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Creating Realism in Video Venue Churches
By: Peter Taylor

It's your first time to this newly built satellite church. The praise leader is on the stage delivering his message. He appears life-like and the background is detailed with rich colors that contrast to create magnificent depth. Matter of fact, there's a close-up, magnified image of the pastor on the two side screens flanking the stage. You can see all the nuances of his facial expression from the back of the room. Nothing seems out of the ordinary. Everything appears to be real with one exception: what you're looking at is not a real person, but a virtual, life-like projection. 

Houses of worship of every size, denomination, and faith are discovering that video projection is a powerful communication tool. But, there's more to simply mounting a projector, screen, and camera system to create video realism at worship services. If you're beginning to consider video projection for your church for overflow and remote video venues, where do you start? The following provides some insight to help you deliver video imagery in worship services that is powerful, realistic, and meaningful.

Is It Real or Is It Memorex?
IMAG (short for image magnification) is a common use of live video during a service. It uses a video camera to show a close-up image of those singing or speaking. This holds true for remote virtual services, where an image of the pastor is projected on the stage's large center screen. Couple this with high-resolution projection, appropriate lighting, and a good screen, and the projected images appear photo realistic. In video-only venues, this close-up realism is key to enhancing or creating an emotional connection with the worshipers. So, what high-resolution display technology should you use? 

Digital vs. Analog
The choice between projecting at standard-definition video levels or high-definition levels continues to challenge worship video departments. As worshipers enjoy their new HD technology at home, they are expecting the same viewing quality at church for the realistic feel. As such, houses of worship are upgrading their projection systems so they can display HD content. 

The difference between HD and traditional projectors is the aspect ratio, amount of pixels used to display an image, and basic projector functionality (computer display vs. video display). Traditional projectors are designed for aspect ratios of 4:3 and 5:4. They also emphasize PC signal processing over HD/video signal processing. HD projectors are designed for wide-screen applications with an aspect ratio of 16:9. They offer high pixel counts, (over 2 million pixels vs. a traditional XGA at 768,000 pixels) and typically provide high-contrast ratios for creating the image depth. 

Today's HD projectors are capable of accepting and displaying 720p and 1080i and p formats.  Each video frame in the 720p format has a resolution of 1280 horizontal pixels by 720 vertical pixels. The 1080p format video frames have a resolution of 1920 horizontal pixels by 1080 vertical pixels. In order to achieve the best in IMAG or virtual imaging realism, you'll need to take advantage of the higher pixel counts such as 1080 HD resolution.

Purity of Signal
It is important to note that just adding HD projection does not make the visual system HD. Every component along the way has to be capable of dealing with the high-definition signal for the system to be considered truly HD. This includes cameras, switchers/routers, image processors, and image capture/playback devices. A pure HD signal results in dramatically less video artifacts, more true colors, and better gray scale capability. Popular digital transmission formats include HD-SDI, DVI, and fiber optics.

Creating the Visual Environment for Realism
To best enhance the worship experience, your visual system must be properly integrated into the worship space. 

Select the right screen. 
The decision to use front or rear projection depends on several factors, including ambient light level, throw distance, and physical surroundings. High ambient light on the front screen produces a loss of contrast and makes the image appear washed out. A rear projection screen will typically provide the best viewing results for worshipers and help maintain contrast ratios that lead to realism. If space is limited, you can use mirror bouncing to decrease the amount of space behind the screen.

Many of today's video venue churches are using a large center screen, flanked by two smaller side screens that work well for IMAG and the display of worship messages.  Text-only presentations work fine with the standard 4:3 aspect ratio. But, 16:9 formats allow you to take advantage of today's HD projection and typically are a better for projecting on the stage center screen.

For center screen applications, rear projection will fill the screen only if there is enough distance between the lens and the screen. You'll also need to use an enclosed, dedicated space to eliminate any competing light that will deteriorate the image contrast.

Depending on the size of the screen and the amount of detail you want in the image, you may consider employing a multi-projection system that is edge blended.

It's also important to determine the screen properties. For example, many churches use front projected screens with matte white finishes because they are viewable from wide angles. They also posses good reflectivity indexes and are easy to maintain. To increase the contrast ratio, a grey tint screen can be used.

Determine screen placement and size.
Proper screen placement ensures that the displayed image can be easily, comfortably seen from any location within the worship center. A center and side screen configuration should keep worshipers focused on the speaker, while providing added information that does not distract but enhance the worship service. A good rule of thumb is the screen viewing angle should be no more than 15 degrees above the horizontal eye level.
Ask yourself the following questions when considering screen placement:

* How high should the screen be above the stage for optimal viewing? For realism, the screen has to go down to the stage floor.

* Will the screen integrate aesthetically with the church's architectural style? Why not use a curved screen or even a round screen? There are a few projector manufacturers that offer Warping technology to handle this application.

