1. An image processing device, comprising: a memory; and a processor coupled to the memory and configured to: obtain a plurality of images captured by an image capture device that is directed forward and moves along with a moving body, and detect a feature point of an image as being caused by light reflected from a surface of an object located inside the moving body, based on a positional relationship between the feature point among feature points in the image and feature points in at least one other image among the plurality of images, and wherein the image is from among the plurality of images, and the feature point is detected as being caused by light reflected, when the feature point exists in the image which is captured at a time when the moving body travels in a direction different from an image capture direction of the image capture device, and the positional relationship indicates the feature point in the image remains at the same position as in the at least one other image while positions of the feature points in the image changes from positions in the at least one other image.