Abstract: An adapter device is provided for connection to a printer and an image input device, such as a document scanner or digital camera, that enables the printer to operate as a digital copier for image data received from the image input device. The adapter device includes an input/output controller, memory and a processor. The input/output controller controls the exchange of information with the printer and with the image input device. The memory buffers input device driver software for the image input device and printer driver software for the printer, and also stores image data output by the image input device. The processor is responsive to commands made from a control panel to initiate operation of the image input device under control of the input device driver software. The processor also processes image data from the image input device under control of the printer driver software and generates printer data to be printed by the printer.

Abstract: A dispersed-dot stochastic dither array is provided for rendering halftone images having excellent visual quality and are created by a minimum density variance method. The minimum density variance method considers the statistical distribution of the pixels in the image, and is unrelated to previous techniques based on either spatial frequencies or spatial distances, such as the blue noise mask and the void and cluster algorithm. By minimizing the variance in the number of dots within each local region of the image, a smooth and dispersed distribution of dots may be obtained. The method of the present invention also offers the flexibility to accommodate particular design considerations, through the selection of the size and shape of the image regions, the weighting of the cost function, and the option of guiding the selection of dots with "target" dot profile images.