A real‐time encoding and decoding system for nonlinear HDTV editor

A real‐time encoding and decoding system (REDS) for HDTV that can be used for nonlinear HDTV editing in studio has been developed. The intrapicture coding of motion JPEG is implemented and optimized in the REDS so that a high‐quality image can be recovered for the nonlinear editing. The REDS has a parallel architecture with multiple programmable digital signal processors (DSP) and reconfigurable field programmable logic devices (FPLD). The HDTV image is spatially partitioned and concurrently processed by the multiple processors. The programmable DSPs perform the discrete cosine transform and quantization to reduce the spatial redundancy of the HDTV image, whereas the FPLDs perform the variable length coding to reduce the statistical redundancy. In addition, field‐based quantization matrices are developed for HDTV images. The REDS has the programmability and the random accessibility of image frames, the two most important features for a nonlinear HDTV editing system. © 2000 John Wiley & Sons, Inc. Int J Imaging Syst Technol 11, 152–157, 2000     

Optimal image formats for advanced television and the NII

Various high-definition television (HDTV) and advanced television (ATV) scanning parameter sets have been proposed, including the “Grand Alliance” proposal before the U.S. Federal Communications Commission. However, the American Society of Cinematographers has recommended that the proposed 16:9 aspect ratio should be replaced by a simpler and more pleasing 2:1 aspect ratio. Various proposed and existing formats of interest include 640 × 480, 864 × 648, 1024 × 768, 1152 × 864, and 1280 × 1024 for computer screens, and widescreen formats at or near 2 megapixels. When these formats are analyzed in the context of forming the basis for a suitable hierarchy of scalable resolutions and temporal rates with this new aspect ratio in mind, some significant patterns emerge. Certain fundamental issues in constructing a convenient hierarchy include progressive scanning (no interlace), square pixels (or simple squeezes), and a simple fractional relationship between members of the hierarchy, both temporally and in resolution. There is also a need to exceed 70 Hz in display rate for the wide, bright screens of HDTV/ATV. There is great value in compatibility with computer displays, which exceed 70 Hz with various common resolutions in today's ubiquitous 4:3 aspect ratio. The development of a national and global information infrastructure (NIL/GII) would benefit greatly from such commonality of computer and HDTV/ATV formats. There will be a need for every display to present the richest possible image quality in support of the presentation of text, graphics, and still images, as well as our national and world hertage of high-resolution films. It will also be necessary to develop guidelines for the composition of images and text by taking into account the common display formats which will be available. This is done by understanding the common “safe area” throughout the variety of existing and future displays, and by considering legibility on each. The best possible architecture for digital HDTV/ATV for the United States and internationally will be needed to support the major NII/GII applications, including health care, library access, education, collaborative and remote work, interactive news, on-line commerce, and many other uses in addition to entertainment..©1994 John Wiley & Sons Inc     

数字视频系统开发测试平台及其实现

报告了自主研制的基于ＰＣ计算机ＰＣＩ总线的数字视频产品的开发测试平台。该系统以其功能强、通用性好、便于扩充、使用方便等伏良性能已成功地应用在高清晰度电视（ＨＤＴＶ）信源解码器的演示、视频编码器和复用器的研制以及标准清晰度数字电视（ＳＤＴＶ）的开发过程中，具有广阔的应用前景。     

Video compression for the grand alliance: A historical perspective

This article outlines the evolution of the Grand Alliance (GA) highdefinition television (HDTV) standard from its divided beginnings among several systems to its final state as the proposed standard for HDTV transmission in the United Stales today. Earlier video compression standards are briefly described, and their influence on the first four all-digital HDTV proposals is demonstrated. The salient features of each proposed video compression system are high-lighted, and the more recent MPEG-2 compression standard is introduced. MPEG-2 was adopted as the basis for video compression by the GA, a group of the former HDTV competitiors. The formation of the GA is described, and the work of its Video Compression Specialists Group on evaluating modifications to MPEG-2 is reviewed.©1994 John Wiley & Sons Inc     

