A computer is configured to acquire first region information indicating a region of an object in an input image, the first region information being output from a first object detection model used by a first object detection device, acquire an attribute of the object, cause the first object detection device to output output data including second region information obtained by changing the first region information by a predetermined amount for a trigger object having the attribute satisfying a condition defined as a trigger, and makes it difficult for a cloner to notice and suppressing a loss of functionality in object detection.