[기술자료] 스포츠에서 슬로모션 조건을 충족하는 LED 드라이버
본문 요약:
국제 종합 스포츠 올림픽이 TV 앞에 앉아 있는 서포터즈에게 수준 높은 스포츠 프로그램을 선보이기 위해 각국이 중계방송을 한다. 고품질의 스포츠 프로그램을 제공하는 성공적인 키 중 하나는 슬로모션 재생입니다.
슬로모션 재생은 선수의 움직임을 전용으로 할 수 있으며, 때로는 심판들이 정확하고 공정한 결정을 내리는 데 사용될 수 있습니다. 기존의 비디오 속도는 NTSC 시스템의 경우 24fps(초당 프레임 수)이고 PAL/SECAM 시스템의 경우 25fps입니다.
느린 동작은 fps를 증가시켜 이루어집니다. 따라서 인공 광원으로부터 일정한 빛을 제공하는 것이 슬로 모션 캡처를 위한 성공의 열쇠입니다.
전류 리플 및 깜박임 계수
전통적인 스포츠 경기장 조명 시스템은 많은 전기 에너지를 소비하는 메탈할라이드 라이트(HID)를 기반으로 합니다. 이에 따라 HID를 LED 조명 시스템으로 교체하는 경기장이 늘고 있습니다.
에너지 절약 외에, 경기장에서 LED 조명을 사용할 때의 다른 장점으로는 더 넓은 조광 범위, 균일하게 분산된 조명, 더 나은 색 렌더링(CRI>80), 더 낮은 유색 조명, 시스템 재시동 시 대기 시간, 더 긴 수명, 저속 비디오 캡처를 위한 깜박임 없음 또는 낮은 깜박임 등이 있습니다.
전기 에너지 변동 수준을 결정하는 LED 드라이버가 LED 조명 시스템의 깜박임 성능을 판단하는 핵심 구성 요소입니다. LED 드라이버의 이상적인 출력 전류는 시간이 지남에 따라 안정적이어야 합니다.
경기장의 슬로모션 요구 사항
2016년 유럽축구연맹(UEFA) 경기장 조명 가이드에 따르면 300fps 미만의 저속 동작 비디오 캡처가 가능한 엘리트 레벨 A 경기장의 조명 시스템의 평균 플리커 계수는 5% 미만이어야 합니다
결론:
슬로 모션 비디오 캡처는 인공 조명에 따라 매우 달라집니다.
드라이버는 LED 조명 시스템에서 깜박이는 성능을 결정하는 핵심 구성 요소입니다.
목적과 요구 사항에 따라 MEANWELL은 고객이 저속으로 움직이는 캡처 애플리케이션에 적합한 LED 조명 시스템을 신속하게 구축할 수 있도록 완전한 제품군과 기술 지원을 제공합니다.
The international multi-sport Olympics held in Rio de Janeiro, Brazil is just finished this summer. Each country has corresponding broadcaster to present high quality sport programs to supporters who unfortunately was not able to watch the game on site but sit in front of TV. One of successful keys providing high quality sport program is the slow motion replay.
ㅊ Slow motion replay can provide dedicated movement of athletes and sometimes it could be used for judges to make a precise and fair decision. The conventional video speed is 24 fps (frame per second) for NTSC system and 25 fps for PAL/SECAM system.
The averaged Flicker factor of lighting system should be less than 5% for Elite Level A stadium under 300 fps slow motion video capturing according to the Union Européenne de Football Association (UEFA) stadium lighting guide 2016. The Level A and B stadium should have averaged Flicker factor less than 12% where the Level C stadium should have averaged Flicker factor less than 20%.
The Current ripple of LED driver
The Current ripple parameter can be found in the datasheet of constant current LED driver. For instance, MEAN WELL HLG-320H-C series has Current ripple 5%. The actual measured Current ripple can refer to the online test report. As shown in the Figure 2, the measured Current ripple is 1,14% which meets the 5% requirement for Elite Level A stadium in UEFA.
The slow motion video capturing is very depending on the artificial light. The driver is the key component to determine the flickering performance in a LED lighting system. Depending on the purpose and requirement, MEAN WELL offers a complete product line and technical support such that customer can quickly build up a LED lighting system suitable for slow motion capturing applications.
