In a vehicle air conditioning system, a cold accumulator is disposed between a downstream air side of a cooling heat exchanger and an upstream air side of an air mixing door, to be cooled by cold air having passed through the cooling heat exchanger. In one embodiment, methods and systems to generate image fingerprints are provided. Each guiding member includes a guiding surface and a distance between the guiding surfaces decreases from an upper end to a lower end of each guiding member.