Doubt in the specific line

could you please explain the following code?

k = zeros(img_h, img_w, 4);
k(:,:,1) = (fxx./((1 + fx.^2).^(3/2))).*fvr; % hor
k(:,:,2) = (fyy./((1 + fy.^2).^(3/2))).*fvr; % ver
k(:,:,3) = (f11./((1 + f1.^2).^(3/2))).*fvr; % \
k(:,:,4) = (f22./((1 + f2.^2).^(3/2))).*fvr; % / 

Wr = 0;

bla = k(:,:,1) > 0;
for y=1:img_h
    for x=1:img_w
        if(bla(y,x))  %%% I cant understand (bla(y,x))
            Wr = Wr + 1;
        end

Answer 1

[KSSV]

It is bad to ask such questions......asking to explain a specific line or a code. You have code in hand, play around with that. Print the values, run the code in debug and you can make yourself clear with the code.

bla = k(:,:,1) > 0;

In the above case bla is a logical matrix. It will have 0, and 1's. 0 where the condition >0 is not met and 1's where the condition > 0 is met.

if(bla(y,x)) 

In the above line a if condition is used, the conditon is met or if is executed if bla(x,y) is 1 or the if contion is not met.

Answer 2

[Walter Roberson]

The code

Wr = 0;
bla = k(:,:,1) > 0;
for y=1:img_h
    for x=1:img_w
        if(bla(y,x))  %%% I cant understand (bla(y,x))
            Wr = Wr + 1;
        end
    end
end

can be entirely replaced with

Wr = nnz(k(:,:,1) > 0);

You are just counting the number of places that k(:,:,1) is true.