Abstract: 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.