The CCD camera has to be positioned at a distance where the flame of maximum height can be captured. The camera should be aligned perpendicular to the front plane of the flame.
Once the camera position is fixed, it should not be disturbed or moved to a new position in order to avoid variable magnification.
CNG fuel is set to the desired flow rate using calibrated rotameter and ignited at the tube exit.
At a particular fuel flow rate, video of the flame should be taken for certain time.
This procedure is repeated for different fuel flow rates.
The time period of video for each flame should be kept constant in order to extract equal number of frames from the videos.
