Analysis of response‐time compensation for black‐frame insertion

Abstract— An impulsive driving technique has been widely adopted for the elimination of motion blur in LCDs. Although the problem of slow temporal response time is very well known for LCDs, the inherent motion blur of moving objects in hold‐type displays has a more‐serious impact on display performance. It is well known that even very fast LCDs with zero response time still suffer from the motion‐blur artifact due to hold‐type driving effects. However, a fast temporal response is also critical in order to maximize the blur‐reduction effect even in the case of impulsive driving. In this paper, the special behavior of LC molecules in an impulsive driving environment has been analyzed especially for the case of black‐frame insertion, and we propose an effective means to implement optimized response‐time compensation (RTC) for the black‐frame insertion technique.     

Motion‐blur characterization on liquid‐crystal displays

Abstract— In this paper, several methods to characterize motion blur on liquid‐crystal displays are reviewed. Based on the assumptions of smooth‐pursuit eye tracking and one‐frame temporal luminance integration, a simple algorithm has been proposed to calculate the normalized blurred edge width (N‐BEW) and motion‐picture response time (MPRT) with a one‐frame‐time moving‐window function to LC temporal step response curves. A custom measurement system with a fast‐eye‐sensitivity‐compensated photodiode has been developed to characterize motion blur based on LC response curves (LCRCs). MPRT values obtained by using the algorithm mentioned above and those from the smooth‐pursuit‐camera methods agree. Perception experiments were conducted to validate the correspondence between the simulated results and actual perceived images by the human eyes. In addition, the insufficiency of MPRT to evaluate motion blur on impulse‐type light‐generation LCDs, by analyzing the measurement results of a scanning backlight LCD, is discussed.     

Characterizing displays by their temporal aperture: A theoretical framework

Abstract— The spatio‐temporal aperture and sample rate of a video display determines both the static and dynamic resolution of the video signal that is rendered. The dynamic display characteristics like the visibility of large‐area flicker, motion judder, and motion blur can be derived from the frame rate and the temporal extent of the pixel aperture (i.e., the temporal aperture). For example, liquid‐crystal displays (LCDs) have an aperture that is relatively small in the spatial dimension and wide in the temporal domain. Consequently, moving objects displayed on an LCD suffer from motion blur. Especially in TV applications, the temporal dimension has a large impact on the overall picture quality. The temporal aperture, together with the frame rate, is shown to predict the amount of perceived large‐area flicker, motion judder, and motion blur and also the performance of motion‐blur reduction algorithms for LCDs. From this analysis it is further determined how to obtain the optimal temporal aperture of a television display, for which not only properties of the human visual system (HVS), but also the properties of the video signal have to be taken into account.     

A perceived sharpness metric based on the luminance slope and overshoot of the motion‐induced edge‐blur profile

To reduce perceived motion blur on liquid crystal displays, typically various techniques such as overdrive, scanning backlight, black‐data insertion, black‐field insertion, and frame rate up‐conversion are widely employed by the liquid crystal display industry. These techniques aim to steepen the edge transitions by improving the dynamic behavior of the light modulation. However, depending on the implementation, this may result in the perception of irregularly shaped motion‐induced edge‐blur profiles. It is not yet fully understood how these irregularities in the steepened edge‐blur profiles contribute to the perceived sharpness of moving objects. To better understand the consequences of several motion‐blur reduction techniques, a perception experiment is designed to evaluate the perceived sharpness of typical motion‐induced edge‐blur profiles at several contrast levels. Relevant characteristics of these profiles are determined on the basis of the perception results by means of regression analysis. As a result, a sharpness metric with two parameters is established, where one parameter relates to the edge slope and the other to the overshoot/undershoot part of the motion‐induced edge‐blur profile.     

A new driving method introducing a display period for AMOLEDs

Abstract— We have proposed an Advanced‐Clamped‐Inverter driving method for the fabrication of AMOLEDs, in which one frame period is divided into an addressing period and a display period. This driving method enables the AMOLEDs to produce excellent moving images without motion blur and false pixels, and has peak‐luminance characteristics because of its unique light‐emission scheme of the OLED elements. Good inter‐pixel uniformity was also achieved in a previous clamped‐inverter driving method. We fabricated AMOLEDs and experimentally confirmed their characteristics.     

