Generation method of image restoration filter, image processing method, image pickup apparatus, image processing apparatus, and recording medium

An image processing method for correcting, through a fixed-point arithmetic, a deterioration of an image captured through an optical system using an image restoration filter that is generated by a method for generating the image restoration filter, the method for generating the image restoration filter, comprising:

• a first step of setting a target restoration gain value representative of a target restoration degree of an absolute value of an optical transfer function of the optical system, within a restoration gain limiting value calculated by dividing a maximum value operable through a fixed-point arithmetic by a data point number of the optical transfer function;
• and
• a second step of generating, through the fixed-point arithmetic, a frequency characteristic of the image restoration filter based on the target restoration gain value set by the first step.

An image processing apparatus configured to generate an image restoration filter used to correct a deterioration of an image captured through an optical system, the image processing apparatus comprising:

• a controller configure to set a target restoration gain value representative of a target restoration degree of an absolute value of an optical transfer function of the optical system, within a restoration gain limiting value calculated by dividing a maximum value operable through a fixed-point arithmetic by a data point number of the optical transfer function;
• and
• an image processor configured to generate, through the fixed-point arithmetic, a frequency characteristic of the image restoration filter based on the target restoration gain value set by the controller.

A non-transitory computer-readable medium configured to store a method for generating an image restoration filter used to correct a deterioration of an image captured through an optical system, the method comprising:

• a first step of setting a target restoration gain value representative of a target restoration degree of an absolute value of an optical transfer function of the optical system, within a restoration gain limiting value calculated by dividing a maximum value operable through a fixed-point arithmetic by a data point number of the optical transfer function;
• and
• a second step of generating, through the fixed-point arithmetic, a frequency characteristic of the image restoration filter based on the target restoration gain value set by the first step.