HDTV transmission formats and migration path

The current proposal for terrestrial broadcasting of HDTV in the United States incorporates a flexible approach toward encoding and transmission. Specifically, the format used to encode an HDTV picture will not be fixed. Instead, a variety of transmission formats will be available, unlike the current (NTSC) system. Furthermore, although a basic set of formats will exist initially, it is possible that this set can change over time, depending on the evolution of relevant technologies. This article will consider various topics related to the current and future transmission formats associated with HDTV systems in the United States. This article discusses the usefulness of allowing multiple transmission formats and describes the formats which will be immediately available for HDTV broadcasting, as agreed upon by the Grand Alliance. The relationship between source formats, transmission formats, and display formats are discussed, with reference to some of the signal processing modules required to convert between formats. Finally, the migration of HDTV to incorporate additional formats is addressed. This report describes a method of achieving this migration in a backward-compatible manner, so that the basic HDTV receivers will not become obsolete.©1994 John Wiley & Sons Inc     

All-optical digital 4 × 2 encoder based on 2D photonic crystal ring resonators

The photonic crystals draw significant attention to build all-optical logic devices and are considered one of the solutions for the opto-electronic bottleneck via speed and size. The paper presents a novel optical 4 × 2 encoder based on 2D square lattice photonic crystals of silicon rods. The main realization of optical encoder is based on the photonic crystal ring resonator NOR gates. The proposed structure has four logic input ports, two output ports, and two bias input port. The photonic crystal structure has a square lattice of silicon rods with a refractive index of 3.39 in air. The structure has lattice constant ‘a’ equal to 630 nm and bandgap range from 0.32 to 044. The total size of the proposed 4 × 2 encoder is equal to 35 μm × 35 μm. The simulation results using the dimensional finite difference time domain and Plane Wave Expansion methods confirm the operation and the feasibility of the proposed optical encoder for ultrafast optical digital circuits.     

3‐D spatiotemporal subband decomposition of image sequences by mathematical morphology

Abstract

An efficient 3‐D spatiotemporal image sequence decomposition method using mathematical morphology is described in this paper. The method can be used to decompose the spectrum of the input signal into 8 and 4 spatiotemporal subband images. It does this using two different sets of structuring elements. After decomposition, each band image can be decimated and coded for data transmission. This subband pyramid scheme preserves the number of pixels which existed in the original image, has an efficient hierarchical data structure, and allows parallel implementation. Therefore, this scheme has great potential for High Definition Television (HDTV) coding, multimedium video compression, etc. As regards filtering, the unique advantages of morphology over the linear filtering approach are: 1) it utilizes direct geometric interpretations; and 2) it is simple and efficient when used in conjunction with parallel/pipelining hardware. Some image sequence examples are given to show the effectiveness of this approach.     

The IBM POWER visualization system: A system for HDTV postproduction,and more

The unique combination of processing power, memory capacity, and I/O bandwidth found in the IBM POWER Visualization System (PVS) makes it an ideal tool for high-end, format and resolution-independent, digital postproduction applications. From computer graphics rendering to video editing, rotoscoping, and special effects, the versatile nature of this general-purpose computer allows it to adapt constantly to the specific tasks required during almost any phase of the postproduction process. In this articles, we first examine the hardware architecture of the PVS with specific attention paid to the different subsystems and peripherals which provide the large computational power and bandwidth necessary to do HDTV editing and effects work. Next, we describe the PVS system software layer which enables application level software to fully use all of the capabilities of the hardware. We then explore a novel on-line, nonlinear editing and effects environment available for the PVS, which allows HDTV resolution material to be digitally edited and processed at full resolution. Finally, we conclude by describing some of the applications of the PVS which allow it to be used in a variety of other ways.©1994 John Wiley & Sons Inc     

All-optical compact encoder assembled by polymer fibres

An all-optical encoder based on a 3 × 3 crossed structure was assembled by stacking three polymer fibres. The encoding functions were predicated theoretically and demonstrated experimentally with very good agreement. The total insertion loss of the device is about 1 dB and the extinction ratio is larger than 10 dB. The output state can be controlled by launching optical signals to different input port, and the input state can be identified according to the output state. We believe that the all-optical compact encoder would be used in high-density PICs.     

