US 6,788,808 B1Granted

Method and device for optically determining depth

AssigneeKoninklijke Philips Electronics N.V.

InventorsCornelis W. A. M. Van Overveld, Antonius A. C. M. Kalker

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Abstract

The depth and orientation of a surface patch relative to a camera are determined. A first and second image of the surface patch are obtained from different viewpoints. Various predicted combinations of depth and orientation values are associated with the surface patch. Different available combinations may have different orientations. Each predicted combination predicts a correspondence between points in the first and second image, corresponding points viewing identical locations on the surface patch. One searches for a best combination of depth and orientation so that among the available combinations the best combination results in a minimum aggregate of differences between pixel values of the first and second image at corresponding points.

Claims10

Dependent claims

A method of optically determining, for a plane containing different camera viewpoints on respective optical axes perpendicular to the plane, respective distances between the plane and points on or near a surface patch that does not lie in a plane perpendicular to the optical axes of the camera and is visible in first and second images point projected from said viewpoints, the method comprising the steps of

a) obtaining said first and second images containing the surface patch that does not lie in a plane perpendicular to the optical axes of the camera viewed from the different viewpoints,
b) estimating distances of said points to said plane and orientations of small flat surfaces at each of said points without segmenting the surface patch into smaller patches;
c) applying to said first image an image-to-image mapping function based on the estimated distances and orientations to predict which pixel values of the first image correspond to pixel values of the second image;
d) determining differences between the predicted pixel values of the second image and actual corresponding pixel values of the second image;
e) aggregating the determined differences;
f) repeating steps b) through e) with new estimates unless said steps have already been repeated for a predetermined number of iterations;
and
g) determining, based on the lowest aggregate of determined differences from among iterations of steps b) through e), a best matching set of points, and correspondingly, orientations and distances to the plane.

5 more elements

A device for optically determining, for a plane containing different camera viewpoints on respective optical axes perpendicular to the plane, respective distances between the plane and points on or near a surface patch that does not lie in a plane perpendicular to the optical axes of the camera and is visible in first and second images point projected from said viewpoints, viewing depth, the device comprising:

an image capture circuit configured for a) obtaining said first and second images containing a surface patch that does not lie in a plane perpendicular to the optical axes of the camera as viewed from the different viewpoints;
and
a search unit configured for:
b) estimating distances of said points to said plane and orientations of small flat surfaces at each of said points without segmenting the surface patch into smaller patches;
c) applying to said first image an image-to-image mapping function based on the estimated distances and orientations to predict which pixel values of the first image correspond to pixel values of the second image;
d) determining differences between the predicted pixel values of the second image and actual corresponding pixel values of the second image;
e) aggregating the determined differences;
f) repeating steps b) through e) with new estimates unless said steps have already been repeated for a predetermined number of iterations;
and
g) determining, based on the lowest aggregate of determined differences from among iterations of steps b) through e), a best matching set of points, and correspondingly, orientations and distances to the plane.

7 more elements

Dependencies are inferred from the claim text.