Filter page
The Filter page of the Source Extraction dialog set inclusion limits on basic source properties measured by the Extract Sources command. After objects are detected, their properties are computed. Values set in this dialog are used to filter out objects that do not fall inside the selected limits. For example, setting Area Min = 2 assures that sources having a single pixel are not includes in the final source list. Conversely, if you only want to detect single pixels, uncheck Area Min and then set Area Max = 2. Only items that are checked are used.
These parameters set criteria for sources being retained in the list of detected sources. A filtering parameter is used only if its box is checked.
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Area |
Sets limits for the source area, measured in pixels. |
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Ellipticity |
Sets limits for the ellipticity, or the value 1 – b/a, where b is the minor axis and a is the major axis. |
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Peak |
Sets limits for the peak pixel value, as a percentage of the range found in the detection area. |
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Spacing |
Sets a lower limit on the distance between sources, measured in pixel units between their centers. When 2 sources are closer than this distance, one of them will be deleted. |