# US 8,786,788 B2 · System and method for image aspect preservation in multiple projector alignment

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- Number: US 8,786,788 B2
- Document ID: US8786788B2
- Status: Granted
- Kind: B2
- Application number: 13/866,659
- Filed: 2013-04-19
- Published: 2013-10-24
- Granted: 2014-07-22
- Earliest claimed: 2012-04-20
- Assignees: Mersive Technologies, Inc.
- Applicants: Mersive Technologies, Inc.
- Inventors: Christopher O. Jaynes; Russell Huonder
- Web page: https://patentgrep.com/patent/US8786788B2

## CPC

- H04N 9/3185: {Geometric adjustment, e.g. keystone or convergence (optical or mechanical adjustment of convergence H04N9/317; using scanning means H04N3/22; optical or mechanical adjustments of projectors not peculiar to the presence of an electronic spatial light modulator G03B21/14)}
- H04N 9/3147: {Multi-projection systems (video walls G06F3/1446)}
- H04N 9/3194: {including sensor feedback}
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

A method is disclosed herein that derives a post-alignment transform that is applied to the input source after the application of an alignment transform to ensure that when each source illuminates the screen, the display is aligned and retains the correct displayed aspect ratio. The transform takes into account the alignment transform and the input source aspect, and then performs a secondary, post-processing transformation that corrects the distortion induced by the alignment transform. This aspect-preserving function is a linear transform that maps pixels in the aligned space to the aligned and aspect-correct space and can be applied to the input signal after the first alignment transform, or, in the case where the alignment transform is also linear, transforms can be directly combined to derive a compound multi-projector, aspect preserving transform. In this way, the input signal to the projectors will be aligned as well as retain proper aspect.

## Claims

### Claim 1

A method for preserving aspect ratio in a system using a plurality of projectors arranged in a configuration for displaying overlapping images on a display surface comprising:
determining an input aspect ratio of the configuration;
using an alignment transform to map video signals input to the plurality of projectors into a partially overlapping continuous image on the display surface;
computing a displayed aspect ratio of the image on a viewable rectangular region on the display surface;
computing an aspect preserving transform using the input aspect ratio and the displayed aspect ratio of the image; and
applying the transform to the video signals input to the projectors.