1. An object detection apparatus mounted in a vehicle, the object detection apparatus comprising: a storage storing plural image recognition dictionaries each describing reference data for an object to be detected, and plural image recognition techniques each used to detect the object from an input image captured by an imaging unit of the vehicle with use of one of the plural image recognition dictionaries, each of the plural image recognition techniques including a different image recognition algorithm different in a recognition mechanism; a first acquirer configured to acquire an operating state of a lighting device of the vehicle; a selector configured to select, according to the operating state of the lighting device acquired by the first acquirer, one of the plural image recognition dictionaries stored in the storage and one of the plural image recognition techniques stored in the storage; a detector configured to detect the object in the input image by applying image recognition processing to the input image with use of the image recognition dictionary and the image recognition technique selected by the selector; wherein the plural image recognition dictionaries are differentiated in image brightness, contrast, color and sharpness depending on environmental conditions caused by the operating state of the lighting device of the vehicle; and each of the plural image recognition techniques include image correction in which at least one of the brightness, the contrast, the color and the sharpness of the input image is adjusted prior to application of the image recognition algorithm.
2. The apparatus of claim 1 , further comprising a second acquirer configured to acquire an operating state of a wiper of the vehicle, wherein the selector is further configured to select, according to the operating state of the lighting device acquired by the first acquirer and the operating state of the wiper acquired by the second acquirer, one of the plural image recognition dictionaries stored in the storage and one of the plural image recognition techniques stored in the storage.