All Phase Biorthogonal Transform Research Articles

Interpolation Filter Design Based on All-Phase DST and Its Application to Image Demosaicking

Based on a deep understanding of all-phase digital filter (APDF) design and all-phase biorthogonal transform (APBT), this paper will further study the windowed all-phase digital filter (WAPDF) and windowed all-phase biorthogonal transform (WAPBT), discuss the principle of the WAPBT, and provide a unified construction method of the all-phase transform (APT). Based on a type of orthogonal transform, i.e., discrete sine transform (DST), an interpolation filter called an all-phase DST (APDST) filter is constructed and used for image demosaicking; it is compared with bilinear interpolation and all-phase inverse discrete cosine transform (APIDCT) interpolation filters, to test its performance in image interpolation and provide analysis and discussion. The experimental results show that APIDCT and APDST filters with a size of 7 × 7 are similar in interpolation performance, but better than the bilinear interpolation method. In addition to its use in image interpolation demosaicking, the low-pass filter designed in this paper can also be widely used in image interpolation, image denoising, image resizing, and other fields of image processing.

Anti-HEVC Recompression Video Watermarking Algorithm Based on the All Phase Biorthogonal Transform and SVD

ABSTRACTWith the rapid development of Internet of Things and multimedia technologies, people are paying more attention to the security of images and videos. To further improve the security of video content, a video watermarking algorithm based on the high efficiency video coding (HEVC) compression domain is proposed in this paper. The scheme embeds watermark information in the quantized coefficients, which can solve the cumulative error caused by watermark embedding. Moreover, the all phase biorthogonal transform (APBT), an improved transform, is used to compress the watermark data at the digital watermark preprocessing stage, optimize the watermark embedding scheme, and improve the embedding capacity of video watermarking. Due to the characteristics of HEVC video coding, most HEVC video watermarking schemes based on compression domain cannot resist recompression attack. To solve this problem, on the basis of APBT and singular value decomposition, an anti-HEVC recompression video watermarking algorithm is proposed and can effectively resist the HEVC recompression. Experimental results show that even when the quantization parameter is larger than 40, the extracted watermark still has good image quality. In addition, the algorithm also has a good performance in noise resistance.

Feature-Based Image Watermarking Algorithm Using SVD and APBT for Copyright Protection

Watermarking techniques can be applied in digital images to maintain the authenticity and integrity for copyright protection. In this paper, scale-invariant feature transform (SIFT) is combined with local digital watermarking and a digital watermarking algorithm based on SIFT, singular value decomposition (SVD), and all phase biorthogonal transform (APBT) is proposed. It describes the generation process of the SIFT algorithm in detail and obtains a series of scale-invariant feature points. A large amount of candidate feature points are selected to obtain the neighborhood which can be used to embed the watermark. For these selected feature points, block-based APBT is carried out on their neighborhoods. Moreover, a coefficients matrix of certain APBT coefficients is generated for SVD to embed the encrypted watermark. Experimental results demonstrate that the proposed watermarking algorithm has stronger robustness than some previous schemes. In addition, APBT-based digital watermarking algorithm has good imperceptibility and is more robust to different combinations of attacks, which can be applied for the purpose of copyright protection.

All Phase Biorthogonal Transform Based on GPU

In this paper, all phase biorthogonal transform (APBT) based on parallel algorithm is proposed. It can solve two problems. First, block-based DCT transform coding has serious blocking artifacts when the image is highly compressed at low bit rate. Second, APBT can solve the problem about blocking artifacts, but it does not have a fast algorithm, it has a low efficiency when APBT applies to image processing. So APBT based on parallel algorithm can solve the above problems, and it provides more space for improving the processing speed of APBT. We use the CUDA toolkit based on GPU which is released by NVIDIA to design the parallel algorithm of APBT. Experimental results show that the maximum speedup ratio of parallel algorithm of APBT can reach more than 40 times with a very low version GPU, compared with conventional serial APBT. And the reconstructed image using the proposed algorithm has the same performance with the serial one in terms of objective quality and subjective effect. The proposed parallel algorithm based on GPU of APBT also can be used in image compression, video compression, the edge detection, and some other fields of image processing.

