# US 10,769,814 B2 · Camera parameter calculation apparatus based on the average pixel values

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- Number: US 10,769,814 B2
- Document ID: US10769814B2
- Status: Granted
- Kind: B2
- Application number: 16/242,291
- Filed: 2019-01-08
- Published: 2019-05-09
- Granted: 2020-09-08
- Earliest claimed: 2016-09-08
- Assignees: Panasonic Intellectual Property Management Co., Ltd.
- Applicants: Panasonic Intellectual Property Management Co., Ltd.
- Inventors: Nobuhiko Wakai; Kunio Nobori; Takeo Azuma; Satoshi Sato; Ayako Maruyama; Mikiya Nakata
- Web page: https://patentgrep.com/patent/US10769814B2

## CPC

- G06T 7/80: Analysis of captured images to determine intrinsic or extrinsic camera parameters, i.e. camera calibration
- G01B 11/24: for measuring contours or curvatures
- G01B 21/042: {Calibration or calibration artifacts (G01B3/30, G01B9/02072 take precedence)}
- H04N 13/239: using two two-dimensional [2D] image sensors having a relative position equal to or related to the interocular distance (H04N13/243 takes precedence)
- H04N 13/246: Calibration of cameras
- G06T 2207/10024: Color image
- G06T 2207/30244: Camera pose
- H04N 23/62: Control of parameters via user interfaces
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G01B: MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

Provided are: a point group obtainer that obtains three-dimensional point group data indicating three-dimensional locations of each of a plurality of three-dimensional points included in an imaging space of one or more cameras; a camera parameter calculator that (i) obtains corresponding points, for each of the plurality of three-dimensional points, in individual images captured using the one or more cameras, based on the three-dimensional point group data and an initial camera parameter of each camera, and (ii) calculates a camera parameter of each camera on the basis of the initial camera parameter of each camera and pixel values, included in the individual images, at the corresponding points; and a camera parameter outputter that outputs the calculated camera parameter of each camera.

## Claims

### Claim 1

A camera parameter calculation apparatus, comprising:
a point group obtainer that obtains three-dimensional point group data indicating three-dimensional coordinates of a plurality of three-dimensional points included in a common imaging space of one or more cameras;
a camera parameter calculator that (i) calculates image coordinates of corresponding points, for each of the plurality of three-dimensional points, in one or more images captured using the one or more cameras, based on the three-dimensional point group data and one or more initial camera parameters of the one or more cameras, and (ii) calculates one or more camera parameters of the one or more cameras, based on pixel values, included in the one or more images, at the image coordinates; and
a camera parameter outputter that outputs the one or more camera parameters,
wherein the one or more cameras and the one or more initial camera parameters are in one-to-one relationship, the one or more cameras and the one or more images are in one-to-one relationship, and the one or more cameras and the one or more camera parameters are in one-to-one relationship, and
wherein the one or more cameras are two or more cameras,
the camera parameter calculator calculates the one or more camera parameters on the basis of a plurality of differences, and
each of the plurality of differences is a difference between:
one pixel value from among pixel values at corresponding points, for one three-dimensional point from among the plurality of three-dimensional points, in individual images captured by the two or more cameras; and
an average value for said pixel values.

### Claim 2 (depends on 1)

The camera parameter calculation apparatus according to claim 1,
wherein the difference is an absolute value of the difference between the pixel value and the average value.

### Claim 3 (depends on 1)

The camera parameter calculation apparatus according to claim 1,
wherein the difference is a square value of the difference between the pixel value and the average value.