Articles

• Case study -- Connecting Classrooms

• Creating Spaces – Houses of Worship

• Projector Images and Room Light Levels

• Stories For The Road Warrior

• Choosing The Right Projector

• Image Quality

• How Secure Are You?

• Why Use An Authorized Dealer?

In the more sparsely populated areas of the world, it’s difficult to deliver education to the most students at reasonable costs. That’s the case in a 15,000-square-mile area of Alberta, Canada where six high schools teach as few as 12 students at a time. More importantly, not all the schools teach courses that are required for admission into the universities, so some of the students didn’t have a way to continue their education.

That has changed, for the better, with a project called Rural Advancement Community of Learners (RACOL) which beginning in 2002, funded technology to link these schools together to deliver consistent, high quality courses.

First, a broadband network was installed to link the schools. The network, called SuperNet, is powerful enough to handle real-time broadband, including videoconferencing, multicasting, voice-over-IP, etc. It is said to be 1,000 times faster than a home-cable Internet connection.

Next, an MPEG-2 videoconferencing system was installed, and each classroom has videoconferencing capabilities

Students sit in “learning suites” -- rooms equipped with a collection of monitors and interactive video displays.

Classrooms are equipped with two large monitors at the front of each room plus two smaller monitors at the back which duplicate what is on the front monitors. The images displayed on the screens are the same at all school locations. Students can see the teacher on one monitor and a six-way split-screen displaying the six classrooms on the other monitor.

Customized touch screens with “question buttons” allow students to let teachers know when they have questions and the teacher, who can see each classroom, can answer them. They also have an “I’m lost” button so the teacher knows when to stop and review the information.

Each location also has a Rear Projection SMART Board 3000i interactive whiteboard, a document camera and a CD-ROM/DVD/video player. The teacher uses the 3000i to access and control computer applications. Teachers and students can also write on the interactive whiteboard using their finger or a stylus. All the activity performed on the 3000i is viewed live by students in every location on their respective 3000i's. The lessons are then stored and made available to students for review later via streaming video.

Students can switch between watching the image of the instructor, the other students and the 3000i and bookmark areas they want to view again. The system is currently being used to teach math, physics, science, French, aboriginal studies and career and life management.

Each location also contains four Polycom Via Video units that enable students at different locations to work together in small groups

Everything that happens synchronously is stored and made available to members of the class asynchronously via streaming video. A special application has been developed to allow a student to switch between the image of the instructor, the students or the electronic whiteboard while the sound continues, and to bookmark locations in the stream for later review.

Of course, many of these technologies can be used to link any sort of organization with satellite locations. It’s just wonderful to see technology so well applied to such a worthy cause as education of students who otherwise wouldn’t have access. And, as one official put it: “Although it sounds like an expensive system, the learning suites will actually save money. It’s hard to get someone as specialized as a physics teacher into some of those schools.” Give us a call at 866-595-3368!

Throughout history, prophets and religious figures had to “seek the high ground” in order to be seen and heard by their followers. Today, churches, temples and mosques (reflecting many centuries of construction and architectural styles) are keeping pace with their media-savvy congregations in order to get their messages – and inspiration – across to the faithful using professional audiovisual equipment.

Whether it’s the first audiovisual installation for a small country chapel, a modernization-upgrade for a large, urban synagogue, or a full television ministry broadcast center, almost every house of worship today recognizes the value of visual and audio techniques.

Those who haven’t yet adapted might not realize that today’s technologies and the tricks of the business we use in our installations have surmounted most problems with combining the high technology of today with the tradition and history of worship. The concerns that sometimes arise are:

• Fear – We’re very traditional; our members won’t know how to use it and we might break it. (Today’s equipment is very user-friendly.)
• Esthetics – All that bulky high-tech stuff will detract from the beauty of our church. (The clever, compact and low-profile design of modern equipment can be hidden or well-integrated by professional designers.)
• Acoustics – Our cantor sounds great right where he is; why should we make any changes? (We haven’t seen an audio system yet that couldn’t be improved so that the entire congregation hears the same quality sound.)
• Cost – That’s a luxury for mega-size congregations; we only have two services on the weekend. (Systems these days are designed for flexibility so that you can start small and add functionality as desired.)

