Projectors

Projectors often exhibit varied behavior when used for multi-projection with soft-edge blending. Factors such as image matrix technique, optical lens, and projection surface play a significant role in determining the quality of blended multi-projection.

Projector types

When it comes to creating the ultimate multi-projector setup, choosing the right projector is crucial. Projectors come in various types, each utilizing different technologies to produce images. Understanding these technologies and their advantages and disadvantages can help you make an informed decision. Let's explore the main types of projectors: LCD, DLP, LED, LCoS, and Laser projectors.

LCD (Liquid Crystal Display) Projectors

LCD (Liquid Crystal Display) is a display technology that uses liquid crystals as optical elements. In an LCD projector, the light source passes through color filters and then enters the liquid crystal panel. The liquid crystal panel controls the amount of light passing through, which is then projected through a lens to form an image.

Advantages:

• Color Accuracy: LCD projectors are known for their excellent color accuracy and sharp images.
• Affordability: Generally more affordable compared to other types.
• Reliability: These projectors are typically reliable and require low maintenance.

Disadvantages:

• Contrast Ratio: LCD projectors often have lower contrast ratios, meaning blacks may appear more like dark grays.
• Screen Door Effect: This is where the grid lines of the LCD panel are visible（at low resolution）, which can be distracting.

DLP (Digital Light Processing) Projectors

DLP (Digital Light Processing) is a display technology that uses digital micro mirrors as optical elements. In a DLP projector, the light source passes through a spinning mirror, dividing the light into the three primary colors: red, green, and blue. The digital micro mirrors then control the projection of these colors, which are subsequently projected through a lens to form an image.

Advantages:

• High Contrast: DLP projectors offer high contrast ratios, producing deeper blacks.
• Smooth Motion: Excellent at handling motion, making them great for video playback.
• Compact Design: Generally more compact and lightweight.

Disadvantages:

• Rainbow Effect: Some users may see flashes of color, known as the "rainbow effect."

LED (Light Emitting Diode) Projectors

LED projectors use LED lights to produce the image. These LEDs can be red, green, and blue, which are combined to create the full spectrum of colors needed for the projected image. The light from the LEDs passes through the projection technology (either LCD panels or a DLP chip) to create the image, which is then projected onto the screen.

Advantages:

• Longevity: LEDs have a long lifespan, often up to 20,000 hours.
• Energy Efficiency: They are energy-efficient and produce less heat.
• Consistent Color: LED projectors maintain consistent color performance over time.

Disadvantages:

• Brightness: Generally, LED projectors are not as bright as their lamp-based counterparts.
• Cost: They can be more expensive upfront.

Laser Projectors

Advantages:

• Brightness: Extremely bright, suitable for large screens and well-lit environments.
• Color Accuracy: Exceptional color performance and contrast.
• Long Lifespan: Laser light sources have a very long lifespan and require minimal maintenance.

Disadvantages:

• Cost: Typically, laser projectors are the most expensive.
• Complexity: They may require professional installation and setup.

Ultra-Short-Throw Projectors (UST) and Mirror Lenses

Projection surface

• The projection surface greatly affects the quality of the display. Note that black color from a projector indicates no light projection, so the surface's color acts as a color filter for the entire projection.
• Ideal projection surfaces (projection screens, dome liners, projection foils, or paints) should be reflective to enhance brightness and efficiency (referred to as "gain") while being matte to avoid light spots and reflections.
• The worst type of projection surface would be black polished glass, whereas a matte white surface offers the best results.
• For the best tradeoff and results between dark or monochrome content and projection surface properties we suggest a projection surface "gain" of 0.6!.

Content

• The content displayed can either hide or highlight the limitations of soft-edge blending. Bright, colorful, and dynamic content is forgiving and can mask imperfections, while solid colors, smooth gradients, and shades reveal issues like color mismatches, blending mask problems, and brightness non-uniformity.
• Considering the content can help optimize the projection setup within a given budget. Bright and colorful projections can use lower-budget projectors, while whiteboards or sky content (e.g., for flight simulators) demand higher-quality projectors and blending.

Setting up the projectors

• Use projectors of the same model and type.
• Use projectors with the same lamp hours.
• Ensure all projection image parameters (brightness, contrast, gamma, color modes) are identical.
• Use the projectors native resolution. Avoid image scaling in the projectors.
• Turn off any dynamic functions, such as dynamic gamma or brightness.
• Choose the "Neutral" or "Video" mode over other projector image enhancement modes like: "Presentation," "Eco," "Game," etc.
• Set gamma between 2.2 and 2.4 (Standard gamma value).