An imaging apparatus and method provides a wide dynamic range and is capable
of
displaying an improved color in low-luminance regions, and an image signal processing
method thereof. In the imaging apparatus, a first process divides the voltage level
of an analog image signal into a plurality of sections and amplifies the analog
image signal with a plurality of different gains according to each section, and
a second process converts the analog image signal amplified with the different
gains into a digital signal, and non-linearly gamma-corrects the digital signal
according to each section. The plurality of different gains may be inversely proportional
to the luminance level of the analog image signal. Thus, the level of an analog
signal in a low-luminance region is amplified with a gain greater than in a high-luminance
region before gamma correction, so that signal-to-noise (S/N) ratio in the low-luminance
region of an image is increased, thereby improving sensitivity of the image following
gamma correction. Accordingly, a wide dynamic range is provided. An optional chrominance
controller of the imaging apparatus controls chrominance gain of the digital signal
and outputs the result, thereby displaying an improved color in low-luminance regions
of the image.
