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.

Choosing a Repair Method based on the Defect Type

The table below matches the defect type to a command that can be used to correct it.

Use for repairing this type of defect:

Commands:

Isolated high or low pixels.

Create Pixel Mask

Apply Pixel Mask

Interactive Repair

Clean Image Set

 

 

Residual high or low pixels that were not corrected by removing the dark current

Create Pixel Mask

Apply Pixel Mask

Interactive Repair

Clean Image Set

 

 

CCD hot columns and cold traps.

Edit Blemish Mask

Apply Blemish Mask

 

 

Cluster defects larger than 1 or 2 pixels in area.

Edit Blemish Mask

Apply Blemish Mask

 

 

Cosmic rays and ionizing radiation events.

Clean Image Set

Cosmic Ray Filter

Median Filter

 

 

Removing stars, such as those interfering with local background measurements for photometry.

Star Removal Module

 

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.

Cosmetic Repair Commands

Apply Blemish Mask

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.

Apply Pixel Mask

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.

Clean Image Set

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.

Cosmic Ray Filter

Automatically detects and repairs isolated pixels and small clusters of hot pixels as are often caused by cosmic rays and ionizing radiation.

Create Pixel Mask

Used to create a pixel mask by detecting isolated pixels that are very high or very low.

Edit Blemish Mask

Creates and edits a blemish mask, which is a text-based description of blemish locations.

Edit Pixel Mask

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.

Interactive Repair

Provides a pixel zapping tool used to repair pixels by interactively marking them on an image.

Star Removal

Used to remove interfering stars or other point sources from the image. This is typically used before doing photometry on the image.

Related Topics

Contents, Calibrating Images, Image Sets