Ohnishi Madoka, Oda Koichi
Tokyo Woman's Christian University, Tokyo, Japan.
Iperception. 2020 Dec 26;11(6):2041669520981102. doi: 10.1177/2041669520981102. eCollection 2020 Nov-Dec.
This study examined the effect of character sample density on legibility. As the spatial frequency component important for character recognition is said to be 1 to 3 cycles/letter (cpl), six dots in each direction should be sufficient to represent a character; however, some studies have reported that high-density characters are more legible. Considering that these seemingly contradictory findings could be compatible, we analyzed the frequency component of the character stimulus with adjusted sample density and found that the component content of 1 to 3 cpl increased in the high-density character. In the following three psychophysical experiments, high sample density characters tended to have lower contrast thresholds, both for normal and low vision. Furthermore, the contrast threshold with characters of each sample density was predicted from the amplitude of the 1 to 3 cpl component. Thus, while increasing the sample density improves legibility, adding a high frequency is not important in itself. The findings suggest that enhancing the frequency components important for recognizing characters by adding the high-frequency component contributes to making characters more legible.
本研究考察了字符样本密度对易读性的影响。由于据说对字符识别重要的空间频率成分是1至3周/字母（cpl），每个方向上六个点应该足以表示一个字符；然而，一些研究报告称高密度字符更易读。考虑到这些看似矛盾的发现可能是兼容的，我们分析了具有调整后样本密度的字符刺激的频率成分，发现1至3 cpl的成分含量在高密度字符中增加。在接下来的三个心理物理学实验中，无论是正常视力还是低视力，高样本密度字符的对比度阈值往往较低。此外，根据1至3 cpl成分的幅度预测了每个样本密度字符的对比度阈值。因此，虽然增加样本密度可提高易读性，但增加高频本身并不重要。研究结果表明，通过添加高频成分来增强对识别字符重要的频率成分有助于使字符更易读。
