Decision tree accelerated CTU partition algorithm for intra prediction in versatile video coding.

Versatile video coding (VVC) achieves enormous improvement over the advanced high efficiency video coding (HEVC) standard due to the adoption of the quadtree with nested multi-type tree (QTMT) partition structure and other coding tools. However, the computational complexity increases dramatically as well. To tackle this problem, we propose a decision tree accelerated coding tree units (CTU) partition algorithm for intra prediction in VVC. Firstly, specially designated image features are extracted to characterize the coding unit (CU) complexity. Then, the trained decision tree is employed to predict the partition results. Finally, based on our newly designed intra prediction framework, the partition process is early terminated or redundant partition modes are screened out. The experimental results show that the proposed algorithm could achieve around 52% encoding time reduction for various test video sequences on average with only 1.75% Bjontegaard delta bit rate increase compared with the reference test model VTM9.0 of VVC.

ADA-Tucker: Compressing deep neural networks via adaptive dimension adjustment tucker decomposition.

Despite recent success of deep learning models in numerous applications, their widespread use on mobile devices is seriously impeded by storage and computational requirements. In this paper, we propose a novel network compression method called Adaptive Dimension Adjustment Tucker decomposition (ADA-Tucker). With learnable core tensors and transformation matrices, ADA-Tucker performs Tucker decomposition of arbitrary-order tensors. Furthermore, we propose that weight tensors in networks with proper order and balanced dimension are easier to be compressed. Therefore, the high flexibility in decomposition choice distinguishes ADA-Tucker from all previous low-rank models. To compress more, we further extend the model to Shared Core ADA-Tucker (SCADA-Tucker) by defining a shared core tensor for all layers. Our methods require no overhead of recording indices of non-zero elements. Without loss of accuracy, our methods reduce the storage of LeNet-5 and LeNet-300 by ratios of 691× and 233 ×, respectively, significantly outperforming state of the art. The effectiveness of our methods is also evaluated on other three benchmarks (CIFAR-10, SVHN, ILSVRC12) and modern newly deep networks (ResNet, Wide-ResNet).

Video traffic characteristics of modern encoding standards: H.264/AVC with SVC and MVC extensions and H.265/HEVC.

Video encoding for multimedia services over communication networks has significantly advanced in recent years with the development of the highly efficient and flexible H.264/AVC video coding standard and its SVC extension. The emerging H.265/HEVC video coding standard as well as 3D video coding further advance video coding for multimedia communications. This paper first gives an overview of these new video coding standards and then examines their implications for multimedia communications by studying the traffic characteristics of long videos encoded with the new coding standards. We review video coding advances from MPEG-2 and MPEG-4 Part 2 to H.264/AVC and its SVC and MVC extensions as well as H.265/HEVC. For single-layer (nonscalable) video, we compare H.265/HEVC and H.264/AVC in terms of video traffic and statistical multiplexing characteristics. Our study is the first to examine the H.265/HEVC traffic variability for long videos. We also illustrate the video traffic characteristics and statistical multiplexing of scalable video encoded with the SVC extension of H.264/AVC as well as 3D video encoded with the MVC extension of H.264/AVC.

[Irreversible image compression in radiology. Current status]. / Irreversible Bilddatenkompression in der Radiologie. Aktueller Status.

Due to increasing amounts of data in radiology methods for image compression appear both economically and technically interesting. Irreversible image compression allows markedly higher reduction of data volume in comparison with reversible compression algorithms but is, however, accompanied by a certain amount of mathematical and visual loss of information. Various national and international radiological societies have published recommendations for the use of irreversible image compression. The degree of acceptable compression varies across modalities and regions of interest.The DICOM standard supports JPEG, which achieves compression through tiling, DCT/DWT and quantization. Although mathematical loss due to rounding up errors and reduction of high frequency information occurs this results in relatively low visual degradation.It is still unclear where to implement irreversible compression in the radiological workflow as only few studies analyzed the impact of irreversible compression on specialized image postprocessing. As long as this is within the limits recommended by the German Radiological Society irreversible image compression could be implemented directly at the imaging modality as it would comply with § 28 of the roentgen act (RöV).

[Telemedicine in Ophthalmology: A Useful Tool in Store-and-Forward Counselling?]. / Telemedizin in der Augenheilkunde: Ein Hilfsmittel in der konsiliarischen Mitbeurteilung?

Side by side with the progress in computers and imaging, telemedicine has already been used successfully in a large number of specialties of medicine. But high-quality images are not always suitable for transfer via modem because of their file size. The present experimental study was conducted to determine the effects of image compression by the JPEG algorithm on image quality and on the reliability of diagnosis after compression. Digital photographs of the retina were taken and the JPEG compressed images assessed by an experienced ophthalmologist. The present study showed a high reliability of diagnosis and a good agreement between the observations taken at the patient and at the computer. For this reason, JPEG image compression algorithm is suitable for reducing image size for producing high-quality images manageable for transmitting via modem in a store-and-forward teleophthalmological system.