how can I have a single number as the result of dividing two numbers?

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2NOR_Kh 2022-8-22

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评论： 2NOR_Kh 2022-8-23

matlab.mat

在 MATLAB Online 中打开

I am implementing this formula in MATLAB:

I[i], is the intensity of my signal and i is the index for each row. My code is as follow:

I attached my signal to this message.

Based on the formula, each time for specific i, I should have a number and then put it in the ith u. but in my code the result of the division is a matrix each time(xc(:,i)./diff((accum))) and I have no idea how to fix it.

M1=length(xc);  
accum1=zeros(M1,1);
accum=zeros(M1+1,1);
a=zeros(1,N);
N=200;
for i=1:N
    for j=i:N
        accum1=accum1+(xc(:,j));
    end
    accum(1:M1) = accum1;
    a(1,i)=xc(:,i)./(2*diff((accum)));
    accum1=zeros(M1,1);
    accum=zeros(M1+1,1);
end

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Chunru 2022-8-23

Can you explain the meaning of Δ in your formula?

It seems that the use of "diff" to accum produces a vector rather than a scalar.

2NOR_Kh 2022-8-23

编辑：2NOR_Kh 2022-8-23

this is the definition:

"measurements of I[i] are given by the integrated signal over a small distance, defined by the pixel size Δ and commonly related to the coherence length of the light source"

so I get that "small distance" or saying Δ as diiferentiate function.

But, now that I am thinking, my implementation is not correct. It is saying that delta or Δ is the pixel size, I am not working with pixels but does it mean that this delta is a constant?

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Answer 1

Image Analyst 2022-8-23

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https://ww2.mathworks.cn/matlabcentral/answers/1783685-how-can-i-have-a-single-number-as-the-result-of-dividing-two-numbers#answer_1030880

编辑：Image Analyst 2022-8-23

在 MATLAB Online 中打开

matlab.mat

Try this:

s = load('matlab.mat')
xc = s.xc;
[rows, columns] = size(xc)
subplot(2, 2, 1);
imshow(xc, []);
subplot(2, 2, 2);
hold on;
grid on;
for col = 1 : columns
    plot(xc(:, col), '-', 'LineWidth', 1);
end
delta = 2; % Whatever it is....
% Compute u for each column.
sumi = cumsum(xc);
for col = 1 : columns
    u = zeros(rows, 1);
    % Reinitialize
    for i = 1 : rows
        % Compute sum from i+1 to the end
        theSum = sumi(end, col) - sumi(i, col);
        u(i) = xc(i) / (2 * delta * theSum);
    end
    subplot(2, 2, 3:4);
    plot(u, '-')
    hold on
end
grid on;