Abstract
An electro-optical Visibility Quality Meter (VQM) has been developed to provide quantitative measurements of MTF (modulation transfer function, an index of contrast reduction as a function of target size). VQM meter data showed excellent agreement with human visual tests under a variety of visibility degradations (windshield fogging, icing, dust and road film, interior reflections, glare, etc.). Since many of the driver's visual tasks involve visual targets which are relatively large but low in contrast, visibility is often limited by contrast threshold rather than by resolution threshold. The VQM provides a practical and simple means for establishing and monitoring standards of driver visibility quality in automotive glazing systems. A final report for the National Highway Traffic Safety Administration (contract DOT-HS-6–01426) provides details of the contruction of the VQM, the optical properties of the test samples, the correlations between meter data and human visual data, and the implications of this research for minimum visibility standards and driver vision screening programs.
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