SIGNAL PROCESSING DEVICE, SIGNAL PROCESSING METHOD, AND IMAGING DEVICE

An input signal for each of three primary color components is converted into a luminance signal and a color signal by a color space conversion part 11. A gain setting part 12 sets a gain for the color signal obtained by color space conversion according to a signal level of a setting reference signal generated on the basis of the input signal, for example, the luminance signal. A gain adjustment part 14 performs gain adjustment of the color signal with the gain set by the gain setting part 12, and in a case where the luminance signal is larger than a threshold set according to a dynamic range for each color component, the gain adjustment part 14 makes the subject achromatic so that, even in a case where a light amount of the subject is high, influence of a difference in the dynamic range is little.