In truth, it’s about communication. And die-hard traditionalists can appreciate that if religion doesn’t reach out and grow, the size of the congregation can decline. Houses of worship are used for a variety of purposes – what works well for a visiting guest speaker needs to adapt to a holiday pageant or musical presentation. And audiovisual installations, in many cases, are proving to stimulate and expand religious education programs and, importantly, increase use of the facilities.

Many houses of worship today incorporate complete AV systems into their sanctuaries and other facilities, and regard it as a necessary adjunct to the nature and focus of their particular congregation. Are they youth-oriented? Missionary-oriented? Social and community-service minded? Is music a major component of their religious expression?

Whatever the end-use, an integrated audiovisual system might consist of professional level video projectors, projection screens, video cameras, computers, microphones, speakers, mixing consoles, closed circuit television, special effects lighting and even videoconferencing. Depending on the specific needs, DVD/CD players and recorders, plasma monitors, and electronic whiteboards might assist for particular purposes and applications.

Professional audiovisual technology allows for dynamic presentations with changes of mood, display of inspirational pictures, images, and lyrics. What’s more, announcements, information, video clips, and regular rotations of sermon notes and sacred verses are easily accomplished.

Integrating high-tech audio and video equipment into houses of worship is transforming the experience of congregations to include many different sensory levels. And while lay volunteer/technicians aren’t producing commercials for the Superbowl, many are proving to be creative and enthusiastic learners in using their skills to serve their faith.

Explain your ideas, dreams and budgets to us. Quality audiovisual consultation is available for houses of worship of all shapes and sizes. We can deliver the customized system design that’s right for you. Call toll free: 866-595-3368.

Now that IP infrastructures are likely connecting your facilities, the next thing to consider is upgrading your security systems. Whereas a few years ago security systems were standalone, expensive propositions, they are now considered part of the overall audiovisual system, controlled and monitored in much the same way as your IP-monitored projectors, plasma or LCD screens and lighting systems from onsite or remote locations. Even better, they are now digital and affordable.

CCTV

Closed circuit television is the granddaddy of security systems, having been around for many years. Today’s CCTVs are usually digital videocameras with digital video storage systems, installed over a network with the ability to watch live or review video later over the internet.

CCTV systems are for monitoring ingress and egress and observing infractions as well as serving as deterrence to illegal or objectionable activities. In schools, for example, they help prevent theft, vandalism and bullying. In corporations, they help keep employees and proprietary information safe. In retail stores, as seen in many television police dramas, they help identify robbers. In many cases, too, it can help emergency response personnel assess situations before traveling to the location, so they better know how many emergency workers and what equipment will be needed.

Fire Protection and Alarm Systems

Fire protection and alarm systems are often integrated into the enterprise network system, including heat and smoke detection, and motion sensors at doors and in sensitive spaces. These systems can even automatically turn on emergency lighting.

Access Control

In many organizations, there are locations that everyone can enter, and some that are restricted to only certain employees. Access control systems let the security team monitor and track movement. One of the older methods of providing access control was badges. Newer methods included a panel on the door with numbered pushbuttons and employees entered a code, which triggered the door to open.

The newest systems include similarly numbered keypads but these are now connected to the network for tracking access.

Even newer are biometric systems which not only monitor access, but monitor exactly who entered and when.

Most biometric access control systems are fingerprint ID systems, that allow for control and audit of access privileges. The employee places their finger on a pad and the system matches it to the person or if the fingerprint isn’t recognized, it prevents access.

These biometric systems also control access to individual PCs and workstations and at an even deeper level, control what network resources can be accessed.

There are also biometric systems that use the iris in the eye for identification, since the iris is as unique as a person’s fingerprint.

And newer yet are facial recognition systems that can detect and identify people as they pass by a camera. This is often used in conjunction with CCTV systems. It’s especially beneficial in applications where there are watch lists, such as airports or government offices.

Other organizational functions can also be included in the network security systems these days, such as time and attendance and parking control.

