Optics of photorefraction: orthogonal and isotropic methods.

H C Howland, O Braddick, J Atkinson, B Howland
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引用次数: 77

Abstract

Analysis of the optics of photorefractively computed ray tracing shows that, for short camera-to-subject distances, the function relating image size to defocus of the eye is not symmetrical for errors of focus in front of and behind the camera. This asymmetry is exploited in the new method of isotropic photorefraction, in which the supplementary cylinder lenses of the original orthogonal photorefractors are replaced by defocusing of the camera lens itself. By comparing photographs taken with the camera focused in front of and behind the subject, the sign of the eyes' defocus (myopic or hyperopic relative to the camera) can be determined. The axis of any astigmatism is readily apparent as the direction in which the photorefractive images are elongated. The method is well adapted for the refractive screening of infants and young children.

光折射光学:正交法和各向同性法。
对光折射率计算光线追踪的光学分析表明,对于较短的相机到被摄体的距离,由于相机前后的聚焦误差,图像大小与眼睛离焦的函数不是对称的。这种不对称性在各向同性光折射的新方法中得到了利用,在这种方法中,原始正交光折射器的辅助圆柱体透镜被相机镜头本身的散焦所取代。通过比较相机在被摄对象前后聚焦拍摄的照片,可以确定眼睛离焦的迹象(相对于相机的近视或远视)。任何散光的轴很容易明显的方向,其中光折变图像被拉长。该方法适用于婴幼儿屈光检查。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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来源期刊
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期刊介绍: OSA was published by The Optical Society from January 1917 to December 1983 before dividing into JOSA A: Optics and Image Science and JOSA B: Optical Physics in 1984.
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