Scanning and Image Processing
Images in this collection are derived from scans performed both at USGS and at the LPI. USGS images were constructed from 25 micron (approx. 1000 dpi) scans of Lunar Orbiter film, digitally mosaiced, and made available on the web at 100 microns (spprox.250 dpi). More information on USGS image sources is available at the USGS Lunar Orbiter Digization Project website. The Lunar Orbiter 16 x 20 inch prints from the LPI collection were scanned using a sheet-feeder scanner to create an archival digital file. Each print was digitized as an 8-bit grayscale image at 300 dpi, producing a file of approximately 29 MB in TIFF format.
Cosmetic enhancement has been done on all images to remove horizontal banding, and to enhance image contrast, using USGS's ISIS 3 software. First, USGS images were rotated 90° counterclockwise to match the orientation of the LPI images, and so that north is generally "up" in the photos. All images were imported into ISIS and converted to 16-bit grayscale. A series of high- and low-pass horizontal destriping filters, based on USGS's LO destriping cookbook procedures, were applied. Because of the slight size differences between the USGS and LPI scans, slightly different values were used in the destriping process, which can be seen in our destriping script for USGS scans and our script for LPI scanned images. The images were minimally contrast enhanced, based on absolute min and max values (to preserve as much information as possible), and exported out of ISIS as PNGs. These PNG were then converted to JPG and resized for the web. We've also provided links to the original raw images at USGS, where applicable.
NOTE — The Lunar Orbiter Photo Gallery is offered as a tool for identifying specific images for use in research projects. For some applications, the images will be suitable in their existing form. However, the processing they received may not be appropriate for all research projects. Higher-fidelity versions of the Lunar Orbiter photographs are available and can be obtained. More information regarding the USGS scans, including technical contacts, can be found at their Lunar Orbiter Digization Project website. Fore more information regarding LPI scans, please contact us at [email protected].