Image Signal Processor (ISP) - definition
Image signal processor, which is also known as Image Processor or Image Processing Unit renders or process the image captured by a digital or other type of camera. It is nothing but a chip specialized with various image processing algorithm to process a RAW image to machine readable compressed image. Previously, in smart phone or cameras it was a separated chip-set or IC, but nowadays it is integrated with main CPU (Central Processing Unit) or additional GPU (Graphic Processing Unit).