Can anyone please help me correct the error in this program for generating a binary image from rgb image?

% plot
r = 1;
t=0:0.002:1;
a=zeros(500);
s=zeros(500);
for i=1:500 
    a(i)= deg2rad(t(i)*90);
    s(i) = (r*pi*t(i)) / 2;
    xc(i) = r * sin(a(i));
    yc(i) = r * sin(a(i));
    x(i) = xc(i) + ( s(i) * sin(a(i)));
    y(i) = yc(i) - ( s(i)* cos(a(i)));
   plot(x,y)

end
   % rasterize it to an 50 row x 100 col image;
nRow = 50;
nCol = 100;
xNode = linspace(min(x),max(x),nCol);
yNode = linspace(min(y),max(y),nRow);
yInterp = interp1(x,y,xNode,'cubic','extrap');
xi = 1:nCol;
yi = round(interp1(yNode,1:nRow,yInterp,'linear','extrap'));

im = accumarray([yi(:), xi(:)],1,[nRow,nCol]);
imagesc(im);
% define threshold frequency
threshold=125;
% obtain the image size
[M,N,clrs]=size(im);
 M=10
 N=10  
 clrs=2
 %convert the image into type double for matlab operations
 tempimage=double(im);
 % create space for the lightened image
 filteredimage = zeros(M,N,2);
 % compute the average of all color intensities
 temp1=(tempimage(:,:,1)+ tempimage(:,:,2))/2;
 % compare this with the threshold
 temp2=temp1 > threshold;
 %convert it to a range from 0-255
 filteredimage(:,:,1)=255 * double(temp2);

   filteredimage(:,:,2)=filteredimage(:,:,1);
   %
   newimage=uint8(filteredimage);
   figure
   image(newimage);
   axis off

[Image Analyst]

Isn't this a duplicate of your first post http://www.mathworks.com/matlabcentral/answers/153903-hey-i-have-written-this-code-for-conversion-of-plot-to-rgb-image-followed-by-conversion-to-binary-i???

[Devanshee Tanna]

It is, I did not post the code in a proper format, hence the repost. If you could help me get the required output of a binary image, I shall be grateful to u! Ur suggestion of replacing imagesc(im) with image()/imshow() could not give me that.. if you could verify and tell me? thanks!

Answer 1

[yonatan gerufi]

if you have image processing toolbox you can use " im2bw " function.