Motion Magnified Video Application To Machinery Diagnosis

Vibration detection can be performed by a meter or a single channel spectrum analyzer. The former has quantified vibration amplitude levels since the 1950s, while the latter was able to implement the Fast Fourier Transform (FFT) since the 1960s to break vibration down into its frequency components. Multiple channel FFT analyzers enabled the process of Operating Deflection Shape (ODS) determination, which has been an important tool in visualizing the vibration of the machine and its system, including the foundation and piping networks. The input for ODS is the phase-linked signal set from a group of accelerometers, moved over often hundreds of test points. The data is superimposed onto a CAD model, and then scaled-up vibrations are animated at frequencies of interest. This process provides valuable insights but is time-consuming and therefore expensive each time it is applied by experts, and it is error-prone. An alternative method has been developed that is based on the evaluation of high resolution/high-speed videos. The method provides information equivalent to a high-sensor-count ODS, by treating each pixel as an accelerometer, using the pixel’s light intensity modulation to translate information embedded in the video into vibration motion able to be observed and interpreted by human investigators. This method is known by some as Motion-Magnified Video (MMV).


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