The slow motion is achieved by increasing the fps. Each captured frame or image needs to have equal light to avoid any uncomfortable visual effect or simply called flickering shown in the video. Therefore providing a constant light from artificial light source is the key to success for slow motion capturing. The amount of flickering is determined by the parameter so called Flicker factor or Percent flicker. This article explains why Flicker factor affects the performance of slow motion and how MEAN WELL’s LED driver can fulfill the requirement.
Figure 1
Illustration of Current ripple and Percent flicker or Flicker factor for stadium applications
where Imax , Imin is the maximum and minimum output current respectively;
EHmax , EHmin is the measured maximum and minimum illuminance in time
Current ripple and Flicker factor
The traditional lighting system for sport stadium is based on metal halide light (HID) which consumes lots of electrical energy. Therefore more and more stadium is replacing HID with LED lighting system. Except for energy saving, other advantages of using LED lighting in stadium include wider dimming range, uniformly distributed light, better color rendering (CRI>80), lower stray light, no waiting time when re-start the system, longer life time, no or low flickering for slow motion video capturing.
Figure 1
Illustration of Current ripple and Percent flicker or Flicker factor for stadium applications
where Imax , Imin is the maximum and minimum output current respectively;
EHmax , EHmin is the measured maximum and minimum illuminance in time
Current ripple and Flicker factor
The traditional lighting system for sport stadium is based on metal halide light (HID) which consumes lots of electrical energy. Therefore more and more stadium is replacing HID with LED lighting system. Except for energy saving, other advantages of using LED lighting in stadium include wider dimming range, uniformly distributed light, better color rendering (CRI>80), lower stray light, no waiting time when re-start the system, longer life time, no or low flickering for slow motion video capturing.
The physical operating mechanism of LED is to convert the electrical energy from LED driver into the light. If there is a variation in the electrical energy, similar variation (not same but luckily smaller) will be presented in the output light format. Such variable light results the unequal light in each frame when in slow motion.
As result LED driver which determines the level of electrical energy variation is the key component to judge the flickering performance of a LED lighting system. The ideal output current of a LED driver should be flat and stable over time. The real output current shows a repetitive variation over a fixed period and such parameter is called Current ripple with formula shown in the Figure 1. The Flicker factor or Percent flicker parameter is used to evaluate the variation or flickering performance from an artificial light. The designer of LED lighting system can just take the Current ripple from driver to quickly evaluate the flickering performance because the Flicker factor result of light would be similar and slightly better than Current ripple of driver.
Slow motion requirement for stadium
Slow motion requirement for stadium
The averaged Flicker factor of lighting system should be less than 5% for Elite Level A stadium under 300 fps slow motion video capturing according to the Union Européenne de Football Association (UEFA) stadium lighting guide 2016. The Level A and B stadium should have averaged Flicker factor less than 12% where the Level C stadium should have averaged Flicker factor less than 20%.
The Current ripple of LED driver
The Current ripple parameter can be found in the datasheet of constant current LED driver. For instance, MEAN WELL HLG-320H-C series has Current ripple 5%. The actual measured Current ripple can refer to the online test report. As shown in the Figure 2, the measured Current ripple is 1,14% which meets the 5% requirement for Elite Level A stadium in UEFA.
Figure 2 Current ripple from specification of MEAN WELL HLG-320H-C series (Left);
The measured Current ripple from test report of HLG-320H-C1400 with output current 1400 mA (Right)
그림 2 MEAN WELL HLG-320H-C 시리즈 사양의 전류 리플(왼쪽)
출력 전류가 1400mA(오른쪽)인 HLG-320H-C1400의 테스트 보고서에서 측정된 전류 리플
Summary
The measured Current ripple from test report of HLG-320H-C1400 with output current 1400 mA (Right)
그림 2 MEAN WELL HLG-320H-C 시리즈 사양의 전류 리플(왼쪽)
출력 전류가 1400mA(오른쪽)인 HLG-320H-C1400의 테스트 보고서에서 측정된 전류 리플
Summary
The slow motion video capturing is very depending on the artificial light. The driver is the key component to determine the flickering performance in a LED lighting system. Depending on the purpose and requirement, MEAN WELL offers a complete product line and technical support such that customer can quickly build up a LED lighting system suitable for slow motion capturing applications.
제품문의 사항은 에버넷전자 영업부 (031-465-2206)로 연락 바랍니다.
원글 출처 : MEANWELL / 국문 번역: 에버넷전자