Baochen Jiang

Design and implementation of the smart meter in vehicle-to-grid

With the development of electric vehicles and smart grid, vehicle-to-grid (V2G) will become an inevitable. This paper presented a smart meter applied to vehicle-to-grid. The smart meter is introduced according to the function and characteristic of energy measurement chip ADE7758 and the microprocessor chip S3C2440 is also used in the circuit system. According to the difference of phase angle between the current and the voltage waveform in the electric grid, the energy consuming direction can be judged. Therefore, the consumption energy or export energy of an electric vehicle can be calculated. With the smart meter, bidirectional communication and remote control can be achieved between electric vehicle and the grid. Besides the special functions above, the smart meter is able to measure voltage and current, active and reactive power, and other electric parameters.

Shape Adaptive All Phase Biorthogonal Transform and Its Application in Image Coding

Abstract —In this paper shape adaptive all phase biorthogonal transform (SA-APBT) for coding arbitrarily shaped image segments is proposed. The proposed transform can be used in region-based image compression instead of the shape adaptive discrete cosine transform (SA-DCT). Region-based image coding method is made up of three procedures: image segmentation, contour coding and texture coding. An image is divided into region-of-interest (ROI) and background area by image segmentation. Both areas are encoded and decoded independently. Experimental results on test images show that compared with SA-DCT at the same bit rates, the PSNRs and visual effects of reconstructed images based on SA-APBT are comparable to the one based on SA-DCT especially at low bit rates. And the SA-APBT transform coefficients are quantized uniformly, while the SA-DCT transform coefficients are quantized according to different quantization steps in the quantization table. So the quantization based on SA-APBT is simpler and computational complexity is reduced.

Windowed All Phase Biorthogonal Transform and Its Application in JPEG-Like Image Compression

This paper proposes new concepts of the windowed all phase biorthogonal transform (WAPBT), which is inspired by the all phase biorthogonal transform (APBT). In the light of windowed all phase digital filter theory, windowed all phase biorthogonal transforms is proposed. The matrices of WAPBT based on DFT, WHT, DCT and IDCT are deduced, which can be used in image compression instead of the conventional DCT, and the image compression scheme proposed in this paper is called WAPBT-based JPEG (WAPBT-JPEG). With optimal window sequence of WAPBT for image compression obtained by using generalized pattern search algorithm (GPSA), the peak signal to noise ratio (PSNR) and visual quality of the reconstructed images using the WAPBT-JPEG is outgoing DCT-based JPEG (DCT-JPEG) and APBT-based JPEG (APBT- JPEG) approximately at all bit rates. What is more, by comparison with DCT-JPEG, the advantage of proposed scheme is that the quantization table is simplified and the transform coefficients can be quantized uniformly. Therefore, the computing time becomes shorter and the hardware implementation is easier. Index Terms—Windowed all phase biorthogonal transform (WAPBT), image compression, discrete cosine transform (DCT), JPEG algorithm, generalized pattern search algorithm (GPSA), windowed all phase digital filter (APDF)

Adaptive Threshold Edge Detection Algorithm Based on APDCSF and Anti-symmetrical Biorthogonal Wavelet Transform

This paper proposes an edge detection algorithm based on adaptive threshold which is obtained by histogram matching edge gradient value. The implementation of this algorithm is made up of three procedures: all phase discrete cosine sequency filtering, wavelet decomposition and adaptive threshold processing. The image is decomposed into low frequency and high frequency subbands by using all phase discrete cosine sequency filter (APDCSF). Experimental results on test images reveal that compared with the edge detection algorithm based on artificial threshold, the proposed one can create dynamic threshold adaptively and show better edge detection performance especially in terms of edge positioning accuracy.

Video compression based on wavelet transform and DBMA with motion compensation

In video compression, it can reduce the redundant information efficiently by motion estimation (ME) and motion compensation (MC), and less code is used to encode as much information as possible. In this paper, I frame encoding adopts wavelet transform and set partitioning in hierarchical trees (SPIHT) algorithm; for P frames, each frame sets the reconstructed frame of its previous frame as a reference frame, and then P frames proceed to code with ME and MC. In the step of ME, trading off between accuracy and computational complexity, adaptive fast search (AFS) algorithm combining with nodal search-based deformable block matching algorithm (NS-DBMA) is adopted to search for the matched block; and then in the MC process, wavelet transform combining with zerotree entropy (ZTE) algorithm is adopted according to the characteristics of residual image data. Meanwhile rate control is carried out in ZTE algorithm. Experimental results show that the proposed algorithm performs well for video sequences with complex motion and rich details, and reduces blocking artifacts obviously. Index Terms—video compression, motion estimation (ME), motion compensation (MC), wavelet transform, nodal search- based deformable block matching algorithm (NS-DBMA), adaptive fast search (AFS)

