Image processing apparatus, image capturing apparatus, image processing method and storage medium storing image processing program

An image capturing apparatus comprising:

• an image sensor configured to perform image capturing through an image capturing optical system;
• and
• an image processing apparatus configured to perform an image process on a first image produced by using output from the image sensor,
• wherein the image processing apparatus comprises:
• a memory storing coefficient data containing coefficients to be used in an approximation function to approximate a point spread function of the image capturing optical system, the coefficients having values different depending on an optical state of the image capturing optical system;
• and
• a processor configured to perform the image process,
• wherein the processor is configured to:
• produce, as the image process, an approximated point spread function by using (a) the coefficient of the coefficient data corresponding to the optical state in the image capturing and (b) two of a pixel pitch of an image sensor used for the image capturing, a kernel size of a filter to be used for a sharpening process on the first image and number of taps of the filter;
• produce the filter by using the approximated point spread function;
• and
• produce a second image that is a sharpened image by applying the filter to the first image.

An image processing method configured to perform an image process on a first image produced by image capturing through an image capturing optical system, the method comprising:

• providing coefficient data containing coefficients to be used in an approximation function to approximate a point spread function of the image capturing optical system, the coefficients having values different depending on an optical state of the image capturing optical system;
• and
• performing the image process,
• wherein the image process comprises:
• producing an approximated point spread function by using (a) the coefficient of the coefficient data corresponding to the optical state in the image capturing and (b) two of a pixel pitch of an image sensor used for the image capturing, a kernel size of a filter to be used for a sharpening process on the first image and number of taps of the filter;
• producing the filter by using the approximated point spread function;
• and
• producing a second image that is a sharpened image by applying the filter to the first image.

A non-transitory computer-readable storage medium storing an image processing program as a computer program configured to cause a computer to:

• provide coefficient data containing coefficients to be used in an approximation function to approximate a point spread function of an image capturing optical system, the coefficients having values different depending on an optical state of the image capturing optical system;
• and
• perform the image process,
• wherein the image process comprises:
• producing an approximated point spread function by using (a) the coefficient of the coefficient data corresponding to the optical state in the image capturing and (b) two of a pixel pitch of an image sensor used for the image capturing, a kernel size of a filter to be used for a sharpening process on the first image and number of taps of the filter;
• producing the filter by using the approximated point spread function;
• and
• producing a second image that is a sharpened image by applying the filter to the first image.