In the stadium lighting design, a detailed analysis of the problems of adequate illumination and uniformity of illumination, sufficient brightness and glare-free illumination, proper shadow and color correctness, and effects of stroboscopic effects, must be understood and discussed above. Mastery can do a good job of lighting design.
For a long time, many sporting events have shown a worldwide tendency, which is why they justified the need to play and train at dusk or in the evening. Therefore, stadium lighting is an important content of the stadium design and is more complicated. It not only needs to meet the requirements of athletes to watch the game and the audience, but also to meet the requirements of the color temperature, illumination, illumination uniformity and other requirements of the shooting film and television live broadcast, this requirement is much higher than the requirements of the athletes and the audience. Modern stadiums generally use high-power 1.8kW, 2kw metal halide lamps as light sources, which have high optical performance (about 80 ~ 100Lm / w), high color rendering, color temperature between 5000 ~ 6000K, to meet the high-definition color TV Broadcasting (HDTV) requirements for outdoor lighting. To do this, to make a modern stadium lighting design, the designer must understand and grasp the following issues: There should be sufficient illumination and illumination uniformity, brightness and glare-free lighting, proper shadow effects, and correctness of colors. Strobe effects, etc.
1, adequate illumination
The brightness of an object is very important for people's visual impact, and it is also very important for television broadcasts. Like the reflection of an object, its brightness is expressed by the term "illuminance", which is not often used by people. According to reports, the early floodlighting scheme used high-power incandescent lamps with an illuminance of about 150 lx, which satisfies athletes and spectators at the time. After the emergence of black-and-white television broadcasting services, according to the requirements of television broadcasting, it is necessary to increase the illuminance by increasing the voltage of incandescent lamps by 10% or replacing the lighting sources with high-pressure mercury lamps of 1000W. With the first method, the output power of the lamp can be increased by 35%, but the price paid is to increase the power load, and the lamp life is reduced from 1000h to 250h; when the high-pressure mercury lamp is used, the illumination can be increased by 50%. Without increasing the electricity load.
Before the advent of the color television service, the 200lx level of illumination was sufficient. The total stadium lighting output power is about 250kw, which is generally used to increase the horizontal illumination to improve the performance of the lighting device. The increase in vertical illuminance is mainly to increase the visibility from the audience to the athletes.
In the 1990s, television broadcasts were required to be colored in domestic and international sporting events held in many countries. Color television has higher requirements for lighting quality than black-and-white television. International sports organization and wide
The broadcasting television agency puts forward the following requirements for stadium lighting fixtures:
(1) The minimum illuminance required for the entire stadium is 800lx, and the illuminance should be from l-1.5m on the ground plane and perpendicular to the plane of the main camera.
(2) For a long focal length closed lens, the required illuminance is not less than 1400 lx. The necessary illumination for the color television service. It also depends on the factors of the local environment. Such as air pollution, it mainly determines the quality of the required picture. Picture quality is one of the main factors. Higher-speed sports require smaller apertures and higher illuminance of the camera lens. When the television camera lens has only a relatively small aperture, super broadcast (ie, high-quality images) requires higher illumination. Color TV cameras are the most commonly used zoom lens, usually only f:2 aperture, when the large focal length can meet the needs of a certain sports game broadcast range, but also increase the aperture. Therefore, when designing lighting, the designer should consider apertures at least f:2.8 to f:4 or f:5.6, and the most common lens aperture f:2 to f:5.6 is the required vertical illuminance, as shown in Table 1.
Exposure time | Lens aperture | |||
F:2 | F: 2.8 | F:4 | F: 5.6 | |
1/50s | 300 | 600 | 1200 | 2400 |
1/100s | 600 | 1200 | 2400 | 4800 |
Color television imaging requires that the vertical illuminance be increased to 2000 lx as much as possible. In practice, this value is subject to economic constraints and also to the glare caused by high illumination.
The national sports industry standard TY/T1002.1-2005 “Sports Lighting Use Requirements and Test Methods Part I: Outdoor Soccer Fields and Integrated Stadiums†stipulates that the standard values ​​of lighting for outdoor football fields and integrated stadiums are shown in Table 2.
