Image rotation with substantially no aliasing error

Abstract

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 dislosed. 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.

Description

BACKGROUND OF THE INVENTION [0001] 1. Technical Field [0002] The present invention relates generally to document imaging and, more particularly, to image rotation with substantially no aliasing error in the resulting image. [0003] 2. Related Art [0004] Digital imaging of documents, photographs and other objects provides numerous advantages including the ability to easily process, analyze and communicate images. One common method of creating a digital image is scanning. During scanning, a rectangular window, called an image buffer, which includes the image is typically created. An actual image is then extracted from the image buffer so further data analysis may be conducted on just the image. It is not an infrequent occurrence, however, for the object being scanned to be skewed or angled relative to the image window representation of the image buffer. During the extraction process, it therefore becomes advantageous to rotate the image to attain a properly justified replication. [0005...

AI Technical Summary

Benefits of technology

"The invention provides a method, system, and computer program product for rotating images without creating aliasing errors. This is achieved by extracting image data from the buffer and creating a rotated image using weighted sums of data points based on the skew angle of the image and the location of data points. This results in a more accurate and high-speed image rotation process that reduces data storage space requirements."

Problems solved by technology

Present extraction processes are often inadequate for creating accurate replications of images after rotation because the extraction process imposes mistakes in the images.

Current correction methods for these mistakes are inadequate, processor intensive and time consuming.

Another challenge faced by users of digital imaging is to balance the desire to retain details in images while minimizing storage space for images.

Data compression techniques, for example JPEG, have been developed to increase the ability to retain details, but reduction of data storage remains a problem.

Images