The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

Touradj Ebrahimi - One of the best experts on this subject based on the ideXlab platform.

  • New approach to JPEG 2000 compliant region of interest coding,” SPIE 46 th Annual Meeting
    2014
    Co-Authors: Diego Santa-cruz, Touradj Ebrahimi
    Abstract:

    Region Of Interest (ROI) coding is one of the innovative functionalities supported by JPEG 2000, the new ISO/ITU-T still image coding standard developed by the Joint Photographic Experts Group (JPEG). It enables a non-uniform distribution of the image quality between a selected region (the ROI) and the rest of the image (background). This feature is obtained by scaling background coefficients in the wavelet domain. According to the ROI Maxshift method defined in JPEG 2000 part 1 (baseline algorithm), the background bit-planes are down-shifted below all ROI coefficients. In addition, the ROI can have any shape as the latter does not need to be transmitted to a JPEG 2000 decoder (no Codestream overhead due to the coding of the shape). On the contrary, this method requires decoding of all ROI coefficients before accessing bit-planes of the background. Furthermore, it uses large shifting values that significantly increase the number of total bit-planes to encode. In JPEG 2000 part 2 (extensions), a generic (Scaling based) ROI coding has been included. This method supports any scaling values. In particular, it allows a rough control on both ROI and background qualities distributions in the Codestream, but implies the derivation of a ROI bit-mask at the decoding side. This paper starts by providing some hints on how to choose an optimal Maxshift scaling value, as well as how to pad the ROI extra bits appearing during the shift operation. Then, it proposes an encoding algorithm that combines advantages o

  • Scrambling for Privacy Protection in Video Surveillance Systems
    2010
    Co-Authors: Frederic Dufaux, Touradj Ebrahimi
    Abstract:

    Abstract—In this paper, we address the problem of privacy protection in video surveillance. We introduce two efficient approaches to conceal regions of interest (ROIs) based on transform-domain or Codestream-domain scrambling. In the first technique, the sign of selected transform coefficients is pseudorandomly flipped during encoding. In the second method, some bits of the Codestream are pseudorandomly inverted. We address more specifically the cases of MPEG-4 as it is today the prevailing standard in video surveillance equipment. Simulations show that both techniques successfully hide private data in ROIs while the scene remains comprehensible. Additionally, the amount of noise introduced by the scrambling process can be adjusted. Finally, the impact on coding efficiency performance is small, and the required computational complexity is negligible. Index Terms—Privacy, selective encryption, surveillance, video processing

  • Scrambling for Privacy Protection in Video Surveillance Systems
    IEEE Transactions on Circuits and Systems for Video Technology, 2008
    Co-Authors: Frederic Dufaux, Touradj Ebrahimi
    Abstract:

    In this paper, we address the problem of privacy protection in video surveillance. We introduce two efficient approaches to conceal regions of interest (ROIs) based on transform-domain or Codestream-domain scrambling. In the first technique, the sign of selected transform coefficients is pseudorandomly flipped during encoding. In the second method, some bits of the Codestream are pseudorandomly inverted. We address more specifically the cases of MPEG-4 as it is today the prevailing standard in video surveillance equipment. Simulations show that both techniques successfully hide private data in ROIs while the scene remains comprehensible. Additionally, the amount of noise introduced by the scrambling process can be adjusted. Finally, the impact on coding efficiency performance is small, and the required computational complexity is negligible.

  • privacy enabling technology for video surveillance
    Mobile multimedia image processing for military and security applications. Conference, 2006
    Co-Authors: Frederic Dufaux, Mourad Ouaret, Yousri Abdeljaoued, Alfonso Navarro, Fabrice Vergnenegre, Touradj Ebrahimi
    Abstract:

    In this paper, we address the problem privacy in video surveillance. We propose an efficient solution based on transform-domain scrambling of regions of interest in a video sequence. More specifically, the sign of selected transform coefficients is flipped during encoding. We address more specifically the case of Motion JPEG 2000. Simulation results show that the technique can be successfully applied to conceal information in regions of interest in the scene while providing with a good level of security. Furthermore, the scrambling is flexible and allows adjusting the amount of distortion introduced. This is achieved with a small impact on coding performance and negligible computational complexity increase. In the proposed video surveillance system, heterogeneous clients can remotely access the system through the Internet or 2G/3G mobile phone network. Thanks to the inherently scalable Motion JPEG 2000 Codestream, the server is able to adapt the resolution and bandwidth of the delivered video depending on the usage environment of the client.

