Image-signal processing unit

An image-signal processing unit comprising:

• a receiver that receives an image signal from an imaging device, said imaging device comprising a plurality of pixels on the light-receiving surface, each of said pixels being covered with one of four color filters, said four color filters each passing one of four different complementary colors, said pixels generating a complementary color signal component according to the amount of light passing through said covering color filter, said image signal comprising a plurality of said complementary color signal components;
• a first luminance calculation block that calculates wide-band luminance by summing four of said complementary color signal components corresponding to said four different complementary colors;
• a primary-color signal generation block that generates primary color signal components of three primary colors based on said complementary color signal components;
• a third luminance calculation block that calculates narrow-band luminance by summing three of said primary color signal components, each multiplied by a coefficient from a third coefficient combination, for each of said pixels, based on said image signal, wherein the ratio of the coefficient by which the first primary color signal component is multiplied, to the coefficient by which the second primary color signal component is multiplied, is lower than the ratio in the first coefficient combination, said wide-band luminance corresponding to the sum of a plurality of primary color signal components, each multiplied by a coefficient from said first coefficient combination;
• a comparison block that compares said wide-band luminance with a threshold value;
• and
• a luminance-signal correction block that calculates a corrected luminance by subtracting said narrow-band luminance multiplied by a coefficient for multiplying from said wide-band luminance if said wide-band luminance is greater than said threshold value, said coefficient for multiplying being predetermined between zero and one.