Wall, Floor, and Ceiling Surfaces
Now that you have an idea of the necessary size, shape, and orientation of a TelePresence room, the following sections discuss the importance of colors, textures, patterns, and the acoustical behavior of the wall, floor, and ceiling surfaces within the environment.
The color, Light Reflectivity Value (LRV), texture, and patterns of visible wall surfaces greatly influence the quality of the video experience and the capability of the TelePresence system to accurately reproduce human skin tones. In addition, certain wall surface materials provide better acoustic behavior than others. Some materials reflect sound, whereas others absorb it. The most common types of wall surface construction materials are gypsum drywall, wood paneling, brick or cinder block, and glass.
Considering Surface Pattern and Texture
The first element to consider is the pattern and texture of the material. The patterns and textures of wood grain surfaces and brick and cinder block materials can create odd visual disturbances in the video and therefore should be avoided on all wall surfaces that are within the camera's field of view. Likewise, surfaces with horizontal or vertical lines, such as wood paneling, should ideally be avoided. Finally, surfaces with busy patterns such as wallpaper are discouraged. The optimal choice is painted gypsum drywall.
Considering Surface Acoustic Properties
The second aspect is the acoustic behavior of the material. The wall surfaces should absorb sound from within the room and from outside the room. Sound emanating from within the room should be absorbed by the wall material rather than reverberate off of it. The amount of sound reflected by a material is the Noise Reduction Coefficient (NRC). The higher the NRC rating, the more sound is absorbed by the material. In addition, sound emanating from within the room should not transfer through the wall material, nor should sound emanating from outside the room transfer through the wall material into the room. The amount of sound absorbed as it penetrates through a material is the Sound Transmission Class (STC). The higher the STC rating, the more sound is absorbed as it passes through the walls. This also applies to doors and windows. Doors should be solid, not hollow, and the door jambs should be sealed to reduce the amount of noise allowed to transfer through the cracks around the sides, top, and under the door. The section "Acoustics," later in the chapter, covers NRC and STC ratings in greater detail.
Although wood and gypsum drywall tend to absorb sound, materials such as brick or cinder block and glass surfaces tend to reflect sound. Finished wood surfaces such as paneling can also be highly reflective. Therefore, even if the wall surface in question is outside the view of the cameras, it might still be undesirable from an acoustical perspective. However, an acoustically reflective surface on one side of the room can be offset by an acoustically absorptive surface on another, so just because the material is acoustically reflective does not mean you shouldn't use it in certain portions of the room for its aesthetic appeal.
Considering Surface Color and Light Reflectivity Value
The third aspect is the color and Light Reflectivity Value (LRV) of the surface. LRV is a measure of how much light is reflected off a painted surface and, conversely, how much is absorbed. Figure 8-22 illustrates a simple LRV scale.
Figure 8-22 Light Reflectivity Value (LRV) scale
Depending on the amount of pigment within the paint, deep, dark colors tend to absorb certain light spectrums while reflecting others. For example, a cherry or mahogany wood desk or cabinet can create a reddish hue on objects within the camera's field of view and cause certain people's skin tones to look too red. Other colors can give people a greenish or yellowish hue making them look ill. People who work with cameras and video equipment, such as studio camera crews, newscasters, and the like know full well the effects that different paint colors have on people's skin tones. The behavior of the paint color also depends on the color temperature and intensity of the light within the room. The section "Lighting and Illumination," later in this chapter, provides more detail about light color temperature and luminosity.
For the uninitiated, rather than delving into the theory behind these concepts and expecting TelePresence customers to become overnight experts in paint colors, Cisco has attempted to simplify this entire issue by defining a palette of recommended colors to choose from that provide optimal flesh tone depiction within the Cisco-specific camera, codec, and plasma technology. For the specific color temperature and luminosity of a CTS-3000 or CTS-1000 environment, Cisco has found that the best choice of paint colors are those that are of a neutral tone, are chromatically tame, and fall within an LRV range of 18 to 20 percent. Other TelePresence vendors and even future models of Cisco TelePresence solutions might provide slightly different color recommendations based on the design of their systems and the type of virtual experience they want to create. For example, a TelePresence solution designed for a doctor's office or a hospital's surgery room, or a solution designed for a presenter on stage in front of a virtual audience might have radically different paint color and lighting recommendations.
However, because of the vast number of different color systems and paint manufacturers throughout the world, it has not been possible for Cisco to specify exact color reference indexes on a global level. Therefore, Cisco took the approach of selecting several paint colors from Benjamin Moore and providing those as "example" recommended colors. The list that follows provides the currently recommended Benjamin Moore colors:
- Wilmington Tan: HC-34
- Huntington Beige: HC-21
- Woodstock Tan: HC-20
- Cork: 2153-40
- Classic Caramel: 1118
- Fairmont Gold: 1071
- Peach Brandy: 112
Considering Surfaces in Camera Field of View
The last item to discuss is any other wall surface treatments or adornments that might be within the camera's field of view. This includes door and window frames, cabinetry, recessions and other aesthetic wall construction, paintings, signs and company logos, or any other object that has a surface that is within the camera's field of view. The same principles of color, texture, and pattern described previously apply to these objects as well. In addition, avoid bright contrasts, such as neon lights within a sign or company logo, and reflective surfaces, such as glass picture frames and dry-erase boards; however, some amount of contrast is encouraged. For example, window treatments, a company logo, or an oil painting that complements the look and feel of the room can provide just the right amount of contrast to complement a large surface of painted gypsum drywall.
