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This paper describes a method for measuring the radius of curvature of mirrors by measuring the size of the reflected image. The image is generated by a video camera, captured using an image grabber board and analyzed using custom software on a standard computer. The system is shown to be capable to higher resolution than the current SAE defined spherometer and capable of determining radius of curvature over a smaller area. The latter is particularly important in using the system for measuring aspheric mirrors.

This paper presents a review of the work which has been done on determining appropriate automotive mirror reflectivity levels for good vision as well as glare protection. In addition, its presents the results of two recent studies on the effects of glare on driver vision. In the first, the level is determined at which glare from an interior mirror degrades the driver's forward vision. Four different ambient conditions are included. The second study looks at the effect of mirror transition time on discomfort and disability due to glare. Several current mirror systems are compared to the recommended parameters.

When the brightness of a test stimulus which is colored is matched in luminance to a fixed white reference, it is usually found that the colored stimulus will appear brighter than the white stimulus. Reflectivity is determined by measuring the luminance of reflected light. Therefore, although a white object reflected from both a colored mirror and a neutral mirror with the same reflectivity will have the same luminance, the object reflected from the colored mirror will look brighter because color has been imparted to it by the mirror. This study examined the effect of this added brightness on driver performance. Three colors were studied; blue, green and amber, each at three purity levels; 0.0, 0.3, and 0.6. Brightness was measured as the luminance of a neutral stimulus which appeared equal in brightness to the colored stimulus. Performance was measured as the ability to detect the presence of a vehicle in a roadway scene typical of those viewed in a rearview mirror.