Kingdom F, Moulden B, Hall R
Department of Psychology, Reading University, Whiteknights, Berkshire, UK.
J Opt Soc Am A. 1987 Dec;4(12):2342-54. doi: 10.1364/josaa.4.002342.
Two experiments are described that investigate the detectability of signals embedded in spatially uncorrelated visual noise. The signals were thin lines extending vertically from the top to the bottom of the noise background and were essentially of two classes. One class consisted of signals whose pixel luminances were spatially uncorrelated, the other of signals whose pixel luminances were sinusoidally modulated along their length. In both classes the space-average luminance of the signals was greater than that of the noise. In the first experiment it was found that the modulated signals were more visible than the unmodulated, even though the space-average luminance of both types was equal. For the modulated signals visibility was proportional to the amplitude of modulation and inversely proportional to the spatial frequency of modulation. Neither an ideal-observer model nor an energy-integrator model was found to give a good account of the results. On the other hand, a model referred to as the maximum filter output model gave an excellent account of the data. The model employed a simple energy-integrating filter approximately 0.8 deg in length and recorded the filter's maximum output for every potential signal, indicating the signal as the line that gave the largest output. In a second experiment, modulated signals that contained added random luminance perturbation were used, and again the model was found to give a good fit to the data. The findings are discussed in the context of known properties of cortical-bar detectors.
本文描述了两项实验，研究嵌入空间不相关视觉噪声中的信号的可检测性。信号是从噪声背景的顶部垂直延伸到底部的细线，主要分为两类。一类信号的像素亮度在空间上不相关，另一类信号的像素亮度沿其长度呈正弦调制。两类信号的空间平均亮度均高于噪声。在第一个实验中发现，即使两类信号的空间平均亮度相等，调制信号也比未调制信号更易被看见。对于调制信号，可见性与调制幅度成正比，与调制空间频率成反比。研究发现，理想观察者模型和能量积分器模型都无法很好地解释实验结果。另一方面，一个被称为最大滤波器输出模型的模型对数据给出了很好的解释。该模型使用了一个长度约为0.8度的简单能量积分滤波器，并记录每个潜在信号的滤波器最大输出，将给出最大输出的线指示为信号。在第二个实验中，使用了包含额外随机亮度扰动的调制信号，该模型再次被发现与数据拟合良好。本文在已知的皮质条检测器特性的背景下讨论了这些发现。
