Method and apparatus for coding an image object of arbitrary shape

Abstract

It is known to represent a square block of an image which has a maximum horizontal or vertical extension N as N vectors each representing one column or row, and encode it using an N×N discrete cosine transform matrix. We introduce a technique which transforms an input vector, or array, representing a portion of an arbitrarily-shaped object block in which the maximum horizontal or vertical extension is at most N, by adding to it additional padding elements, to produce a vector or array which can be encoded using an N×N discrete cosine transform. The padding maximises the number of transformed elements which are zero. We propose encoding arbitrarily-shaped objects based on this padding technique.

Description

[0001]Notice: More than one reissue application has been filed for the reissue of U.S. Pat. No. 6,718,066. The present application is a Reissue Continuation Patent Application of U.S. Reissue patent application Ser. No. 11 / 400,072, filed Apr. 6, 2006, entitled “METHOD AND APPARATUS FOR CODING AN IMAGE OBJECT OF ARBITRARY SHAPE,” now abandoned, which is a re-issue application of U.S. Pat. No. 6,718,066 (patent application Ser. No. 09 / 637,883), filed Aug. 14, 2000 and assigned to the assignee of the presently claimed subject matter.FIELD OF THE INVENTION[0002]The present invention relates to methods and apparatus for padding one or more input vectors, or a data array, representing an image object by adding components to it, to generate vector(s) or an array which can be encoded using a transform, such as a discrete cosine transform (DCT). The invention further relates to methods and apparatus for encoding the image object using the transformed vector(s) or array.BACKGROUND OF THE INVE...

AI Technical Summary

Benefits of technology

[0033]As pointed out above, since standard SA-DCT employs not just an 8×8 DCT matrix, but also DCT matrices for each value of K, it cannot be implemented using known chipsets which implement 8×8 DCT in a highly efficient manner. By contrast, the present invention can be performed using a known chipset since it uses only an 8×8 DCT. It is true that to produce the padding elements a calculation is required, and this would usually require a new chipset, but the degree of computation required to compute the padding elements may be much less (in terms of both the number of multiplications and of additions), and therefore is easier to design. By constr

Problems solved by technology

In many such applications the available bandwidth is limited, so some form of compression is required.

A disadvantage of standard SA-DCT is that since standard SA-DCT employs not just an 8×8 DCT matrix, but also DCT matrices for each value of K, it cannot be implemented using known chipsets which implement 8×8 DCT i

Images