1. An image processing apparatus comprising: a first correction unit configured to perform correction processing of subtracting a first dark image obtained in a state without radiation irradiation from an object image, thereby removing a dark component of the object image; an evaluation value obtaining unit configured to obtain an evaluation value by a varying dark component included in a corrected image that has undergone the correction processing based on the first dark image and a second dark image obtained after the first dark image; and a second correction unit configured to perform correction processing of removing the varying dark component from the corrected image based on the evaluation value.