1. An image processing method of detecting a particular imaging object from images captured by an image processing device that includes an imaging part and an irradiating part, comprising: capturing and obtaining plural captured images by the imaging part; performing a detection process to determine whether the particular imaging object is included in the plural captured images; obtaining an irradiated image captured with irradiating light by the irradiating part in an imaging direction of the imaging part and an non-irradiated image captured without irradiating light by the irradiating part, when it is determined that the particular imaging object is not included in a predetermined number of captured images among the plural captured images; comparing, by the image processing device, the irradiated image and the non-irradiated image; and judging, by the image processing device, presence/absence of the particular imaging object in a region to be captured by the imaging part on the basis of a result of the comparing of the irradiated image and the non-irradiated image.