  Designed at the Crimean Astrophysical Observatory the SL-method of stellar
magnetic field measurement is based on the calculation of the distance between
the centers of gravity of the left and right circularly polarized components of
the spectral line. The SL-method is free from the limitations of the
LSD-method, namely its requirement for weak magnetic fields, weak spectral
lines, the same shape of polarized profiles. Also, this method is free from
model limitations of the PCA, NDD and ZCD methods also. The SL-method involves
the calculation of the magnetic field using individual spectral lines and the
subsequent formation of uniform arrays of the magnetic field measurements. The
formation of the arrays is based on different criteria, e.g. using spectral
lines of a chemical element, assumption of the same physical conditions in the
areas of the spectral line formation, a statistically significant difference
between the values of the magnetic field calculated from different arrays of
spectral lines etc. If there are several arrays of spectral lines, it is
necessary to obtain normalized polarized profiles using predetermined
parameters for each array: the magnitude of the field, wavelength for
normalization, Lande factor and the central residual intensity of the line. In
this paper, we present a method of normalization of polarized profiles based on
the dependence of the residual intensity of the observed polarized profiles on
their central residual intensity (COntour Algorithm of the Line Approximation:
COALA). The SL and COALA methods strong depend on the signal-to-noise ratio and
a number of used unblended spectral lines. In this work the application of the
proposed method is demonstrated for synthetic polarized spectra and for
circularly polarized spectra of the yellow subgiant $\beta$ Aql (Sp G8 IV)
obtained on 2014 October 06.