Sports classification | Camera type | Uniformity of illumination | light source | Glare level GR | ||||||
Level Eh | Vertical Ey | Level | vertical | Color temperature/K | Color rendering index Ra | |||||
U1 | U2 | U1 | U2 | |||||||
Amateur training and entertainment | - | 150 | - | 0.3 | 0.5 | - | - | >4000 | ≥65 | <55 |
Amateur club | - | 300 | - | 0.4 | 0.6 | - | - | >4000 | ≥65 | <50 |
Professional training / domestic competition | - | 500/750 | - | 0.5 | 0.7 | - | - | >4000 | ≥80 | <50 |
Domestic and international competitions with television broadcasts | Fixed camera | 1000~2000 | 1,000 | 0.6 | 0.8 | 0.4 | 0.6 | >4000 | ≥80 | <50 |
High-definition television broadcast | Slow motion | 1500~3000 | 1800 | 0.6 | 0.8 | 0.5 | 0.7 | >5500 | ≥90 | <50 |
Fixed camera | 1400 | 0.5 | 0.7 | |||||||
Moving camera | 1,000 | 0.3 | 0.5 | |||||||
. . . Emergency television broadcast | Fixed camera | 1,000 | 700 | 0.5 | 0.7 | 0.3 | 0.5 | >4000 | ≥80 | <50 |
Note: 1 In the table U1=Emin/Emax, U2=Emin/Eave
2 The provisions for vertical illuminance and uniformity in the table refer to the main camera direction, and the secondary camera direction can be reduced by one level.
3 The horizontal illuminance refers to the maintenance of the average illuminance on the ground, and the vertical illuminance refers to the maintenance of the average illuminance of the vertical plane of 1.5M from the ground or the direction of the main camera.
4 The horizontal illuminance can be 0.5 to 2.0 times the vertical illuminance (0.75 to 1.5 times recommended).
5 The illuminance values ​​listed in the table can maintain the average illuminance value, and the maintenance factor should be taken as 0.8. This value can be reduced to 0.7 for heavily fogged and heavily polluted areas.
2, illumination uniformity
The illuminance uniformity required for color photography is much greater than black-and-white photography or visual appreciation, both for horizontal illuminance and vertical illuminance. In fast-moving event competitions, the lighting needs to have sufficiently high illumination and good uniformity in order to operate the camera without distorting the picture. The maximum brightness ratio between the brightest part and the darkest part of the main picture part of color photography and video recording cannot be greater than 40:1. The reflection and illuminance uniformity of different objects is the cause of the brightness ratio. If the brightness ratio exceeds this value, a clear shadow or backlight phenomenon occurs, resulting in overexposure or underexposure, and the color television broadcast will be distorted.
The illuminance uniformity measures U1 and U2 with a single parameter. U1 is the ratio between the minimum illumination and the maximum illumination in the stadium, that is U1 = Emin/Emax; U2 is the ratio of the minimum illumination and the average illumination in the stadium, that is U2 = Emin/Eave. Uniformity of illumination can be divided into horizontal illumination uniformity and vertical illumination uniformity.
There are different vertical illuminances at different locations on the stadium's playing field, which can cause confusion when shooting from a distance, especially when there are fast sports games. The uniformity of vertical illuminance on the plane facing the edge of the main camera or a plane facing a fixed main camera should be better than Evmin/Evmax=0.4. In the case of one or more main camera areas, satisfying this requirement guarantees that In the vertical plane of the actual camera position facing the area or areas, sufficient illuminance can be obtained. It also ensures that the secondary camera can shoot anywhere in the limited area around the venue. Ultimately, satisfying these requirements also ensures that the players at the venue have a sufficient three-dimensionality.
A good level of illuminance uniformity is very important to avoid camera adjustment problems. The uniformity of the horizontal illuminance at the playing field should be better than Ehmin/Ehmax=0.5.
It is also important that there is no major change in horizontal illumination over a certain distance. In order to have a suitable lighting gradient, the horizontal and vertical illuminance changes from the grid point to the neighboring grid points cannot exceed 20% of the grid point. The ratio between the average horizontal illuminance and the average vertical illuminance must be between 0.5 and 2.0. .
In order to ensure the uniformity of the illumination of the stadium, the floodlights installed on the lighthouses of 30 to 40 meters in height on the four corners of the stadium and the light cloth lights on the stands of 20 to 30 meters in height must be adjusted. The uniformity of illuminance is achieved by a certain number of adjustable floodlights. The above mentioned uniformity values ​​can be achieved by installing no less than 30 ç› narrow beam projectors on each field angle lighthouse. . If a wide-beam-distribution spotlight is used, the number of projectors used can be reduced, but the result is glare to the viewer. If the light is used in the bleachers on the stands, the use of medium-beam and narrow-beam lamps will have a much better spread effect.
