低通滤波下影响汉字辨认正确率的因素初探  

Exploration of the factors that affect the correct identification rate of low-pass filtered Chinese characters

作　　者：郭迎暄[1] 王晨晓[1] 贺极苍[1] 陈湘君[1] 吕帆[1] 

机构地区：[1]温州医学院附属眼视光学院,浙江温州325027

出　　处：《眼视光学杂志》2009年第4期273-277,共5页Chinese Journal of Optometry & Ophthalmology

基　　金：浙江省自然科学基金项目(Y2080831);温州市科技局项目(Y20060227)

摘　　要：目的探讨字频、空间频率、笔画数和近视程度对汉字图片辨认正确率的影响。方法矫正视力或裸眼视力不低于1.0的33位被试者参加本实验,按照近视程度分成高、中、低度近视三组,测量他们在110cm距离处对3种笔画数(少、中、多)、2种字频(常用字和生僻字)和9个截止空间频率(1.00cpc、1.25cpc、1.58cpc、1.99cpc、2.51cpc、3.98cpc、6.30cpc、9.98cpc、无滤波)随机组合的低通滤波下汉字图片辨认的正确率。对每位被试者的测试结果进行最小二乘法拟合,得到汉字临界截止空间频率及最大辨认正确率。结果少笔画汉字组:常用字和生僻字的临界截止空间频率均值分别为(1.73±0.71)cpc和(2.20±0.68)cpc,最大辨认正确率均值为(99.33±0.09)%和(99.18±0.10)%;中笔画汉字组:常用字和生僻字的临界截止空间频率均值分别为(1.89±0.14)cpc和(2.38±0.25)cpc,最大辨认正确率均值为(98.93±1.04)%和(96.00±2.35)%;多笔画汉字组:常用字和生僻字的临界截止空间频率均值分别为(2.43±0.63)cpc和(6.17±1.41)cpc,最大辨认正确率均值为(97.02±0.35)%和(88.59±1.33)%。相同空间频率和笔画数组,常用字与生僻字的辨认正确率差异显著(P<0.01)。截止空间频率≤2.51cpc时,汉字辨认正确率差异显著(P<0.01);截止空间频率>2.51cpc时,汉字辨认正确率差异无显著性(P=0.392)。不同近视程度组汉字辨认正确率差异没有统计学意义(P>0.05)。结论低通滤波下汉字图片辨认的正确率受到字频、笔画数和空间频率成分的影响,但是不受近视程度影响。Objective To investigate the influence of word frequency, spatial frequency, character strokes and myopia status in identifying Chinese characters. Methods Thirty-three subjects with best corrected or uncorrected habitual visual acuity ≥220/20 in both eyes were enrolled in this study. They were divided into three groups： low myopes, moderate myopes and high myopes. Low-pass filtered Chinese characters contained three stroke categories （sparse strokes, medium strokes and dense strokes, based on the number of strokes in the characters）, two word frequencies （common characters and rare characters） and nine low-pass spatial frequencies （1.00 cycle/character, 1.25 cpc, 1.58 cpc, 1.99 cpc, 2.51 cpc, 3.98 cpc, 6.30 cpc, 9.80 cpc and unfiltered）. The factors were randomly selected for presentation. Identification of the correct rate was measured at a distance of 110 cm. The correct identification rate of each subject was fitted using the least square method. Results In the sparse-stroke Chinese character group, the means of the critical cut-off spatial frequencies for common characters and rare characters were 1.73 cpc and 2.20 cpc, respectively, and the means for the correct identification rate were 99.33% and 99.18%. In the medium-stroke Chinese character group, the means of the critical cut-off spatial frequencies for common and rare characters were 1.89 cpc and 2.38 cpc, respectively, and the means for the correct identification rate were 98.93% and 96.00%. In the densestroke Chinese group, the means of the critical cut-off spatial frequencies for common and rare characters were 2.43 cpc and 6.17 cpc, respectively, and the means for the correct identification rate were 97.02% and 88.59%. For the same stroke and spatial frequency, the means of the correct identification rate of common and rare Chinese characters were significantly different （P=0.001）. When cut-off frequency was ≤2.51 cpc, the correct identification rates for different spatial frequencies were significantly different （P=0.001）

关 键 词：空间频率 低通滤波 字频 辨认模式 

分 类 号：B842[哲学宗教—基础心理学]