An object tracking method comprising: detecting a target object in a first-type input image that is based on light in a first wavelength band; tracking the target object in the first-type input image based on detection information of the target object and by selecting a first tracker corresponding to a measured quality of the first-type input image from among multiple trackers , wherein the first tracker is trained using images that are captured using light of the first wavelength band and that have a quality that is specific for the first tracker , and providing the first-type input image to the first tracker ; measuring a reliability of the first-type input image by comparing the first-type input image to at least one image stored in a first database, DB ; and when the reliability of the first-type input image is lower than a first threshold, controlling at least one of a light source and camera and switching a first modality referring to an operation associated with the first wavelength band to a second modality referring to an operation associated with a second wavelength band different from the first wavelength band to track the target object in a second-type input image based on light in the second wavelength band using the detection information and by selecting a second tracker corresponding to a measured quality of the second-type input image from among multiple trackers , wherein the second tracker is trained using images that are captured using light of the second wavelength band and that have a quality that is specific for the second tracker , and providing the second-type input image to the second tracker . detecting a target object in a first-type input image that is based on light in a first wavelength band; tracking the target object in the first-type input image based on detection information of the target object and by selecting a first tracker corresponding to a measured quality of the first-type input image from among multiple trackers , wherein the first tracker is trained using images that are captured using light of the first wavelength band and that have a quality that is specific for the first tracker , and providing the first-type input image to the first tracker ; measuring a reliability of the first-type input image by comparing the first-type input image to at least one image stored in a first database, DB ; and when the reliability of the first-type input image is lower than a first threshold, controlling at least one of a light source and camera and switching a first modality referring to an operation associated with the first wavelength band to a second modality referring to an operation associated with a second wavelength band different from the first wavelength band to track the target object in a second-type input image based on light in the second wavelength band using the detection information and by selecting a second tracker corresponding to a measured quality of the second-type input image from among multiple trackers , wherein the second tracker is trained using images that are captured using light of the second wavelength band and that have a quality that is specific for the second tracker , and providing the second-type input image to the second tracker . <EOS>