APBT-JPEG Image Coding Based on GPU

In wireless multimedia sensor networks (WMSN), the latency of transmission is an increasingly problem. With the improvement of resolution, the time cost in image and video compression is more and more, which seriously affects the real-time of WMSN. In JPEG system, the core of the system is DCT, but DCT-JPEG is not the best choice. Block-based DCT transform coding has serious blocking artifacts when the image is highly compressed at low bit rates. APBT is used in this paper to solve that problem, but APBT does not have a fast algorithm. In this paper, we analyze the structure in JPEG and propose a parallel framework to speed up the algorithm of JPEG on GPU. And we use all phase biorthogonal transform (APBT) to replace the discrete cosine transform (DCT) for the better performance of reconstructed image. Therefore, parallel APBT-JPEG is proposed to solve the real-time of WMSN and the blocking artifacts in DCT-JPEG in this paper. We use the CUDA toolkit based on GPU which is released by NVIDIA to design the parallel algorithm of APBT-JPEG. Experimental results show that the maximum speedup ratio of parallel algorithm of APBT-JPEG can reach more than 100 times with a very low version GPU, compared with conventional serial APBT-JPEG. And the reconstructed image using the proposed algorithm has better performance than the DCT-JPEG in terms of objective quality and subjective effect. The proposed parallel algorithm based on GPU of APBT also can be used in image compression, video compression, the edge detection and some other fields of image processing.

Bayer Patterned Image Compression Based on Structure Conversion and APBT

The color filter array (CFA) captures only one-third of the necessary color intensities and the full color image is generated from the captured data by interpolation. In recent years, the algorithm of Bayer patterned image compression based on “structure conversion” has achieved better image quality. On the basis of previous work, a new algorithm based on the all phase biorthogonal transform (APBT) and all phase IDCT (APIDCT) interpolation is proposed in this paper. Instead of the conventional JPEG compression, APBT is applied to the JPEG image compression (APBT-JPEG), which significantly reduces complex multiplications and makes the quantization table easier. In the interpolation step, APIDCT interpolation method is introduced. Experimental results show that the proposed algorithm outperforms the one based on “structure conversion”; and the APIDCT interpolation performs close to the conventional interpolation methods. Therefore, the algorithm proposed in this paper is more suitable for Bayer image compression.

Color Image Compression Based on Directional All Phase Biorthogonal Transform

There are images in which some directional edges other than the vertical or horizontal ones dominate. So the conventional discrete cosine transform (DCT) may not be the best choice for them. Directional DCT framework is able to provide a better coding performance for image blocks that contain directional edges. In addition, the all phase biorthogonal transform (APBT) algorithm can improve the performance of compression. In the light of directional DCT and APBT, directional APBT is proposed and applied to color image coding. Experimental results show that this framework can indeed improve the compression performance of color image remarkably.

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)

ASPL-APBT Algorithm for Block Compressed Sensing Image Reconstruction

 Abstract—Based on the block compressed sensing (BCS) framework, a new and non-orthogonal transform named all phase biorthogonal transform (APBT) is introduced to exploit the image sparsity, reduce the encoding complexity and be applicable to the blocked image easily. APBT exploits the signal sparsity better than DCT, and meanwhile it overcomes the defects of multiscale transform such as wavelet transform with high computational complexity and the feature of not being applicable to the blocked image. In order to improve the efficiency of BCS reconstruction, the accelerated smoothed projected Landweber (ASPL) iteration algorithm is put forward. Combined with the sparse constraints in APBT, the BCS-ASPLAPBT reconstruction algorithm is advanced. Experimental results demonstrate that the proposed algorithm outperforms the method of using DCT sparsifying coupled with common SPL iteration not only in the aspect of PSNR, but in terms of the reconstruction time and the iteration number.

APBT-based Image Coding at Low Bit Rates with Down-sampling and All Phase DCT Interpolation

The conventional JPEG standard adopts the Discrete Cosine Transform (DCT), which usually needs the more complex quantization table and adjusting the bit rate results more complex multiplications. Based on the theory of All Phase Biorthogonal Transform (APBT), this paper proposed a novel image coding algorithm based on down-sampling, APBT-based image compression (APBT-JPEG) and interpolation. In the algorithm, down-sampling to the image data after the All Phase DCT (APDCT) filtering before compression and subsequently interpolation to the decompressed image are applied and especially APBT is used in the image compression step instead of the DCT. In the interpolation step, cubic convolution interpolation and the APDCT interpolation were used respectively. Experimental results show that the proposed scheme outperforms the conventional DCT-based JPEG (DCT-JPEG) compression scheme at low bit rates both in terms of PSNR and visual quality.

All phase biorthogonal transform and its application in JPEG-like image compression

This paper proposes new concepts of the all phase biorthogonal transform (APBT) and the dual biorthogonal basis vectors. In the light of all phase digital filtering theory, three kinds of all phase biorthogonal transforms based on the Walsh transform (WT), the discrete cosine transform (DCT) and the inverse discrete cosine transform (IDCT) are proposed. The matrices of APBT based on WT, DCT and IDCT are deduced, which can be used in image compression instead of the conventional DCT. Compared with DCT-based JPEG (DCT-JPEG) image compression algorithm at the same bit rates, the PSNR and visual quality of the reconstructed images using these transforms are approximate to DCT, outgoing DCT-JPEG at low bit rates especially. But the advantage 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 easier.