3, brightness and glare
The luminous intensity of a luminous body per unit projected area in a given direction is referred to as the brightness of the luminous body in this direction. The role of the TV camera is somewhat similar to human vision. Both the camera and human eyes use the intensity of the perceived lighting as the brightness. Therefore, the picture contrast and its background are the most important for the picture quality.
Glare can cause a reduction in visual function. Therefore, glare should be limited and measured. There are key locations for various sports events where high-brightness light sources are strictly prohibited from producing glare in the athlete's field of vision. Which are the key locations for sports competitions? For the audience, the front view of the public area on the side of the stadium and the back of the goal are the worst. When designing the direction of the floodlight, these positions are used to assess glare control. In bad locations, these points are key locations.
Corner cloth light installation method. The height of the lighthouse shall ensure that the angle between the bottom row of lamps on the tower and the center point of the court is not less than 20 degrees. . In order to reduce glare for athletes and spectators, this angle can be relaxed to 30. However, the investment in such lighthouses will increase, and the ratio of vertical and horizontal illuminance will decrease. The lighthouse should be set at the midpoint of the court's sideline to an outward bias of 5. To ensure the vertical illuminance of athletes near the sideline. By increasing this angle, the glare is reduced for the bottom line player, and the vertical illuminance increases at the same time. The limit of increasing the angle depends on whether the stand canopy obstructs the normal lighting of the lamp and whether or not it creates a shadow on the court. At the same time, the lighthouse should also be located at least 15 outside the midpoint of the goal. To limit the glare of players in the goal area when corner kicks are played.
The above two angle limit lines determine the position of the lighthouse. The ideal lighthouse should be as close as possible to the extension of the stadium diagonal line. In order to ensure that the entire stadium has lighting, the angle between the bottom row of lights to the stadium and the angle of the court is not greater than 70. , so as to effectively determine the minimum distance from the lighthouse to the corner of the stadium. The four-corner lighting is shown in Figure 1.
Lateral lighting mode. Floodlight installation requirements are suitable for multi-tower arrangements and light strip arrangements. Looking from the direction of the vertical axis of the stadium, the minimum value of α is 20. Only suitable for training venues and low-level playing fields, where glare control levels are low. α is 25. At the same time, the glare control is better and there is a higher vertical illuminance. Although the increase in α is conducive to the control of glare, the vertical illuminance component is reduced, and the investment in the lighthouse or cloth lighthouse will be greatly increased. It is not possible to increase the stand upright to increase the α angle. The elevation angle of the floodlight near the edge is determined by β. If there is a proper ratio between the horizontal illumination and the vertical illumination, β should not be
Greater than 75. . If the luminaire does not have a suitable beta angle on the edge of the stands, the floodlights can be mounted under the canopy or in other special ways. See Figure 2 for lateral lighting.
The number of floodlights for each stadium project is determined by the illuminance within the site. In the four-corner lighting mode, the number of lighthouses is less than the number of sidelights. Therefore, there is less light entering the field of view of the athletes or spectators. On the other hand, the number of floodlights used in four-corner lighting is greater than the number of lateral lighting lamps. From any point in the stadium, the sum of the light intensity of each lighthouse floodlight is more than the lateral light and multi-tower. The light intensity of the light with a cloth lamp is greater. In general, the choice of cloth lighting and the exact location of the lighthouse depend more on the cost or site conditions than the lighting factor.
Glare index GR (FlareRating) = 10 ~ 90, GR = 10 that the glare has little effect on humans, GR = 90 that glare is unbearable to humans. Any position on the site, GR = 50 means that the glare "just allowed."
Considering avoiding the dark background of the stadium, a part of the light should be directed to the stands. The lighting of the stands should also be taken into account. In order to make the TV screen clear in television, the vertical illuminance of the stadium auditorium should not be less than 0.25 of the vertical illuminance of the stadium. This will ensure that there is sufficient contrast between the playing field and the background. This level of illumination can be achieved by the overflow light from the stadium lighting.
The problem of glare can be solved only by coordinating the contradictions between the audience and the athletes. Therefore, the design should consider the light distribution, installation method, lamp hanging height, and other factors of the flood light. This coordination should be done by the designer.
