An imaging library for a digital still camera

We describe the design and implementation of an efficient and compact image processing library for a digital still camera based on a programmable microcontroller-DSP processor. The library is designed for use in both off-line (e.g. NT based Pentium platforms) as well as on-line (microcontroller-DSP processor implementation) systems. To satisfy the constraints of embedded systems the library was designed to operate on an input image using the concept of band processing. In such a method, the input image is divided into an appropriate number of data bands (strips). The image bands are then processed separately using a pipeline of band based operators. The processed bands are then collected into a single output image. Most of the operators incorporated in the library take advantage of the band processing mechanism and operate on a stream of such image bands. This scheme not only alleviates the memory space requirements but also lends itself to multithreading and parallel processing implementations with potential for even faster performance. The library was optimized in terms of code size (31 kilobytes) and processing speed (1.98 sec. on an 1008/spl times/800 input image in the acquisition mode of operation) to meet the current requirements of a size less than 250 kilobytes and a processing speed of less than 2 seconds/image.