A contour compensation circuit that generates a contour-compensated signal
by which a signal level of a contour of the object is emphasized, from an
image signal obtained by an image pickup of an object. This circuit
includes a reverse gamma controller, a contour compensation signal
generator, and a calculator. The reverse gamma controller determines a
standard channel from among the channels constituting the image signal,
and obtains a liner standard channel from the standard channel by the
reverse control. The contour compensation signal generator generates a
contour compensation signal from the liner standard channel. The control
signal generator computes a comparative value from the liner standard
channel and the contour compensation signal, and generates a control
signal based on a comparison between the comparative value and a
threshold value. The calculator computes the contour-compensated signal
based on the contour compensation and control signals, and the liner
standard channel.