Object Recognition


Viewpoint variation




Ideal Observer Analysis of Human 3D Object Discrimination

In work with Zili Liu (NEC Research Institute, Princeton NJ) and David C. Knill (U. Pennsylvania), we have developed a novel approach, based on ideal observer analysis, for measuring the ability of human observers to use image information for 3D object perception. We compute the statistical efficiency of subjects relative to an ideal observer for a 3D object classification task. After training to 11 different views of a randomly shaped thick wire object, subjects were asked which of a pair of noisy views of the object best matched the learned object. Efficiency relative to the actual information in the stimuli can be as high as 20%. Increases in object regularity (e.g. symmetry) lead to increases in the efficiency with which novel views of an object could be classified. Furthermore, such increases in regularity also lead to decreases in the effect of viewpoint on classification efficiency. Human statistical efficiencies relative to a 2D ideal observer exceeded 100%, thereby excluding all models which are sub-optimal relative to the 2D ideal.

Liu, Z., & Kersten, D. (2003). Three-dimensional symmetric shapes are discriminated more efficiently than asymmetric ones. J Opt Soc Am A Opt Image Sci Vis, 20(7), 1331-1340. (preprint)

Liu, Z., Kersten, D. And Knill, D.C. (1999) Stimulus information or internal representation?--a case study in human object recognition. Vision Research. 39, 603-612. (pdf)

Liu, Z. and Kersten, D. (1998) 2D Observers in 3D Object Recognition? Vision Research., 38, 2507-2519. (pdf)

Liu, Z., Knill, D. C. &;Kersten, D. (1995). Object Classification for Human and Ideal Observers.Vision Research, 35, 549-568.


Illumination variation

Braje, W. L., Legge, G. E. & Kersten, D. (2000). Invariant recognition of natural objects in the presence of shadows. Perception, 29, 383-98. (earlier version: pre-print PDF)

Braje, W.L., Kersten, D., Tarr, M.J. and Troje, N.F. Illumination effects in face recognition. (1998) Psychobiology. 26 (4), 371-380.

Tarr, M. J., Kersten, D., & Bülthoff, H. H. (1998). Why the visual system might encode the effects of illumination. Vision Research, 38, 2259-2275. (pdf)


 

e-mail: kersten@eye.psych.umn.edu

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