The left and right sides have a different number of elements

please help me fix the error~~~

this is my code and

%% 3. Fourier descriptor
%① Make the matrix above. 
%Find the positions (x1, x2) of foreground pixels valued '1' and save them to ‘pos’ array.
input=[0 0 0 0 0 0 0; 0 0 0 1 0 0 0; 0 0 1 0 1 0 0; 0 1 0 0 0 1 0; 0 0 1 0 1 0 0; 0 0 0 1 0 0 0; 0 0 0 0 0 0 0];
pos=boundary4(input); 

%② Make a vector ‘comp’ that contains complex numbers: 
%real value: x1 of an element of ‘pos’,imaginary value: x2 of an element of ‘pos’.
comp=complex(pos(:,1),pos(:,2)); 

%③ Do Fourier transform with ‘comp’ and save the result to ‘ft’.
ft=fft(comp); 

%Make zero vector ‘ft1’ which has same size of ‘ft’ and save only first and second element value of ‘ft’ to ‘ft’1.
ft1=zeros(size(ft)); 
ft1(1:2) =ft(1:2); 

%④ Do inverse transform of ‘ft1’ and display the results by plotting imaginary numbers.
figure
subplot(1,2,1);
plot(input), axis ([1,14,1,14]), axis square
title('input');
subplot(1,2,2);
plot(ifft (ft1),'o'), axis ([1,14,1,14]), axis square
title('output');

this is the fxn to get the boundary

function out=boundary4(image)

n=[0 1;-1 0;0 -1;1 0];

flag=1;
cc=[];
[x,y]=find(image==1);
x=min(x);
imx=image(x,:);
y=min(find(imx==1));
first=[x y];
dir=3;

while flag==1
    tt=zeros(1,4);
    newdir=mod(dir+3,4);
    for i=0:3
        j=mod(newdir+i,4)+1;
        tt(i+1)=image(x+n(j,1),y+n(j,2));
    end
    d=min(find(tt==1));
    dir=mod(newdir+d-1,4);
    x=x+n(dir+1,1);y=y+n(dir+1,2);
    cc=[cc;x y];
    if x==first(1)&y==first(2)
        flag=0;
    end
end

out =cc;

and i get this error

Unable to perform assignment because the left and right sides have a different number of elements.

Error in boundary4 (line 19)
        tt(i+1)=image(x+n(j,1),y+n(j,2));

Error in script (line 57)
pos=boundary4(input);

[Rena Berman]

(Answers Dev) Restored edit

Answer 1

[VBBV]

tt(:,i+1)=image(x+n(j,1),y+n(j,2))

Change this line to above