Perceptual decision making is prone to errors, especially near threshold. Physiological, behavioural and modeling studies suggest this is due to the intrinsic or 'internal' noise in neural systems, which derives from a mixture of bottom-up and top-down sources. We show here that internal noise can form the basis of perceptual decision making when the external signal lacks the required informati...

People perceive and conceive of activity in terms of discrete events. Here the authors propose a theory according to which the perception of boundaries between events arises from ongoing perceptual processing and regulates attention and memory. Perceptual systems continuously make predictions about what will happen next. When transient errors in predictions arise, an event boundary is perceived...

Perceptual learning is a training induced improvement in performance. Mechanisms underlying the perceptual learning of depth discrimination in dynamic random dot stereograms were examined by assessing stereothresholds as a function of decorrelation. The inflection point of the decorrelation function was defined as the level of decorrelation corresponding to 1.4 times the threshold when decorrel...

One patient with left spatial neglect (FM) and four right-brain damaged controls without neglect were tested on a line bisection task with pictures of neutral and emotional faces of the same size as unilateral cues. Our aim was to investigate whether bisection biases induced by cuing can be better explained as the result of a direct perceptual lengthening of the cued part of the line or, altern...

In this paper, a multigrid motion compensation video coder based on the current human visual system (HVS) contrast discrimination models is proposed. A novel procedure for the encoding of the prediction errors has been used. This procedure restricts the maximum perceptual distortion in each transform coefficient. This subjective redundancy removal procedure includes the amplitude nonlinearities...

We propose a general method for gradient-based training of neural network (NN) models to scale multidimensional signal data. In the case of image data, the goal is to fit models that produce images of high perceptual quality, as opposed to simply a high peak signal to noise ratio (PSNR). There have been a number of perceptual image error measures proposed in the literature, the majority of whic...

The concept of perceptual image quality and its measurements are discussed. A distinction is made between appreciation-oriented and performance-oriented quality. It is argued that in both cases psychometrical scaling is a very important method with respect to the measurement of perceptual quality and the strength of its dimensions and therefore is indispensable if one wants to relate these attr...

Simple visual features, such as orientation, are thought to be represented in the spiking of visual neurons using population codes. I show that optimal decoding of such activity predicts characteristic deviations from the normal distribution of errors at low gains. Examining human perception of orientation stimuli, I show that these predicted deviations are present at near-threshold levels of c...

Performance on perceptual-motor (PM) tasks should not be affected by cognitive workload (CW). Subjects performed a novel task that combined a ”recall” version of the n-back task and a PM distractor task. Subjects’ performance was significantly worse on the PM task when CW was increased. As CW was manipulated, the perceptual and motor requirements of both the n-back task and the PM task remained...

PURPOSE To evaluate associations between stereoacuity and presence, type, and severity of vision disorders in Head Start preschool children and determine testability and levels of stereoacuity by age in children without vision disorders. METHODS Stereoacuity of children aged 3 to 5 years (n = 2898) participating in the Vision in Preschoolers (VIP) Study was evaluated using the Stereo Smile II...