1. An object detection apparatus comprising: a storage section storing a plurality of selection patterns as combinations of one of a plurality of recognition dictionaries and one of a plurality of image recognition algorithms, each of the recognition dictionaries describing reference data of a detection object, each of the recognition algorithms being for recognizing the detection object within an input image based on the recognition dictionaries; a processor operable as a specifying unit specifying at least one of a distance from a position of a vehicle on which the object detection apparatus is mounted to a target corresponding to the detection object within the input image and a state of light of the input image; the processor operable as a selection unit selection one from the plurality of the selection patterns based on at least one of the distance from the position of the vehicle to the target and the state of the light specified by the specifying unit; and the processor operable as a detection unit detecting the detection object within the input image by performing an image recognition process using the image recognition dictionary and the image recognition algorithm included in the selection pattern selected by the selection unit; wherein the distance to the target is estimated based on a position of a lowermost part of the input image corresponding to the target relative to a position of a vanishing point of the input image.