Method and system for projector calibration

Patent metadata

Field	Value
Publication number	US-10080004-B2
Application number	US-201414534855-A
Country	US
Kind code	B2
Filing date	Nov 6, 2014
Priority date	Nov 6, 2014
Publication date	Sep 18, 2018
Grant date	Sep 18, 2018

Abstract

The present disclosure relates to a method for calibrating a projector. The method includes projecting a test pattern onto a scene or an object within the scene and capturing the test pattern using a camera. Once the test pattern image has been captured by the camera, the method further includes estimating by a processing element a perspective projection matrix, warping the estimated projection matrix based on a non-linear distortion function, and modifying the projector to project light based on the distortion function. The present disclosure also relates to a presentation or projection system including two types of projectors for projecting an output presentation having a second image overlaid on a first image.

First claim

What is claimed is:

1. A method of calibrating a projector comprising: receiving by a processing element a first calibration image of a first calibration pattern comprising a plurality of pattern elements projected onto a projection surface; detecting by the processing element the plurality of pattern elements in the first calibration image by an image analysis algorithm; generating a perspective projection matrix by the processing element by modeling the projector as a pinhole device with a pinhole approximation to provide a first calibration approximation based on the detected pattern elements in the first calibration image and the first calibration pattern; and determining by the processing element a two-dimensional non-linear mapping function to correct inaccuracies in the first calibration approximation resulting from the pinhole approximation by analyzing the first calibration image to compensate for distortion characteristics inherent to the projector, wherein the non-linear mapping function is determined by comparing by the processing element the first calibration image and the perspective projection matrix.

2. The method of claim 1 , further comprising determining by the processing element a three-dimensional position of the plurality of pattern elements.

3. The method of claim 1 , further comprising generating by the processing element a calibrated image by transforming the first calibration image using the non-linear mapping function.

4. The method of claim 1 , further comprising determining by the processing element a transformation amount for each of the pluralities of pattern elements.

5. The method of claim 1 , further comprising creating by the processing element a look up table using the non-linear mapping function.

6. The method of claim 5 , further comprising interpolating by the processing element values within the look up table to increase the number of values.

7. The method of claim 1 , further comprising:
receiving by the processing element a second calibration image of a second calibration pattern projected onto a projection surface, wherein the second calibration pattern is different than the first calibration pattern.

8. The method of claim 7 , wherein generation of the perspective projection matrix further comprises analyzing the second calibration image and the second calibration pattern.

9. The method of claim 1 , further comprising:
modifying by the processing element an input image based on the two-dimensional non-linear mapping function to generate a modified input image, wherein the modified input image accounts for distortion that will occur when the input image is projected by the projector; and
transmitting the modified input image to the projector for projection on the display surface.

Assignees

• Disney Entpr Inc

Inventors

• Grundhofer Anselm

Classifications

• G06T3/0093

  Physics · mapped topic

• G01B11/2513

  with several lines being projected in more than one direction, e.g. grids, patterns · CPC title

• H04N9/3185 Primary

  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) · CPC title

• G01B11/2504

  Calibration devices · CPC title

• H04N9/3194

  including sensor feedback · CPC title