Image processing apparatus, image pickup apparatus, storage medium for storing image processing program, and image processing method

A storage medium for storing an image processing program for causing a computer to process RGB Bayer array image data obtained from an image pickup device of an RGB Bayer array, the image processing program being for causing the computer to execute:

• a noise reduction step of applying noise reduction to the RGB Bayer array image data for each of RGB channels with a first noise reduction amount, and calculating first noise-reduced RGB Bayer array image data, and also applying the noise reduction to at least the G channel with a second noise reduction amount smaller than the first noise reduction amount, and calculating second noise-reduced G-channel image data;
• a color difference calculation step of calculating first noise-reduced color difference data (R−G) at a position of R and first noise-reduced color difference data (B−G) at a position of B, based on the first noise-reduced RGB Bayer array image data;
• and
• an RGB calculation step of calculating R image data, G image data and B image data at respective pixel positions, based on the first noise-reduced color difference data (R−G) and (B−G), and the second noise-reduced G-channel image data.

An image processing method of processing RGB Bayer array image data obtained from an image pickup device of an RGB Bayer array, comprising:

• a noise reduction step of applying noise reduction to the RGB Bayer array image data for each of RGB channels with a first noise reduction amount, and calculating first noise-reduced RGB Bayer array image data, and also applying the noise reduction to at least the G channel with a second noise reduction amount smaller than the first noise reduction amount, and calculating second noise-reduced G-channel image data;
• a color difference calculation step of calculating first noise-reduced color difference data (R−G) at a position of R and first noise-reduced color difference data (B−G) at a position of B, based on the first noise-reduced RGB Bayer array image data;
• and
• an RGB calculation step of calculating R image data, G image data and B image data at respective pixel positions, based on the first noise-reduced color difference data (R−G) and (B−G), and the second noise-reduced G-channel image data.