Your organization can benefit from or all of these functions and as network audiovisual experts, we can do an assessment and estimate of what will work best for you. Give us a call at 866-595-3368!

Projector Images and Room Light Levels

When projectors are used in a variety of classroom and conference room locations it becomes important to determine the projector light level necessary to provide a suitable image. The amount of light provided by the projector is an important factor in determining its image visibility, price and size.

This article describes the concepts related to projector light output and the effects of ambient or background light from other sources in the room. To accomplish this the image contrast ratio is introduced and related to the image light level compared to the background light.

Image on the Screen

To understand the projector and the environment we need to remember that the "image" we see is what counts. The screen is where the "image" appears. The screen acts as the surface that reflects the light in the image back to our eyes. When considering various projection configurations the screen can be much larger than the image. Just remember it is the light from the projector that creates the image, which provides the information or picture of interest.

For a projector, the number of "lumens" indicates the amount of light coming from the lens. For an all white image, the light is distributed evenly over the image when it is projected on the screen. An actual image can be composed of dark areas where the light is not present or other area where there is a color such as red or green. However, a projector is rated for the maximum amount of light with a full white image.

One way to think about the light from the projector is that it is analogous to water coming out of a showerhead. As the distance from the showerhead increases the spray spreads out over a larger area. The amount of water remains constant whether one is close to the showerhead or further back. What happens as we get further away is that the amount of water over a fixed small area like your hand becomes less.

This same effect happens with the projector light as we increase the image size. The light over a small fixed area becomes less. There is still the same total amount of light, but it just gets spread over the larger image.

As mentioned, light is measured by a unit called "lumen". A projector provides a certain number of lumens. The lumens are distributed over the image area. To determine the actual lumen level, a full white image is projected and measurements taken at 9 locations in the white image. The image size is also measured and the total lumens calculated.

As the image becomes larger, there are less lumens present in any fixed area such as a square foot (an area equal to 1 foot by 1 foot). The lower the light in a unit area, the less bright the image becomes.

For example an image of 3 by 4 feet has an area of 12 square feet. If the projector has a 1000 lumen output then there are 1000/12= 83 lumens in each square foot of the image.

If the image on the screen is increased to 6 by 8 feet by projecting at a longer distance, then the area is 48 square feet and the lumens per square foot becomes 1000/48= 21 lumens per sq. ft. Thus by increasing the image size 4 times, we have reduced the lumens per sq. ft. by 4 times.

Since lumens describe the amount of light used to produce the image, it is directly related to what our eyes see, and is what we call the image brightness. For this example when the image size was increased 4 times the brightness was reduced by 4 times.

It is important to remember that the image brightness is determined by the size of the image projected. For projectors we can move them closer to the screen to produce smaller images that are brighter. However, we usually employ the projector to provide a large image. Thus there is a tradeoff between the image size and the brightness for any projector. To increase the image size and keep the same brightness image, we must use a projector that outputs more lumens.

Employing a higher output projector appears to be a simple solution, but the lumen output is one of the primary factors that govern the cost of the projector. Consequently, in the real world, a good choice is a projector with the minimum number of lumens to get the job done.

A second important consideration is that in most rooms there is another source of light that falls on the screen. This is the ambient or background light from windows and lamps in the room.

Background Light

Most projector environments are never totally dark. The ambient light that falls on the screen produces a background light level with the image being projected on top. It is this background or ambient light that must be considered when determining how large an image should be and how many lumens are needed.

To understand this we can extend the shower analogy. If the shower is located outdoors when a rainstorm is in progress there is additional water along with water from the showerhead.

Thinking about this situation we all know that as the background light increases, it becomes more difficult to see a projected image. The image becomes dull and it may appear "washed out".

What really is happening is that the image had its "contrast" reduced by the ambient light. The amount of light contributing to the image remains the same, however, more light has been added to the screen by other light sources in the room.

Consider the situation as shown in Figure 2, where the room lights contribute 200 ambient lumens over the total 3 x 4 foot screen. For an image, this results in a background light level of 200/12 = 16 lumens for each square foot of the screen. Now if our projector provided 83 lumens on each square foot when the image was white, then total amount of light on the area is 83 + 16 = 99 lumens.