  • Secure JPEG 2000 - JPSEC
    2003 Ieee International Conference on Acoustics Speech and Signal Processing Vol Iv Proceedings: Signal Processing for Communications Special Sessions, 2003
    Co-Authors: Touradj Ebrahimi, R. Grosbois
    Abstract:

    The Joint Photographic Experts Group (JPEG) has recently rolled out a\nnew still image coding standard called JPEG 2000. This standard\nintegrates an efficient image compression scheme with functionalities\nrequired by multimedia applications, such as progressiveness up to\nlossless coding, region of interest coding, and error resiliency.\nSecurity is a concern in many applications, and therefore also a desired\nfunctionality. This paper provides readers with insights and examples of\nhow to combine security solutions with JPEG 2000 compression. Tools for\nJPEG 2000 compressed image integrity, access control, and copyright\nprotection are presented. They can be either applied to a JPEG 2000\nCodestream, or directly integrated into the coding/decoding operations,\nresulting in a fully compliant JPEG 2000 image.

Hitoshi Kiya - One of the best experts on this subject based on the ideXlab platform.

  • Codestream level secure identification for jpeg 2000 images under various compression ratios
    Asia-Pacific Signal and Information Processing Association Annual Summit and Conference, 2016
    Co-Authors: Kenta Iida, Hitoshi Kiya
    Abstract:

    A secure identification scheme for JPEG 2000 code-streams is proposed in this paper. The aim is to securely identify JPEG 2000 images generated from the same original image, without decoding images. Features used for the identification are extracted from header parts in a JPEG 2000 Codestream. The proposed scheme does not provide any false negative matches under various compression ratios, while most of image hashing-based schemes do not guarantee this performance. Existing identification schemes that do not provide any false negative matches can not be securely carried out. Due to such a situation, we propose an identification system based on a fuzzy commitment scheme, which is a well-known secure protocol for biometric template protection. Moreover, an error correction technique with 1-bit parity is considered to achieve the system. The experiment results show the proposed scheme is effective in terms of true positive matches, while keeping the security high.

  • Codestream-Based Identification of JPEG 2000 Images with Different Coding Parameters
    IEICE Transactions on Information and Systems, 2012
    Co-Authors: Osamu Watanabe, Takahiro Fukuhara, Hitoshi Kiya
    Abstract:

    A method of identifying JPEG 2000 images with different coding parameters, such as code-block sizes, quantization-step sizes, and resolution levels, is presented. It does not produce false-negative matches regardless of different coding parameters (compression rate, code-block size, and discrete wavelet transform (DWT) resolutions levels) or quantization step sizes. This feature is not provided by conventional methods. Moreover, the proposed approach is fast because it uses the number of zero-bit-planes that can be extracted from the JPEG 2000 Codestream by only parsing the header information without embedded block coding with optimized truncation (EBCOT) decoding. The experimental results revealed the effectiveness of image identification based on the new method.

  • a moving object detection scheme in Codestream domain for motion jpeg encoded movies
    Pacific Rim Conference on Multimedia, 2010
    Co-Authors: Masaaki Fujiyoshi, Yuji Tachizaki, Hitoshi Kiya
    Abstract:

    This paper proposes a scheme for detecting moving objects (MOs) from a Motion JPEG (MJ) coded video recorded by a stationary camera. The proposed scheme detects MOs without decoding a compressed video, whereas the ordinary motion detecting schemes have to decompress the video. For MOs detection, the correlation based on the positive and negative sign of discrete cosine transformed (DCT) coefficients of video frames is used in the proposed scheme. A DCT sign is encoded separately from its corresponding magnitude, so the signs are directly extracted from a MJ compressed Codestream, that is, no need to decompress the coded video. In the proposed scheme, MOs are detected in each 8 × 8-sized block of two adjacent video frames where the block is the MJ compression unit. Experimental results show that an usage of surrounding blocks in a detection decreases both false positive and false negative detections.

