Experimental Aesthetics Group, Institute of Anatomy I, University of Jena School of Medicine, Jena University Hospital Jena, Germany.
Front Hum Neurosci. 2013 Apr 1;7:106. doi: 10.3389/fnhum.2013.00106. eCollection 2013.
The spatial characteristics of letters and their influence on readability and letter identification have been intensely studied during the last decades. There have been few studies, however, on statistical image properties that reflect more global aspects of text, for example properties that may relate to its aesthetic appeal. It has been shown that natural scenes and a large variety of visual artworks possess a scale-invariant Fourier power spectrum that falls off linearly with increasing frequency in log-log plots. We asked whether images of text share this property. As expected, the Fourier spectrum of images of regular typed or handwritten text is highly anisotropic, i.e., the spectral image properties in vertical, horizontal, and oblique orientations differ. Moreover, the spatial frequency spectra of text images are not scale-invariant in any direction. The decline is shallower in the low-frequency part of the spectrum for text than for aesthetic artworks, whereas, in the high-frequency part, it is steeper. These results indicate that, in general, images of regular text contain less global structure (low spatial frequencies) relative to fine detail (high spatial frequencies) than images of aesthetics artworks. Moreover, we studied images of text with artistic claim (ornate print and calligraphy) and ornamental art. For some measures, these images assume average values intermediate between regular text and aesthetic artworks. Finally, to answer the question of whether the statistical properties measured by us are universal amongst humans or are subject to intercultural differences, we compared images from three different cultural backgrounds (Western, East Asian, and Arabic). Results for different categories (regular text, aesthetic writing, ornamental art, and fine art) were similar across cultures.
几十年来，人们对字母的空间特征及其对可读性和字母识别的影响进行了深入研究。然而，关于反映文本更全局方面的统计图像特性的研究却很少，例如可能与其美学吸引力相关的特性。已经表明，自然场景和各种视觉艺术作品都具有具有尺度不变的傅里叶功率谱，该谱在对数-对数图中随频率增加呈线性下降。我们想知道文本图像是否具有此属性。正如预期的那样，规则类型或手写文本的图像的傅里叶谱具有高度各向异性，即，垂直，水平和倾斜方向的光谱图像特性不同。此外，文本图像的空间频率谱在任何方向上都不是尺度不变的。与美学艺术品相比，文本的频谱在低频部分的下降更平缓，而在高频部分则更陡峭。这些结果表明，通常，相对于美学艺术品，规则文本的图像包含较少的全局结构（低空间频率）相对于精细细节（高空间频率）。此外，我们研究了具有艺术诉求（华丽的印刷和书法）和装饰艺术的文本图像。对于某些度量，这些图像的平均值介于规则文本和美学艺术品之间。最后，为了回答我们所测量的统计特性是否在人类中是普遍的，还是受到文化差异的影响，我们比较了来自三个不同文化背景（西方，东亚和阿拉伯）的图像。不同类别的结果（规则文本，美学书写，装饰艺术和美术）在文化之间相似。
