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

An image processing apparatus comprising:

• a processing unit configured to perform noise reduction processing and material decomposition processing using a plurality of images corresponding to a plurality of different radiation energies obtained by irradiating an object with radiation and performing imaging,
• wherein the processing unit
• generates a thickness image after noise reduction by applying, to a thickness image of a material obtained by the material decomposition processing, filter processing using a filter for which a coefficient is set based on a pixel value of an accumulation image obtained based on combining of the plurality of images, and
• generates an image by material re-decomposition processing using the thickness image after noise reduction and the accumulation image.

An image processing method comprising:

• performing noise reduction processing and material decomposition processing using a plurality of images corresponding to a plurality of different radiation energies obtained by irradiating an object with radiation and performing imaging,
• wherein in the performing,
• a noise reduction image is generated by applying filter processing for each frequency component obtained by resolving a thickness image of a material obtained by the material decomposition processing into a plurality of frequencies, and
• an image by material re-decomposition processing is generated using the thickness image after noise reduction, which is obtained by combining the noise reduction images for each frequency component and an accumulation image obtained based on combining of the plurality of images.