Perception-based model simplification for motion blur rendering

Motion blur effects are important to motion perception in visual arts, interactive games and animation applications. Usually, such motion blur rendering is quite time consuming, thus blocking the online/interactive use of the effects. Motivated by the human perception in relation to moving objects, this paper presents simplified geometric models that enable to speedup motion blur rendering, which has not been tracked in motion blur rendering specifically. We develop a novel algorithm to simplify models with motion-aware, to preserve the features whose characteristics are perceivable in motion. We deduce the formula to outline the level of detail simplification by the object moving velocity. Using our simplified models, methods for motion blur rendering can achieve the rendering quality as using the original models, and obtain the processing acceleration mostly. The experimental results have shown the effectiveness of our approach, more acceleration with the larger models or faster motion (e.g. for the dragon model with over a million facets, the motion-blur rendering via hierarchical stochastic rasterization is sped up by over 27 times).     

Flicker visibility in scanning‐backlight displays

Abstract— Scanning‐backlight technology reduces motion blur caused by the sample‐and‐hold effect of traditional liquid‐crystal displays. A side effect of impulse‐type backlight systems is that large‐area flicker may be introduced (like in displays using cathode‐ray tubes). The seriousness of the perceived large‐area flicker is investigated in perception experiments for various implementations of a scanning‐backlight system and for different types of image material. Results show that the main factors contributing to the visibility of large‐area flicker are refresh rate, temporal luminance distribution within a frame period, spatial luminance distribution in the image, and whether or not there is motion in the image.     

Controlling Motion Blur in Synthetic Long Time Exposures

In a photo, motion blur can be used as an artistic style to convey motion and to direct attention. In panning or tracking shots, a moving object of interest is followed by the camera during a relatively long exposure. The goal is to get a blurred background while keeping the object sharp. Unfortunately, it can be difficult to impossible to precisely follow the object. Often, many attempts or specialized physical setups are needed. This paper presents a novel approach to create such images. For capturing, the user is only required to take a casually recorded hand‐held video that roughly follows the object. Our algorithm then produces a single image which simulates a stabilized long time exposure. This is achieved by first warping all frames such that the object of interest is aligned to a reference frame. Then, optical flow based frame interpolation is used to reduce ghosting artifacts from temporal undersampling. Finally, the frames are averaged to create the result. As our method avoids segmentation and requires little to no user interaction, even challenging sequences can be processed successfully. In addition, artistic control is available in a number of ways. The effect can also be applied to create videos with an exaggerated motion blur. Results are compared with previous methods and ground truth simulations. The effectiveness of our method is demonstrated by applying it to hundreds of datasets. The most interesting results are shown in the paper and in the supplemental material.     

Evaluation of motion performance on scanning‐backlight LCDs

Abstract— The scanning‐backlight technique to improve the motion performance of LCDs is introduced. This technique, however, has some drawbacks such as double edges and color aberration, which may become visible in moving patterns. A method combining accurate measurements of temporal luminance transitions with the simulation of human‐eye tracking and spatiotemporal integration is used to model the motion‐induced profile of an edge moving on a scanning‐backlight LCD‐TV panel that exhibits the two drawbacks mentioned above. The model results are validated with a perception experiment including different refresh rates, and a high correspondence is found between the simulated apparent edge and the one that is perceived during actual motion. Apart from the motion‐induced edge blur, the perception of a moving line or square‐wave grating can also be predicted by the same method starting from the temporal impulse and frame‐sequential response curves, respectively. Motion‐induced image degradation is evaluated for both a scanning‐ and continuous‐backlight mode based on three different characteristics: edge blur, line spreading, and modulation depth of square‐wave grating. The results indicate that the scanning‐backlight mode results in better motion performance.     

一种基于运动估计的3D视频降噪算法

在视频图像降噪中,时域滤波比空域滤波在保护边缘和细节,提高PSNR方面更具有优势。根据此原理,提出了一种基于运动估计的3D降噪算法。该3D降噪算法结合了时域滤波和空域滤波。在时域上,基于运动估计在当前帧的前一帧和后一帧中同时搜索匹配块。对搜索到的匹配块进行运动强度检测,如果运动强度较小,就进行时域滤波,如果运动强度过大,就为对当前块进行空域滤波。另外,设计了噪声标准差估计单元,能够根据噪声标准差自动调整运动强度检测阈值,准确判断块的运动强度。同时,估计出的噪声标准差也用作空域滤波器的参数。     

