Some Problems of Practical Image Restoration

Ivan R. King

Astronomy Department, University of California, Berkeley, CA 94720

Abstract:

This discussion begins by noting that stellar photometry is often done quite effectively on unrestored images. Even when restoration is necessary, one must be wary of sophisticated methods, many of which distort photometric values. Fourier methods are photometrically reliable, and Wiener filtering leads to reasonably good restorations. The statistics of pixels in a restoration presents new problems, which have been only partly solved. A completely unsolved problem is presented: estimating the arithmetic difference between two images that have different PSFs and different . The discussion concludes with a plea for methods that are available and transparent to the ordinary user of HST.

This is likely to be the least technical and most nave of all the papers presented at this meeting. I come before you not as an expert but as a user, and not as a contributor but as a consumer. I could suggest that I am on the invited program only because I can't convince Bob Hanisch that I don't know anything about image restoration, but that would not be totally fair. I think that Bob really did want you to hear from some people who represent the user community of image restoration. I do have a certain amount of experience with it, and I have some scars to show for it.

• To Restore or Not to Restore?
• Problems of Photometry on Restored Images
• Problems of Fourier Restorations
• An Example of a Perplexing Problem
• A Plea to the Learned
• Conclusion
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