METHOD FOR CALIBRATING A STEREOSCOPIC PHOTOGRAPHY DEVICE

• US 20140204181A1
• Filed: 02/22/2012
• Published: 07/24/2014
• Est. Priority Date: 02/24/2011
• Status: Active Grant

• Current Assignee: Nintendo European Research and Development SAS (Nintendo Company Limited)
• Original Assignee: Mobiclip Company
• Inventors: Delattre, Alexandre, Larrieu, Jrme
• Granted Patent: US 9,787,970 B2
• Time in Patent Office: Days
• US Class Current: 348/47
• CPC Class Codes: G06T 2207/10012 Stereo images
• CPC Class Codes: G06T 7/85 Stereo camera calibration
• CPC Class Codes: H04N 13/239 using two 2D image sensors having a relative position equal to or related to the interocular distance H04N13/243 takes precedence
• CPC Class Codes: H04N 13/246 Calibration of cameras

Abstract

The present invention concerns the field of stereoscopic photography devices and more precisely calibration thereof.

The invention proposes a method for calibrating a stereoscopic photography device that calculates a set of correction parameters for the images. These parameters are classed according to an order of importance. The first-order correction parameters are estimated first, the second-order correction parameters secondly. Advantageously, the first-order parameters are refined by taking account of the estimation values of the second-order parameters. Advantageously, a measurement of the relevance of the scene is carried out before the actual calibration.

Claims

1. Method for calibrating a stereoscopic photography device having two cameras for capturing a right-hand image and a left-hand image, said device having a plurality of defects, each of these defects being able to be corrected by applying a transformation to at least one of the two captured images, said defects being hierarchized in at least two orders:

a step of estimating the correction parameters for the defects of a given order;

a step of estimating the correction parameters for the defects of a second order higher than the first order;

a new step of estimating the correction parameters for the first-order defects, the estimation of the second-order parameters being used for a new estimation of the correction parameters for the first-order defects;

characterised in that four orders are used, comprising

a global translation offset of the image;

a horizontal and vertical trapezium deformation;

a rotation;

a zoom factor.

2. Calibration method according to claim 1, characterised in that the defects that are chosen to be corrected are chosen from:

a global translation offset of the image;

a horizontal and vertical trapezium deformation;

a rotation;

a zoom factor;

a barrel or pincushion distortion.

3. Calibration method according to claim 1, characterised in that it also comprises a step of calculating an index of the relevance of the scene.

4. Calibration method according to claim 3, characterised in that the calculation of an index of relevance of the scene comprises:

a step of calculating histograms of the right and left images;

a step of calculating the parallaxes on a plurality of areas of the left and right images;

a step of calculating an index of details of the scene according to the spread of the histograms and the indices of correlation between the areas of the right and left images;

a step of calculating a distance index that will be greater, the more the parallax indices are uniformly low;

a step of forming the relevance index according to the detail index and the distance index.