This may initially appear to be a benefit since the light level has increased, however, where the image has no light, in a dark area, there is still the 16 lumens present. Since images are composed of bright and dark, we can consider the effect on the image by considering the "contrast".

Image Contrast

The "contrast" is a measure of the brightest to the darkest area of the image. The contrast of the prior example is just the 99 lumen bright level divided by the dark level of 16 or 99/16 = 6. If we double the light from the projector to 2000 lumens the contrast almost doubles. The bright region is 182 (83+83+16) divided by the dark level still at 16, or 182/16 = 11. Thus the contrast has gone from 6 to 11.

If on the other hand, when the amount of room light is doubled, the bright area level becomes 115, (83 + 32) and the dark region increases to 32 lumens. Thus the contrast is 115/32 = 4. With a contrast as low as 4, we must ask what is a good contrast for the image on the screen?

Contrast levels of 2 let us see the image but not very clearly. A contrast of 20 permits viewing most images but does still not product a rich vibrant image. Contrast levels in excess of 200 produce great images.

Most projectors today produce images with contrasts exceeding 200, however when projected on a screen with room light present the resulting contrast is far less. How can we know what effect the room light will have on the resulting contrast and can we determine the amount of light needed from the projector? Another way to consider the situation is to ask how much do we need to reduce the ambient light level to produce a suitable image?

There are several ways to answer these questions. One is by a trial with various light level projectors. Another way is measuring the amount of room light on the screen and estimating the contrast.

Still another way is to use a projector with a known lumen output and set the image size to simulate a larger image with increased lumen output. To do this, one way is to take the known lumen projector and make the image 1/4 of the size of the image desired. If this image has a satisfactory brightness and contrast then you need a projector that has 4 times the amount of lumens.

For example, if we go back to the example where we had a 1000 lumen projector the image can be projected to a 3 x 4 ft. area on a larger screen. If the image contrast is satisfactory, then this lumen level could be predicted for a larger image size. An image of 6 x 8 ft. will have an area 4 times larger and thus the projector will be required to deliver 4000 lumens to form an equivalent contrast image.

Ambient Light Levels

Another option is to reduce the background light. This could consist of blocking the light from windows and turning down the lights to reduce the light falling on the screen.

In most cases the very dark theater setting does not work well for school, conference, or lecture rooms. For most cases the average background at the screen is usually under 2 lumens per square foot.

In some cases where windows are present it becomes very difficult to block the light. However, in any case where sunlight is entering the room some form of shading is typically required. This is because direct sunlight has a tremendous amount of lumens. One 3 by 3 foot window can easily permit over 2,000 lumens to enter the room.

Compare this to the case where the background is only 2 lumens per square foot and the projector has an output of 1000 lumens. Here the maximum contrast for a 4 x 3 foot image is the 83 lumens from the screen plus the 2 lumens background to yield 85 lumens in a bright area and 2 lumens in the dark for a contrast of 42 (85/2). A contrast of 42 may not seem high but it is what people typically observe in rooms with a comfortable lower light level.

Summary

Using the concepts described we can evaluate different projectors and the effect from the environment. Remember the light from the projector is not reduced as it crosses the space to the screen. However, if the projected image becomes larger, the light in a fixed area becomes less and the image appears less bright.

We now know how to calculate the change using the image area.

The second major factor is the background light. This causes the image to become washed out or reduces the contrast.

Many projectors today are in the 1000 to 3000 lumen range and the background light level will be a major factor in determining the contrast. Consequently it is important that for an optimum image the background light be reduced down to the lowest level possible.

There are other ways to predict the contrast such as using a light meter to measure the amount of lumens. In addition there are special screens and rear projection configurations that improve the contrast. While these methods do provide higher contrast levels they typically require an increased cost.

With existing projectors and a simple screen we are usually limited to the option of controlling the background light. However, even when employing higher light output projectors there still may be a problem with the background light. That is because of the tremendous amount of light during normal daylight or the indoor light levels we prefer for comfortable living. Thus, in almost all projector installations the image brightness and contrast become the most important factors.

Stories for the Road Warrior