Embedded Compression Technique Research Articles

WHDVI: A wireless high definition video interface technique for digital home

Owing to the rapid progress of semiconductor industry, the vision of digital home is getting more real. For this reason, many high speed transmission standards have been proposed. For digital home, multimedia sources come from various media players. Display media are also with this diversity. At present, the corresponding transmission standards are dedicated for some media players. This will be a bottleneck for integration of various multimedia systems. This paper proposes a wireless high speed video transmission system compatible for various digital media player and display media. This project can support various display resolutions from high-definition television (HDTV) (1280×720) to Blu-ray Disc (1920×1080). The core technology can be classified into two categories: (1). embedded compression techniques, (2). wireless transmission techniques. With the high integration on multimedia and communication technique, the proposed design exploits the realization on wireless high data-rate transmission in a digital home environment.

움직임 보상된 웨이블릿 기반의 비디오 코딩 시스템에 적용 가능한 임베디드 압축 코덱 알고리즘

In this paper, a low-complexity embedded compression (EC) Codec algorithm for the wavelet video coder is applied to reduce excessive external memory requirements. The EC algorithm is used to achieve a fixed compression ratio of 50 % under the near-lossless-compression constraint. The EC technique can reduce the 50 % memory requirement for intermediate low-frequency coefficients during multiple discrete wavelet transform stages compared with direct implementation of the wavelet video encoder of this paper. Furthermore, the EC scheme based on a forward adaptive quantization and fixed length coding can save bandwidth and size of buffer between DWT and SPIHT to 50 %. Simulation results show that our EC algorithm present only PSNR degradation of 0.179 and 0.162 dB in average when the target bit-rate of the video coder are 1 and 0.5 bpp, respectively.

웨이블릿 변환의 메모리 크기와 대역폭 감소를 위한 Prediction 기반의 Embedded Compression 알고리즘

본 논문에서는 JPEG2000 부호화 시스템의 과도한 메모리 요구 사항을 감소시키기 위해 예측 부호화 기반의 새로운 임베디드 압축(Embedded Compression, EC) 알고리즘을 제안한다. 본 논문의 EC 기법은 EC가 적용되지 않은 DWT 프로세서와 비교하여 DWT 과정에서 발생하는 임시적인 저주파 웨이블릿 계수들의 메모리 접근 및 크기를 50 %로 줄일 수 있다. 무손실의 영상 압축 시스템에 널리 쓰이면서 단순하지만 좋은 성능을 갖는 LOCO-I(LOw COmplexity LOssless COmpression for Image)와 MAP(Median Adaptive Predictor) 예측기를 제안한 EC 알고리즘에 적용하였다. 제안한 예측 기반의 EC 알고리즘은 예측 오차 값들을 인코딩하기 위하여 포워드 적응형 양자화와 고정 길이 코드를 사용한다. 시뮬레이션 결과를 통해 예측기가 LOCO-I와 MAP인 경우, 본 논문에서 제안한 EC 알고리즘에 의한 평균적인 PSNR 저하는 각각 0.48 dB와 0.26 dB임을 알 수 있다. 선행 논문 [9]에서 제안한 하다마드 변환(MHT) 기반의 EC 알고리즘과 비교하여 평균적인 PSNR이 약 1.39 dB 향상된다. In this paper, a new prediction based embedded compression (EC) codec algorithm for the JPEG2000 encoder system is proposed to reduce excessive memory requirements. The EC technique can reduce the 50 % memory requirement for intermediate low-frequency coefficients during multiple discrete wavelet transform (DWT) stages compared with direct implementation of the DWT engine of this paper. The LOCO-I predictor and MAP are widely used in many lossless picture compression codec. The proposed EC algorithm use these predictor which are very simple but surprisingly effective. The predictive EC scheme adopts a forward adaptive quantization and fixed length coding to encoding the prediction error. Simulation results show that our LOCO-I and MAP based EC codecs present only PSNR degradation of 0.48 and 0.26 dB in average, respectively. The proposed algorithm improves the average PSNR by 1.39 dB compared to the previous work in [9].

Low complexity embedded compression algorithm for reduction of memory size and bandwidth requirements in the JPEG2000 encoder

In this paper, a new and low-complexity embedded compression (EC) algorithm for the JPEG2000 encoder system is proposed to efficiently reduce memory requirements. The proposed EC algorithm is used to achieve a fixed compression ratio of 50% under the near-lossless compression constraint. Through the EC technique, the memory requirement for intermediate low-frequency coefficients during multiple DWT stages can be reduced by a factor of 2 compared with direct implementation of the JPEG2000 encoder. By jointly considering the coding flow of both block-based 2D-DWT and bit-plane coders, the EC scheme combines an efficient quantization and simple entropy coder to reduce memory transaction bandwidth between DWT and bit-plane coder (BPC) to 50%. Furthermore, this EC reduces the size of code-block memory from DWT to BPC. Experiment results based on standard test image benchmarks show that our proposed EC algorithm presents only PSNR degradation of 1.05 dB on average when the target compression ratio is fixed at 50%. Our EC can be applicable to the JPEG2000 encoding system to save memory size and bandwidth requirements with minor picture quality degradation. The proposed EC algorithm is also computationally simple, reducing latency time and creating sufficient accessibility.

Wavelet image compression--the quadtree coding approach.

Perfect reconstruction, quality scalability, and region-of-interest coding are basic features needed for the image compression schemes used in telemedicine applications. This paper proposes a new wavelet-based embedded compression technique that efficiently exploits the intraband dependencies and uses a quadtree-based approach to encode the significance maps. The algorithm produces a losslessly compressed embedded data stream, supports quality scalability, and permits region-of-interest coding. Moreover, experimental results obtained on various images show that the proposed algorithm provides competitive lossless/lossy compression results. The proposed technique is well suited for telemedicine applications that require fast interactive handling of large image sets, over networks with limited and/or variable bandwidth.