An image analysis apparatus detects a periodic signal corresponding to an arrangement of a grid, which is required to reduce scattered radiation components from an object, from an image obtained by radiation imaging using the grid. The image analysis apparatus includes: a setting unit configured to set a plurality of regions on the image an obtaining unit configured to obtain statistic information of pixel values corresponding to each of the plurality of regions of the image based on the image a selection unit configured to select at least one measurement region from the plurality of regions based on the statistic information and a detection unit configured to detect the periodic signal using image data of the selected measurement region.
