• Title/Summary/Keyword: afterimage

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Visual Quality Optimization for Privacy Protection Bar-based Secure Image Display Technique

  • Park, Sanghyun;Kang, Sang-ug
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.11 no.7
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    • pp.3664-3677
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    • 2017
  • Abrupt scene changes generally incur the afterimage effect. So, the unblocked image portion is still viewed by human eyes just after it is blocked by some pattern. Yovo's secure display method utilized this phenomenon and it is systematically analyzed using computational afterimage modeling by replacing the complex afterimage effect via simple low-pass filtering. With this approach, realistic images perceived by the human eye can be computationally generated at every single moment, especially reflecting the afterimage effect. The generated images are compared with the original images to determine the factors that affect the image quality of the secure display method. The simulation results demonstrate that the ratio of the unblocked portion to the blocked portion of an image and the playback rate are two primary factors related to the recognized image quality. We also found that the two factors are still effective for generalized secure display techniques.

The additive mixture of induced colors by background colors in the afterimage (색채 잔상 지각에서 배경 색에 의해 유도된 색의 가산 혼합 현상 탐구)

  • Kim Sun Ah;Chung Chan-Sup
    • Korean Journal of Cognitive Science
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    • v.15 no.4
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    • pp.21-30
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    • 2004
  • Additive color mixture of two different background colors appeared in the afterimage of a gray circle centered on an isoluminant bichromatic background (red/green, blue/green, or blue/yellow background). The chromatic mixture still appeared in the afterimage of a gray circle on a bichromatic background at different luminance levels, and also appeared in a large test field. The saturation of the induced color was observed to increase as the overall luminance of adaptation background stimulus increase of the size of test field decreases. It was found that the chromatic mixture does not appear with a chromatic or achromatic boundary inserted on the center of the test field. The boundary seems to prevent the induced color on each side of test field from spreading to the other side so that the induced color does not appear mixed but divided into two different colors. Without a boundary on the test stimulus, the color information induced in the afterimage seems to be too weak to create a subjective boundary between the two colors and consequently propagate inward appearing mixed.

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The Principle of Moving Image and the Development of the Optical Instruments in the 19th Century - On the Theory of Afterimage Effect and the Scientific Development of Moving Image - (동영상의 원리와 19세기 시각기구의 발전과정 - 잔상이론과 동영상의 과학적 발전에 대해 -)

  • LEE, Sang-Myon
    • Korean Association for Visual Culture
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    • v.19
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    • pp.189-221
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    • 2012
  • This thesis investigates the development of optical instruments in the 19th century, before the birth of the cinema, and the principle of the perception of moving images. For this purpose it traces the development stages of the optical instruments which demonstrated 'illusion of movement' from 1820s when the 'persistence of vision' had begun to be researched by scientists. Then, it examines the theory of the 'persistence of vision' or 'afterimage effect' known as the principle in the perception of illusion of movement produced from moving images. The optical instruments in the 19th century that presented the illusion of movement began with the Thaumatrope (double-sided picture disc), and appeared from the Phenakistiscope/Stroboscope (revolving disc), the Zoetrope (revolving drum) and the Praxinoscope (mirror-reflexive revolving drum), and in 1892 the Projection-Praxinoscope presented firstly the moving pictures (animation) on the screen. According to the research of psychology and physiology in the early 20th century it has been recognized that the 'afterimage effect' theory is not sufficient to explain the perception of illusion of movement from the moving images which is closely related to the particularity of the visual perception system of the human eyes. Since then, the Phi-phenomenon suggested 1912 by the Gestalt psychologist, Max Wertheimer (1880-1943), is regarded as the most persuasive theory until now, although it is still imperfect.

