The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 05, 1991
Filed:
Nov. 03, 1989
Shepard L Siegel, Derry, NH (US);
Datacube Inc., Peabody, MA (US);
Abstract
The invention provides a method and apparatus for performing image data compression. Initially, a two-dimensional block of image data in a spatial domain is transformed by a transform coder, resulting in a two-dimensional array of activity coefficients in a frequency domain. The array is then serialized and quantized, yielding a one-dimensional array of coefficients with a leading coefficient and an original trailing coefficient. Next, a portion of the array is selected by choosing a new trailing coefficient based on a setable ratio of the energy of the new short array to the energy of the original array. Lastly, an end-of-block symbol is appended after the new trailing coefficient, and the selected portion of the array is encoded using an entropy coder. The invention allows image data to enjoy enhanced compression with good image fidelity, and allows image fidelity to degrade gracefully in trade for higher degrees of image compression.