Robust landmarks for machine vision and methods for detecting said landmarks

摘要

Methods and apparatus for measuring orientation and distance. In one example, an orientation dependent radiation source emanates radiation having at least one detectable property that varies as a function of a rotation of the orientation dependent radiation source and/or an observation distance from the orientation dependent radiation source (e.g., a distance between the source and a radiation detection device). In one particular example, the rotation of the source is determined from a position or phase of the orientation dependent radiation on an observation surface of the source, and the observation distance between the source and the detection device is determined from a spatial frequency of the orientation dependent radiation. In another example, an image metrology reference target is provided that when placed in a scene of interest facilitates image analysis for various measurement purposes. Such a reference target may include automatic detection means for facilitating an automatic detection of the reference target in an image of the reference target obtained by a camera, and bearing determination means for facilitating a determination of position and/or orientation of the reference target with respect to the camera. In one example, the bearing determination means of the reference target includes one or more orientation dependent radiation sources.