Improved Picture Quality Research Articles

23-11 最小2乗法による逆ハーフトーン処理における画質改善

23-11 最小2乗法による逆ハーフトーン処理における画質改善

Joint rate control with look-ahead for multi-program video coding

In this paper, we present a new joint rate control algorithm for a multi-program video compression system using MPEG-2 compatible video encoders. The proposed joint rate control is based on both the feedback and look-ahead approaches. It dynamically distributes the channel bandwidth among the program encoders according to the relative complexities of the programs using picture and coding statistics. As opposed to previous works in this area, our algorithm does not restrict the encoders to operate with identical group of pictures (GOP) structures, i.e. the GOP boundaries need not be synchronized among the different encoders. The proposed algorithm allows adaptive distribution of the channel bandwidth among the programs, even at the start of encoding. Furthermore, it assures quick reaction to scene changes, where a feedback approach requires an unavoidable delay. Experimental results show that the proposed joint rate control with look-ahead results in improved picture quality in comparison with a pure feedback approach.

Improvement in the picture quality of moving pictures for matrix displays

— When a picture moves linearly at a specific velocity, its spectrum is distributed in the gaps between the high-order harmonics in the 3-D spatial-frequency region, and therefore the pass band of the picture spectrum is apparently extended. The extension of the pass band does not contribute to picture quality in the RGB-trio arrangement, but in some mosaic arrangements it may improve picture quality by eliminating discoloring of details due to human-vision characteristics. The relation between picture motion and quality, which can be represented by the 3D Nyquist limits, can be verified by experiment or by the simple TFZP method. Subjective evaluation of the RGGB-mosaic shows that, when the picture moves linearly, discoloring is almost completely eliminated at a velocity that can be estimated from the structure of the 3D Nyquist limits incorporating human-vision characteristics. Good picture quality can be obtained at a velocity of 1 dot/field. The TFZP method makes it possible to verify the region where discoloring is eliminated by directly observing a cross-section of the 3D Nyquist limits that incorporates human-vision characteristics.

ディスプレイ ＩＤＷ’９９関連 ワッフルリブ構造による高輝度ＡＣ形プラズマディスプレイ

50 inch AC-PDPs were developed by using waffle-structured barrier ribs. The ribs improve picture quality by preventing light from leaking neighboring cells. Black stripes are used to reduce external light reflection. The use of improved barrier ribs, phosphor, and new driving methods resulted in peak luminance of 560 cd/m2 and a darkroom contrast ratio of 560 : 1.

Low-delay, low-complexity rate reduction and continuous presence for multipoint videoconferencing

We propose new methods and architecture for low-delay, low-complexity video bit-rate reduction and continuous presence for multipoint videoconferencing. Rate reduction is performed in the discrete cosine transform (DCT) domain to achieve both low delay and low complexity. Requantization is applied to the originally quantized DCT coefficients, and the requantization errors are stored in a frame buffer in the DCT domain instead of the pixel domain. Skipped macroblocks in the original coded bitstream are processed to improve picture quality. The QCIP-to-CIF combiner is used to realize continuous presence. Asymmetric frame rates and pipelined combination on the group-of-blocks level lead to significantly reduced insertion delay compared to the published methods in the literature. Both simulation and real-time implementation results are reported to validate the proposed methods and architecture.

SXnet: A Practical Approach to Digital Video Networking—A Migration Path to Digital Video Distribution as Applied to the Broadcast News Operation

The arrival of digital video equipment in the broadcast industry brought high expectations of increased efficiency and convenience in addition to improved picture quality. Many believed that video and audio material would be treated similarly to computer files for managing, processing, and transferring via computer networks and servers. This analogy to computer data systems–as used in office automation, for example–is too simplistic and cannot be applied directly to the demanding video and audio system architecture of a broadcast facility. Stringent requirements must be placed on broadcast A/V systems to deliver high volumes of data, in continuous streams, to a multitude of users. Realtime throughput and predictable delays are all essential for on-air applications. While many approaches are available, this paper discusses the concept and implementation of a novel peer-to-peer networking system that addresses the specific requirements of the news broadcast environment. The paper emphasizes the merit of a simple solution to manage A/V material between MPEG-2 4:2:2 MP@ML Betacam SX workstations.

