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Thanks for your interest in the Intel® RealSense Platform.
We don’t have a direct way to specifically get the head position in 3D coordinates, however, you could use the Projection APIs to get the depth data from the bounding boxes. If you use the Face or Head Bounding Boxes then find the center point and you can use Projection to map to depth. Please take a look at this link: Intel® RealSense™ SDK 2016 R2 Documentation.
Moreover, regarding your last question, we would like to let you know that The Point Converter Utility was originally developed to be used with the Hand module, and Hand is supported only in F200 and SR300.
Hope this information helps.