  • A Codestream domain authentication and tamper localization scheme for JPEG 2000
    2010 10th International Symposium on Communications and Information Technologies, 2010
    Co-Authors: Marielena Palacios Perez, Masaaki Fujiyoshi, Hitoshi Kiya
    Abstract:

    This paper proposes a tamper detection and localization scheme for JPEG 2000 coded images. The proposed scheme signs a JPEG 2000 compressed Codestream without decompressing it, i.e. in the Codestream domain. The generated signature is directly inserted to the Codestream so that the sign is not needed to transmit separately. The signature insertion in the proposed scheme complies with Codestream structure, so a standard JPEG 2000 decoder simply neglects the signature and the decoded image is not distorted. Tamper detection compares the signature extracted from the signed Codestream and the signature regenerated from the Codestream. Since the signature is generated in encoded codeblocks, tampered regions are spatially localized as well as tampered positions are localized in the Codestream domain. Experimental results show the effectiveness of the proposed scheme.

  • Codestream domain scrambling of moving objects based on dct sign only correlation for motion jpeg movies
    International Conference on Image Processing, 2007
    Co-Authors: K. Kuroiwa, Masaaki Fujiyoshi, Hitoshi Kiya
    Abstract:

    This paper proposes a moving objects scrambling method for Motion JPEG movies that consists of two parts: a moving objects detection based on DCT sign-only correlation (DSOC) and a partial scrambling. DSOC is the correlation of the positive and negative signs of DCT coefficients. Utilizing the Codestream structure of Motion JPEG movies and the relation between motion and DSOC, the proposed moving objects detection is achieved in Codestream domain. The proposed scrambling is also achieved in Codestream domain by inverting signs of DCT coefficients that each sign is independently encoded as one bit. The Codestream domain processing in this method serves low processing time and keeps coding efficiency. Moreover, the proposed method completely descrambles scrambled Codestreams to the original without any knowledge on the position and shape of moving objects. Simulation results show the effectiveness of the proposed method.

Student Member - One of the best experts on this subject based on the ideXlab platform.

  • 1Low Complexity JPEG2000 Rate Control through Reverse Subband Scanning Order and Coding Passes Concatenation
    2016
    Co-Authors: Student Member
    Abstract:

    Abstract — This letter introduces a new rate control method devised to provide quality scalability to JPEG2000 Codestreams containing a single or few quality layers. It is based on a Reverse subband scanning Order and a coding passes Concatenation (ROC) that does not use distortion measures based on the original image. The proposed ROC method allows a flexible rate control when the image has already been encoded, using negligible computational resources and obtaining the same efficiency as when using quality layers. Besides, the proposed ROC can be used in the encoding process to reduce the coder complexity, avoiding to encode unnecessary coding passes and achieving a competitive performance in terms of MSE. Index Terms — JPEG2000 standard, rate distortion optimiza-tion, quality scalability, interactive transmissions. I

  • Correspondence LDPC-Based Iterative Joint Source-Channel Decoding for JPEG2000
    2014
    Co-Authors: Student Member, Ali Bilgin, Michael W. Marcellin, Bane Vasic
    Abstract:

    Abstract—A framework is proposed for iterative joint source-channel de-coding of JPEG2000 Codestreams. At the encoder, JPEG2000 is used to per-form source coding with certain error-resilience (ER) modes, and LDPC codes are used to perform channel coding. During decoding, the source decoder uses the ER modes to identify corrupt sections of the Codestream and provides this information to the channel decoder. Decoding is carried out jointly in an iterative fashion. Experimental results indicate that the proposed method requires fewer iterations and improves overall system performance. Index Terms—Error resilience (ER), joint source/channel coding, JPEG2000, LDPC. I

  • Dynamic Contrast-Based Quantization for Lossy Wavelet Image Compression
    2008
    Co-Authors: Student Member, S S Hemami, Senior Member
    Abstract:

    Modern lossy image compression algorithms exploit characteristics of the human visual system; however, whereas psychophysical results are commonly reported in terms of contrast, the majority of compression strategies incorporate contrast sensitivity only in an implicit fashion (e.g., by weighting quantizer step sizes). This paper presents a contrast-based quantization strategy for use in wavelet-based lossy image compression. Based on the results of recent psychophysical experiments using wavelet subband quantization distortions and natural-image backgrounds, subbands are quantized such that the distortions in the reconstructed image exhibit specific root-mean squared (RMS) contrasts, and such that edge-structure is preserved across scale-space. Within a single, unified framework, the proposed contrast-based strategy yields images which are competitive in visual quality with results from current visually lossless approaches at high bit-rates, and which demonstrate improved visual quality over current visually lossy approaches at low bit-rates. This strategy operates in the context of non-embedded and embedded quantization, the latter of which yields a highly scalable Codestream which provides the best-possible visual quality at all bit-rates; a specific application of the proposed algorithm to JPEG-2000 is presented. I

