  Context: The study of stellar structure and evolution depends crucially on
accurate stellar parameters. The photometry from space telescopes has provided
superb data that allowed asteroseismic characterisation of thousands of stars.
However, typical targets of space telescopes are rather faint and complementary
measurements are difficult to obtain. On the other hand, the brightest,
otherwise well-studied stars, are lacking seismic characterization. Aims: Our
goal is to use the granulation and/or oscillation time scales measured from
photometric time series of bright red giants (1.6$\leq$Vmag$\leq$5.3) observed
with BRITE to determine stellar surface gravities and masses. Methods: We use
probabilistic methods to characterize the granulation and/or oscillation signal
in the power density spectra and the autocorrelation function of the BRITE time
series. Results: We detect a clear granulation and/or oscillation signal in 23
red giant stars and extract the corresponding time scales from the power
density spectra as well as the autocorrelation function of the BRITE time
series. To account for the recently discovered non-linearity of the classical
seismic scaling relations, we use parameters from a large sample of Kepler
stars to re-calibrate the scalings of the high- and low-frequency components of
the granulation signal. We develop a method to identify which component is
measured if only one granulation component is statistically significant in the
data. We then use the new scalings to determine the surface gravity of our
sample stars, finding them to be consistent with those determined from the
autocorrelation signal of the time series. We further use radius estimates from
the literature to determine the stellar masses of our sample stars from the
measured surface gravities. We also define a statistical measure for the
evolutionary stage of the stars.
