Hemoglobin is one
of the most important blood elements,
and its
optical properties will determine all other optical properties of
human blood. Since the refractive index (RI) of hemoglobin plays a
vital role as a non-invasive indicator of some illnesses, accurate
calculation of it would be of great importance. Moreover, measurement
of the RI of hemoglobin in the laboratory is time-consuming and expensive;
thus, developing a smart approach to estimate this parameter is necessary.
In this research, four viable strategies were used to make a quantitative
correlation between the RI of hemoglobin and its influencing parameters
including the concentration, wavelength, and temperature. First, alternating
conditional expectations (ACE), a statistical approach, was employed
to generate a correlation to predict the RI of hemoglobin. Then, three
different optimized intelligent techniques—optimized neural
network (ONN), optimized fuzzy inference system (OFIS), and optimized
support vector regression (OSVR)—were used to model the RI.
A bat-inspired (BA) algorithm was embedded in the formulation of intelligent
models to obtain the optimal values of weights and biases of an artificial
neural network, membership functions of the fuzzy inference system,
and free parameters of support vector regression. The coefficient
of determination, root-mean-square error, average absolute relative
error, and symmetric mean absolute percentage error for each of the
ACE, ONN, OFIS, and OSVR were found as the measure of each model’s
accuracy. Results showed that ACE and optimized models (ONN, OFIS,
and OSVR) have promising results in the estimation of hemoglobin’s
RI. Collectively, ACE outperformed ONN, OFIS, and OSVR, while sensitivity
analysis indicated that the concentration, wavelength, and, lastly,
temperature would have the highest impact on the RI.