* What structure is required to support the screen? Motorized screens can be very heavy!

* What viewing distance is needed?

Screen size plays an important role in determining screen placement. You can calculate a 4:3 or 16:9 screen size by using the following formula: screen height is 1/6 to 1/8 of the distance to the most distant viewer.

Create the best lighting conditions. 
Lighting factors—such as light levels, back lighting, and color temperature—play a significant role in IMAG and center screen virtual imaging. For example, house lighting above the screen can wash out the image. With IMAG, a slight shadow across the pastor's face that is normally not noticeable could look like a dark blotch to someone watching the large screen. House lighting needs to be balanced. The worshipers should be able to take notes, but they should also be able to see the screens clearly. A completely dark area around the "virtual" screen is always best.

Also, controlling the color temperature through lighting can be used to create convincing image depth and realism. For the best IMAG, cover the stage using a variety of light fixtures with colored gels. This combination will simulate a true white light. The different colors will also help to create realistic skin tones and accurate scene color reproduction.

Position the cameras properly. 
The key challenge is to place the cameras where they won't distract the worship service, yet give you a vantage point for capturing the best IMAG shots. Depending on your budget and possible placement options, you have two choices: (1) placing the cameras as close as possible to get the best waist-up shot, or (2) placing the cameras at the back of the room. Typical close-up applications position cameras anywhere from 30 to 50 feet from the stage or on the stage itself. Booms can be used and remote controlled cameras can reduce the impact of perceived distraction.

Placing the cameras at the back of the room may incur additional lens cost. You'll need a large lens capable of capturing a tight head and shoulders shot. Other camera position considerations include positioning the camera lens parallel to the subject's eyes and using a camera platform to set the vertical height. A fixed camera shot for center screen should show close to actual height of praise leader.

Optimizing the Projector for Realism
Many houses of worship are implementing the latest projection technologies, such as DLP, LCD, and LCoS. The first two offer projectors with brightness suitable for large worship venues. However, LCD can be very difficult to color balance. For realism, DLP technology offers the most life like colors and more responsive video. Some of these systems include special features and functions with easy-to-use menu options to help you set the proper color balance, contrast, brightness, and image blending.  Let's take a close look on how to properly set these conditions to achieve optimum results for image realism.

Color balance the image.
For video IMAG applications, the projected image should be balanced to the stage lighting and camera feed to make the image appear real. The IMAG begins with the camera. Typically, a camera's color temperature is set by shooting the proper color chart according to the applied lighting. It is then adjusted to a calibrated reference monitor that indicates the resulting color coordinates through signal distribution. Once the camera is properly balanced and fed to the projectors, the projected image can be adjusted accordingly to reproduce the proper color coordinates. This ensures a "balanced system." It helps to use a color meter to measure the color coordinates being reflected from the screens. Otherwise, adjust the projected images visually to match the reference monitor. This ensures the viewers see the same images on the screens as the cameras.

Adjust brightness and contrast.
Proper adjustment of the brightness and contrast levels significantly improves the "depth," which is important to achieving image realism. If the projected image does not appear "realistic," it then becomes a distraction rather than an attraction.

To properly set the brightness and contrast, adjust the projectors to the displayed source. With IMAG, the balanced camera system should shoot a gray scale pattern containing full black and full white content. If the content is computer generated, the computer output should generate a gray scale pattern with full black and full white in order to adjust the projectors.

Adjust the brightness of the projector while observing the black content in the projected image. Make sure the black level is as dark as possible without "crushing" the black details in the image. Adjust the contrast setting while observing the white portion of the projected content. Set it so that the maximum dynamic range can be seen and the white details are not "crushed." Too much contrast results in the loss of detail in the white segments.

Here is a note on lamp technology. Lamp technology plays a big role in a projector's ability to deliver realism. The majority of projectors today use either Xenon or high-pressure Mercury vapor lamps (UHP, UHE, UHM, etc). Xenon lamps are known for producing accurate, realistic colors and ensure stable color performance over the life of the lamp. High-pressure Mercury vapor type lamps are less expensive, long lasting, and brightness efficient. But, they can lose their color reproduction capabilities over time and often long before the recommended lamp life change. Overall, Xenon lamps are considered the best choice for high-quality, high-definition imaging.

It should be noted that not all projectors have the ability to be setup to produce life-like video.

Realistic IMAG and center screen imaging can be powerful tools to enhance the worship experience. They should be seamlessly integrated with all aspects of your worship center or overflow area and other A/V features for the best results. Be sure to involve the right professionals—such as qualified display systems specialists, lighting consultants, and other A/V experts—in the planning, design, and implementation of your visual environment. You'll need them to work closely with your technical staff and ministerial users to ensure optimum results. 

Peter Taylor is the director of sales and national sales manager for H.O.W. at Barco NA, www.barco.com, and a worldwide authority on HOW visualization.

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