Related Experiment Video
Updated: Jun 23, 2026

Measurement of X-ray Beam Coherence along Multiple Directions Using 2-D Checkerboard Phase Grating
Published on: October 11, 2016
Summation characteristics of the detection of compound gratings
S Plainis1, N R A Parry, A Panorgias
1Institute of Vision and Optics (IVO), School of Health Sciences, University of Crete, Heraklion, Crete, Greece.
Abstract:
Many classical experiments have shown that two superimposed gratings are more easily detected than a single grating, in keeping with probability theory. Here we test the rules for the detection of 2-component compound gratings by extending the range of parameters used in previous experiments. Two complementary methods of deriving summation indices are described. Data are presented so that the conditions for the transition from probability to neural summation are easily identified. True probability summation occurs only when grating contrasts are carefully perceptually equalised and spatial frequency differs by more than a factor of 2. A wide range of contrast ratios of the component gratings were explored such that gratings were at different contrasts, relative to respective thresholds. We find clear evidence of suppressive interactions when the compound gratings are composed of a close to threshold low frequency component and a below-threshold higher spatial frequency component.
Related Concept Videos
Graded Potential
Graded potentials fall into two categories: depolarizing and hyperpolarizing. Depolarizing graded potentials typically occur when sodium (Na+) or calcium...
Integration of Synaptic Events
¹H NMR: Complex Splitting
Splitting diagrams or splitting tree diagrams are routinely used to depict such complex couplings. While drawing splitting diagrams, the splitting with the larger coupling constant is usually applied first.
¹H NMR Signal Integration: Overview
¹H NMR: Interpreting Distorted and Overlapping Signals
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are slanted or...