  • An optimized content-aware authentication scheme for streaming JPEG-2000 images over lossy networks
    2008
    Co-Authors: Zhishou Zhang, Student Member, Qibin Sun, Wai-choong Wong, Susie Wee, Senior Member, John Apostolopoulos
    Abstract:

    Abstract—This paper proposes an optimized content-aware authentication scheme for JPEG-2000 streams over lossy networks, where a received packet is consumed only when it is both decodable and authenticated. In a JPEG-2000 Codestream, some packets are more important than others in terms of coding dependency and image quality. This naturally motivates allocating more redundant authentication information for the more important packets in order to maximize their probability of authentication and thereby minimize the distortion at the receiver. Towards this goal, with the awareness of its corresponding image content, we formulate an optimization framework to compute an authentication graph to maximize the expected media quality at the receiver, given specific authentication overhead and knowledge of network loss rate. System analysis and experimental results demonstrate that the proposed scheme achieves our design goal in that the rate-distortion (R-D) curve of the authenticated image is very close to the R-D curve when no authentication is required. Index Terms—Content-aware, digital signature, JPEG-2000, signature amortization, stream authentication

Senior Member - One of the best experts on this subject based on the ideXlab platform.

  • Dynamic Contrast-Based Quantization for Lossy Wavelet Image Compression
    2008
    Co-Authors: Student Member, S S Hemami, Senior Member
    Abstract:

    Modern lossy image compression algorithms exploit characteristics of the human visual system; however, whereas psychophysical results are commonly reported in terms of contrast, the majority of compression strategies incorporate contrast sensitivity only in an implicit fashion (e.g., by weighting quantizer step sizes). This paper presents a contrast-based quantization strategy for use in wavelet-based lossy image compression. Based on the results of recent psychophysical experiments using wavelet subband quantization distortions and natural-image backgrounds, subbands are quantized such that the distortions in the reconstructed image exhibit specific root-mean squared (RMS) contrasts, and such that edge-structure is preserved across scale-space. Within a single, unified framework, the proposed contrast-based strategy yields images which are competitive in visual quality with results from current visually lossless approaches at high bit-rates, and which demonstrate improved visual quality over current visually lossy approaches at low bit-rates. This strategy operates in the context of non-embedded and embedded quantization, the latter of which yields a highly scalable Codestream which provides the best-possible visual quality at all bit-rates; a specific application of the proposed algorithm to JPEG-2000 is presented. I

  • An optimized content-aware authentication scheme for streaming JPEG-2000 images over lossy networks
    2008
    Co-Authors: Zhishou Zhang, Student Member, Qibin Sun, Wai-choong Wong, Susie Wee, Senior Member, John Apostolopoulos
    Abstract:

    Abstract—This paper proposes an optimized content-aware authentication scheme for JPEG-2000 streams over lossy networks, where a received packet is consumed only when it is both decodable and authenticated. In a JPEG-2000 Codestream, some packets are more important than others in terms of coding dependency and image quality. This naturally motivates allocating more redundant authentication information for the more important packets in order to maximize their probability of authentication and thereby minimize the distortion at the receiver. Towards this goal, with the awareness of its corresponding image content, we formulate an optimization framework to compute an authentication graph to maximize the expected media quality at the receiver, given specific authentication overhead and knowledge of network loss rate. System analysis and experimental results demonstrate that the proposed scheme achieves our design goal in that the rate-distortion (R-D) curve of the authenticated image is very close to the R-D curve when no authentication is required. Index Terms—Content-aware, digital signature, JPEG-2000, signature amortization, stream authentication

Michael W. Marcellin - One of the best experts on this subject based on the ideXlab platform.

