Investigation for developing a calibration method for non-destructive examination of tree trunks

Vibration signals spreading in tree stumps change dependent of a long list properties like the type of the tree, the current moister content or the inner structure of it - does it contain any knots or decay areas in the signal path. These properties change the signal properties traveling in the stumps and the measured properties can be used to determine the inner structure of it. To be able to determine the inner structure accurately, both the precise arrangement and distance of the sensors or the exact signal properties in an intact portion of the stump needs to be known. With a use a of a proper calibration setup these parameters can be measured and the results can be used for adjusting the examination algorithm to get more precise results. In this paper, I would like to present a fist approach of creating such a calibration method and selecting an appropriate sensor from a hardware based on National Instruments equipment and software.