Image interpolation circuit architecture and method for fast bi-cubic interpolation of image information

Abstract

A circuit architecture and method are provided for interpolating a first color value associated with a first color and a second color value associated with a second color for use in generating a pixel that represents a portion of a digital image, based on a third color value that is associated with a third color. Pixel data generated by a digital image sensor is serially received at a register array organized in rows and columns that correspond to pixels of interest that are used in a bicubic interpolation process. Values stored in registers of the register array are coupled to and continuously available to four (4) dot product modules and an interpolator. As the serial data arrives, it is clocked stepwise through the registers, and concurrently used by the dot product modules and interpolator to compute the first color value and the second color value. Data that reaches the end of a line of registers is moved into a corresponding shift register for temporary storage until it is needed again. Advantageously, the method may be implemented in integrated circuit hardware and using fast combinational logic with no CPU multiply operations and no floating-point operations. A particular application is in interpolating complementary colors for pixel information received from a color area sensor, such as a CCD image sensor, in a digital camera.