Invention Grant
- Patent Title: Method for lossless digital shearing and rotation with fine angular increments
- Patent Title (中): 无损数字剪切和精细角度增量旋转的方法
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Application No.: US12920217Application Date: 2010-02-10
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Publication No.: US08639059B2Publication Date: 2014-01-28
- Inventor: Andrew Batrac
- Applicant: Andrew Batrac
- International Application: PCT/IB2010/050616 WO 20100210
- International Announcement: WO2011/007265 WO 20110120
- Main IPC: G06K9/36
- IPC: G06K9/36 ; G06K9/32 ; G09G5/00

Abstract:
The present invention discloses methods for lossless shearing and/or rotation of two-dimensional (2D) data, including digital images, with minute discrete angular increments, carried out only by permutations in the Fourier frequency domain, by exploiting the natural shear occurring as a result of computing a single one-dimensional discrete Fourier transform (DFT) of 2D arrays. Rotations in general, especially for oblong arrays, occur on elliptical paths. Circular rotation, by an angle of arctan(1/width), is achieved on square arrays. When each dimension is multiple of a smaller N, the rotation/shear angle can be increased to arctan(2N/width). Rotation steps can be repeated in long, animation-like series, with neither loss nor degradation of the Fourier content; so much so that tracing the steps back does restore the original data with remarkable precision.
Public/Granted literature
- US20110221778A1 METHOD FOR LOSSLESS DIGITAL SHEARING AND ROTATION WITH FINE ANGULAR INCREMENTS Public/Granted day:2011-09-15
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