Rotary encoding for intravascular ultrasonic imaging systems

Images produced with an intravascular ultrasound system (IVUS) can be distorted because of uncertainty in the instantaneous angular position of a rotating ultrasonic transducer. A rotary encoder placed in proximity to the transducer is required to detect the problem; however, size constraints make a conventional electromechanical or optomechanical encoder difficult to implement. Measurements that test the feasibility of a software-derived encoder, based of the rate of decorrelation of ultrasonic RF lines with angle, are reported. Provided that the instantaneous angular velocity of the transducer can be measured, adjustments can be made to the pulse rate of the transducer, which would eliminate the image distortion.     

论高清晰度电视和电影的图像质量

本文论述了电视分解率的基本概念和最新的高清晰度电视(HSTV)扫描格式相应的技术数据,并综述和分析了国际上对电影和HDTV在这方面的技术研究成果。基本结论是HDTV和影院放映35毫米电影的图侣质量相当。本文为电视图像质量的研究提供了渊博而精粹的基础,必将促进我国高清晰度电视的发展。     

高清晰度电视与电影图像质量的评价

高清晰度电视的出现,大大地缩短了电视图像与电影图像之间的差距。本文从制作高清晰度电视节目所需的性能参数的角度,比较了ＨＤＴＶ图像和电影图像的质量。这些性能参数包括：图像锐度、灵敏度与曝光指数,以及噪声。给出了它们之间的对比关系式,评价了ＨＤＴＶ摄像机与彩色负片的总体性能。     

Image coding based on wavelet feature vector

In this article, an efficient image coding scheme that takes advantages of feature vector in wavelet domain is proposed. First, a multi‐stage discrete wavelet transform is applied on the image. Then, the wavelet feature vectors are extracted from the wavelet‐decomposed subimages by collecting the corresponding wavelet coefficients. And finally, the image is coded into bit‐stream by applying vector quantization (VQ) on the extracted wavelet feature vectors. In the encoder, the wavelet feature vectors are encoded with a codebook where the dimension of codeword is less than that of wavelet feature vector. By this way, the coding system can greatly improve its efficiency. However, to fully reconstruct the image, the received indexes in the decoder are decoded with a codebook where the dimension of codeword is the same as that of wavelet feature vector. Therefore, the quality of reconstructed images can be preserved well. The proposed scheme achieves good compression efficiency by the following three methods. (1) Using the correlation among wavelet coefficients. (2) Placing different emphasis on wavelet coefficients at different decomposing levels. (3) Preserving the most important information of the image by coding the lowest‐pass subimage individually. In our experiments, simulation results show that the proposed scheme outperforms the recent VQ‐based image coding schemes and wavelet‐based image coding techniques, respectively. Moreover, the proposed scheme is also suitable for very low bit rate image coding. © 2005 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 15, 123–130, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ima.20045     

Effect of different traversal schemes in integral image coding

Integral imaging (InIm) is a highly promising technique for the delivery of three-dimensional (3D) image content. During capturing, different views of an object are recorded as an array of elemental images (EIs), which form the integral image. High-resolution InIm requires sensors with increased resolution and produces huge amounts of highly correlated data. In an efficient encoding scheme for InIm compression both inter-EI and intra-EI correlations have to be properly exploited. We present an EI traversal scheme that maximizes the performance of InIm encoders by properly rearranging EIs to increase the intra-EI correlation of jointly coded EIs. This technique can be used to augment performance of both InIm specific and properly adapted general use encoder setups, used in InIm compression. An objective quality metric is also introduced for evaluating the effects of different traversal schemes on the encoder performance.     

3D multiwavelet based block coding algorithm for compression of volumetric medical images

Three dimensional (3D) medical images possess some specific characteristics that should be utilized by an efficient compression scheme. In this article, one such compression scheme for volumetric 3D medical image data is presented. Two processes involved in this scheme are decorrelation and encoding. Decorrelation of the 3D data is realized through 3D multiwavelet transform with apt prefiltering so as to give good representation of the image which could be exploited by the encoder. Encoding is done through proposed Block Coding Algorithm, which is embedded, block based, and wavelet transform coding algorithm without maintaining any list structures. The idea behind this algorithm is to sort the 3D transform coefficients in to a 1D array with respect to declining thresholds and to use state table to keep track of the blocks and coefficients that has been coded. In the experiment conducted on various 3D magnetic resonance and computed tomography images of human brain with multiwavelets such as Geronimo–Hardin–Massopust, Chui‐Lian, and orthogonal symmetric/antisymmetric (SA4), efficiency of the proposed scheme was weighed against the state of art encoders such as 3D Set Partitioning in Hierarchical Trees, 2D Set Partitioned Embedded BloCK Coder, and No List SPIHT. Attributes used for performance measurements are peak signal to noise ratio, bit rate, and structural similarity index of reconstructed image with respect to original image. © 2014 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 24, 182–192, 2014     