A method of de-interlacing with motion compensated interpolation

De-interlacing is a picture format conversion from an interlaced picture to a progressive picture. Multi-format digital broadcast and progressive display require de-interlacing technology. For this purpose, a motion adaptive method is used widely. In the motion adaptive method, the picture quality is not high enough in the motion area. Motion compensation may be effective for the improvement of picture quality. However, it sometimes causes visible distortion. We propose a new method to solve the problems of motion compensation. It consists of small blocks with large motion estimation, adaptive interpolation control by intra/inter differences and smooth motion switching. We measured the performance of the de-interlacing method objectively. It is found that the SNR of the proposed method becomes 4 to 7 dB better than the non-compensation method.

10.4: Phased Reset Timing for Improved Digital Micromirror Device™ (DMD™) Brightness

AbstractA new DMD™ architecture and operation is described in which the DMD cells are horizontally partitioned into re se t groups, each of which is loaded and reset with time phasing. Phased reset operation of reset groups affords a significant improvement in brightness and picture quality by allowing a more efficient pulse width modulation pattern.

P‐43: Evaluation of Moving‐Picture Quality on 42‐in. PDP

AbstractThe effect of new signal processing and driving methods introduced to 42‐inch HDTV DC PDP to improve moving picture quality is evaluated by both computer simulation and subjective evaluation of the moving pictures. The results show that our techniques sufficiently improve picture quality for practical use in the HDTV PDP receiver.

Improvement of the range compression in SAR image reconstruction

In order to improve picture quality in the range direction of synthetic aperture radar (SAR), a method is proposed to add post processing to range compression by using a Kalman filter. The picture quality of the SAR image is determined by the resolution and the noise of the reconstructed image. In order to improve the resolution in the range direction, the spread of the reconstructed image in the range direction is thought to blur the image. A Kalman filter is used to reduce blurring in image processing and is applied to the signals after range compression. The statistical quantity of additive noise contained in the received signal after range compression is computed and is used in filter design so that the additive noise is also reduced. The effectiveness of the above methods is demonstrated by a computer experiment for image reconstruction. Further, a method is discussed for determination of the design parameters of the Kalman filter. It is shown that the reconstructed image is improved by use of a filter designed with approximations to these parameters. © 1998 Scripta Technica. Electron Comm Jpn Pt 1, 81(2): 45–54, 1998

Improvement of the range compression in SAR image reconstruction

In order to improve picture quality in the range direction of synthetic aperture radar (SAR), a method is proposed to add post processing to range compression by using a Kalman filter. The picture quality of the SAR image is determined by the resolution and the noise of the reconstructed image. In order to improve the resolution in the range direction, the spread of the reconstructed image in the range direction is thought to blur the image. A Kalman filter is used to reduce blurring in image processing and is applied to the signals after range compression. The statistical quantity of additive noise contained in the received signal after range compression is computed and is used in filter design so that the additive noise is also reduced. The effectiveness of the above methods is demonstrated by a computer experiment for image reconstruction. Further, a method is discussed for determination of the design parameters of the Kalman filter. It is shown that the reconstructed image is improved by use of a filter designed with approximations to these parameters. © 1998 Scripta Technica. Electron Comm Jpn Pt 1, 81(2): 45–54, 1998

画質改善

画質改善

A 1.2-W single-chip MPEG2 MP@ML video encoder LSI including wide search range (H±288, V:±96) motion estimation and 81-MOPS controller

An MPEG2 MP@ML video encoder large-scale integrated circuit (LSI) has been developed including an 81 MOPS controller and motion estimator. By using two adaptive algorithms, a wide motion-estimation search area (/spl plusmn/288 pixels horizontal and /spl plusmn/96 pixels vertical) was achieved with computation complexity of only 0.5% (20 GOPS) of full search block-matching algorithm. By using this expanded motion-estimation search area, there is a significant improvement in picture quality for coding fast motion sequences. The power consumption was reduced by using an efficient pipeline architecture and optimizing the circuitry, especially in the motion-estimation block and the data transfers for the external SDRAM. The 13.7/spl times/12.4 mm/sup 2/, 4.5-M transistor device using 0.4-/spl mu/m CMOS technology dissipates 1.2 W at 3.3 V.

