Quantification
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Note The availability of this feature depends on the camera model.
9.1 Introduction
Quantitative Optical Gas Imaging (QOGI) extends Optical Gas Imaging (OGI) to provide
a quantitative result. While OGI can qualitatively detect the presence of a gas leak, QOGI
will quantify the gas leak and provide a measurement of leak rate or concentration.
Quantification mode is specially designed to be used for QOGI applications. The data
acquisition and analysis is integrated in the camera and the quantification results are dis-
played on the camera screen. The results are automatically saved.
9.1.1 Field equipment
The plume extraction algorithm is change based, therefore it requires a steady image to
separate the plume from the background. This requires the operator to place the camera
on a tripod to perform any quantification measurement.
In addition to the tripod, a thermometer and a tape measurer (or infrared range finder)
are recommended as the operator will need to provide the ambient temperature and dis-
tance from the camera to the leak.
An anemometer is also recommended, though not absolutely required. The operator will
provide an estimate of the wind conditions (calm, normal or high), not an exact wind
speed measurement.
9.2 User interface
1. Mode selection
2. Parameters
3. Measurements
4. Delta T
5. Start measurement
9.2.1 Quantification parameters
For accurate quantification results, it is important to set the quantification parameters ac-
cording to the current conditions.
• Temperature refers to the temperature of the gas. It is common to use the ambient
temperature to represent the gas temperature. The assumption being made is that
the gas will quickly equilibrate to ambient temperature, even if there is a pressure drop
at the leak source.
#T810605; r. AD/92464/92464; en-US
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