Visualization Stations – The Big Picture Within Reach

You may not know the term Visualization Stations. It is a term that was created specifically to describe any visual presentation scape that is used to display video or graphical content used to present ideas to others. Visualization Stations are used to present anything to anybody. It could be a large display in a meeting space or conference room enabling presentations of grand ideas and comparative data.
 It might be a huge display in a lobby or atrium presenting graphical and video images. It could be a vast, interactive surface that allows participants to collaborate in training, simulation or design environments. In short, a Visualization Station enables people to communicate and exchange their ideas more effectively. Today, most people associate large video displays and display walls with multiple LCD panels. Commonly called “video walls”, these tiled LCD display walls provide a cost-effective way to build a large presentation scape. However, this is not the only effective way to cover a large area with images. Video projection is another cost-effective way to do this. With new laser-driven, high-output projectors, extremely large areas can be turned into Visualization Stations. And, narrow-pitch direct-view LED can be an effective solution when high-output and contrast is required to make an eye-popping presentation in even the most challenging ambient light environments. Let’s take a moment to examine the pros and cons of each.
Barco Unisee

LCD

LCD display panels come in all kinds of sizes. From the computer monitor on your desk to the television in your living room, these displays have become the de facto standard for high-resolution display products. In the commercial world, LCD displays are available up to 100” diagonal, and beyond. These large displays can be considered as the foundation to a Visualization Station all by

themselves. However, there is still a cost barrier in these larger displays, and the largest sizes can be challenging to even get down a hallway and into a room. So, with the use of a video wall controller, integrators can tile multiple smaller LCD displays and mount them to make one large video display of almost any size. The clear advantage of LCD is availability. There are many choices and competitive pricing. We’re all familiar with LCD and this technology has been around quite a while. The new offerings, like Barco’s UniSee, make installation and servicing extremely easy, more so than any similar technology.

There are two major issues with tiled LCD video walls.

First, tiled LCD displays have seams. Economy LCD displays have bezels. No matter how you consider it, it’s like looking through a multi-paned window. The new LCD video wall displays have seams less than 2mm. Some have seams less than 1mm. There’s still a visible seam. Second, standard LCD displays offer around 500 NITS brightness. (consumer LCD panels typically have <400 NITS) Several manufacturers offer 700 NITS or greater output on their specialty LCD displays. In a high ambient light environment, even 800 NITS might not be enough brightness resulting in a washed-out look. This is certainly true where direct sunlight is in play. According to SMPTE (Society of Motion Picture and Television Engineers), the ratio of display brightness and light from ambient sources should be a ratio of at least 5:1. As a reference, sunlight streaming through a window will often exceed 20,000 lux! Direct sunlight outdoors can be 125,000 lux! NITS x Pi = lux Lux / Pi = NITS Using this formula, a 350 NITS consumer LCD display outputs 1100 lux. Then, using the 5:1 SMPTE recommendation, you can extrapolate that the consumer LCD can operate properly in up to 220 lux ambient lighting. You can likewise say that a 500 NITS commercial LCD display outputs 1570 lux. When you divide that by 5, the maximum ambient light is 314 lux. The right way to calculate this is with a light meter. It’s a worthwhile tool to have. Say, you measure the ambient light in a corporate lobby on a sunny day at 2,000 lux. Will an LCD video wall be the right choice? Let’s work backward. 2,000 lux divided by Pi (3.1416) equals 637 NITS. Apply the 5:1 rule and multiply 637 x 5 = 3,185 NITS. That’s what you need to reproduce a good picture on a sunny day. No, the LCD video wall would not be a good choice.

PROJECTION

High-output video projectors have a place in the large video wall space. They can produce a very high lumen (lux per square meter) output. Especially when considering the new laser-driven projectors, this can provide a huge image at a reasonable cost. The caveat with projection is that ambient light can wash-out the projection screen. So, to determine whether projection is the right choice you must consider again the ambient light conditions.

