Experimental investigation of reed instrument functioning through image analysis of reed opening

An image analysis procedure was developed to analyse front view video recordings of the motion of a musical instrument's reed. For each image of the movie, this procedure allows to extract various geometrical characteristics of the reed opening such as area, width and length of the two main dimensions. The technique is applied to static measurements on double-reeds throughout the normal range of playing pressures when the reed is inserted into an artificial blowing machine. Measuring the opening area as a function of the applied pressure shows a constant reed stiffness. Long-term deformations of the reed found in the stiffness measurement are related to the visco-elasticity of the reed material, and the parameters of relaxation are determined using long-term recordings of the reed opening. Moreover, the reed opening area is found to be proportional to the distance between reed blades, which is confirmed for oscillating regimes.