TY - JOUR
T1 - Long-range template matching follows spatial inhomogeneity, short-range spatial filtering, square-law contrast transduction and the addition of internal noise
AU - Meese, T.
AU - Summers, R.
N1 - ECVP 2012 Abstracts
PY - 2012/9
Y1 - 2012/9
N2 - Since the 1970s and 1980s, the standard view of spatial vision has been that contrast detection involves probability summation over multiple short-range filter-elements, typical of those found in the primary visual cortex. However, more recent work has favoured a model involving physiological integration of luminance contrast over substantial parts of the image, concluding that in previous studies, the effects of a square-law transducer followed by linear summation of noise with the signal have combined to masquerade as probability summation. Here we addressed the details of the contrast integration process by comparing it to an ideal observer model, which was progressively adjusted until it fitted our area summation results (1 to 32 cycles square). We argue that observers use spatially extensive templates (with diameters of several cycles) that operate on the luminance contrast image, but only after retinal inhomogeneity, short-range filtering, square-law transduction and the addition of internal noise. Ideal templates that are matched to the image after the effects of the three processing stages above, provide the modeler with a convenient implementation but might imply a greater level of sophistication than is needed to explain the results.
AB - Since the 1970s and 1980s, the standard view of spatial vision has been that contrast detection involves probability summation over multiple short-range filter-elements, typical of those found in the primary visual cortex. However, more recent work has favoured a model involving physiological integration of luminance contrast over substantial parts of the image, concluding that in previous studies, the effects of a square-law transducer followed by linear summation of noise with the signal have combined to masquerade as probability summation. Here we addressed the details of the contrast integration process by comparing it to an ideal observer model, which was progressively adjusted until it fitted our area summation results (1 to 32 cycles square). We argue that observers use spatially extensive templates (with diameters of several cycles) that operate on the luminance contrast image, but only after retinal inhomogeneity, short-range filtering, square-law transduction and the addition of internal noise. Ideal templates that are matched to the image after the effects of the three processing stages above, provide the modeler with a convenient implementation but might imply a greater level of sophistication than is needed to explain the results.
UR - http://pec.sagepub.com/content/41/1_suppl/1
M3 - Conference abstract
SN - 0301-0066
VL - 41
SP - 52
JO - Perception
JF - Perception
IS - Suppl.1
T2 - 35th European Conference on Visual Perception
Y2 - 2 September 2012 through 6 September 2012
ER -