Perception is often viewed as a process that transforms physical variables, external to an observer, into internal psychological variables. Such a process can be modeled by a function coined perceptual scale. The perceptual scale can be deduced from psychophysical measurements that consist in comparing the relative differences between stimuli (i.e. difference scaling experiments). However, this approach is often overlooked by the modeling and experimentation communities. Here, we demonstrate the value of measuring the perceptual scale of classical (spatial frequency, orientation) and less classical physical variables (interpolation between textures) by embedding it in recent probabilistic modeling of perception. First, we show that the assumption that an observer has an internal representation of univariate parameters such as spatial frequency or orientation while stimuli are high-dimensional does not lead to contradictory predictions when following the theoretical framework. Second, we show that the measured perceptual scale corresponds to the transduction function hypothesized in this framework. In particular, we demonstrate that it is related to the Fisher information of the generative model that underlies perception and we test the predictions given by the generative model of different stimuli in a set a of difference scaling experiments. Our main conclusion is that the perceptual scale is mostly driven by the stimulus power spectrum. Finally, we propose that this measure of perceptual scale is a way to push further the notion of perceptual distances by estimating the perceptual geometry of images i.e. the path between images instead of simply the distance between those.

翻译：感知通常被视为将观察者外部的物理变量转化为内部心理变量的过程。此类过程可通过称为感知标度的函数建模。感知标度可从心理物理测量中推导得出——这类测量通过比较刺激之间的相对差异（即差异缩放实验）实现。然而，这种研究方法常被建模与实验领域忽视。本文通过将感知标度嵌入近期概率感知模型，论证了测量经典物理变量（空间频率、朝向）与非经典物理变量（纹理插值）感知标度的重要意义。首先，我们证明在理论框架下，假设观察者对空间频率或朝向等单变量参数具有内部表征（即使刺激本身是高维的）并不会产生矛盾性预测。其次，我们证明实测感知标度与该框架假设的转导函数相对应。具体而言，我们论证该标度与感知生成模型的费舍尔信息相关，并通过一组差异缩放实验验证不同刺激生成模型的理论预测。核心结论表明：感知标度主要受刺激功率谱驱动。最终我们提出，感知标度测量作为拓展感知距离概念的手段，可通过估计图像的感知几何（即图像间的路径）而非单纯计算图像间距离来推进研究。