| dc.description.abstract | Like colour video displays and laser printers, laser photoplotters are raster scan devices. For such devices, the pixel stream representing the image must be generated in real time, and in the (scan line) order required. However, the typical size of the images photoplotters produce is an order of magnitude higher than that of video displays and laser printers, precluding the use of full-size bitmap memories. These requirements pose particular implementation problems for the raster image processor generating the pixel stream.The parallel RIP system presented here is aimed at high-resolution laser photoplotters, and features a largely scalable performance ranging from 40 to several hundred megapixels per second. It is built with standard components such as graphics microprocessors and VRAM memories. Its architecture is that of a distributed memory multiprocessor system with a global ring-like topology. And most importantly, it can be programmed using the traditional sequential programming paradigm. Only minor additions are needed to sequential graphical algorithms to be executable on the system with an arbitrary number of processors.A prototype 8-processor PRIP system has been built and tested generating printed circuit board images for a direct imaging photoplotter. The prototype exhibits a near-linear speedup with respect to a monoprocessor solution. Architectural simulations indicate that the system can be expanded to well over 10 processors. | en_US |
