- 期刊
- OpenAccess
如何提升視障者的中文閱讀速度
How to Increase Chinese-Character Reading Speed for Vision-Impaired Persons
摘要
本研究的目的在發展一套能提升視障者中文閱讀速度的方法。此方法係依據量測視障者的視覺對比敏感函數以得到其實際的視力狀況，藉由強化其缺損的對比敏感函數部分來補償其視力。在實驗中，我們收集了十九位經屈光校正後視力為1.0的受測者（平約年齡23.6±2.4歲，年齡範圍22至26歲）及十位因不同原因所造成優眼視力介於0.02至0.1之間的視障者（平均年齡29.5±9.1歲，年齡範圍18至42歲）之視覺對比敏感函數，以各別視障者之視覺對比敏感函數對正常視力者的平約視覺對比敏感函數作運算，求得其視力惡化函數。藉已知的視力惡化函數，我們可將中文文字作適當的影像處理以強化視障者之視覺對比敏感函數缺損部分。在量化評估上，我們以三篇具有字數及筆劃多寡相接近的短文（字體為細明體）分別作以下的處理；(1)依據其視力惡化函數作文字影像的強化；(2)轉換成黑底白字；(3)常用的白底黑字。我們依視障者之視覺對比敏感函數調整其能辨識字體的大小，請其朗誦此三篇短文並錄音，以計算閱讀的速度。若以白底黑字文章的閱讀速度為參考值，結果顯示視障者對作過文字影像強化及黑底白字的文章，其平均的閱讀速度分別提高了25%及19%，顯示文字的強化確實能幫助視障者的閱讀能力。
關鍵字
無資料並列摘要
The purpose of this study is to develop a method by which the vision-impaired people can increase their reading speed in Chinese articles. The method is based on obtaining the contrast sensitivity function of the vision-impaired people so that their detailed visual acuity can be fully understood and the deficient visual contrast sensitivity can thereafter be compensated by enhancing the visual signals. We recruited 19 subjects whose refractive errors were corrected to 1.0 (mean age=23.6±2.4 year, ranged 22 to 26 year) and 10 vision-impaired subjects whose best visual acuities were between 0.02 and 0.1 (mean age=29.5±9.1 year, ranged 18 to 42 year). All the subjects' contrast sensitivity functions were obtained. 'Visual degradation transfer function (VDTF) of a visual-impaired subject was determined by calculating the quotient of CSF of the visual-impaired subject to the average CSF of the normal subjects. According to the VDTF, the weaken part of the CSF in the spatial domain of the subject is enhanced through image processing technique while reading Chinese characters. For quantitative evaluation, we provided 3 short articles with nearly same numbers of characters and complexity with the following manipulation, respectively: (1) the characters were enhanced according individual VDTF; (2) the characters were printed in white on black background; (3) as usual, the characters were printed in black on white background. The size of the article characters was then adjusted so that the subject could barely recognize. The visual-impaired subjects were asked to read out the articles and their voices were also recorded so that the reading speed can be estimated. If the reading speed for the article of black characters on white background is taken for reference, then the average reading speed for character-enhanced article increases 25% and white characters on black background increases 19% respectively, showing that characters-enhanced material can surely help the visual-impaired peoples in their reading capability.