Projection Screens
In controlled lighting conditions, you can utilize a video wall controller with edge-blending to combine the output of multiple projectors to create an extremely large Visualization Station at an affordable price. Something like this could be used for a video backdrop in a performance space, or for a large auditorium or lecture hall. In conditions with ambient light, you must select a screen fabric with ambient light rejection or face the screen away from ambient light (windows) and use the 5:1 rule as we did above. Remember that the lumens rating of the projector is the same as lux, but you have to calculate the size of each projector’s screen area to arrive at the actual lux output.

Let’s work that out.

First, edge-blended projectors should have an overlap of about 30% to get the best results. So, if you need to have a 3840 x 1080 image, you need three, not two projectors. Two projectors will give you about 2688 x 1080, ideally. I’ve done video backdrops with three projectors and about a 35:9 aspect ratio. So, let’s say we’re making a 35’ x 9’ video backdrop like I did. We must deal with each projector by itself. So, each projector can fill a 16’ x 9’ screen. To find the lumens needed, calculate the total area of the screen in square feet. Measure the amount of ambient light at the screen location. Multiply that number by 5 and multiply the result by the area of the screen. In this case, the ambient light at the screen is only 10 foot-candles. 10 x 5 x 144 = 7200 lumens.  We’ll need three, 7200-lumen projectors. Now in most cases, you’ll have much more ambient lighting than I had on-stage in a controlled lighting environment of an auditorium. But, you get the idea. You also can see where it can get impossible in high ambient light situations.

LED Screen
This is where you have the horsepower to overcome high ambient light environments. Direct-view LED displays can output 10,000 NITS for indoor applications, and well over 25,000 NITS for outdoor applications. They’re totally seamless and have no bezels. The main thing you need to understand is pixel pitch and viewing distance.
Any LED display is made up of individual LED semi-conductors in red, blue and green. This means that the picture is made up of a bunch of dots. The wide-pitch LED displays like you see in outdoor signs are often made with discrete LEDs, like the power light on equipment. These can’t be packed too tightly together as at close viewing distances, they look like a bunch of dots. Think scoreboards. Now, they have surface-mounted (SMD) LED modules that are really small. These modules can be soldered on the boards so there’s less than 1mm space between them. These are called narrow-pitch or sometimes ultra-fine pitch LEDs. The closer the dots, the closer you can view it without “seeing” the dots. Here’s what you need to know. The general rule of thumb is that you multiply the pixel-pitch by 3.5 to find the minimum viewing distance. In actuality, it can be as little as 1mm to 1 meter (3.2 feet). So, you’ll start by determining the viewing distance in the proposed system design. The divide that distance by 3.5 to get the pitch you’ll need. In outdoor signage, the traffic speed is also a factor. It’s all about how the human brain processes a bunch of dots at a given viewing behavior. For outdoor signs, you are usually looking at 16mm, 10mm and perhaps even 7mm pitch. For Visualization Stations, where the focus is clearly on the image, you’ll be considering 4mm and less. Thus, the term “ultra-fine pitch.”

Let’s work this out.

We’re specifying a direct-view LED display for a house of worship. The first row of seating is about 20 feet back from the display location. 20 / 3.5 = 5.7mm pitch. There’s no available 5.7mm pitch available, so you’ll choose between say a 4mm, and a 7mm. In this case, I’d recommend using the 4mm because there’s not a huge difference in cost. However, in close viewing, and especially in interactive environments like boardrooms where the presenter might be right up on the display, the cost between a 1.2mm and 0.9mm pitch can be quite a lot of money. In summary, there are a few solutions to consider. Whether you choose LCD, projection, or direct-view LED will depend on all of the criteria we discussed here, as well as the total cost of ownership. When you have a project that requires a large video display solution, call your Starin team and we’ll assist you in choosing the correct solution and we’ll provide a complete, turnkey solution that guarantees success for you and for your customer.