Image processing apparatus, image pickup apparatus, lens apparatus, image processing method, and storage medium for correcting color shading in image data

A lens apparatus attachable to and detachable from an image pickup apparatus, the lens apparatus comprising:

• an optical system;
• a memory configured to store color shading information according to a characteristic of the optical system for use with a correction of color shading in image data acquired by the image pickup apparatus;
• and
• a communicator configured to communicate with the image pickup apparatus,
• wherein the communicator transmits the color shading information stored in the memory to the image pickup apparatus according to a request from the image pickup apparatus,
• wherein the image data corresponds to an optical image that has passed through an optical filter that separates light that has passed through the optical system into a first color component, a second color component, and a third color component,
• wherein the color shading information includes information regarding a value of the first color component, a value of the second color component, and a value of the third color component, and differs according to a focal length of the optical system, and
• wherein the color shading information is calculated using values of a spectral transmittance of each image height in the optical system,
• wherein the color shading information is calculated using a measurement value of a spectral transmittance of the optical system, a spectral transmittance of the optical filter, and a spectral distribution of a light source.

An image processing method comprising the steps of:

• acquiring image data, and
• correcting color shading in the image data using color shading information according to a characteristic of an optical system,
• wherein the image data corresponds to an optical image that has passed through an optical filter that separates light that has passed through the optical system into a first color component, a second color component, and a third color component,
• wherein the color shading information includes information regarding a value of the first color component, a value of the second color component, and a value of the third color component, and differs according to a focal length of the optical system, and
• wherein the color shading information is calculated using values of a spectral transmittance of each image height in the optical system,
• wherein the color shading information is calculated using a measurement value of a spectral transmittance of the optical system, a spectral transmittance of the optical filter, and a spectral distribution of a light source.

An image processing apparatus comprising:

• a memory storing instructions;
• and
• processor configured to execute the instructions to:
• acquire image data, and
• correct color shading in the image data using color shading information according to a characteristic of an optical system,
• wherein the image data corresponds to an optical image that has passed through an optical filter that separates light that has passed through the optical system into a first color component, a second color component, and a third color component,
• wherein the color shading information includes information regarding a value of the first color component, a value of the second color component, and a value of the third color component, and differs according to a focal length of the optical system, and
• wherein the color shading information is calculated using values of a spectral transmittance of each image height in the optical system,
• wherein the color shading information is calculated using a numerical simulation value of a spectral transmittance of the optical system, a spectral transmittance of the optical filter, and a spectral distribution of a light source.