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@@ -0,0 +1,21 @@
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+% ppd2distance.m
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+%
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+% This function convert pixels per degree to a pair of two distances for a
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+% monitor based experiment. It takes as inpu the distance from the monitor and
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+% returns the second dimension
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+%
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+% input:
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+% ppd - pixels per degree
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+% pixNum - number of pixels
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+% distance - distance from monitor. This can be any number since the system is
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+% underdetermined
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+%
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+% output:
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+% monitorDim - monitor size for the provided data
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+
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+function monitorDim = ppd2distance(ppd, pixNum, distance)
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+ thetaDeg = pixNum / ppd;
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+ thetaRad = thetaDeg * pi / 180;
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+
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+ monitorDim = 2 * distance * tan(thetaRad / 2);
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+end
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