### Abstract

The structure of receptive fields of human visual detectors was investigated by studying their phase response. Observers were required to discriminate between pairs of periodic stimuli that differed in phase by 180° (reversed in contrast). The stimuli comprised 256 harmonics, smoothly filtered in amplitude, and congruent in phase at the origin. Reversal discrimination thresholds were measured as a function of the phase of the harmonics. Thresholds were slightly higher for phases around 45°, consistent with the idea that all discriminations were mediated by independent detectors with 0 or 90° phase response (assuming probability summation between them). Discrimination thresholds were also measured with a pedestal stimulus, of phase complementary to that of the test gratings. For discriminations between 0 and 180° (cosine phase), or 90 and 270° (sine phase), the complementary pedestal had little effect, implying independence of detectors in sine and cosine phase. However, for discrimination between 45 and 225° (stimuli containing both sine and cosine components) the complementary pedestal, which also contained both sine and cosine components, facilitated greatly discrimination thresholds. The results suggest that there exist two classes of detectors, one with a Fourier phase spectrum of 0, the other with a Fourier phase spectrum of 90°. This implies that the receptive fields are symmetric, one class having even-symmetry (line-detectors), the other odd-symmetry (edge-detectors).

Original language | English |
---|---|

Pages (from-to) | 419-431 |

Number of pages | 13 |

Journal | Vision Research |

Volume | 29 |

Issue number | 4 |

DOIs | |

Publication status | Published - 1989 |

### Fingerprint

### Keywords

- Edge detectors
- Phase
- Receptive fields
- Symmetry

### ASJC Scopus subject areas

- Ophthalmology
- Sensory Systems

### Cite this

*Vision Research*,

*29*(4), 419-431. https://doi.org/10.1016/0042-6989(89)90006-0

**Evidence for edge and bar detectors in human vision.** / Burr, David C.; Morrone, M. Concetta; Spinelli, Donatella.

Research output: Contribution to journal › Article

*Vision Research*, vol. 29, no. 4, pp. 419-431. https://doi.org/10.1016/0042-6989(89)90006-0

}

TY - JOUR

T1 - Evidence for edge and bar detectors in human vision

AU - Burr, David C.

AU - Morrone, M. Concetta

AU - Spinelli, Donatella

PY - 1989

Y1 - 1989

N2 - The structure of receptive fields of human visual detectors was investigated by studying their phase response. Observers were required to discriminate between pairs of periodic stimuli that differed in phase by 180° (reversed in contrast). The stimuli comprised 256 harmonics, smoothly filtered in amplitude, and congruent in phase at the origin. Reversal discrimination thresholds were measured as a function of the phase of the harmonics. Thresholds were slightly higher for phases around 45°, consistent with the idea that all discriminations were mediated by independent detectors with 0 or 90° phase response (assuming probability summation between them). Discrimination thresholds were also measured with a pedestal stimulus, of phase complementary to that of the test gratings. For discriminations between 0 and 180° (cosine phase), or 90 and 270° (sine phase), the complementary pedestal had little effect, implying independence of detectors in sine and cosine phase. However, for discrimination between 45 and 225° (stimuli containing both sine and cosine components) the complementary pedestal, which also contained both sine and cosine components, facilitated greatly discrimination thresholds. The results suggest that there exist two classes of detectors, one with a Fourier phase spectrum of 0, the other with a Fourier phase spectrum of 90°. This implies that the receptive fields are symmetric, one class having even-symmetry (line-detectors), the other odd-symmetry (edge-detectors).

AB - The structure of receptive fields of human visual detectors was investigated by studying their phase response. Observers were required to discriminate between pairs of periodic stimuli that differed in phase by 180° (reversed in contrast). The stimuli comprised 256 harmonics, smoothly filtered in amplitude, and congruent in phase at the origin. Reversal discrimination thresholds were measured as a function of the phase of the harmonics. Thresholds were slightly higher for phases around 45°, consistent with the idea that all discriminations were mediated by independent detectors with 0 or 90° phase response (assuming probability summation between them). Discrimination thresholds were also measured with a pedestal stimulus, of phase complementary to that of the test gratings. For discriminations between 0 and 180° (cosine phase), or 90 and 270° (sine phase), the complementary pedestal had little effect, implying independence of detectors in sine and cosine phase. However, for discrimination between 45 and 225° (stimuli containing both sine and cosine components) the complementary pedestal, which also contained both sine and cosine components, facilitated greatly discrimination thresholds. The results suggest that there exist two classes of detectors, one with a Fourier phase spectrum of 0, the other with a Fourier phase spectrum of 90°. This implies that the receptive fields are symmetric, one class having even-symmetry (line-detectors), the other odd-symmetry (edge-detectors).

KW - Edge detectors

KW - Phase

KW - Receptive fields

KW - Symmetry

UR - http://www.scopus.com/inward/record.url?scp=0024598268&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0024598268&partnerID=8YFLogxK

U2 - 10.1016/0042-6989(89)90006-0

DO - 10.1016/0042-6989(89)90006-0

M3 - Article

C2 - 2781732

AN - SCOPUS:0024598268

VL - 29

SP - 419

EP - 431

JO - Vision Research

JF - Vision Research

SN - 0042-6989

IS - 4

ER -