The perceived blur in natural images is predominantly determined by Off signals.
The perceived blur in natural images is predominantly determined by Off signals.
复制标题
自然图像中的感知模糊主要由 Off 信号决定。
作者：
Sato;H.;Motoyoshi;I.;& Sato;S.
随着其在较高空间频率的功率降低，图像似乎变得模糊。这项研究考察了感知到的模糊是否只取决于亮/暗(开/关)对比度的一个或两个。在实验中，通过将较高空间频率的ON或OFF分量的功率降低的测试图像与ON和OFF分量都有不同程度降低的参考刺激进行匹配来测量测试图像的主观模糊。测试刺激有5个级别的模糊，通过减少20%到100%的高频功率而产生。我们发现，当关闭分量减少时，图像与原始图像相比明显变得模糊，而当关闭分量减少时，几乎没有观察到影响。这种不对称性在各种自然图像中都很明显，但在字母和方波栅格等人工刺激中也很明显。我们还发现，适应由小黑点组成的纹理(关闭)会使随后呈现的图像比适应亮点组成的纹理(打开)更加模糊。这些结果表明，高空间范围内的OFF分量是决定感知模糊的关键因素。
Images appear to be blurred as its power at higher spatial frequencies is reduced. The present study examines whether the perceived blur depends on only one or both of the bright/dark (On/Off) contrast polarities. In experiments, the subjective blur of test image in which the power of either On or Off component at higher spatial frequencies is reduced was measured by matching them to reference stimuli in which both On and Off components were reduced by various degree. The test stimulus had 5 levels of blur generated by reducing high-frequency power between 20 and 100%. We found that the image appears to be markedly blurred as compared to the original when Off component is reduced, whereas little effect was observed when On component is reduced. This asymmetry is prominent for a variety of natural images, but also evident for artificial stimuli such as letters and square-wave gratings. We also found that adaptation to a texture composed of small dark dots (Off) made the subsequently presented image more blurred than adaptation to a texture of bright dots (On). These results suggest that Off component within high spatial range is the critical factor determining perceived blur.