Hello dear..., all.

I have a basic question.

I can't understand how to calculate value of "ppf".

An age-dependent differential pathlength factor (DPF) was computed for each participant, I think.

I used default value of ppf "1", and it run without any problem.

Although I wonder if it's okay to keep the default.

Kind regards,

Sae

As for above question,

I have understood by checking some articles etc... .

Thank you.

Sae

Excellent. For the benefit of others, can you paste the citation here of the article you read? Thanks

Here is a Matlab code for working out DPF (which can be entered as a substitute for PPF in Homer3, due to a lack of PVF values)

The example here is for ages 18-30 and wavelengths 780nm and 850nm but you can play around with the parameters to suit your data

% Define the wavelength values lambda1 = 780; % Wavelength in nm lambda2 = 850; % Wavelength in nm % Define the age range ages = 18:30; % Ages from 18 to 30 % Initialize arrays to store DPF values for both wavelengths DPF_780nm = zeros(size(ages)); DPF_850nm = zeros(size(ages)); % Parameters for the DPF calculation a = 223.3; b = 0.05624; c = 0.8493; d = -5.723E-7; e = 0.001245; f = -0.9025; % Calculate DPF for each age at both wavelengths for i = 1:length(ages) A = ages(i); DPF_780nm(i) = a + b * A^c + d * lambda1^3 + e * lambda1^2 + f * lambda1; DPF_850nm(i) = a + b * A^c + d * lambda2^3 + e * lambda2^2 + f * lambda2; end % Display the results disp('Age DPF (780nm) DPF (850nm)'); disp([ages', DPF_780nm', DPF_850nm']); Age DPF (780nm) DPF (850nm) % Define the wavelength values lambda1 = 780; % Wavelength in nm lambda2 = 850; % Wavelength in nm % Define the age range ages = 18:30; % Ages from 18 to 30 % Initialize arrays to store DPF values for both wavelengths DPF_780nm = zeros(size(ages)); DPF_850nm = zeros(size(ages)); % Parameters for the DPF calculation a = 223.3; b = 0.05624; c = 0.8493; d = -5.723E-7; e = 0.001245; f = -0.9025; % Calculate DPF for each age at both wavelengths for i = 1:length(ages) A = ages(i); DPF_780nm(i) = a + b * A^c + d * lambda1^3 + e * lambda1^2 + f * lambda1; DPF_850nm(i) = a + b * A^c + d * lambda2^3 + e * lambda2^2 + f * lambda2; end % Display the results disp('Age DPF (780nm) DPF (850nm)'); disp([ages', DPF_780nm', DPF_850nm']); Age DPF (780nm) DPF (850nm) 18.0000 5.8768 4.8786 19.0000 5.9075 4.9094 20.0000 5.9381 4.9399 21.0000 5.9683 4.9702 22.0000 5.9984 5.0003 23.0000 6.0283 5.0302 24.0000 6.0580 5.0599 25.0000 6.0875 5.0894 26.0000 6.1168 5.1187 27.0000 6.1460 5.1478 28.0000 6.1749 5.1768 29.0000 6.2038 5.2056 30.0000 6.2325 5.2343