9732793 Low noise muffler development by optimization of muffler internal structure - study on muffler internal structure to use multivariate analysis : Hisashi Natori (Hino Motors, Ltd.)
- Publisher
- Elsevier Science
- Year
- 1998
- Tongue
- English
- Weight
- 141 KB
- Volume
- 19
- Category
- Article
- ISSN
- 0389-4304
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✦ Synopsis
This paper concerns a low-pass filtering method for evaluating the visibility of shapes. With this method, observers discriminate the shapes of images that are filtered in gradually lower spatial frequencies. Legibility is evaluated by measuring the discrimination threshold cut-off frequencies. The method has been validated in practical situations where visual information carried by high spatial frequencies is degraded. Such situations are surprisingly common under unfavourable conditions, including peripheral viewing, mesopic or scotopic vision, isoluminance, image motion, and also in the eyes of elderly persons and clinically impaired eyes.
The numerals of 14 font families were evaluated using this method. The legibility evaluations showed good agreement among the observers, and several working hypotheses were suggested about the legibility of characters.