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1 (JBE Vol. 21, No. 4, July 2016) (Regular Paper) 21 4, (JBE Vol. 21, No. 4, July 2016) ISSN (Online) ISSN (Print) LED a), b) A Study on Color Reproduction and Flatness of the LED Light Source in Broadcasting Lighting Young-Jin Kim a) and Gooman Park b) Tungsten Halogen. Tungsten Halogen. LED. LED Tungsten Halogen. LED. LED Tungsten Halogen. LED. Abstract At the on-site of broadcasting production, the light source of tungsten halogen has been used as a primary light source for representing video images. Although tungsten halogen light has drawn attention in terms of the color reproducibility which is more similar to the sun light than that of other light sources, meanwhile it had problems in energy efficiency. Recently, the LED light source with high efficiency and long lifetime of the energy source has started getting attention as a substitute light source at the broadcast field. Because of the unique light emission principles, compared with tungsten halogen, LED light source has different characteristics in the quality of the light projected from the light source and color reproduction of the video image through a camera. These characteristics cause the delayed introduction of the LED as the broadcast light source. In this study we measured the quality characteristics of the flatness of the color reproduction and light of the LED light source and will present the experimental data whether it is suitable as the broadcasting light source compared to a reference light source of tungsten halogen. In addition, we suggested the future challenges and standards which are needed to expand usage of LED as a broadcast light source. Keyword : LED Light Source, Light Source of Tungsten Halogen, Color reproducibility, Light Flatness a) (KBS) b) IT (Dept. of Electronics IT Media Engineering, Seoul National University of Science and Technology) Corresponding Author : (Gooman Park) gmpark@seoultech.ac.kr Tel: ORCID: This study was supported by the Research Program funded by the Seoul National University of Science and Technology Manuscript received January 18, 2016; Revised March 8, 2016; Accepted May 6, 2016.

2 1 : LED (Young-Jin Kim et al.: A Study on Color Reproduction and Flatness of the LED Light Source in Broadcasting Lighting).....,. (Tungsten Halogen Lamp), (Fluorescence Lamp), LED Lamp (Light Emitting Diode Lamp) ,,.,,,. (Floodlight)... (Spotlight), LED, 1970 LED, 1980 LED, 1990 LED LED 1996 LED LED 21.. LED. LED 4~5. LED LED LED. LED LED., LED.

3 (JBE Vol. 21, No. 4, July 2016), LED Camalign Chart Vector., LED. LED LED,. LED LED. LED 1 (2010) TV LED LED LED. LED, LED TV LED. LED. LED (2011) LED. LED,. LED KBS. LED. 1 LED. LED. LED,. LED.. 1..,..,. 3200K, 5600K. 50K 50K. 3200K..

4 1 : LED (Young-Jin Kim et al.: A Study on Color Reproduction and Flatness of the LED Light Source in Broadcasting Lighting). CC (Color Conversion Filter). CC R, G, B. Ra, ,. TV Ra 85, Ra 95. TV, ,,,,..... LED. LED. LED.. 1. Fig. 1. The desirable flatness of the light source

(JBE Vol. 21, No. 4, July 2016). 1. ( ) LED. 3, 2,. LED 3200K. 1 LED 1 LED. LPS-10PA, LQB-1.5. 2. KONIKA MINOLTA CS-2000 Ikegami HDK-790EX.

2. The overview of the measurement system The value of Floodlight Vector The value of Spotlight Vector 3.

5 (JBE Vol. 21, No. 4, July 2016). 1. ( ) LED. 3, 2,. LED 3200K. 1 LED 1 LED. LPS-10PA, LQB KONIKA MINOLTA CS-2000 Ikegami HDK-790EX. Waveform WFM7120 (Tektronix) CamAlign chart (JW-CDM28R-v8.5), CPU chart (Ikegami). 3. ( ) 3.1 LED Fig. 2. The overview of the measurement system The value of Floodlight Vector The value of Spotlight Vector 3. Fig. 3. The reference value of Tungsten Halogen Floodlight and Spotlight

6 1 : LED (Young-Jin Kim et al.: A Study on Color Reproduction and Flatness of the LED Light Source in Broadcasting Lighting) 4. Fig. 4. The overview of flatness measurement 3 LED CPU White Balance CamAlign. (380nm) (789nm) 1234 msec Spot 6m, Flood 3m , 60, 90 4 (A, B, C ) 150, 200 (D, E ) ( ) 3, 4M. LED Floodlight of A s productions Ra K

7 (JBE Vol. 21, No. 4, July 2016) LED Floodlight of B s productions Ra K LED Floodlight of C s productions Ra K LED Spotlight of A s productions Ra K LED Spotlight of B s productions Ra K

1 : LED (Young-Jin Kim et al.: A Study on Color Reproduction and Flatness of the LED Light Source in Broadcasting Lighting) LED Spotlight of C s productions Ra K 97 3332 5.

