Patent ID: 8155433

Claim:
A method of determining the location in space of a selected point in a digital image of the earth obtained by a camera, the image comprising a rectangular image having four corners and corresponding to an image space, wherein the digital image is associated with data indicating the geo-location coordinates for the points in the ground space corresponding to the four corners of the image, comprising the steps of: (a) performing independently and in parallel a recursive partitioning of both the image space and the ground space into successively smaller quadrants until a pixel coordinate in the image space assigned to the selected point is within a predetermined limit (Δ) of the center of a final recursively partitioned quadrant in the image space, and (b) calculating a geo-location of the point in the ground space corresponding to the selected point in the image space from the final recursively partitioned quadrant in the ground space corresponding to the final recursively partitioned quadrant in the image space; wherein step (a) comprises the steps of: 1) calculating the intersection of two diagonal lines in the ground space; 2) finding the center point in the image space by equal subdivision; 3) determining whether the pixel coordinate of the selected point in the image is within the predetermined limit (Δ) of the image center point in step 2), and if not then: 4) finding the quadrant in the image that contains the selected point using the center determined in step 2); 5) reducing the image space into a new image space corresponding to the quadrant found in step 4); 6) calculating the coordinates of the selected point in the new reduced image space quadrant; 7) finding the quadrant in the ground space corresponding to the quadrant found in step 4); 8) reducing the ground space into a new ground space corresponding to the found quadrant in step 7); 9) calculating the geo-location coordinates of the corners of the new ground space found in step 8); and 10) repeating steps 1-9 until the determination at step 3) is answered in the affirmative.