Related Experiment Video
Updated: May 16, 2026

A Two-interval Forced-choice Task for Multisensory Comparisons
Published on: November 9, 2018
Amplitude difference and similar time course of impulse responses in positive- and negative-contrast detection
1Department of Engineering, Graduate School of Engineering, Kochi University of Technology, Japan. shilin.sl@gmail.com
Abstract:
Temporal impulse response functions (IRFs) were measured to investigate the temporal characteristics of positive- and negative-contrast detection in human vision. The IRFs were estimated using models from sequential double-pulse thresholds measured by the psi method. The results indicated that thresholds for positive contrast detection were significantly higher than those for negative contrast detection. However, positive- and negative-contrast IRFs were similar except for the first peak amplitude, reflecting the difference in sensitivity that originates from the summation operation rather than the linear filtering of the visual system.
Related Concept Videos
Difference from Background: Limit of Detection
The LOD indicates the presence or absence...
Basic Operations on Signals
Time Reversal mirrors a continuous-time signal about the vertical axis at t=0. This is achieved by substituting t with −t. For example, if a signal x(t) is considered, the time-reversed signal is x(−t). This operation can be graphically represented, showing the mirrored signal.
Even and Odd Signals
Basic Discrete Time Signals
The unit impulse or sample sequence is mathematically expressed as zero for all n values except at n=0, where it is one. The unit impulse sequence, denoted by δ(n), is the first difference of the unit step sequence, while the unit step sequence u(n) is the...

