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51 lines
1.9 KiB
Matlab
51 lines
1.9 KiB
Matlab
function I=image_contextual_surround_plaid(csize,vsize,ssize,cwavel,s1wavel,s2wavel,angle1,angle2,phasec,phases1,phases2,contc,cont1s,cont2s)
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% csize = the diameter of the centre patch (pixels)
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% vsize = the width of the blank area between the centre and surround
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% ssize = the width of the surrounding annulus (pixels)
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% cwavel = the wavelength of the sin wave in the centre patch (pixels)
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% s1wavel = the wavelength of the 1st sin wave in the surround (pixels)
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% s2wavel = the wavelength of the 2nd sin wave in the surround (pixels)
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% angle1 = angle between centre sinusoid and 1st surround sinusoid
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% angle2 = angle between centre sinusoid and 2nd surround sinusoid
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% phasec = the phase of the central grating
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% phases1 = the phase of the 1st sin wave in the surround
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% phases2 = the phase of the 2nd sin wave in the surround
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% contc = contrast of central patch
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% cont1s = contrast of 1st surround sinusoid
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% cont2s = contrast of 2st surround sinusoid
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cfreq=2*pi./cwavel;
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s1freq=2*pi./s1wavel;
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s2freq=2*pi./s2wavel;
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angle1=-angle1*pi/180;
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angle2=-angle2*pi/180;
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phasec=phasec*pi/180;
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phases1=phases1*pi/180;
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phases2=phases2*pi/180;
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%define image size
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sz=fix(csize+2*vsize+2*ssize);
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if mod(sz,2)==0, sz=sz+1;end %image has odd dimension
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I=zeros(sz);
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%define mesh on which to draw sinusoids
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[x y]=meshgrid(-fix(sz/2):fix(sz/2),fix(-sz/2):fix(sz/2));
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yc=-x*sin(0)+y*cos(0);
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ys1=-x*sin(angle1)+y*cos(angle1);
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ys2=-x*sin(angle2)+y*cos(angle2);
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%make sinusoids with values ranging from 0 to 1 (i.e. contrast is positive)
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center=0.5+0.5.*contc.*cos(cfreq*yc+phasec);
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surround=0.5+0.5.*cont1s.*cos(s1freq*ys1+phases1)+0.5.*cont2s.*cos(s2freq*ys2+phases2);
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%define radius from centre point
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radius=sqrt(x.^2+y.^2); %for circular gratings
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%radius=max(abs(x),abs(y)); %for square gratings
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%put togeter image from components
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I=surround;
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I(find(radius<vsize+csize/2))=0.5;
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I(find(radius<csize/2))=center(find(radius<csize/2));
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I(find(radius>ssize+vsize+csize/2))=0.5;
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