A Case Study on the Driver's Glare Hazard Assessment by Light Reflection of Curtain Wall Type Buildings (커튼월 고층 건물 빛 반사에 의한 운전자 눈부심 가능성)

  • Song, Hyung-Jun;Seo, Young Kyo
    • Journal of the Korean Society of Safety
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    • v.36 no.2
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    • pp.26-31
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    • 2021
  • Buildings with glass curtain walls have become popular due to their appealing aesthetics and ability to let in natural light. However, light reflection from the glass surface is unavoidable in these buildings. In particular, the reflection of light from the glass envelope can create afterimage glare, a hazard to nearby drivers and pedestrians. Despite this potential danger, glare from buildings with curtain walls has not been well-studied. Hence, we analyzed the effect of light reflection on glare around a glass-enclosed skyscraper, depending on its surface reflectance. We investigated the potential hazard of glare to drivers using a commercially available software program. The results indicate that the direction of light reflection is distinctive when the incident angle of solar light increases. Moreover, this light reflection is high enough to induce an afterimage to drivers and pedestrians near the building. We found that keeping the reflectance of the building surface under 3% is required to minimize the afterimage hazard to drivers. Consequently, we recommend managing glass reflectance and installing additional traffic safety systems to reduce traffic accidents near curtain wall buildings.

An Implementation of FPGA Embedded System for Real-Time SONAR Signal Display Using the Triple Buffering Method (삼중 버퍼링 방법을 이용한 실시간 소나 신호 디스플레이를 위한 FPGA 임베디드 시스템의 구현)

  • Kim, Dong-Jin;Park, Young-Seak
    • IEMEK Journal of Embedded Systems and Applications
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    • v.9 no.3
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    • pp.173-182
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    • 2014
  • The CRT monitor display system for SONAR signal that are commonly used in ships or naval vessels uses vector scanning method. Therefore the processing circuits of the system are complex. Also the purchase of parts is difficult as well as high-cost because the production had been shut down. FPGA-based embedded system is flexible to various digital applications because it can be able to simplify processing circuits and to make a easy customized design for end user, and it provides low-cost high-speed performance. In this paper, we describe an implementation of FPGA embedded system for real-time SONAR signal display using the triple buffering method to overcome some weakness of existing CRT system. Our system provides real-time acquisition and display capability of SONAR signal, and removes afterimage effect that is a critical problem of the system proposed in the preceding study.

Thee contour extraction algorithm of the moving Object using the CCD camera (CCD Camera를 이용한 이동체의 궤적 추출 알고리즘)

  • Lim Cheong;Kim Yong-Deak
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.42 no.2 s.302
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    • pp.81-86
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    • 2005
  • It is not easy to find and extract a moving object from its background. The extraction method is specific as what it is and how its environment is. So recently the more general method which is less affected by its environmental elements is required. So, In this paper we report on the moving object extraction algorithm using the features of the interlaced-image-capturing method which is adopted in the CCD Camera, an afterimage for exposing time and the fact that an afterimage has same color level. Unlike much of existing algorithms it is use oかy one stationary picture to apply this algorithm.

A Study on FPGA Design for Rotating LED Display Available Video Output (동영상 표출이 가능한 회전 LED 전광판을 위한 FPGA 설계에 관한 연구)

  • Lim, Young-Sik;Lee, Seung-Ho
    • Journal of IKEEE
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    • v.19 no.2
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    • pp.168-175
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    • 2015
  • In this paper, we propose FPGA design technique for rotating LED display device which is capable of displaying videos with the use of the afterimage effect. The proposed technique is made up of image data correction process based on inverse gamma correction and error diffusion, block interleaving process, and data serial output process. The data correction process based on inverse gamma correction and error diffusion is an image data correction step in which image data received are corrected by inverse gamma correction process to convert the data into linear brightness characteristics, and by error diffusion process to reduce the brightness reduction phenomenon in low-gray-level which is caused by inverse gamma correction. In the block interleaving process, the data of the frames entered transversely are first saved in accordance with entrance order, and then only the longitudinal image data are read. The data serial output process is applied to convert the parallel data in a rotating location into serial data and send them to LED Driver IC, in order to send data which will be displayed on high-speedy rotating LED Bar. To evaluate the accuracy of the proposed FPGA design technique, this paper used XC6SLX45-FG484, a Spartan 6 family of Xilinx, as FPGA, and ISE 14.5 as a design tool. According to the evaluation analysis, it was found that goal values were consistent with simulation values in terms of accurate operation of inverse gamma and error diffusion correction, block interleaving operation, and serialized operation of image data.