  • lossless multi component image compression based on integer wavelet coefficient prediction using convolutional neural networks
    Data Compression Conference, 2020
    Co-Authors: Eze Ahanonu, Michael W. Marcellin, Ali Bilgin
    Abstract:

    This work extends the single component Wavelet Prediction Compression (WPC) framework proposed earlier to lossless compression of multi-component imagery. WPC employs a series of convolutional neural networks (CNNs) to generate predictions of wavelet detail subbands, using subbands within the same discrete wavelet transform (DWT) decomposition level. Prediction residuals are then coded in place of original coefficients in the compressed Codestream. At the decoder, predictions are reproduced using an identical set of CNNs, and combined with residuals to achieve perfect subband (and image) reconstruction. The proposed Multi-Component Wavelet Prediction Compression (MCWPC) framework extends WPC to multi-component by considering both inter-and intra-component redundancies, resulting in improved spatial and spectral decorrelation of DWT coefficients. Compression results (Table 1) show MCWPC achieves 7.2% and 23.8% bit-rate reductions over JPEG2000 in the YUV and RGB colorspaces, respectively.

  • Visually Lossless JPEG 2000 for Remote Image Browsing
    Information-an International Interdisciplinary Journal, 2016
    Co-Authors: Han Oh, Ali Bilgin, Michael W. Marcellin
    Abstract:

    Image sizes have increased exponentially in recent years. The resulting high-resolution images are often viewed via remote image browsing. Zooming and panning are desirable features in this context, which result in disparate spatial regions of an image being displayed at a variety of (spatial) resolutions. When an image is displayed at a reduced resolution, the quantization step sizes needed for visually lossless quality generally increase. This paper investigates the quantization step sizes needed for visually lossless display as a function of resolution, and proposes a method that effectively incorporates the resulting (multiple) quantization step sizes into a single JPEG 2000 Codestream. This Codestream is JPEG 2000 Part 1 compliant and allows for visually lossless decoding at all resolutions natively supported by the wavelet transform as well as arbitrary intermediate resolutions, using only a fraction of the full-resolution Codestream. When images are browsed remotely using the JPEG 2000 Interactive Protocol (JPIP), the required bandwidth is significantly reduced, as demonstrated by extensive experimental results.

  • Correspondence LDPC-Based Iterative Joint Source-Channel Decoding for JPEG2000
    2014
    Co-Authors: Student Member, Ali Bilgin, Michael W. Marcellin, Bane Vasic
    Abstract:

    Abstract—A framework is proposed for iterative joint source-channel de-coding of JPEG2000 Codestreams. At the encoder, JPEG2000 is used to per-form source coding with certain error-resilience (ER) modes, and LDPC codes are used to perform channel coding. During decoding, the source decoder uses the ER modes to identify corrupt sections of the Codestream and provides this information to the channel decoder. Decoding is carried out jointly in an iterative fashion. Experimental results indicate that the proposed method requires fewer iterations and improves overall system performance. Index Terms—Error resilience (ER), joint source/channel coding, JPEG2000, LDPC. I

  • Visually Lossless Strategies to Decode and Transmit JPEG2000 Imagery
    IEEE Signal Processing Letters, 2014
    Co-Authors: Leandro Jimenez-rodriguez, Francesc Auli-llinas, Michael W. Marcellin
    Abstract:

    Visually lossless coding allows image codecs to achieve high compression ratios while producing images without visually noticeable distortion. In general, visually lossless coding is approached from the point of view of the encoder, so most methods are not applicable to already compressed Codestreams. This paper presents two algorithms focused on the visually lossless decoding and transmission of JPEG2000 Codestreams. The proposed strategies can be employed by a decoder, or a JPIP server, to reduce the decoding or transmission rate without penalizing the visual quality of the resulting images.

  • AN EFFICIENT JOINT SOURCE-CHANNEL RATE ALLOCATION SCHEME FOR JPEG2000 CodestreamS
    2013
    Co-Authors: Ali Bilgin, Michael W. Marcellin
    Abstract:

    A two-level, hybrid-optimization scheme is proposed for rate allocation of JPEG2000(J2K) transmission over noisy channels. It combines forward error correction (FEC) and J2K error resilience modes to minimize the expected end-to-end image distortion. Subject to a total target bit rate, it forms fixed-length source packets, and can be adapted to fixed-length channel packets in a straightforward manner. The proposed scheme utilizes the source distortionrate characteristics and the BER statistics of the available channel codes. It has complexity less than for a specific J2K Codestream, where is the number of available channel code rates. Performance results with both RCPC and turbo codes for fixed-length source packets are provided to show the effectiveness of the scheme. 1