Motion Deblurring from a Single Image using Circular Sensor Motion

Image blur caused by object motion attenuates high frequency content of images, making post‐capture deblurring an ill‐posed problem. The recoverable frequency band quickly becomes narrower for faster object motion as high frequencies are severely attenuated and virtually lost. This paper proposes to translate a camera sensor circularly about the optical axis during exposure, so that high frequencies can be preserved for a wide range of in‐plane linear object motion in any direction within some predetermined speed. That is, although no object may be photographed sharply at capture time, differently moving objects captured in a single image can be deconvolved with similar quality. In addition, circular sensor motion is shown to facilitate blur estimation thanks to distinct frequency zero patterns of the resulting motion blur point‐spread functions. An analysis of the frequency characteristics of circular sensor motion in relation to linear object motion is presented, along with deconvolution results for photographs captured with a prototype camera.     

A study on a driving method of OLED displays for better motion image quality with adaptive temporal aperture control

Degradation of motion image quality by motion blur on hold‐type displays, such as liquid‐crystal displays and organic light‐emitting diode displays, is a well‐known issue. To improve motion image quality, a driving method with a shorter temporal aperture has been proposed. However, a shorter temporal aperture requires higher instantaneous luminance on displays. Higher instantaneous luminance accelerates the lifetime degradation of organic light‐emitting diode. Therefore, we have been developing a driving method with adaptive temporal aperture control for a longer lifetime and better motion image quality. However, two image quality degradations were perceived when this driving method was applied. One of these degradations was caused at the boundary between the different temporal apertures. The other degradation was caused by switching the temporal aperture between frames. Hence, we have also proposed transition area and period insertion methods to suppress these degradations. In this paper, we discuss the mechanism of these degradations and confirm the effectiveness of our proposed methods by subjective evaluations. In the results, the degradations were suppressed by inserting 80 lines of transition area and by inserting 50 frames of transition period.     

A novel driving method and device to reduce color breakup in color‐sequential displays

Abstract— Color‐sequential displays offer a better luminous efficiency, a higher spatial resolution, and a lower cost than conventional displays. However, a common problem is that visual effects cause color edge‐blurring of a moving picture, a phenomenon called color breakup or rainbow effects. Most driving methods, such as increasing the frame rate and inserting a black/white frame or another color sub‐frame to reduce the color breakup in color sequential displays has been presented in many papers, but every method has some limitations and problems. An innovative driving method and device to reduce the color‐breakup phenomenon will be demonstrated in this paper, designed without increasing the driving frequency. Instead, the brightness is increased by one third at the very least. Our method divides the driving frequency into four sub‐frames (WRGB), which is operated at 180 Hz compared to 240 Hz for conventional driving. Our result shows that the image quality is improved. The color‐breakup simulation based on “eye trace integration” and compensated white light will also be presented in this paper.     

A high image quality organic light‐emitting diode display with motion blur reduction for ultrahigh resolution and premium TVs

In this paper, we present a high image quality organic light‐emitting diode (OLED) display with motion blur reduction technology. Our latest work includes driving method that reduces motion blur using an adaptive black data insertion, brightness compensation technology, the simple structure pixel with low capacitance coupling for horizontal noise, and the multifunction integrated gate driver. The moving picture response time (MPRT) value of the OLED display panel with a fast response time was significantly affected by the frame frequency and the compensation driving method. The MPRT value of the large‐size OLED display panels was significantly decreased by using the integrated gate driver circuit with an MPRT reduction method. The decrease in the MPRT value originated from the turning of the emitting pixels off in advance resulting from providing black data. The integrated gate drivers were designed to achieve the normal display, the black data insertion, and the compensation mode. The MPRT value of the 65‐in. ultrahigh‐definition (UHD) OLED panels was decreased to 3.4 ms by using an integrated gate driver circuit. The motion blur of large‐size OLED display panels was significantly reduced due to a decrease in the MPRT value.     

Motion Blur for EWA Surface Splatting

This paper presents a novel framework for elliptical weighted average (EWA) surface splatting with time‐varying scenes. We extend the theoretical basis of the original framework by replacing the 2D surface reconstruction filters by 3D kernels which unify the spatial and temporal component of moving objects. Based on the newly derived mathematical framework we introduce a rendering algorithm that supports the generation of high‐quality motion blur for point‐based objects using a piecewise linear approximation of the motion. The rendering algorithm applies ellipsoids as rendering primitives which are constructed by extending planar EWA surface splats into the temporal dimension along the instantaneous motion vector. Finally, we present an implementation of the proposed rendering algorithm with approximated occlusion handling using advanced features of modern GPUs and show its capability of producing motion‐blurred result images at interactive frame rates.     

