Abstract It is a great challenge to present realistic light sources in a virtual environment given the limited luminance range of an electronic display. Previous studies show that a glare illusion can enhance the perceived luminance of an area, which is an effective way to improve the realism of light sources in virtual environments. However, it is unclear what kinds of luminance gradients are appropriate for generating virtual light sources. In this study, we investigated the quantitative rule governing the perception of self-luminosity and applied the rule to improve the fidelity of light sources in virtual environments. In particular, light spots with different luminance gradients were presented on a liquid-crystal display (LCD). The participants were asked to report whether or not a luminance spot looked like a self-luminous light source. The probability of the spot being identified as a light source was calculated at each luminance gradient. We observed a critical band of luminance gradients which are a range of power-law exponent. Once the luminance gradient of an image fell into that range, the image was mainly perceived as self-luminosity. The critical band could not be explained by either the local luminance contrast or the total luminance energy. Interestingly, natural image statistics showed that the band matched with the luminance gradients of light sources in natural images. The perception of self-luminosity depends on the specific luminance gradients which are accumulated by human perceptual experience to light sources on natural images. Moreover, we generated virtual light sources with different surrounding luminance gradients and the gradients around the peak of the critical band won the highest rating of perceptual fidelity. These results provide a quantitative description of the perception of self-luminosity, which offers a guideline of how to improve the fidelity when rendering light sources in a virtual environment.

中文翻译：

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将虚拟光源渲染为看起来像电子显示器中的真实光源：用于感知自发光的临界亮度梯度带

摘要 鉴于电子显示器的亮度范围有限，在虚拟环境中呈现逼真的光源是一个巨大的挑战。先前的研究表明，眩光错觉可以增强区域的感知亮度，这是提高虚拟环境中光源真实感的有效方法。然而，目前尚不清楚什么样的亮度梯度适合生成虚拟光源。在这项研究中，我们研究了控制自发光感知的定量规则，并将该规则应用于提高虚拟环境中光源的保真度。特别是，在液晶显示器 (LCD) 上呈现了具有不同亮度梯度的光点。参与者被要求报告一个亮点是否看起来像一个自发光光源。在每个亮度梯度下计算该点被识别为光源的概率。我们观察到亮度梯度的临界带，这是一个幂律指数范围。一旦图像的亮度梯度落入该范围，图像主要被感知为自发光。临界带不能用局部亮度对比度或总亮度能量来解释。有趣的是，自然图像统计表明该波段与自然图像中光源的亮度梯度相匹配。自发光的感知取决于人类感知经验对自然图像上的光源所积累的特定亮度梯度。而且，我们生成了具有不同周围亮度梯度的虚拟光源，临界带峰值附近的梯度获得了感知保真度的最高评级。这些结果提供了对自发光感知的定量描述，为在虚拟环境中渲染光源时如何提高保真度提供了指导。