International Business Machines Corporation

Robert E Shirley

Clair Frederick Rohe

Ravi Prakash

William Wyche Plyler

Michael A Duncan

Dennis D Leak

Jeffrey E Journey

Robert R Plyler

A system, method and program product for rotating a first image in an image buffer such that the resulting, rotated image is substantially free of an aliasing error, i.e., broken lines, stair stepped edges, etc., is disclosed. An algorithm is applied to the first image that uses weighted sums of data points of the first image to create the rotated image. The weighting is based on the skew angle and data point location of the first image. The resulting rotated image also has a reduced data storage space requirement compared to rotated images created by prior art techniques.

Image rotation with substantially no aliasing error

A peripheral interface device that is adaptable into a computer system and which provides a communication interface for a plurality of external devices. The peripheral interface device comprises: a plurality of transfer control logic (TCL) modules, wherein each TCL module provides a dedicated interface for an associated one of the external devices, and wherein multiple TCL modules can communicate in parallel with their associated external devices; and a dual port memory (DPM) device that is in communication with an input/output bus of the computer system, wherein the DPM device can selectively communicate with each of the plurality of TCL modules.

Peripheral interface system having dedicated communication channels

An image represented by an array of digitally valued picture elements is selectively reduced or expanded in size by the extraction or insertion of spaced apart rows and lines of picture elements, at positions which are the closest approximation to the newly scaled base, whether smaller or larger. In reproducing a given image, for example, the image may be concurrently or successively scanned by an array of photo detector elements and a plurality of digitally valued picture elements corresponding to grey scale values across the image, and distributed with a given resolution, may be generated. These values may be processed in real time, or stored in a comparable array for subsequent processing. In either event, the number of rows and lines in the array are modified in accordance with the desired scale factor, and these discrete changes are introduced at the closest approximation to optimum positions. In enlargement, the added lines are duplicative of the next adjacent line, whereas in reduction the lines are simply deleted and subsequent lines of picture elements are shifted to close the gaps and provide a continuous image. A dot generator array, such as an ink jet array, responsive to the digital values of the picture elements, operates in scanning fashion across a copy sheet and generates the image, at a modified scale factor in a single or in successive scans, which may occur at the same location or after transmission of the digitally valued picture data to a different location. However, other conventional image reproducing systems such as a cathode ray tube, electrostatic or thermal recording system may be utilized.

System and method for generating enlarged or reduced images

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Charlotte, NC, United States of America

Robert E Shirley