Motion artifacts on 240‐Hz OLED stereoscopic 3D displays

Temporal multiplexing is a popular approach for presenting different images to the two eyes in stereoscopic 3D (S3D) displays. We examined the visibility of flicker and motion artifacts—judder, motion blur, and edge banding—on a 240‐Hz temporally multiplexed S3D OLED display. Traditionally, a frame rate of 120 Hz (60 Hz per eye) is used to avoid visible flicker, but there is evidence that higher frame rates provide visible benefits. In a series of psychophysical experiments, we measured the visibility of artifacts on the OLED display using temporal multiplexing and those of a 60‐Hz S3D LCD using spatial multiplexing. We determined the relative contributions of the frame rate of the content, update rate of the display, duty cycle, and number of flashes. We found that short duty cycles and low flash numbers reduce the visibility of motion artifacts, while long duty cycles and high flash numbers reduce flicker visibility.     

Comparisons of motion‐blur assessment strategies for newly emergent LCD and backlight driving technologies

Abstract— Compared to the conventional cathode‐ray‐tube TV, the conventional liquid‐crystal TV has the shortcoming of motion blur. Motion blur can be characterized by the motion‐picture response‐time metric (MPRT). The MPRT of a display can be measured directly using a commercial MPRT instrument, but it is expensive in comparison with a photodiode that is used in temporal‐response (temporal luminance transition) measurements. An alternative approach is to determine the motion blur indirectly via the temporal point‐spread function (PSF), which does not need an accurate tracking mechanism as required for the direct “spatial” measurement techniques. In this paper, the measured motion blur is compared by using both the spatial‐tracking‐camera approach and the temporal‐response approach at various backlight flashing widths. In comparison to other motion‐blur studies, this work has two unique advantages: (1) both spatial and temporal information was measured simultaneously and (2) several temporal apertures of the display were used to represent different temporal PSFs. This study shows that the temporal method is an attractive alternative for the MPRT instrument to characterize the LCD's temporal performance.     

Controlled tracking in urban terrain: Closing the loop

We investigate the challenging problem of integrating detection, signal processing, target tracking, and adaptive waveform scheduling with lookahead in urban terrain. We propose a closed‐loop active sensing system to address this problem by exploiting three distinct levels of diversity: (1) spatial diversity through the use of coordinated multistatic radars; (2) waveform diversity by adaptively scheduling the transmitted waveform; and (3) motion model diversity by using a bank of parallel filters matched to different motion models. Specifically, at every radar scan, the waveform that yields the minimum trace of the one‐step‐ahead error covariance matrix is transmitted; the received signal goes through a matched‐filter, and curve fitting is used to extract range and range‐rate measurements that feed the LMIPDA‐VSIMM algorithm for data association and filtering. Monte Carlo simulations demonstrate the effectiveness of the proposed system in an urban scenario contaminated by dense and uneven clutter, strong multipath, and limited line‐of‐sight.     

流动颗粒显微图像测量技术研究

针对显微环境下流动颗粒测量的需要,构建了测量平台,研制了基于MEMS 工艺的测量器件。在分析流动颗粒显微图像特征的基础上,提出了基于颗粒运动特性的图像 测量流程,其中提出了基于基准桢差分的目标提取算法,解决了流动颗粒目标分割的问题, 根据图像运动模糊的退化模型,研究了图像模糊恢复的问题。最后以润滑油中的磨损颗粒为 例,验证了该文的分析方法对流动颗粒检测的有效性。     

Evaluation of liquid‐crystal‐display motion blur with moving‐picture response time and human perception

Abstract— The moving‐picture response time (MPRT) for measuring liquid‐crystal‐display (LCD) motion blur was studied by several organizations in 2001. To determine the LCD motion blur that humans perceive, subjective evaluation experiments using the method of adjustment was conducted to find a strong correlation between perceived motion blur and extended blurred edge time (EBET) of the MPRT measurements. MPRT thus clearly indicates the degree of which humans perceive motion blur.