METHOD AND SYSTEM FOR SECURE CODING OF ARBITRARILY SHAPED VISUAL OBJECTS

• US 20110158470A1
• Filed: 06/19/2009
• Published: 06/30/2011
• Est. Priority Date: 08/11/2008
• Status: Abandoned Application

• Current Assignee: The Governing Council of the University of Toronto (University of Toronto)
• Original Assignee: The Governing Council of the University of Toronto (University of Toronto)
• Inventors: Martin, Karl, Plataniotis, Konstantinos
• Application Number:
  US13/002,192
• Publication Number:
  US 20110158470A1
• Time in Patent Office: Days
• US Class Current: 382/100
• CPC Class Codes: H04N 19/20 using video object coding
• CPC Class Codes: H04N 19/467 characterised by the embedded information being invisible, e.g. watermarking
• CPC Class Codes: H04N 19/647 using significance based coding, e.g. Embedded Zerotrees of Wavelets [EZW] or Set Partitioning in Hierarchical Trees [SPIHT]

Abstract

The present invention relates to a method and system for secure coding of arbitrarily shaped visual objects. More specifically, a system and method are provided for encoding an image, characterized by the steps of selecting one or more objects in the image from the background of the image, separating the one or more objects from the background, and compressing and encrypting, or facilitating the compression and encryption, by one or more computer processors, each of the one or more objects using a single coding scheme. The coding scheme also is operable to decrypt and decode each of the objects.

Claims

1. A computer implementable method for securely encoding an image, characterized by the steps of:

a. selecting one or more objects in the image from the background of the image;

b. separating the one or more objects from the background; and

c. compressing and encrypting, or facilitating the compression and encryption, by one or more computer processors, each of the one or more objects using a single coding scheme.

2. The method of claim 1, characterized in that the one or more objects can be decrypted and decoded using the single coding scheme.

3. The method of claim 1, characterized in that the selection of the one or more objects defines a shape mask, the shape mask enabling the compression and encryption of the one or more objects differently than the background.

4. The method of claim 1, characterized in that at least two objects are selected, wherein the single coding scheme is configurable and is applied differently for at least two of the objects.

5. The method of claim 1, characterized in that the one or more objects are arbitrarily shaped.

6. The method of claim 1, characterized in that the background is viewable without requiring decryption and decompression of all of the one or more objects.

7. The method of claim 1, characterized in that the one or more objects include texture and shape, wherein the single coding scheme is configurable and is applied differently to the texture and shape.

8. The method of claim 1, characterized in that the image is one of a plurality of related images defining an image sequence, wherein the single coding scheme is configurable and wherein for each particular object the same coding scheme configuration is applied in each related image.

9. A computer implementable method for encoding an image using a secure ST-SPIHT (Shape and Texture Set Partitioning in Hierarchical Tree) scheme, characterized by the steps of:

a. selecting an object from the image;

b. obtaining in a first color space a matrix of color texture samples of the image;

c. obtaining a shape mask of spatial positions inside the object and outside the object;

d. converting the matrix to a converted matrix in a second color space and applying the shape mask to the converted matrix;

e. transforming the converted matrix to a transformed matrix using a shape-adaptive discrete wavelet transform;

f. coding, or facilitating the coding, by one or more computer processors, the transformed matrix and the shape mask with a ST-SPIHT coder to produce a unified embedded output bit-stream; and

g. selectively encrypting the output bit-stream using a stream cipher applied to individual bits using a private key.

10. The method of claim 9, characterized in that the first color space is RGB and the second color space is YC_bC_r.

11. The method of claim 9, characterized in that the spatial positions inside the object are represented in the shape mask by “

1” and

the spatial positions outside the object are represented in the shape mask by “

0”

.

12. The method of claim 9, characterized in that the ST-SPIHT scheme codes both the shape and the texture of an image in parallel to produce one unified embedded output bit-stream.

13. The method of claim 9, characterized in that the ST-SPIHT scheme produces either a lossy or lossless code, as chosen by a user.

14. The method of claim 9, characterized in that the level of output bit-stream encryption is controlled by a user.

15. The method of claim 9, characterized in that the ST-SPIHT coder may be instructed not to code the shape mask.

16. The method of claim 9, characterized in that the output bit-stream may be encrypted at any time once coded by the ST-SPIHT coder.

17. The method of claim 9, characterized in that complete recovery of the image is achieved with a correct decryption private key.

18. A computer implementable method for decoding an image using a secure ST-SPIHT (Shape and Texture Set Partitioning in Hierarchical Tree) scheme, characterized by the steps of:

h. decrypting an output bit-stream using a stream cipher applied to individual bits using a private key;

i. decoding, or facilitating the decoding, by one or more computer processors, the bit-stream using a ST-SPIHT decoder to provide incremental instructions to the decryption stream cipher as to which bits to decrypt, and obtain a transformed matrix and a shape mask;

j. inverse transforming the transformed matrix to a converted matrix in a second color space using an inverse shape-adaptive discrete wavelet transform; and

k. converting the converted matrix to a matrix in a first color space for representing color texture samples of the image.

19. The method of claim 18, characterized in that an unencrypted portion of the output bit-stream cannot be decoded without the private key since the decoder requires complete knowledge of a prior encrypted portion of the output bit-stream.

20. A computer system for securely encoding an image, the computer system comprising one or more computers configured to provide, or provide access to, a secure coding and decoding utility, the secure coding and decoding utility characterized in that it is operable to:

l. select one or more objects in the image from the background of the image;

m. separate the one or more objects from the background; and

n. compress and encrypt, or facilitate the compression and encryption, by one or more computer processors, each of the one or more objects using a single coding scheme.

21. The system of claim 20, further characterized in that the secure coding and decoding utility is operable to decrypt and decode each of the one or more objects using the single coding scheme.

22. The system of claim 20, characterized in that the selection of the one or more objects defines a shape mask, the shape mask enabling the compression and encryption of the one or more objects differently than the background

23. A computer program product for securely encoding an image, the computer program product comprising computer instructions and data which when made available to one or more computer processors configure the one or more computer processors to provide a secure encoding and decoding utility, the secure encoding and decoding utility characterized in that it is operable to:

o. select one or more objects in the image from the background of the image;

p. separate the one or more objects from the background; and

q. compress and encrypt, or facilitating the compression and encryption, by one or more computer processors, each of the one or more objects using a single coding scheme.

24. The computer program product of claim 23, characterized in that the secure encoding and decoding utility is operable to decrypt and decode each of the one or more objects using the single coding scheme.

25. The computer program product of claim 23, characterized in that the selection of the one or more objects defines a shape mask, the shape mask enabling the secure coding and decoding utility to securely encode the one or more objects differently than the background.