4, the impact of shadows
Bright contrast and shadows at the same time impede the correct adjustment of the contrast of the television camera, which will affect the quality of the TV picture. Too much darkness can also affect the visual comfort level. On the other hand, shadows are important for television broadcasters and viewers, especially when there are fast-moving high-speed passing football games, if there is no shadow effect, the distance The audience far away from the ball cannot follow the target.
Carefully adjusting the floodlights, while avoiding the adverse factors that affect lighting, can result in better shadow effects.
5, color correction
In most sports, the sense of color is very important. Of course, the color distortion produced by artificial lighting is not subject to color discrimination within the acceptable range. The difference between the two important problems of color characteristics is that the color table—the color representation of the environment being illuminated; the color rendering—the characteristics of the light source that actually represents the color of the object. The color rendering of the light source and the color table are determined by the spectral energy distribution of the light it emits. The color table phenomenon of the light source can be described by the correlated color temperature TK, and the correlated color temperature is mainly in the range of 2000 to 6000K. The lower the color temperature, the more “warm†the color of the light is; the higher the color temperature, the more “cool†the color of the light. The color rendering index of the light source can be represented by the color rendering index Ra. The maximum value of the Ra theory is l00, which is equivalent to the color of the object in the sunlight. The visual atmosphere of the environment is represented by Ra. The higher the Ra, the more pleasant the atmosphere is. As daylight changes during the day, the effects of sunlight should be limited to a minimum, and the corresponding human eye's color discrimination capability will not be too problematic. For the ideal picture, the camera is adjusted to the color state of the installed artificial lighting source. High-definition HDTV broadcasting, color rendering index Ra ≥ 80, preferably 90.
Color correction is important for both viewers and color television broadcast services. TV cameras and color temperature can be adjusted over a wide range to use TVs with color temperatures ranging from 3000 to 6000K for television broadcasts. However, the stadium is an outdoor playground. When choosing a light source, the color temperature of sunlight is 5000 to 6000 K. This may happen. The game starts in daylight, and when the sun sets, it ends in cold light (usually "all weather". This word is used to describe). Under sunset and artificial double light, the color temperature of sunlight and the color temperature of the artificial lighting source are required to be the same so that the television camera can be adjusted continuously.
Light smoothly transitions to artificial lighting.
For the purpose of color television broadcasting, the metal halide lamp has been rapidly developed in recent years. Due to its high operating temperature, high pressure and other conditions, this light source has a color temperature of 3,000 to 6,000 K and thus includes all requirements for color correction. It can meet the requirements of color TV broadcast in outdoor sports venues, so it has been widely used.
6, the effect of stroboscopic effect
When metal halide lamps are used as sports ground lighting, the interruption of the arc, which is determined by the main frequency of the AC power supply, may result in a stroboscopic effect. When designing, the strobe effect should be limited to the minimum. Usually, the light source can be evenly connected to different phases of the three-phase power supply. Lighting at any point on the site is a superposition of different light sources, so that the strobe effect can be minimized. .
7, Shenzhen Stadium Lighting Design
The author had the privilege of participating in the entire process of design, construction, installation, commissioning and acceptance of Shenzhen Stadium in the early 1990s. Location: The stadium is located in Shenzhen Sports Center.
According to the environmental and climatic conditions of Shenzhen City, the spectator stands are used to pick up the roof.
Size: 30,000 seats
Light source: Philips product MVF406/MHD1800w, 320 sets of lamps
Lighting index:
Average illuminance: 1500lx
Average vertical illuminance: l400lx
Color temperature: 5600K
Color rendering index: Ra>90
Glare index: GR=48
Shenzhen Stadium lighting equipment is the first stadium in China to use MVF406 lamps. Synchronizing with the international standard, 320 sets of floodlights adopt the method of lighting the cloth on the canopy, so the lighting effect is better and it is also more economical.
In order to meet the requirements of color television broadcasting, MVF406 high-efficiency spotlights are selected.
Material: high temperature cast aluminum lamp body, high-strength tempered glass, high purity aluminum reflector
Features: Compact structure, small size, light weight
7 different light distributions to meet lighting requirements
Equipped with highly efficient metal halide light source, color rendering index up to 92, color temperature 5600K voltage 220V, 50Hz weight 10.9kg
Applicable places: stadiums, sports grounds, high-rise building facade lighting, high-quality lighting area.
Ningbo Vinny International Trading Co., Ltd , https://www.vinnystationery.com