James J. Clark

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When looking at a scene, observers feel that they see its entire structure in great detail and can immediately notice any changes in it. However, when brief blank fields are placed between alternating displays of an original and a modified scene, a striking failure of perception is induced: identification of changes becomes extremely difficult, even when(More)
Microsaccades, or tiny eye movements that take place during periods of fixation, have long been thought to be random artifacts of the oculomotor system. Here we demonstrate a possible link between microsaccades and covert attention shifts. We designed two psychophysical tasks involving spatial cues that had identical sensory stimuli but differing patterns(More)
Object detection with a learned classifier has been applied successfully to difficult tasks such as detecting faces and pedestrians. Systems using this approach usually learn the classifier offline with manually labeled training data. We present a framework that learns the classifier online with automatically labeled data for the specific case of detecting(More)
The optimal viewing position phenomenon discovered by (O'Regan, J. K., Lévy-Schoen, A., Pynte, J., Brugaillère, B. (1984). Convenient fixation location within isolated words of different length and structure. Journal of Experimental Psychology: Human Perception and performance. 10 (2), 250-257) is characterized by a minimization of gaze duration on a word(More)
Observers inspected normal, high quality colour displays of everyday visual scenes while their eye movements were recorded. A large display change occurred each time an eye blink occurred. Display changes could either involve “Central Interest” or “Marginal Interest” locations, as determined from descriptions obtained from independent judges in a prior(More)
The reconstruction of unctions from their samples at nonuniformly distributed locations is an important ask for many applications. This paper presents a sampling theory which extends the uniform sampling theory of Whittaker et ul. [ l l ] to include nonuniform sample distributions. This extension is similar to the analysis of Papoulis [15], who considered(More)