Daytime atmospheric plume opacity measurement using a camcorder

Wangki Yuen, Yichao Gu, Yalin Mao, Peter M. Kozak, Sotiria Koloutsou-Vakakis, Hyun Keun Son, Kevin Mattison, Bill Franek, Mark J. Rood

Research output: Contribution to journalArticlepeer-review


Digital Optical Method (DOM) software, developed earlier to measure atmospheric plume opacity with digital still cameras, was tested with a camcorder, which captures digital images (as video frames) in visible light wavelengths at 30 Hz. The effect of contrast between two backgrounds when using DOM contrast model was demonstrated through the use of different pixel value measurement wavelengths and different background pairs. Unique contributions presented here are: (1) the camcorder is within the United States Environmental Protection Agency Method 9 individual and average opacity error limits, for black and white plumes with opacity values between 0% and 90%, while enabling real-time opacity measurements; (2) increasing contrast between two backgrounds decreases the opacity measurement error and uncertainty, with all measurements within individual and average opacity error limits for contrast parameter ≥ 0.92; and (3) background choice affects the opacity measurement uncertainty more than camcorder calibration and number of pixels sampled for tested conditions. These contributions are important because they are the first demonstration and evaluation of applying digital image analysis with camcorders to quantify atmospheric plume opacity. Moreover, the results show that obtaining higher contrast between two backgrounds is the most important factor for reducing error in plume opacity measurements to meet acceptable performance criteria. This knowledge increases the reliability of image analysis to provide a low-cost and real-time monitoring method for quantifying atmospheric plume opacity.

Original languageEnglish (US)
Pages (from-to)43-54
Number of pages12
JournalEnvironmental Technology and Innovation
StatePublished - Nov 2018


  • ASTM D7520
  • Digital image
  • Digital optical method
  • Method 9
  • Pixel value

ASJC Scopus subject areas

  • General Environmental Science
  • Soil Science
  • Plant Science


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