Image Averaging for Zoom Out Displays


Select option on Imagery tab of options form

Image averaging takes the average of the pixel at the display location and the adjacent pixels that are not displayed. Averaging is only within rows. It acts much like a smoothing filter, and removes speckle from the image.

This currently works only with untiled imagery, where entire rows are stored in sequence.


Overview image of an entire USGS DOQQ (Digital Ortho Quarter Quad) of the Hanging Rock Canyon map in eastern California. The image on the left shows a zoom out that simply selects pixels from the image, while the image on the right uses averaging.


Overview images of the entire Hanging Rock Canyon DRG. The map on the left shows a zoom out that simple selects pixels from the image, while the image on the right uses image averaging of the pixel at that location and the adjacent pixels that are not displayed. Averaging is only within rows.


Part of the entire Hanging Rock Canyon DRG. The map on the left (or top, depending on your screen size and settings) shows a zoom out that simple selects pixels from the image, while the image on the right uses image averaging .


The averaging views are JPEG images which lose some detail, while the simple zooms are lossless GIFs that show exactly what the program produces.


Last revision 12/24/2009