Repairing Artefacts and Cosmetic Defects
Cosmetic repair tools are used to correct blemishes and other artefacts in images. Use the commands below to repair the following types of defects. In addition, you may wish to create synthetic images and add defects in order to evaluate your repairing techniques.
The table below matches the defect type to a command that can be used to correct it.
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Use for repairing this type of defect: |
Commands: |
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Isolated high or low pixels. |
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Residual high or low pixels that were not corrected by removing the dark current |
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CCD hot columns and cold traps. |
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Cluster defects larger than 1 or 2 pixels in area. |
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Cosmic rays and ionizing radiation events. |
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Removing stars, such as those interfering with local background measurements for photometry. |
In addition to commands listed in the table above, the Combine Image Set command can be used to reject artefacts that do not align at the same pixel locations in an Image Set.
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Repairs lines and rectangular regions of pixels that are always located at the same coordinates, such as hot columns, cold traps, and blemishes larger than 1 pixel in area. |
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Repairs isolated pixels using coordinates loaded from a file containing x,y positions of the bad pixels. Use this for repairing pixels that always are located at the same coordinates, such as hot or cold pixels. |
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Detects ands, optionally, repairs transient bad points and regions which vary in position, such as cosmic ray and ionizing radiation events, as well as poorly corrected hot pixels. |
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Automatically detects and repairs isolated pixels and small clusters of hot pixels as are often caused by cosmic rays and ionizing radiation. |
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Used to create a pixel mask by detecting isolated pixels that are very high or very low. |
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Creates and edits a blemish mask, which is a text-based description of blemish locations. |
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Edits an existing pixel mask or creates new a pixel mask by entering coordinates into a grid. You can also use it to review mask coordinates by sending the Image Cursor to mask coordinates in the mask's source image. |
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Provides a pixel zapping tool used to repair pixels by interactively marking them on an image. |
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Used to remove interfering stars or other point sources from the image. This is typically used before doing photometry on the image. |