Image processing apparatus, image processing method, and non-transitory computer-readable storage medium

An image processing apparatus comprising:

• one or more memories storing instructions;
• and
• one or more processors executing the instructions to:
• execute setting processing for setting a reduced region in an image;
• execute second setting processing for setting an estimation region in the image based on the reduced region;
• execute estimation processing for estimating a noise characteristic of the estimation region;
• and
• execute noise reduction processing that reduces noise in the reduced region according to a parameter based on the noise characteristic,
• wherein in the second setting processing, in a case where an overlaid region in which another image is overlaid is present in the image, the estimation region is set to a region different from the overlaid region.

An image processing method comprising:

• setting a reduced region in an image;
• setting an estimation region in the image based on the reduced region;
• estimating a noise characteristic of the estimation region;
• and
• executing noise reduction processing that reduces noise in the reduced region of the image according to a parameter based on the noise characteristic,
• wherein in the setting of the estimation region, when a surface area of the reduced region is smaller than a threshold surface area, the estimation region is set to be at least as large as the threshold surface area.

A non-transitory computer-readable storage medium having stored thereon a computer program that, when loaded and executed by a computer, causes the computer to:

• set a reduced region in an image;
• set an estimation region in the image based on the reduced region;
• estimate a noise characteristic of the estimation region;
• and
• execute noise reduction processing that reduces noise in the reduced region of the image according to a parameter based on the noise characteristic,
• wherein in the setting of the estimation region, when a surface area of the reduced region is smaller than a threshold surface area, the estimation region is set to be at least as large as the threshold surface area.