how to remove the error"braces indexing not suitable for this kind of variables"?

i have the follawing matrix watermarking code

it has some error i need to remove it

clc
ca=input('enter the matrix')
count=1;
location_array=[[1,4;3,3],[2,3;4,1],[1,6;3,5],[1,5;3,4],[3,4;6,1],[4,3;5,2],[4,2;5,1],[2,6;3,6]];
for i=1:size(ca,1)-1
    for j=1:size(ca,2)-1
        A=ca(i,j);
        B=dct2(A)
        dis_img{1,count}=B
        count =count+1;
    end
end
bin_store={}
watermarked=12
b=de2bi(watermarked)
bin_store=b
count=1;
key=[2,4,5,8];
j=1;
s=200;
for i=1:size(bin_store,2)
    block=dis_img(1,count);
    if bin_store(1,i)==0
        for j=1:4
            ii=location_array{1,key(1,j)}(1,:);
            jj=location_array{1,key(1,j)}(2,:);
            xx=block(ii(1,1),ii(2,1));
            yy=block(jj(1,1),jj(1,1));
            if xx<=yy
            x=xx;
            xx=yy;
            yy=x;
            if xx-yy<=s
                xx=xx+s/2;
                yy=yy-s/2;
            
         else
                if xx-yy<=s
                xx=xx+s/2;
                yy=yy-s/2;
                end
            end
             block(ii(1,1),ii(1,1))==xx;
        block(jj(1,1),jj(1,1))==yy;
        end
    end
        
           if bin_store(1,i)==1
                 for j=1:4
            ii=location_array{1,key(1,j)}(1,:);
            jj=location_array{1,key(1,j)}(2,:);
            xx=block(ii(1,1),ii(1,1));
            yy=block(jj(1,1),jj(1,1));
            ifxx>=yy
            x=xx;
            xx=yy;
            yy=x;
            if xx-yy<=s
                xx=xx+s/2;
                yy=yy-s/2;
            
         else
                if xx-yy<=s
                xx=xx+s/2;
                yy=yy-s/2;
                end
            end
           
                 
        block(ii(1,1),ii(1,1))==xx;
        block(jj(1,1),jj(1,1))==yy;   end
           end
           
                 
dis_img(1,count)=block
count=count+1;
end
embed_image=[]
count=1;

for i=1:size(ca,2)-1
    hori=[]
    for j=1:size(ca,1)-1
        xt=dis_img{1,count};
        xt=idct2(xt);
        hori=horzcat(hori,xt);
        count=count+1
    end
    embed_image=vertcat(embed_image,hori);
end
end

output=embed_image

error that is coming is

Brace indexing is not supported for variables of this type.

Error in watermark (line 25)
            ii=location_array{1,key(1,j)}(1,:);

Answer 1

[Image Analyst]

location_array is not a cell array or table so you cannot use curly braces. See the FAQ:

https://matlab.fandom.com/wiki/FAQ#What_is_a_cell_array.3F