Please can someone help me in moving the gratings pattern randomly to left and right.The code to generate gratings pattern is given below.

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Hannah Mathew
Hannah Mathew 2016-4-1
评论： Image Analyst 2016-4-1
n = 101
[X,Y] = meshgrid(linspace(-pi,pi,n));
sinewave2D = 8*sin(4*X);
figure(1)
imagesc(sinewave2D)
axis equal; axis off; colormap(gray);
contrast = 2;
scaled_sinewave2D = (((contrast.*sinewave2D)+1)*127.5)+1;
image(scaled_sinewave2D)
% rescales numbers between -1 and 1 to lie between 1 and 256
colormap(gray(256))

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回答（1 个）

Image Analyst
Image Analyst 2016-4-1
Instead of X, use X-offset where offset is the distance you want to shift the signal.
offset = 2.5; % Whatever
sinewave2D = 8 * sin(4 * (X - offset));
  2 个评论
Hannah Mathew
Hannah Mathew 2016-4-1
Thanks. I don't need to shift the signal but it has to move continuously to right and left in random order.Can you help me with phase shifting in these codes?
Image Analyst
Image Analyst 2016-4-1
The general formula is
signal = amplitude * sin((2 * pi / period) * (x - phaseShift)).
So just do this:
amplitude = 8; % Whatever you want.
period = 1.5708; % Whatever you want.
% Get random number between -pi and +pi
phaseShift = 2*pi*rand(1) - pi;
signal = amplitude * sin((2 * pi / period) * (x - phaseShift));

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