A computer performs a process to determine whether an object is a predetermined object and a process to control a display unit to generate a first image based on a result of recognized object at a first timing and generate a second image based on a result of the recognized object at a second timing that is later than the first timing if the predetermined object is determined. The first image is an image formed by a pattern of markers representing a skeleton of the object, and the second image is an image formed by a pattern of markers corresponding to the pattern of markers in the first image, and the position of at least one marker of the pattern of markers in the first image differs from the position of the corresponding marker in the second image.