Sketch – An investigation into feature extraction in compressed domain / Kazuki Minemura
The recent advancements of multimedia signal processing techniques enable us to conveniently edit/modify multimedia contents, which are usually available in the compressed form for transmission and storage purposes. Among the compression standards, JPEG for still image and H.264/AVC for video are...
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| Format: | Thesis |
| Published: |
2017
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| Online Access: | http://studentsrepo.um.edu.my/7130/ http://studentsrepo.um.edu.my/7130/4/kazuki.pdf |
| _version_ | 1848773326279802880 |
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| author | Kazuki , Minemura |
| author_facet | Kazuki , Minemura |
| author_sort | Kazuki , Minemura |
| building | UM Research Repository |
| collection | Online Access |
| description | The recent advancements of multimedia signal processing techniques enable us to
conveniently edit/modify multimedia contents, which are usually available in the compressed
form for transmission and storage purposes. Among the compression standards,
JPEG for still image and H.264/AVC for video are the common formats that we handle
in our daily life. As the application of compressed image/video widens, practical
security tools for compressed image/video also become increasingly important. In that
regard, encryption is the process designed to transform a content into an unintelligible
form. Classical encryption approaches (e.g., DES, AES, RSA) handle the bitstream of a
compressed image/video directly, but this approach invalidates many features of the compressed
image/video, including hierarchical decoding and transcoding. In addition, the
computational time of conventional encryption is also high. To overcome the aforementioned
problems, the selective-encryption approach, which encrypts a subset of a compressed
content, has been pursued by many researchers. Although many were proven to
be robust against traditional cryptanalysis, the conventional selective-encryption methods
are vulnerable to non-traditional forms of attack called sketch attack. In this thesis, five
sketch attacks, i.e., four of them are based on DCT coefficients while another one exploits
the statistical features of a coding block, are proposed. Their performances are evaluated
and then compared. Furthermore, as a mean to evaluate the sketch image, an objective
evaluation metric called outline clearness assessment (OCA) is put forward. Moreover,
a selective encryption method for JPEG compressed image is put forward to address the
problem of bitstream size overhead while being robust against both the traditional and
non-traditional attacks. As an application, sketch attack is utilized as a feature extraction
process in H.264/AVC compressed video for text detection purpose. Finally, contributions
and limitations of this study are summarized, and future works are discussed. |
| first_indexed | 2025-11-14T13:40:38Z |
| format | Thesis |
| id | um-7130 |
| institution | University Malaya |
| institution_category | Local University |
| last_indexed | 2025-11-14T13:40:38Z |
| publishDate | 2017 |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | um-71302020-06-11T19:35:21Z Sketch – An investigation into feature extraction in compressed domain / Kazuki Minemura Kazuki , Minemura QA75 Electronic computers. Computer science The recent advancements of multimedia signal processing techniques enable us to conveniently edit/modify multimedia contents, which are usually available in the compressed form for transmission and storage purposes. Among the compression standards, JPEG for still image and H.264/AVC for video are the common formats that we handle in our daily life. As the application of compressed image/video widens, practical security tools for compressed image/video also become increasingly important. In that regard, encryption is the process designed to transform a content into an unintelligible form. Classical encryption approaches (e.g., DES, AES, RSA) handle the bitstream of a compressed image/video directly, but this approach invalidates many features of the compressed image/video, including hierarchical decoding and transcoding. In addition, the computational time of conventional encryption is also high. To overcome the aforementioned problems, the selective-encryption approach, which encrypts a subset of a compressed content, has been pursued by many researchers. Although many were proven to be robust against traditional cryptanalysis, the conventional selective-encryption methods are vulnerable to non-traditional forms of attack called sketch attack. In this thesis, five sketch attacks, i.e., four of them are based on DCT coefficients while another one exploits the statistical features of a coding block, are proposed. Their performances are evaluated and then compared. Furthermore, as a mean to evaluate the sketch image, an objective evaluation metric called outline clearness assessment (OCA) is put forward. Moreover, a selective encryption method for JPEG compressed image is put forward to address the problem of bitstream size overhead while being robust against both the traditional and non-traditional attacks. As an application, sketch attack is utilized as a feature extraction process in H.264/AVC compressed video for text detection purpose. Finally, contributions and limitations of this study are summarized, and future works are discussed. 2017 Thesis NonPeerReviewed application/pdf http://studentsrepo.um.edu.my/7130/4/kazuki.pdf Kazuki , Minemura (2017) Sketch – An investigation into feature extraction in compressed domain / Kazuki Minemura. PhD thesis, University of Malaya. http://studentsrepo.um.edu.my/7130/ |
| spellingShingle | QA75 Electronic computers. Computer science Kazuki , Minemura Sketch – An investigation into feature extraction in compressed domain / Kazuki Minemura |
| title | Sketch – An investigation into feature extraction in compressed domain / Kazuki Minemura |
| title_full | Sketch – An investigation into feature extraction in compressed domain / Kazuki Minemura |
| title_fullStr | Sketch – An investigation into feature extraction in compressed domain / Kazuki Minemura |
| title_full_unstemmed | Sketch – An investigation into feature extraction in compressed domain / Kazuki Minemura |
| title_short | Sketch – An investigation into feature extraction in compressed domain / Kazuki Minemura |
| title_sort | sketch – an investigation into feature extraction in compressed domain / kazuki minemura |
| topic | QA75 Electronic computers. Computer science |
| url | http://studentsrepo.um.edu.my/7130/ http://studentsrepo.um.edu.my/7130/4/kazuki.pdf |