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Astigmatic axis independent spatial frequency and contrast sensitivity target and method
专利权人:
Jack T. Holladay
发明人:
Jack T. Holladay
申请号:
US13088625
公开号:
US08425040B2
申请日:
2011.04.18
申请国别(地区):
US
年份:
2013
代理人:
摘要:
A set of visual targets and a method for using these targets to evaluate the spatial frequency response and contrast sensitivity of the human visual system. The invention includes four choice test, six choice test, sinusoidal bulls eye and fundamental sinusoidal letters or optotype targets. The four and six choice targets feature sinusoidal gratings oriented vertically, horizontally and at angles thereto. The sinusoidal bulls eye target features concentric circular light and dark areas with brightness varying in a radial sinusoidal fashion. The fundamental sinusoidal optotype target features an optotype, such as a letter, that is made up of strokes, each of which have a width that is equal to ½ of a single sinusoidal period.
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