1. An image processing method, comprising: an inputting step of inputting an image data which is obtained by imaging a subject for a predetermined period of time with a medical imaging apparatus and is arranged in time series; an extracting along a time axis step of extracting pixels which satisfy a predetermined condition along a time axis from all the pixels arranged in time series for each pixel coordinate position with respect to each pixel in the image data; and a constructing step of constructing a two-dimensional or three-dimensional image based on the pixels extracted along the time axis in the extracting along the time axis step.