Power system harmonic analysis based on windowed FFT and wavelet transform

Harmonics in power system are harmful to power network. In order to analyze power system harmonic more accurately, a new harmonic analysis algorithm based on interpolating windowed FFT and wavelet transform is proposed. This approach overcomes the shortcoming of FFT having frequency domain localization ability, but without time-domain localization ability. In this paper, the original signal is decomposed into the high-frequency component and the low-frequency component by the discrete wavelet transform. The low-frequency part is analyzed by interpolating windowed FFT algorithm to get the amplitude and phase of every steady harmonic. Simulation experiments are conducted with Matlab. The experimental results show that this method can not only analyze the steady-state harmonic accurately, but also inspect non-steady harmonics effectively.

All Phase Inverse Discrete Sine Biorthogonal Transform and Its Application in Image Coding

—To improve the coding performance in JPEG image compression and reduce the computational complexity, this paper proposes a new transform called All Phase Inverse Discrete Sine Biorthogonal Transform (APIDSBT) based on the All Phase Biorthogonal Transform (APBT) and Inverse Discrete Sine Transform (IDST). Similar to Discrete Sine Transform (DST) matrix and Discrete Cosine Transform (DCT) matrix, it can be used in image compression which transforms the image from spatial domain to frequency domain. Compared with other transforms in JPEG-like image compression algorithm, the Peak Signal-to-Noise Ratio (PSNR) and subjective effects of the reconstructed images using the proposed transform and image coding scheme are better at the same bit rates, especially at low bit rates. The advantage is that the quantization process is simpler and the computational complexity is lower.

A novel deblocking quantization table for luminance component in baseline JPEG

—All Phase Biorthogonal Transform (APBT), a DCTlike transform generated from All Phase Digital Filter (APDF), can be used in baseline JPEG by replacing conventional Discrete Cosine Transform (DCT), and the image compression scheme is called APBT-based JPEG (APBT-JPEG). APBTJPEG can achieve better coding performance but at the expense of an increased computational complexity, because there is no fast algorithm for computing APBT. With our in-depth study on APBT-JPEG, we have found the relation between APBT-JPEG and DCT-JPEG (baseline JPEG) in this paper. In order to avoid extra computational complexity in APBT-JPEG, we propose a novel quantization table used in DCT-JPEG and an almost identical coding performance is achieved compared with APBTJPEG. Tested by natural images, experimental results show that compared with other quantization tables, at low bit rates in DCT-JPEG, the performance both in terms of PSNR and visual quality can be improved by using our proposed quantization table, and the blocking artifacts in reconstructed image have been reduced significantly. For these reasons, we can foresee that the proposed quantization table will be widely used in the future.

Mathematical relation between APBT-based and DCT-based JPEG image compression schemes

—A novel linear transform, called All Phase Biorthogonal Transform (APBT), was generated from All Phase Digital Filter (APDF) theory. APBT can be used in image compression instead of the conventional Discrete Cosine Transform (DCT), and the corresponding image compression scheme is called APBT-based JPEG (APBT-JPEG) which can achieve better coding performance, especially at low bit rates. With in-depth mathematical analysis on the emerging APBTJPEG and conventional DCT-based JPEG (DCT-JPEG), we bring forward a unique insight into the relation between them. The relation is that APBT-JPEG can be implemented by DCTJPEG, using a new quantization table deduced from mathematical analysis. To the best of our knowledge, it is the first time to reveal it, which can be considered to the main contribution of this paper. Finally, experiment results obtained with the test images have verified our proposed conclusion both in terms of objective quality and subjective effect.

Implementation of 2-D biorthogonal wavelet transform using 2-D APDF

All phase digital filter (APDF) is a new type of linear phase FIR digital filter which was proposed in recent years, and a general method to design 2-D FIR digital filters called 2-D APDF is presented in this paper. Firstly, the theory of biorthogonal wavelet transform and 2-D APDF is expounded. Secondly, a novel algorithm is proposed to implement biorthogonal wavelet transform by using 2-D APDF based on DFT and IDCT. The relations between two kinds of filters are discussed. As an important application of biorthogonal wavelet transform, multi-resolution analysis of 2-D image signal could be used to test the feasibility and applicability of the proposed algorithm. Finally, the test image can be reconstructed perfectly in the multi-resolution analysis of 2-D image experiment using MATLAB tool in this paper, and the analysis indicates that the proposed method performs well.