An energy aware DCT (discrete cosine transform) architecture based on the distributed arithmetic concept is proposed. Architectures based on the distributed arithmetic concept are inherently low power as they are mult...
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An energy aware DCT (discrete cosine transform) architecture based on the distributed arithmetic concept is proposed. Architectures based on the distributed arithmetic concept are inherently low power as they are multiplication free algorithms. One characteristic of the DCT is that signal energies are concentrated in only a few coefficients (less than 25%) upon transformation, with the rest (or 75%) of the coefficients being insignificant and negligible. One can skip the computation of these terms without seriously affecting the output signal quality. Exploiting this idea, we propose an energy aware DCT architecture which adaptively trades off image quality with power dissipation. Our simulation results show that the new proposed architecture achieves 60% in power savings with a small degradation in signal quality.
Perfect reconstruction (PR) deinterlacer banks are proposed as new tools for spatio-temporal scalable video codec. The proposed systems separate a progressive video into two different progressive videos of a half fram...
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Perfect reconstruction (PR) deinterlacer banks are proposed as new tools for spatio-temporal scalable video codec. The proposed systems separate a progressive video into two different progressive videos of a half frame rate and are novel from the viewpoint of filter-banks in that interlaced videos are given as intermediate data during analysis and synthesis process. Unlike the conventional filter banks, our systems are constructed in a way unique to multidimensional systems by using invertible deinterlacers which we have proposed before. This paper suggests two kinds of interlaced video formats: the vertical-temporal (VT) Quincunx and face-centered-orthorhombic (FCO) format. As a primal application, a spatio-temporal scalable video codec, or field scalable video codec (FSVC), system is experimented. This technique offers a functionality by which decoding a base layer by itself provides both of half-rate progressive and interlaced videos, and adding an enhancement layer improves the spatio-temporal resolution. Some experimental results of the filter banks combined with JPEG2000 show their potential for practical video codec applications.
In this paper, a new algorithm which adopts the techniques of double prediction and the Pareto probability model was applied to encode the DC term in the JPEG compression process. Conventionally, the DC term was encod...
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ISBN:
(纸本)9781479900145
In this paper, a new algorithm which adopts the techniques of double prediction and the Pareto probability model was applied to encode the DC term in the JPEG compression process. Conventionally, the DC term was encoded by differential coding, i.e., the difference of the DC values between the current block and the previous block. In this paper, we first use the DC terms of four adjacent blocks to predict the current DC value. We then further use the prediction error of the four adjacent blocks to estimate the variance of the prediction error of the current block. We call it the double prediction algorithm. Next, the Pareto distribution is applied to model the probability distribution of the prediction error. Simulation results show that, with the proposed algorithms, the data size required for DC terms is significantly reduced by 25% ~ 60% and a much higher compression rate can be achieved.
This paper presents a dataflow design methodology and an associated co-exploration environment, focusing on the optimization of buffer sizes. The approach is applicable to dynamic dataflow designs and its performance ...
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This paper presents a dataflow design methodology and an associated co-exploration environment, focusing on the optimization of buffer sizes. The approach is applicable to dynamic dataflow designs and its performance is presented and validated by experimental results on the porting of an MPEG-4 Simple Profile decoder to the STM STHORM manycore platform. For the purpose of this work, the decoder has been written using the RVC-CAL dataflow language standardized by ISO/IEC. Starting from this high-level representation it is demonstrated how the buffer size configuration can be optimized, based on a novel buffer size minimization algorithm suitable for a very general class of dataflow programs.
A video encoder architecture for encoding digital video signals based on the MPEG2 video standard up to slice level is described. Function specific architecture is implemented to increase coding eficiency and reduce t...
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A video encoder architecture for encoding digital video signals based on the MPEG2 video standard up to slice level is described. Function specific architecture is implemented to increase coding eficiency and reduce the silicon area for real time encoding. Hierarchical controlling concept is adopted and three stage pipeline encoding method is used in macroblock coding to increase the flexibility of encoding flow and reduce the design effort.
Image authentication importance increases as image acquisition becomes easier with the help of new technologies. Today, almost any phone has a camera with decent performances and sharing images is encouraged by social...
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ISBN:
(纸本)9781538695777;9781538695760
Image authentication importance increases as image acquisition becomes easier with the help of new technologies. Today, almost any phone has a camera with decent performances and sharing images is encouraged by social media. Image tampering is also decreasing in difficulty because of the advances in image editing software. Today's signature-based image authentication techniques rely on storing the image signature until the authentication is needed. This is a disadvantage because the storage support is usually unique, controlled by one entity and could fail. Also, this centralized approach is not fundamentally trustworthy. To solve these problems, the paper proposes a signature-based image authentication method resistant to JPEG compression which makes use of new blockchain technology to store the image signature. With this method, the signature is stored in a decentralized network, significantly increasing the security.
This paper describes the design of a inverse discrete cosine transform (IDCT) to decompress JPEG images. The target application is the decompression of monocromatic photos of candidates in the Brazilian Electronic Bal...
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This paper describes the design of a inverse discrete cosine transform (IDCT) to decompress JPEG images. The target application is the decompression of monocromatic photos of candidates in the Brazilian Electronic Ballot Box. The goals is to develop a constrained implementation which targets a XC4010 FPGA. It is based on the application of two 1-D IDCTs using a local memory as buffer. The design resulted in around two hundred logic cells for a two-pass IDCT, which was implemented and tested in the Xilinx demo board.
We extend the recently proposed spectral integration based psychoacoustic model for sinusoidal distortions to the MDCT domain. The estimated masking threshold additionally depends on the sub-band spectral flatness mea...
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We extend the recently proposed spectral integration based psychoacoustic model for sinusoidal distortions to the MDCT domain. The estimated masking threshold additionally depends on the sub-band spectral flatness measure of the signal which accounts for the non- sinusoidal distortion introduced by masking. The expressions for masking threshold are derived and the validity of the proposed model is established through perceptual transparency test of audio clips. Test results indicate that we do achieve transparent quality reconstruction with the new model. Performance of the model is compared with MPEG psychoacoustic models with respect to the estimated perceptual entropy (PE). The results show that the proposed model predicts a lower PE than other models.
Nowadays, digital images can be easily modified by using software. In this paper, a new blind approach is proposed to detect copy-paste trail in a doctored JPEG image, i.e., to check whether a copied area came from th...
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Nowadays, digital images can be easily modified by using software. In this paper, a new blind approach is proposed to detect copy-paste trail in a doctored JPEG image, i.e., to check whether a copied area came from the same image or not. When a copy-paste procedure is done on an image, especially adding or hiding an object, the block artifact grid contained in the copy-pasted slice is moved together. Since a slice must be placed properly in the target image to avoid obvious vision flaw, the grid in the slice mismatches to the original grid in the target image normally. Our approach utilizes the mismatch information of block artifact grid as a clue of copy-paste forgery. Experiment results demonstrate the efficiency of the proposed approach.
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