Estimation ok a luminance nonlinearity in texture segregation

E. L. Alhston, M. S. Landy, L. T. Maloneyn

Research output: Contribution to journalArticlepeer-review

Abstract

Purpose. Previously (Chubb el al.. .IOSA A II. 2350-2374. 1994), we have isolated a channel used for text me segregation and partial h characterized a luniinance nonhnearily in that channel (measuring Us 3rd- and higher-order polynomial components). We were unable to measure its 1st- and 2nd-order components (the lesponse to mean luminance and to contrast) due to intrusion by other channels with larger receptive lields. Here, we demonstrate a method for tull\ chaiacterizing this luniinance non linearity. Methods. We used the litnuion method of Chubb et al. Stimuli were alternating stripes of textures T + and T Fach texture was a sirid of uniform squares, with grey-levels v in T + and drawn from probability distributions (r) ±a(H9)A,ir ) + cos(6]A,(t ). there n is (he um form probability distribution. A, are /th-order orthogonal polynomials used as histogram unxlitiitfort. B is a direction in a space of miMincs of modulators J., and A and a is a hiiogmm cunirasl. For the pair i/,/1 = i 1.3) and a large set of directions 0, we determined the histogram contrast threshold a θ foi detection ot the texture stripes (2AFC judgments of whether the stripes were oriented vertically or horiJ.onlally). Results. We report fits of a probability summation model to the data combining the previously isolated channel i respond nig to all polynomial orders) and an aggregate response ot any mhei channels (responding to only mean and contrast), allowing us lo estimate the lou-order components of the channel nonhnearil}, Conclusions. Histogram conliast analysis may be extended to fully characteri/e an early nonlincarity in the \iMial system.

Original languageEnglish (US)
Pages (from-to)S637
JournalInvestigative Ophthalmology and Visual Science
Volume38
Issue number4
StatePublished - 1997

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

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