DVC decompression with denoising for picture quality improvement

Digital video cassette (DVC) is a quickly proliferating new standard for real-time digital video recording. DVC is presently used both in consumer and professional applications. In this paper we describe the DVC principles, data organization and video decoding algorithm. Although typically DVC video has very good quality, at low-light levels noise becomes pronounced. We show that noise in the DVC can be reduced by digital postfiltering. For this purpose, a wavelet denoising algorithm is suggested due to its unique properties. Wavelet denoising is described in detail and results of noise reduction are illustrated on examples.

動画像符号化における両方向予測の効果の検証 画質の評価と分析

In this paper, we will examine, through subjective assessment tests, the effectiveness of the bi-directional prediction scheme, which was adopted by MPEG as a standardized coding technique and which is generally assumed to be effective with respect to the coding efficiency. We will also clarify the distinctive picture quality degradation by way of the bi-directional prediction coding scheme, analyze causes, and evaluate the de7gradation quantitatively. Specifically, the assessment results show that the bi-directional prediction scheme works well in most of the sequences with respect to the picture quality improvement, but causes flickers to some sequences. The analyses show that for the picture with high contrast texture the resolution of the decoded image differs between the B-pictures and the P-pictures; this leads to the flicker through the gamma characteristics of a monitor. We will demonstrate that we can evaluate the flicker by simulating the electro-optic conversion process.

S1-3 EDTV-II規格を画質改善に活かすには

S1-3 EDTV-II規格を画質改善に活かすには

Adaptive postprocessing algorithms for low bit rate video signals

A new adaptive postprocessing algorithm to enhance the quality of a noisy video sequence is presented. The algorithm recognizes that the visibility of noise depends on local signal characteristics. It therefore classifies the video signal into different classes and uses separate nonlinear filters matched to each class. The most general version of the algorithm employs motion-compensated frame averaging to improve picture quality in a first stage. A classification algorithm subsequently divides subblocks of pixels in the averaged frame into four classes: edge, smooth, nonsmooth with motion and nonsmooth without motion. Spatial algorithms that perform multilevel median filtering, double median filtering, and median filtering are used for pixels belonging to edge, smooth, and nonsmooth with motion categories. Pixels in the nonsmooth, unmoving category are left unfiltered to preserve corresponding image texture. In a simpler version of this four-class system, the motion cues and motion-compensated frame averaging are eliminated, and the purely spatial filtering is based on a three-class algorithm. When used at the output of a 3-D subband coder at 384 kbps, the spatial postfilter was shown to provide a consistent gain in subjectively evaluated picture quality. Twenty-five viewers participated in an experiment involving three coded sequences. In a pairwise comparison of postfiltered and unfiltered sequences, the postfiltered version was judged to be better in 63 out of 75 instances.

Considerations for system development of one-chip video MUSE (HDTV) decoder

This paper describes system considerations in the development of a 3rd generation MUSE, video signal decoder implemented on a single chip. We achieved low cost while improving picture quality through cost effective improvements in the moving picture filter and through development of special interfacing circuitry which made it possible to use low cost general purpose synchronous DRAMs instead of customized FIFO DRAMs. >

82. 乳房三次元位置決め撮影における画質の向上 : 専用グリッドの検討(撮影 乳房-1)

82. 乳房三次元位置決め撮影における画質の向上 : 専用グリッドの検討(撮影 乳房-1)

A-Si TFT Technologies for AM-LCDS

ABSTRACTA technical trend for a-Si TFTs is their application to large-size, high-pixel density AM-LCDs such as XGA, EWS, and HDTV. In order to realize these LCDs, the TFT device characteristics must be improved. Future technologies, which will be necessary to fabricate TFTs with improved characteristics are as follows(1) Fully self-aligned TFT technology: A SA-TFT structure reduces the feedthrough voltage caused by parasitic capacitance due to gate/source overlap. This results in an improved picture quality and a higher aperture ratio. Fabrication of such a structure would require ion doping technology.(2) Ion doping technology: This non-Mass-separated implantation technique has large area doping capability and much higher doping speed compared to conventional ion implantation technique. The Major problems with the ion doping technique is the implantation of unwanted species which deteriorate the quality of source/drain and channel regions of TFTs.