QUICK METHOD FOR MEASURING WAVEFORM AREA IN PHOTOGRAPHS

A fast and accurate method for measuring waveform area involves simply weighing portions of the photograph. The technique is substantially faster than using a planimeter when measuring the area of a plane figure of complex shape. As an example, a pulsating current waveform is shown in the figure on a background of centimeter squares. The abscissa is time in seconds and the ordinate is current in milliamperes. The area under the waveform has dimensions of milliampere-seconds. The area enclosed by the waveform and the axes may be approximated by (a) taking a picture of the waveform on the oscilloscope screen, (b) carefully cutting out the resulting figure along the axes and the wave, and (c) weighing the cuttings. This weight then is divided by the weight of the photographic image of a single square, as determined by cutting out and weighing a block of such squares and dividing this weight by the number of squares in the block. This measurement technique could also be helpful in a vibration laboratory.

  • Supplemental Notes:
    • This article appeared in a publication Analytical Techniques: A Compilation.
  • Corporate Authors:

    National Aeronautics and Space Administration

    400 Maryland Avenue, SW
    Washington, DC  USA  20546
  • Authors:
    • Kopay, M T
  • Publication Date: 1975-1

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Filing Info

  • Accession Number: 00128509
  • Record Type: Publication
  • Report/Paper Numbers: NASA CR-2028
  • Contract Numbers: MFS-24402, NPO-11612, MFS-16968
  • Files: TRIS
  • Created Date: Apr 21 1976 12:00AM