Image Processing Methods
This picture shows a comparison of the unprocessed Wide Field/ Planetary Camera (WF/PC) image (A) with images produced by three different image restoration techniques (B, C, D). As discussed in the accompanying background information on image processing, all of these techniques attempt to remove the halos which can be seen around stars in the raw image. The techniques used were: B) Jansson's constrained iterative method (from the Space Telescope Science Institute), C) a constrained least squares/maximum entropy method (from the Goddard High Resolution Spectrograph team), and D) Lucy's iterative method (from the WF/PC team.)
In general, these three very different methods give remarkably similar results. Some of the techniques generate slightly sharper images. Also, the cosmic ray (CR) hits have been removed from image D (note, for example, the linear CR feature in the middle right of A, B, and C.) Except for these minor differences, the excellent agreement of these three methods give us confidence that the restored images from all three methods are quite reliable.