it will consider the viewpoint invariant or viewpoint dependent debate and compare both approaches to others like Tarr and Bülthoff’s and Foster and Gilson’s.
According to Humphreys and Bruce (1989), the first stage of object recognition is the early visual processing of the retinal image, as for example Marr’s primal sketch, in which a two dimensional description is formed. In the second stage a description of the object is generated, as for example Marr’s 2 ½ D sketch, in which a description of depth and orientation of visible surfaces is formed in relation to the view point of the observer and is therefore viewpoint dependent. In the third stage (perceptual classification) a structural description is created, similar to the processes forming Marr’s 3D model representation. The main focus of both Marr and Biedermann theories appear to be on the second and third stages of this sequence.
Marr and Nishihara (1978) proposed a theory of object recognition based on generating a 3D object-centered
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