In a first image processing apparatus, a digital image signal representing an image before being subjected to shutting light processing, and an unsharp image signal representing an unsharp mask image used for shutting light processing are formed. The receptacle extends along a longitudinal axis and includes a pair of parallel extending spiral raceways formed in the inner surface of a central opening that extends therethrough, and a keyway formed adjacent its terminus. Stimulation and sensing include electrical, chemical or combinations thereof.