Patent ID: 9043146
Filing Date: 2015-05-26
Classification: G01S,G06F,G06K,G06T,H04N,Y10S

Abstract:
1. A method for determining a current location of a target object in a reference coordinate system when the target object is equipped with at least three active target markers arranged in a known pattern, comprising: (a) defining a location of a camera with respect to the reference coordinate system; (b) capturing an image while the camera is centered on the target object and the active target markers are not on; (c) capturing one or more images while the camera is centered on the target object and one or more of the active target markers are on; (d) processing the images to compute a difference image representing differences between the image captured while all of the active target markers were not on and images captured while one or more of the active target markers were on; (e) computing respective average pixel coordinates for the differences in the difference image corresponding to respective active target markers; (f) for respective active target markers, aiming a laser range finder and transmitting a laser beam in the direction defined by respective pan and tilt angles which are a function of at least pan and tilt angles at which the target object was centered in an image field-of-view of the camera and differences between the respective average pixel coordinates and pixel coordinates of a center of the images; (g) for respective active target markers, acquiring respective range, pan and tilt data subsequent to the transmission of a respective laser beam; (h) computing coordinates of respective points corresponding to the active target markers in the reference coordinate system based on the measured range, pan and tilt data; and (i) comparing respective positions of the respective points whose coordinates were computed from measured data to respective positions of respective points arranged in the known pattern to determine a current position and orientation of the target object defined in terms of the reference coordinate system.