HISTOGRAM CONTRAST ANALYSIS AND THE VISUAL SEGREGATION OF IID TEXTURES
HISTOGRAM CONTRAST ANALYSIS AND THE VISUAL SEGREGATION OF IID TEXTURES
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DOI：
10.1364/josaa.11.002350
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发表时间：
1994-09-01
影响因子：
1.9
通讯作者：
LANDY, MS
中科院分区：
文献类型：
--
作者：
CHUBB, C;ECONOPOULY, J;LANDY, MS
介绍了一种新的心理物理学方法，直方图对比分析，它允许人们测量刺激转换，f，视觉系统使用它来区分不同的图像区域。该方法基于给定的纹理微模式直方图，随机独立地（跨位置）选择纹理微模式构建图像。通过使用不同的分量函数来调制微图案直方图，测量f的不同分量，直到得到可辨别的纹理。当无法获得给定调制分量函数的判别阈值时，可以使用第二种滴定技术来测量该分量对f的贡献。该方法包括对其自身假设的几个强有力的测试。给出了将该方法应用于由随机选择灰度的小而均匀的正方形组成的视觉纹理的实例。特别地，对于固定的平均灰度级mu和固定的灰度级方差sigma2，通过直方图对比分析可以证明，所有由灰度级共同独立、同分布的小正方形组成的纹理，其S类在感知上是初等的，具有以下意义：存在一个单一的灰度实值函数f(S)，使得只有当f(S)作用于I中的灰度级的平均值与f(S)作用于J中的灰度级的平均值显著不同时，S中的两个纹理I和J才可区分。最后，利用直方图对比分析得到f(S)的七阶多项式近似。
A new psychophysical methodology is introduced, histogram contrast analysis, that allows one to measure stimulus transformations, f, used by the visual system to draw distinctions between different image regions. The method involves the discrimination of images constructed by selecting texture micropatterns randomly and independently (across locations) on the basis of a given micropattern histogram. Different components of f are measured by use of different component functions to modulate the micropattern histogram until the resulting textures are discriminable. When no discrimination threshold can be obtained for a given modulating component function, a second titration technique may be used to measure the contribution of that component to f. The method includes several strong tests of its own assumptions. An example is given of the method applied to visual textures composed of small, uniform squares with randomly chosen gray levels. In particular, for a fixed mean gray level mu and a fixed gray-level variance sigma2, histogram contrast analysis is used to establish that the class S of all textures composed of small squares with jointly independent, identically distributed gray levels with mean mu and variance sigma2 is perceptually elementary in the following sense: there exists a single, real-valued function f(S) of gray level, such that two textures I and J in S are discriminable only if the average value of f(S) applied to the gray levels in I is significantly different from the average value of f(S) applied to the gray levels in J. Finally, histogram contrast analysis is used to obtain a seventh-order polynomial approximation of f(S).