  We conducted radio interferometric observations of six pulsars at 610 MHz
using the Giant Metrewave Radio Telescope (GMRT). All these objects were
claimed or suspected to be the gigahertz-peaked spectra (GPS) pulsars. For a
half of the sources in our sample the interferometric imaging provides the only
means to estimate their flux at 610 MHz due to a strong pulse
scatter-broadening. In our case, these pulsars have very high dispersion
measure values and we present their spectra containing for the first time
low-frequency measurements. The remaining three pulsars were observed at low
frequencies using the conventional pulsar flux measurement method. The
interferometric imaging technique allowed us to re-examine their fluxes at 610
MHz. We were able to confirm the GPS feature in the PSR B1823$-$13 spectrum and
select a GPS candidate pulsar. These results clearly demonstrate that the
interferometric imaging technique can be successfully applied to estimate flux
density of pulsars even in the presence of strong scattering.