Lymph node detection method based on multisource transfer learning and convolutional neural network

Recently years, convolutional neural networks (CNNs) have proven to be powerful tools for a broad range of computer vision tasks. However, training a CNN from scratch is difficult because it requires a large amount of labeled training data, which remains a challenge in medical imaging domain. To this end, deep transfer learning (TL) technique is widely used for many medical image tasks. In this paper, we propose a novel multisource transfer learning CNN model for lymph node detection. The mechanism behind it is straightforward. Point-wise (1 × 1) convolution is used to fuse multisource transfer learning knowledge. Concretely, we view the transferred features as priori domain knowledge and 1 × 1 convolutional operation is implemented after pre-trained convolution layers to adaptively combine the transfer information for target task. In order to learn non-linear transferred features and prevent over-fitting, we present an encode process for the pre-trained convolution kernels. At last, based on convolutional factorization technique, we train the proposed CNN model and the encoder process jointly, which improves the feasibility of our approach. The effectiveness of the proposed method is verified on lymph node (LN) dataset: 388 mediastinal LNs labeled by radiologists in 90 patient CT scans, and 595 abdominal LNs in 86 patient CT scans for LN detection. Our method demonstrates sensitivities of about 85%/71% at 3 FP/vol. and 92%/85% at 6 FP/vol. for mediastinum and abdomen respectively, which compares favorably to previous methods.     

基于MSP430的高精度转台角速率校准系统设计

依据GJB1801-1993《惯性技术测试设备主要性能测试方法》设计了一套基于MSP430单片机的高精度转台角速率校准系统,实现了对速率转台的高精度角速率测量校准并给出了测试实例。该系统采用定时测角法,用高精度恒温温补晶振作为时间基准时钟,单片机控制正交解码芯片HCTL-2032对圆光栅传感器输出正交信号进行解码计数,同时设计了硬件周期同步电路保证了系统的等精度测量,最后由上位机应用软件做数据处理并显示、存储、报表打印。校准结果表明：在北京长城计量测试技术研究所超低速转速标准装置上进行角速率（0.001°/s~600°/s）校准,结果最高精度在360°间隔达到3×10-7。     

数字高清晰度电视的多分辨率视频编码

为避免浪费信息资源,利用了可分级性这一全新概念进行多分辨率视频压缩编码。分析了ＭＰＥＧ－２中选择项空间域和信噪比这两种分级技术的性能,对应用这两种技术得到的高清晰度电视图像质量和普通电视图像质量进行了评价,最后指出了这两种技术所存在的问题。     

A microstep controller of a DC servomotor

A microstep controller of a DC servomotor is developed for accurate positioning and smooth movement at low-speed rotation. It consists of digital and analog positioning loops. Dividing one period of quadrature sinusoidal signals generated by an incremental encoder attached to a motor shaft into quarter sections, the digital loop controls the movement between the sections. The analog loop divides each section further into N equiangle segments to control the movement within each section. The effective angle resolution is thus 90°/MN with M being the number of slits etched on an incremental encoder. A prototype controller assembled using monolithic and hybrid integrated components has confirmed the principles of operation. Positioning accuracy was 0.009°±0.002°. A further improvement is possible with this controller by increasing the number of slits on the encoder and reducing the interpolation step size. Positioning accuracy is dominated ultimately by the amplitude fluctuation of quadrature sinusoidal outputs, and thus an automatic amplitude control should be incorporated into the encoder. The controller was first intended for applications such as crystal-pulling apparatus, astronomical observation systems, and tracking radars, which require smoothly rotating mechanisms, but it can also be applied to fine-positioning mechanisms in scanning electron and tunneling microscopes and semiconductor manufacturing equipment