The type of flooring material used within the TelePresence room can greatly affect the acoustical experience of the system. The most common types of flooring surface material are carpet, wood, tile and marble, and raised plenum floors. To be blunt, all materials other than carpet are terrible from an acoustic perspective and should be covered with carpeting. This can be an unfortunate yet necessary step for customers who have invested a lot of money installing beautiful marble floors or those wanting to install a TelePresence system in a room that has a raised plenum floor. There are two aspects to the acoustic behavior of flooring materials that you need to consider:
- The amount of ambient sound that bounces off the surface versus being absorbed by the surface is the Noise Reduction Coefficient (NRC). All flooring surfaces have an NRC rating assigned to them. The higher the NRC rating, the more sound is absorbed by the surface. Carpet provides the highest NRC rating of all flooring surfaces.
- The amount of noise created by walking on the surface. This is the Impact Insulation Class (IIC) and is also commonly referred to as foot fall. All flooring surfaces have an IIC rating assigned to them. The clicking and thumping sounds produced when people walk across a floor surface can reverberate throughout the room. This is especially important for raised plenum floors because the sounds reverberate within the hollow space underneath the floor.
Consider the type of carpet you should use, given that carpet is the inevitable choice:
- Portions of the carpet might be visible within the camera's field of view, depending on the depth of the room. (Refer back to Figure 8-14 in the Depth Requirements section earlier in this chapter.) Therefore, the same principles discussed in the previous section for paint colors, textures, and patterns apply to this portion of floor surface as well. You need to choose a color for your carpet that looks good on camera, is complementary to the rest of the room, and is free of loud or busy patterns. If the carpet is not within the field of view of the camera, you are free to choose whatever colors and patterns suit your artistic desires, although most corporate environments tend to use warm or neutral tones.
- The carpet should not be excessively thick or else the participants will have difficulty rolling their chairs in and out from the table. Standard industrial-strength, short carpeting, typical of what is found in the average corporate conference room is recommended.
- The carpet does not have to be laid in one solid piece. You can use tiled carpet that is applied in sections. This is especially useful on raised plenum floors so that you can still access the floor tiles to run conduit or cabling. However, tiled carpeting can tend to wear around the edges because of foot traffic, so you need to consider how and where it is applied and solicit the advice of a carpeting expert for assistance.
The type of ceiling material used within the TelePresence room can greatly affect the acoustical experience of the system and the illumination. The most common type of ceiling material in corporate environments is dropped ceiling tiles (also known as suspended ceilings). However, metal, wood, gypsum drywall, and cement ceiling surfaces are also found in some locations.
Before analyzing different ceiling materials, it is worth stating that every TelePresence room, regardless of size, needs a ceiling over it. This might seem like an odd thing to say, but some customers have tried to install TelePresence systems in rooms that have an open ceiling. For example, this has been an issue when attempting to demonstrate a TelePresence system in a trade show environment such as a convention center where they build a booth to contain the system.
A ceiling is necessary for two reasons:
- To isolate the room from outside noise, such as foot traffic and conversations in adjacent rooms and hallways.
- Overhead, ceiling-mounted light fixtures are mandatory to provide the proper levels of ambient light throughout the room.
Trade show environments have special ceiling considerations because anytime you put a ceiling over something, all sorts of fire and electrical codes come into play. These subjects are outside the scope of this book. You should consult a company that specializes in constructing trade show booths for details.
Dropped ceilings with removable tiles provide the best acoustical and illumination performance. They also provide the most flexibility for rearranging objects within the ceiling such as light fixtures, air conditioning registers, ceiling-mounted document cameras, and the like. However, dropped ceilings might not be possible if the height of the ceiling is too low. Customers should be aware of the negative consequences and what features they might lose by installing a system in a room that does not have a dropped ceiling. After reviewing this section and referring back to the "Room Height Requirements" section previously in this chapter, when you take all factors into perspective, the best choice might be to find an alternative room.
Two primary considerations when choosing a ceiling material follow:
- Acoustic properties: How much sound is absorbed by the ceiling material?
- Reflectivity: How much light is reflected off the ceiling surface?
Considering the Acoustic Properties of the Ceiling
First, the ceiling material should absorb sound from within the room and from outside the room. Sound emanating from within the room should be absorbed by the ceiling material rather than reflecting off of it. The amount of sound absorbed by a material is the Noise Reduction Coefficient (NRC). The higher the NRC rating, the more sound is absorbed by the material, which, in turn, reduces the amount of acoustic reverberation within the room. In addition, sound emanating from within the room should not transfer through the ceiling material, nor should sound emanating from outside the room transfer through the ceiling material into the room. The amount of sound absorbed as it penetrates through a material is the Sound Transmission Class (STC). The higher the STC rating, the more sound is absorbed as it permeates through the ceiling. These concepts are further explained in the "Acoustics" section later in this chapter. Ceiling tiles with an NRC rating of .80 or greater and an STC rating of 60 or greater are recommended, as described in Table 8-4 and illustrated in Figures 8-40 and 8-41.
Considering the Light Reflectivity of the Ceiling
Second, as discussed in the "Lighting and Illumination" section, the goal of the light fixtures in the ceiling is to fill the room with just the right amount of ambient light. The ceiling material chosen can either complement or detract from this goal. Ceiling materials that are bright in color tend to reflect light off their surface, allowing the light fixtures in the ceiling to reach their full potential. Conversely, ceiling materials that are dark in color tend to absorb light, reducing the effectiveness of the light fixtures in the ceiling and making it more difficult to achieve the proper amount of illumination within the room. Ceiling tiles illustrated that are white or beige in color are reflective in nature. A surface that is too reflective can cause the amount of light bouncing off the ceiling to be uncomfortably bright. The reflectivity of the ceiling surface should not be as reflective as a mirror, for example. It should diffuse the light, while reflecting it to produce a soft glow unnoticeable to the human eye.