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Two layer coding based on JPEG 2000 for HDR images was proposed. The proposed coding scheme, referred to as extended JPEG XT, is an extension of JPEG XT Profile A, and takes advantages as follows: freely bit rate controllability, high compression efficiency, available for over-eight-bits LDR images, and so on. In this paper, some experimental results for the quality of the reconstructed HDR images...
This paper proposes a new inverse tone mapping operator (TMO) with only one parameter. The proposed inverse TMO is based on Reinhard's global operator which is a well-known TMO. Inverse TM operations have two applications: generating an HDR image from an existing LDR one, and reconstructing an original HDR image from the mapped LDR image. In this paper, we focus on the latter application and the proposed...
Encryption-then-Compression (EtC) systems have been considered for the user-controllable privacy protection of social media like Twitter and Facebook. The aim of this paper is to evaluate the security of block scrambling-based encryption schemes, which have been proposed to construct EtC systems. Even though this scheme has enough key spaces for protecting brute-force attacks, each block in encrypted...
A speeding up robust identification scheme for JPEG images is proposed in this paper. The aim of the identification is to robustly identify JPEG images that are generated from the same original image, under various compression conditions such as differences in compression ratios and initial quantization matrices. The conventional scheme that we focus on uses visually protected features to achieve...
This paper introduces a zero-skip quantization (ZS.Q) scheme for the near lossless coding of sparse histogram images. Increases in the range of pixel values and various tone mapping operations on those pixel values mean that the histogram bins often contain no pixels. Recently, this sparseness of the histogram was used to increase the lossless coding performance by introducing histogram packing. This...
The aim of this paper is to adapt automatic jigsaw puzzle solvers, which are methods of assembling jigsaw puzzles, to the field of information security. Encryption-then-Compression (ETC) systems have been considered for the user-controllable privacy protection of digital images in social network services. Block scrambling-based encryption schemes, which have been proposed to construct ETC systems,...
A new two-layer coding scheme based on JPEG 2000 is proposed for HDR images, where coded data consist of two layers: the base-layer for tone mapped LDR version of an HDR image and the enhancement layer. The paper considers the coding scheme as an extended version of the JPEG XT Profile A. JPEG coders used in JPEG XT are replaced with JPEG 2000 ones. Compared to normative JPEG XT coding, the proposed...
This paper is among the first to adapt automatic jigsaw puzzle solvers, which are methods of assembling jigsaw puzzles, to the field of information security. Block-based scrambling encryption schemes, which have been mainly proposed for Encryption-then-Compression (ETC) systems, have enough key spaces for protecting brute-force attacks. However, each block in encrypted images has almost the same correlation...
This paper proposes a novel inverse TMO, which enables to generate HDR images from LDR ones, not only without using any specific parameters but also at low computing costs. Furthermore, the inverse TMO has a new characteristic when an LDR image is mapped from an HDR one by Reinhard's global operator. In the case, the HDR image reconstructed by the proposed method without parameters can be remapped...
This paper proposes an ensemble based automatic speaker recognition (ASV) using adapted score fusion in noisy reverberant environment. It is well known that background noise and reverberation affect the performance of the ASV systems. Various techniques have been reported to improve the robustness against noise and reverberation, and an ensemble based method is one of the effective techniques in the...
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...
This paper proposes a quality improvement method of tone mapped images including compression distortion for the JPEG XT standard, which is a new compression standard for high dynamic range (HDR) images. HDR images are generally required to be mapped to low dynamic range (LDR) ones due to the limitation of display devices. Furthermore, the HDR ones include some compression distortion to be efficiently...
A number of inverse tone mapping operators (TMOs) for dynamic range expansion have been proposed due to the need to visualize low dynamic range (LDR) images on high dynamic range (HDR) devices. This paper proposes a novel inverse TMO, which enables to generate HDR images from LDR ones, not only without using any specific parameters but also at low computing costs. Furthermore, the inverse TMO has...
A secure identification scheme for JPEG XR images is proposed in this paper. The aim is to securely identify JPEG XR images which are generated from the same original image under various compression levels. A property of the positive and negative signs of lapped biorthogonal transform coefficients is employed to achieve a robust scheme against JPEG XR compression. The proposed scheme is robust against...
This paper proposes a fixed-point local tone mapping operation (TMO) for high dynamic range (HDR) images. A TMO is classified in two types: local and global. Although a local TMO offers better results than global one, it requires more resources such as a computational cost and memory space. The proposed method uses fixed-point arithmetic with short data to solve this problem. The method uses an intermediate...
This paper proposes a new way to generate random unitary matrices for biometric template protection. It is well known that the unitary transform-based template protection that is a class of cancelable biometrics systems, has some desirable properties such as being applicable to l2-norm minimization problems. However, its performance and effectiveness depend on the variety of a unitary matrix. The...
In many multimedia applications, image encryption has to be conducted prior to image compression. This paper proposes an Encryption-then-Compression system using a JPEG XR friendly perceptual encryption method, which enables to be conducted prior to JPEG XR compression. The proposed encryption method can provide approximately the same compression performance as that of JPEG XR compression without...
A secure identification scheme for JPEG images is proposed in this paper. The aim is to robustly identify JPEG images which are generated from the same original image under various compression levels in security. A property of the positive and negative signs of DCT coefficients is employed to achieve a robust scheme. The proposed scheme is robust against a difference in compression levels, and does...
The coding performance of the normative encoder of the JPEG XT in profile is analyzed and the problem on the encoder is summarized in this paper. It is pointed out that there is a mismatch in the handling of the quantization error between the normative encoder and the standard decoder. To avoid this problem, an improved structure has been proposed with consideration of the mismatch. The experimental...
The super resolution technique plays an important role in displaying a conventional low resolution (LR) image on a recently developed high resolution (HR) display. In its process, some of enhancement techniques such as de-noising, de-blurring and tone-mapping are combined to increase visual quality. This paper introduces a subset noise bias compensation (NBC) to an LR-to-HR up-conversion process which...
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