Background page
The Background page of the Source Extraction dialog configures the background measurement used by the Extract Sources command. Unless the image has already been flattened, it is best to use the polynomial fit to track the large-scale background changes.
These preferences determine how the background is computed. Sources are detected above a threshold relative to the local background estimate.
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Statistical Estimator |
Calculates the background as a single statistical value based on analysis of the entire image. |
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Click this button to configure the Statistical Estimator using the Region Stat Preferences command. |
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Polynomial Fit |
Calculates the background as the value of a polynomial fit to the entire image surface. |
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X, Y Terms |
Enter the number of terms used for the Polynomial Fit method. For example, 1 term for X fits a constant value in the X (column number) direction, and 3 terms in Y fits a parabola in the Y (row number) direction. |
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Constant Value |
Assigns a fixed value to the background, independent of the image brightness. |
