An image processing apparatus comprising: an image sensor that has an RGBW array including an RGB pixel which is a light receiving element corresponding to wavelength light of each RGB color and a W pixel which is a light receiving element receiving substantially all RGB wavelength light; and an image processing unit that is operable to perform image processing by converting a sensor image formed of an RGBW pixel signal output from the image sensor into a Bayer array image, wherein the image sensor has a periodic array of a unit composition formed of each RGBW pixel, and has an array in which composition ratios of each RGB pixel within the unit composition are the same as each other, the image processing apparatus being characterised in that the image processing unit comprises a demosaic processing unit operable to perform demosaic processing on the sensor image and generate each RGB image signal in which all RGB pixel values are set for each pixel position of the sensor image, wherein the demosaic processing unit has a W pixel interpolation unit operable to generate a whole W pixel image signal by calculating the W pixel value at an RGB pixel position of the sensor image; an RGBW pixel generation unit operable to generate an RGBW corresponding low frequency signal which is a low frequency component of each RGBW pixel signal at each pixel position of the sensor image; and a correlation processing unit operable to input the whole W pixel image signal and the RGBW corresponding low frequency signal, and generate each RGB pixel signal in which all RGB pixel values are set for each pixel position of the sensor image, by calculating a pixel value based on a combination of the whole W pixel image signal and the RGBW corresponding low frequency signals. an image sensor that has an RGBW array including an RGB pixel which is a light receiving element corresponding to wavelength light of each RGB color and a W pixel which is a light receiving element receiving substantially all RGB wavelength light; and an image processing unit that is operable to perform image processing by converting a sensor image formed of an RGBW pixel signal output from the image sensor into a Bayer array image, wherein the image sensor has a periodic array of a unit composition formed of each RGBW pixel, and has an array in which composition ratios of each RGB pixel within the unit composition are the same as each other, the image processing apparatus being characterised in that the image processing unit comprises a demosaic processing unit operable to perform demosaic processing on the sensor image and generate each RGB image signal in which all RGB pixel values are set for each pixel position of the sensor image, wherein the demosaic processing unit has a W pixel interpolation unit operable to generate a whole W pixel image signal by calculating the W pixel value at an RGB pixel position of the sensor image; an RGBW pixel generation unit operable to generate an RGBW corresponding low frequency signal which is a low frequency component of each RGBW pixel signal at each pixel position of the sensor image; and a correlation processing unit operable to input the whole W pixel image signal and the RGBW corresponding low frequency signal, and generate each RGB pixel signal in which all RGB pixel values are set for each pixel position of the sensor image, by calculating a pixel value based on a combination of the whole W pixel image signal and the RGBW corresponding low frequency signals.