Contrast sensitivity to radial frequencies modulated by Jn and j n Bessel profiles

We measured human contrast sensitivity to radial frequencies modulated by cylindrical (Jo) and spherical (j o) Bessel profiles. We also measured responses to profiles of j o, j1, j2, j4, j8, and j16. Functions were measured three times by at least three of eight observers using a forced-choice method. The results conform to our expectations that sensitivity would be higher for cylindrical profiles. We also observed that contrast sensitivity is increased with the j n order for n greater than zero, having distinct orderly effects at the low and high frequency ends. For n = 0, 1, 2, and 4 sensitivity tended to occur around 0.8-1.0 cpd while for n = 8 and 16 it seemed to shift gradually to 0.8-3.0 cpd. We interpret these results as being consistent with the possibility that spatial frequency processing by the human visual system can be defined a priori in terms of polar coordinates and discuss its application to study face perception.

Map of Italy and Switzerland

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Map illustrating the site of the harbours for the proposed Obi-railway : the soundings are all calculated in feet and are based upon the data of the Russian Marine Ministry : the underlined figures are soundings taken by the scooner Bakan, 1887

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Map of the north coast of Russia indicating the proposed trade route of the Obi-railway

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"Daily Mail" map of the war in China

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Map of a part of eastern Asia to show the commercial position of the productive coal fields of Yesso, Japan

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A geological sketch map of the island of Yesso, Japan

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Map of the sources of Snake River : with its tributaries together with portions of the headwaters of the Madison and Yellowstone from surveys and observations of the Snake River Expedition

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Map of the sources of Snake River : with its tributaries together with portions of the headwaters of the Madison and Yellowstone from surveys and observations of the Snake River Expedition

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Map of the Lower Geyser Basin of the Upper Madison River

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Map of the Upper Geyser Basin on the Upper Madison River, Montana Terr.

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A geological and topographical sketch map of the New York and Westmoreland Gas Coal Company's lands, at Manor Sta., Westm'd Co., Pa.

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Drainage map of Colorado

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Preliminary map of Central Colorado showing the region surveyed in 1873 and 1874

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Philips' map of Egypt and the Soudan, including the Valley of the Nile, the Red Sea, Abyssinia, Arabia, etc

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