The Role of Low-Spatial Frequency Components in "High Vision" Experiments
نویسنده
چکیده
Recent discussions about mechanisms for modeling human lightness have centered on whether these mechanisms are the result of “Early Vision”, implying that lightness is calculated before depth is undertaken, or “Mid Vision”, implying the simultaneous solutions of both depth and lightness, or “High Vision” mechanisms that imply depth information is used to estimate lightness. This paper begins by reviewing a series of lightness experiments used as evidence for “High Vision”. In particular, it analyzes the influence of both Simultaneous Contrast and low-spatial frequency components on apparent lightness. Further, this paper investigates a variety of “Diamond Wall” lightness experiments. It argues that further study of the “Diamonds” experiments demonstrates an “EarlyVision” explanation, without reliance on illumination, transparency, apparent depth or junctions. Grays ordinarily look darker on light backgrounds. Two rows of diamonds looked the same on different backgrounds, when the diamond tips crossed into the other background. The addition of different gray tips, consistent with illumination changes, released the rest of the diamonds to no longer match. Grays on light backgrounds reverted to looking darker. Additional experiments show that the introduction of any edge along the light-dark background boundary releases the diamonds to look different in different surrounds. These experiments are arguments for “Early-Vision” lightness mechanisms because simultaneous contrast and low-spatial frequency sampling can account for lightness without the need for high-level mental processes.
منابع مشابه
Figure/ground segregation from temporal delay is best at high spatial frequencies
Two experiments investigated the role of spatial frequency in performance of a figure/ground segregation task based on temporal cues. Figure orientation was much easier to judge when figure and ground portions of the target were defined exclusively by random texture composed entirely of high spatial frequencies. When target components were defined by low spatial frequencies only, the task was n...
متن کاملRole of handedness in the Effects of Low Frequency Noise on cognitive performance of Students of Hamedan University of Medical Sciences.
Background and Aim: Noise is one of the most effective exogenous factors affecting the processing mechanisms of the human brain, which has a major role in the occurrence of human error and occupational accidents. Low frequency noise is usually produced by sources such as ventilation systems, pumps, compressors, diesel engines and gas turbines, and so on. For this reason, the sound is in additio...
متن کاملLinearity across spatial frequency in object recognition
In three experiments, we measured recognition as a function of exposure duration for three kinds of images of common objects: component images containing mainly low-spatial-frequency information, components containing mainly high-spatial-frequency information, and compound images created by summing the components. Our data were well fit by a model with a linear first stage in which the sums of ...
متن کاملSome experiments bearing on the hypothesis that the visual system analyses spatial patterns in independent bands of spatial frequency.
Gratings with three sinusoidal components of high spatial frequency are shown to interact with a sinusoidal grating two octaves lower in frequency. This finding is inconsistent with the hypothesis that the visual system analyses spatial patterns in independent narrowly-tuned bands of spatial frequency.
متن کاملSeparation of edge detection and brightness perception
When a low spatial frequency noise mask is superimposed onto a luminance staircase, the perceived brightness pattern is dramatically altered although the edges remain visible. We measured contrast thresholds for the edges and for the illusory scalloping (Chevreul-illusion), as a function of noise center spatial frequency. The masking tuning functions overlapped, but peaked at different spatial ...
متن کامل