1. A detection device comprising: an image acquisition section that acquires an image that has been captured by an imaging section, and includes an image of an object; a distance information acquisition section that acquires distance information based on a distance from the imaging section to the object when the imaging section has captured the image; a feature quantity calculation section that calculates a feature quantity from the acquired image, the feature quantity relating to at least one of a color, a brightness, a color difference, and a spectrum of the object; a learning feature quantity storage section that stores a learning feature quantity calculated by a learning process based on the distance from the imaging section to the object; and a detection section that detects a target area from the image based on the learning feature quantity, the distance information, and the feature quantity, the learning feature quantity storage section storing the learning feature quantity based on the feature quantity that has been subjected to a correction process based on the distance information, and the detection section performing the correction process on the feature quantity calculated by the feature quantity calculation section based on the distance information acquired by the distance information acquisition section, and detecting the target area based on the feature quantity that has been subjected to the correction process, and the learning feature quantity.