8 1 : LED (Young-Jin Kim et al.: A Study on Color Reproduction and Flatness of the LED Light Source in Broadcasting Lighting) LED Spotlight of C s productions Ra K Fig. 5. The result of measurements of Color rendering and color temperature LED R, G, B. LED LED. LED. LED. LED 2013 LED Ra 93 A 97, B 98, C 99 Ra. A G, Y, R Ra K A 2934K, B 3149K, C 3230K A B, C. C CRI Table 1. The characteristics of Tungsten halogen lighting fixtures in 2014 Division Productions Ra K Flatness Floodlight A s Spotlight A s

546 방송공학회논문지 제21권 제4호, 2016년 7월 (JBE Vol. 21, No. 4, July 2016) LED Floodlight of A s productions in 2013 Ra K 93 3240 LED Spotlight of B s productions in 2013 Ra K 94 3370 그림 6.

하지만 그림 6에 서 보는 것처럼 2013년도에 측정된 Ra 94 수치보다 향상된 결과이다. 색온도는 A사 2993K로 기준 광원과 유사한 수 치를 보였지만 B사와 C사의 경우 높게 나타나고 있다.

9 546 방송공학회논문지 제21권 제4호, 2016년 7월 (JBE Vol. 21, No. 4, July 2016) LED Floodlight of A s productions in 2013 Ra K LED Spotlight of B s productions in 2013 Ra K 그림 년도 색온도 및 연색성 측정 결과 Fig. 6. The result of measurements of Color rendering and color temperature in 2013 스포트라이트의 Ra는 A사의 97, B사의 98, C사의 97로 달리 연색성과 색온도 모두 기준 광원보다 광원특성이 조금 부족하게 나타나고 있다. 하지만 그림 6에 서 보는 것처럼 2013년도에 측정된 Ra 94 수치보다 향상된 결과이다. 색온도는 A사 2993K로 기준 광원과 유사한 수 치를 보였지만 B사와 C사의 경우 높게 나타나고 있다. 측정 결과에서 본 바와 같이 연색성과 색온도에 있어서 LED 스포트라이트 보다 LED 플러드라이트가 좀 더 기준 광원인 텅스텐 할로겐에 근접하게 나타나 향후 LED 스포 트라이트 특성 향상 계발의 필요성이 대두되고 있다. 1.2 DSC Camalign Chart( 과 및 분석 플러드라이트와 저채도 차트)를 통한 측정 결 Camalign Chart를 통한 할로겐 & LED Vector 파형 합성 결과에 비해 전체 적으로 텅스텐 할로겐 광원과 많이 유사해졌음을 알 수 있 으로 본 색상 비교에서는 2013년도 실험 다. 림 8에서 보는 것처럼 LED 플러드라이트, LED 스포트라이트광원의 크로마 성분이 2013년도 비교 실험에서는 그 Yellow부분과 Red부분에서 기준 광원인 텅스텐 할로겐 보다 타났었다(빨간색 파형이 Tungsten Halogen 광원, 강하게 나

10 1 : LED (Young-Jin Kim et al.: A Study on Color Reproduction and Flatness of the LED Light Source in Broadcasting Lighting) LED Floodlight of A s productions comparison with Tungsten halogen spotlight comparison with Tungsten halogen floodlight LED Floodlight of B s productions comparison with Tungsten halogen spotlight comparison with Tungsten halogen floodlight LED Floodlight of C s productions comparison with Tungsten halogen spotlight comparison with Tungsten halogen floodlight

11 (JBE Vol. 21, No. 4, July 2016) LED Spotlight of A s productions comparison with Tungsten halogen spotlight comparison with Tungsten halogen floodlight LED Spotlight of B s productions comparison with Tungsten halogen spotlight comparison with Tungsten halogen floodlight LED Spotlight of C s productions comparison with Tungsten halogen spotlight comparison with Tungsten halogen floodlight 7. Fig. 7. The vector value of Floodlight and Spotlight

8. The vector value of Floodlight and Spotlight in 2013 파형이 LED 광원). 특히 사람의 얼굴을 나타내는 성 분의 기준이 되는 I축은 벡터상에서 텅스텐 할로겐 광원보 다 Yellow쪽으로 3~4도 위상차이가 있었다.

