Advanced Technology for Automatically Adjusting Images

Advanced Technology for Automatically Adjusting Images
Created by Multiple Projectors

Images created using multiple projectors are compelling and immersive. However, setting up and adjusting the projectors for this requires specialized skills and knowledge, and takes time. With ordinary projectors, you need a separate external camera or instrument to help simplify the work. Epson projectors, however, use a special algorithm and built-in cameras to make image adjustment quick and easy.

Example of an image created using multiple projectors

The advanced technology behind the large,
compelling images created with multiple projectors

Images created using multiple projectors

Multi-projection is used for a wide variety of applications and purposes, to bring a space alive by delivering large, compelling images at events, shopping complexes, and more. The use of multiple projectors gives you the freedom to create huge portrait or landscape images that cover entire walls in large venues, but the installation and adjustment work required to perfect such images usually requires advanced alignment skills.

Things such as color, brightness, and pixel position can differ from one projector to another for a variety of reasons, including slight errors in projected images due to differences in individual projector parts and changes in the products over time. So, when multiple projectors are used to form a single image, one must adjust the installation position of the projectors, match their color and brightness, make geometric corrections, and so forth. Many of these adjustments are done manually, and the knowledge and experience of the person making the adjustments greatly affects the outcome. Automating this adjustment work is the best way to reduce the difficulty involved, but achieving a level of accuracy equal to or better than that which can be achieved manually is no small feat.

Built-in cameras and image processing technology

Built-in camera unit

Epson builds cameras and other devices into its projectors to enable auto-adjustment of color, brightness, and various other parameters. When setting up multiple projectors to project a single large, uniform image, the built-in cameras take measurements of the projected images. This data is used to automatically adjust the position, color, brightness, and other characteristics of the projected images.

The built-in cameras make color calibration adjustments easy. They enable pixel color uniformity correction and color correction of the total projected image even without a colorimeter. The cameras themselves are optimized by individually adjusting them at the factory to match the output light. A camera and the human eye have different sensitivities to light wavelengths, so a color that looks the same to a camera might look different to the human eye. The amount of error is reduced by making corrections that bring the projected light measured by the camera closer to the sensitivity of the human eye.

The position of the projection surface must be accurately measured with the cameras to automatically perform geometric correction when using multiple projectors. Epson has enabled the built-in cameras to accurately measure projection position by using a specially designed projection pattern for measurement purposes. The built-in cameras measure the entire projection surface and its surroundings. The measured data are integrated into one projector to cover the entire multi-projection screen.
The time and effort required to set up cameras to take measurements increases along with the number of projectors. With Epson projectors that have built-in cameras, all users have to do is set up the projectors. Furthermore, the cameras are compatible with various optional projection lenses, so there is excellent scalability.
Epson uses a unique algorithm to process the measurements. The measured data are used to facilitate the automatic creation of a single seamless image from tiled images by blending the edges without the need for special equipment. This not only makes it easier to set up a multi-projection system but also makes it easier to readjust the system after a certain period of use, improving convenience.

Example of a multi-projection setup pre- and post-adjustment

Epson projectors with built-in cameras allow you to quickly and easily perform setup and adjustment tasks that previously required separate external devices such as cameras and advanced skills.
To further improve future projector usability, we will increase the accuracy of automatic adjustments and expand the range of applications, with support for three-dimensional and patterned surfaces and more.