Signal processing device and imaging device

An imaging device comprising:

• an optical system configured to change its focal distance in accordance with a wavelength of light;
• an image pickup device having an imaging surface on which an image through the optical system is formed;
• a high spatial frequency range component evaluation unit configured to evaluate a high spatial frequency range component of each of basic colors for each of divided regions for the image picked up by the image pickup device, the divided regions being obtained by dividing the imaging surface of the image pickup device into a plurality of regions;
• a subject distance estimation unit configured to estimate a subject distance for each of the divided regions on the basis of the high spatial frequency range component evaluated by the high spatial frequency range component evaluation unit;
• a filter coefficient generating unit configured to generate a filter coefficient for each of the divided regions on the basis of the subject distance estimated by the subject distance estimation unit;
• and
• a filter operation unit configured to perform a filter operation on the high spatial frequency range component by use of the filter coefficient generated by the filter coefficient generating unit,
• wherein the filter coefficient generating unit is configured to generate the same filter coefficient for adjacent divided regions when a luminance difference, a hue difference, and a chroma difference between the adjacent divided regions are all within respective predetermined ranges.