12 김영진 외 1인 : 방송조명에서 LED광원의 색 재현성과 평탄도 연구 (Young-Jin Kim et al.: A Study on Color Reproduction and Flatness of the LED Light Source in Broadcasting Lighting) The vector value of Floodlight 549 The vector value of Spotlight 그림 년도 플러드라이트와 스포트라이트의 벡터 값 Fig. 8. The vector value of Floodlight and Spotlight in 2013 파형이 LED 광원). 특히 사람의 얼굴을 나타내는 성 분의 기준이 되는 I축은 벡터상에서 텅스텐 할로겐 광원보 다 Yellow쪽으로 3~4도 위상차이가 있었다. 하지만 이번 실험에서는 LED 플러드라이트의 경우 Vector상에서의 크로마 성분과 I축에서의 위상이 기준 광 원인 텅스텐 할로겐과 유사한 특성 (자주색 파형이 텅스 텐 할로겐 광원, 녹색 파형이 LED 광원)을 나타내고 있음 을 알 수 있었다. 다만 C사 제품의 크로마 성분이 기준 광원보다 약간 높게 나왔지만 이는 보정 가능한 범위이 녹색 다. LED 스포트라이트의 비교실험에서도 3개사 광원과 비교하여 2. 평탄도 특성 측정 결과 및 분석 결 평탄도 측정 과 2013년도 보다 개선되어 스튜디오에서 사용하기에 양호한 수치를 보이고 있다. 평탄도 측정은 C1 과 C3, D2와 D4의 지점의 균일성이 중요하다. LED 플러드라이트의 평탄도는 조명기구와 광원의 특성 때문에 D2와 D4 지점의 평탄도 측정이 유의미한 가 번 치가 있다. 이 에 측정된 평탄도를 보면 A사의 D2와 D4 편차는 0.08이고 B사는 각각 0.67과 0.74로 편차는 0.07이다. 이는 2013년도 편차 인 0.09(D4=0.68, D2=0.59)보다 조금 개선된 특성을 나타 의 평탄도는 각각 0.60과 0.68로 그 모두 기준 크로마 성분과 I축 위상도 매우 유사한 데 내고 있다. 스포트라이트의 평탄도는 광원의 형태가 점광원 형태를 이터를 보이고 있다. 표 2. LED 플러드라이트와 스포트라이트t의 평탄도 Table 2. The flatness of LED floodlight and spotlight The flatness of LED floodlight point M A1 A2 A3 A4 B1 B2 B3 B4 C1 C2 C3 C4 D2 D4 E2 E4 A s B s The flatness of LED spotlight point M A1 A2 A3 A4 B1 B2 집적 B3 B4 C1 C2 C3 C4 D2 D4 E2 E4 A s B s

13 (JBE Vol. 21, No. 4, July 2016) LED Table 3. The flatness of LED floodlight and spotlight in 2013 Point M A1 A2 A3 A4 B1 B2 B3 B4 C1 C2 C3 C4 D2 D4 E2 E4 Flood Spot C1 C3, D2 D4. LED LED. LED A C1 C3 0.01(C1=0.92, C3=0.91), D2 D B 0.00, LED A B., LED C1 C3 0.16( =0.16), D2 D4 0.17( = 0.17)... LED. LED,,. LED, LED,. LED, LED. LED LED. DSC Camalign Chart Vector Scope LED LED..,... LED.. LED

14 1 : LED (Young-Jin Kim et al.: A Study on Color Reproduction and Flatness of the LED Light Source in Broadcasting Lighting),. LED LED. (reference) [1] H. J. Chang, Y. J. Kim, Correlation Analysis of LED Characteristics and Color reproduction as Broadcasting Lighting, Broadcasting and Media Magazine, vol.20, no.4, pp44-45, October [2] J. H. Chang, B. C, Park and A. S. Choi Performance Evaluation of LEDs for the Substitution of Fluorescent Lighting Source, JIEIE, November [3] J. S. Lee, W. D. Kim, B. S. Kim, W. T. Han, Study on Analysis of Characteristics of Illuminance and Luminance Distribution of LED Luminaires, JIEIE, vol.22, no.9, September [4] K. S. Lee, N. M. Moon, Analysis of Characteristics of White LED Light Source for TV Lighting, JBE, vol.15, no.4, July [5] J. M. Lee, Study on the effects of the introduction of LED as a light source on broadcasting production system, Broadcasting & Visual Communication The Graduate School of Journalism & Mass Communication Yonsei University, February [6] John Jackman, Lighting for Digital Video & Television, CMC Media LLC, San Francisco, USA, pp28-29, 2004 [7] Ross Lowell, Matters of Light and Depth, Lowell-Light Manufacturing, New York, USA, pp , 1992 [8] Y. J. Kim, Aesthetic Principles and Methods of Lighting, SEONG AN DANG Publishing CO. Mapo, Seoul, pp , May [9] Y. G. Kim, Lighting Production, Communication Books, Inc. Mapo, Seoul, pp84-87, June IT - (KBS)TV ( ) - ORCID : - :, VR : : : : : IT : IT : Georgia Institute of Technology Dept.of ECE, - ORCID : - :,,

(JBE Vol. 23, No. 5, September 2018) (Regular Paper) 23 5, (JBE Vol. 23, No. 5, September 2018) ISSN

(JBE Vol. 23, No. 5, September 2018) (Regular Paper) 23 5, 2018 9 (JBE Vol. 23, No. 5, September 2018) https://doi.org/10.5909/jbe.2018.23.5.636 ISSN 2287-9137 (Online) ISSN 1226-7953 (Print) a), a) The