Optical system design for stereoscopic video-recorder (비디오 입체영상녹화를 위한 광학계 설계)

  • Hong, Kyung-Hee
    • Korean Journal of Optics and Photonics
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    • v.13 no.6
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    • pp.506-509
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    • 2002
  • An optical system for a stereoscopic video recorder is designed with the field of view 42$^{\circ}$ and effective diameter 22 mm. We can use it by attaching it to the front lens of any video camera or camcorder to record a stereoscopic scene. This system is a double Kepler type afocal system to make the image erect and a bi-ocular type to record and display the stereoscopic scene. The optical tube length is folded with several flat mirrors and a beam splitter to be compact. This optical system is composed of 4 groups of lenses and each group serves as a relay lens for minimizing the vignetting effect. Whole field stereoscopic scenes may be captured by perpendicularly polarized alternated recording with a chopper and two perpendicular polarizers, without any loss of light energy. The displayed images may be seen stereoscopically with polarized spectacles and are kinetic because of an afterimage effect.

A line study on movement expression in Dragonball of Toriyama Akira (토리야마 아키라의 <드래곤볼>에 나타난 운동표현에 관한 선 연구)

  • Cho, Dai-Ho;Park, Keong-Cheol
    • Cartoon and Animation Studies
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    • s.31
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    • pp.153-176
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    • 2013
  • In the early 20th century, the some of futurist painter was attempted to represents the 'fast-paced' and 'dynamism' on a two-dimensional picture. The expression of fast-paced and dynamic for look like move image in the painting have evolved as a variety of visual symbol. Visual symbols that represent these movements were settled as the line of the most movement expression in the comic. The of Toriyama Akira gained worldwide popularity is emphasized speed and dynamism as the action genre in cartoon, is nice a data to research the line of the movement expression of cartoon. There is three terms as the action line, The speed line, the effect line on the movement expression in The glossary of in the dictionary of , but it not easy to Separate them by means similar. This study is willing to says the semantically problem of previous lines on the movement expression and to present a new alternative in order to study the line on the movement expression of . This study Separate the line on movement expression from symbolic the perspective and try to newly define by using, was classified lines of four kinds by add the afterimage line on existing the speed line, the motion line, the effect line. First, the speed line was defined as 'The line expressing the movement expression of a moving target as the concept of speed'. It on the way of expression was subdivided the direct as speed line when it alter the shape of the target and the indirect speed line when it alter the background of the target. Second, the motion line was defined as 'The line simplified the moving form or the moving path of moving target'. Third, the effect line was defined as 'the line emphasizing the movement expression of a moving target by Sensory expression or emotional expression. Fourth, the afterimage lines was defined as 'The line expressing slowly moving or swaying the movement expression of target to the afterimage effect. The terminology presented in this study will be able to help the understanding of the line on the movement expression .

A Study on the Spatial Characteristics in the Proun Raum (프로운 라움 공간특성에 관한 연구)

  • 김성혜
    • Korean Institute of Interior Design Journal
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    • no.38
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    • pp.14-20
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    • 2003
  • In 1923, El. Lissitzky designed ‘Proun Raum’ to realize his spatial experiment in paintings that are called 'Proun'. For this, Lissitzky taken Pome 'element' to construct his imaginary space that combine time with space. Especially, Quadrangle make an important role by the reason of its potential energy. In other words, alteration of its four corners turn Quadrangle to rectangle or square, etc, and describe some force, motion and location as itself. Analyzing 'Proun' and 'A and Pangeometry' that describes his spatial concept, spatial characteristics of 'Proun Raum' are comprehended, and the significance of spatial construction method in 'Proun Raum' are summarized as follows; occurrence of spectator's visual guide by elements, secession of afterimage, do-construction of the border.