Patent ID: 7046839

Claim:
A method for performing camera position approximation for determining positions of a device used to capture an image, said method based on photogrammetric principles and comprising: identifying three points in said image captured by said camera, wherein said three points have a known relationship and said image becomes an image plane; projecting said three points' rays into an image space by intersecting each of said three points with a known focal point of said image plane; Choosing a point A on a first of said three points' rays at a location near said image plane; based on said known relationship, identifying a point B on a second of said three points' rays; drawing a circle with its center axis on a path AB and its radius such that known distances between points A and C and points B and C are respected; choosing a point C on said circle closest to a third of said three points' rays; repeating said choosing a point A so as to find a closest point C to said a third of said three points' rays; wherein point A, point B, and point C define said device position and define its x, y, z coordinates; and wherein orientation angles Ω, φ, and κ can be calculated from said x, y, z coordinates of said points A, B, C, thereby defining said camera position.