A field delay circuit aligns the phases of two field signals. An average
value calculation circuit generates an average value signal of the two
field signals. This average value signal can be regarded as a signal that
has undergone a one-dimensional low-pass filter process in the row
direction in which the number of taps for a progressive signal is 2 and
the filter coefficient for each tap is 0.5 and that has then been thinned
to one-half the data. A two-dimensional LPF circuit subjects this average
value signal to a low-pass filter process and eliminates the
high-frequency components (edge components). A subtraction circuit
subtracts the average value signal that has undergone the LPF process
from each field signal and thus extracts the edge components of each
field signal. An amplification circuit multiplies the edge components of
each field signal by a prescribed factor. An addition circuit adds the
resulting amplified edge components to each field signal.