Thomson M G, Foster D H, Summers R J
Neurosciences Research Institute, Aston University, Birmingham B4 7ET, UK.
Perception. 2000;29(9):1057-69. doi: 10.1068/p2867.
Fourier-phase information is important in determining the appearance of natural scenes, but the structure of natural-image phase spectra is highly complex and difficult to relate directly to human perceptual processes. This problem is addressed by extending previous investigations of human visual sensitivity to the randomisation and quantisation of Fourier phase in natural images. The salience of the image changes induced by these physical processes is shown to depend critically on the nature of the original phase spectrum of each image, and the processes of randomisation and quantisation are shown to be perceptually equivalent provided that they shift image phase components by the same average amount. These results are explained by assuming that the visual system is sensitive to those phase-domain image changes which also alter certain global higher-order image statistics. This assumption may be used to place constraints on the likely nature of cortical processing: mechanisms which correlate the outputs of a bank of relative-phase-sensitive units are found to be consistent with the patterns of sensitivity reported here.
傅里叶相位信息在确定自然场景的外观方面很重要，但自然图像相位谱的结构高度复杂，难以直接与人类感知过程联系起来。通过将先前对人类视觉敏感性的研究扩展到自然图像中傅里叶相位的随机化和量化，解决了这个问题。由这些物理过程引起的图像变化的显著性被证明关键取决于每个图像原始相位谱的性质，并且只要随机化和量化过程使图像相位分量移动相同的平均量，就表明它们在感知上是等效的。通过假设视觉系统对那些也会改变某些全局高阶图像统计量的相位域图像变化敏感来解释这些结果。这个假设可用于对皮层处理的可能性质施加约束：发现将一组相对相位敏感单元的输出进行关联的机制与这里报告的敏感性模式一致。
