# US 10,455,138 B2 · Camera calibration with lenticular arrays

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- Number: US 10,455,138 B2
- Document ID: US10455138B2
- Status: Granted
- Kind: B2
- Application number: 15/567,746
- Filed: 2016-04-20
- Published: 2018-05-10
- Granted: 2019-10-22
- Earliest claimed: 2015-04-20
- Assignees: Ian Schillebeeckx; Robert Pless
- Applicants: Washington University
- Inventors: Ian Schillebeeckx; Robert Pless
- Web page: https://patentgrep.com/patent/US10455138B2

## CPC

- G06T 7/80: Analysis of captured images to determine intrinsic or extrinsic camera parameters, i.e. camera calibration
- G03B 13/36: Autofocus systems
- H04N 17/002: {for television cameras}
- G06T 2200/21: involving computational photography
- G06T 2207/10052: Images from lightfield camera
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G03B: APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR (optical parts of such apparatus G02B; photosensitive materials or processes for photographic purposes G03C; apparatus for processing exposed photographic materials G03D)
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

The present disclosure is directed to an approach to solve camera calibration from a single picture of a simply structured light field created by viewing a carefully designed lenticular sheet. The lenticular sheet has different colors visible at different relative orientations and gives linear constraints on the K-1?R matrix which can be decomposed to give the rotation and calibration. The method uses geometric cues from hue measurements and does not require a correspondence between a point in the image and a point on the calibration pattern.

## Claims

### Claim 1

A method of calibrating a camera, the method comprising:
creating a light field with a lenticular array, the lenticular array comprising at least one sheet, the at least one sheet comprising a plurality of colors; and,
using a single picture of the light field to calibrate the camera, wherein the camera is calibrated without information from a correspondence between a point on an image and a point on a calibration object.

### Claim 2 (depends on 1)

The method of claim 1, wherein the plurality of colors are visible at a plurality of locations on the sheet.

### Claim 3 (depends on 1)

The method of claim 1, wherein the sheet comprises plastic.

### Claim 4 (depends on 1)

The method of claim 1, wherein the at least one sheet comprises a plurality of parallel cylindrical lenses.

### Claim 5

A method of calibrating a camera for an augmented reality application, the method comprising:
using a calibration object to create a color-coded light field, wherein the calibration object is based on at least one lenticular array, each lenticular array comprising at least one sheet, the at least one sheet comprising a plurality of colors;
estimating a focal length of the camera and a relative orientation and position of the object from a single image; and,
calibrating the camera, wherein the camera is calibrated without information from a correspondence between a point on an image and a point on a calibration object.

### Claim 6 (depends on 5)

The method of claim 5, wherein the plurality of colors are visible at a plurality of locations on the sheet.

### Claim 7 (depends on 5)

The method of claim 5, wherein the sheet comprises plastic.

### Claim 8 (depends on 5)

The method of claim 5, wherein the at least one sheet comprises a plurality of parallel cylindrical lenses.