Abstract: A prosthetic processing apparatus (200) for use by a visually-impaired subject comprises at least one sensor (104) configured to capture and output physical information of a spatial field, an output interface (208) coupled to a sensory input device which is configured to apply a signal to a sensory pathway of the visually impaired subject, and a processor (202) operatively coupled to the sensor (104) and to the output interface (208). The processor (202) is configured to receive (402) the physical information of the spatial field from the sensor (104), and to process (404) the received information to identify one or more salient features of a predetermined category (such as edges, plane surfaces, human faces and/or bodies) within the spatial field.