1. CONFIDENTIAL University of Toronto Multimedia Lab www.dsp.utoronto.ca Karl Martin kmartin@comm.utoronto.ca | www.dsp.utoronto.ca/~kmartin/ Prof. Kostas Plataniotis kostas@comm.utoronto.ca | www.dsp.utoronto.ca/~kostas/

2. CONFIDENTIALOutline  Technology Overview  Object-Based Coding  Secure Object-Based Coding  Privacy Protection Approach  Example Application Scenario  Video Demonstration 2 Secure Object-Based Coding – Visual Privacy Protection Solution – University of Toronto

3. CONFIDENTIAL Technology Overview  Coding (compression) a necessary component of most imaging systems for transmission/storage  Several standards:  Still images: JPEG, JPEG2000, etc.  Video: MPEG-(1/2/4), H.263, H.264, etc.  Object-Based Coding allows storage of arbitrarily shaped objects 3 Secure Object-Based Coding – Visual Privacy Protection Solution – University of Toronto

4. CONFIDENTIAL Shape + Texture  Object is defined by shape and texture  Benefits of object-based coding:  Allows intelligent processing of individual objects  Objects can have any semantic meaning and be of arbitrary shape  E.g.: face, body, car, suitcase, etc.  Coding schemes: MPEG-4, ST-SPIHT (UofT) Technology Overview (cont’d) 4 Secure Object-Based Coding – Visual Privacy Protection Solution – University of Toronto

5. CONFIDENTIAL  Secure Object-Based Coding  Combines encryption with object-based coding  Object texture (and optionally shape) is confidential, enforced via private key  Efficient encryption algorithm integrated into coder, supporting real-time operation  Encrypted objects completely obscured to viewers without correct private key  Provision of correct key allows perfect recovery (decryption) of coded object Technology Overview (cont’d) 5 Secure Object-Based Coding – Visual Privacy Protection Solution – University of Toronto

6. CONFIDENTIAL  Wavelet-based scheme for images and video  MPEG-4 -based scheme for video Technology Overview (cont’d) 6 Secure Object-Based Coding – Visual Privacy Protection Solution – University of Toronto Original Object Encrypted Object (texture only) Encrypted Object (texture and shape)

7. CONFIDENTIAL  Protect visual data of persons appearing in surveillance-style images/video  Treat face or full body images as objects of interest  Code and encrypt objects separate from background  Reversible – Private decryption key to decrypt face/body images provided based on appropriate authority  Background not encrypted – for “general” viewing Privacy Protection Approach 7 Secure Object-Based Coding – Visual Privacy Protection Solution – University of Toronto

8. CONFIDENTIAL Example Application Scenario 8 Secure Object-Based Coding – Visual Privacy Protection Solution – University of Toronto

9. CONFIDENTIAL Example Application Scenario (cont’d) 9 Secure Object-Based Coding – Visual Privacy Protection Solution – University of Toronto Original Sequence Protected Sequence Protected Sequence (attempted access with incorrect key)

10. CONFIDENTIALConclusion  Secure object-based coding provides privacy protection solution for images and video  Arbitrarily-shaped objects such as face/body can be coded and encrypted separate from background  Reversible encryption allows access to protected visual data with provision of secret decryption key  Efficient encryption approach supports real- time operation 10 Secure Object-Based Coding – Visual Privacy Protection Solution – University of Toronto