Difference between revisions of "PTAverage"
Revision as of 03:21, 8 February 2007
PTAverage averages several identical image into one density enhanced output file. Drop all images onto the application icon. The images can come from a digital camera or scanner.
PTAverage is a small utility which reduces noise in scanned images, and increases density. Often, the dynamic range of scanners is limited by random noise of the CCD or the lamp. In that case averaging of several scans can be used to remove noise and improve image quality. This is especially useful in panoramic imaging where large dynamic ranges are common.
Generate several identical scans of the same image. Be sure to scan with exactly the same settings, and do not touch the film holder. Any misalignment of the images will blur the final result. The more scans you make, the better will be the noise reduction. Using 2 images increases density D by 0.15, 5 images by 0.36 and 10 images by 0.5. Of course, at some point the random noise is suppressed below the detection limits of the device in which case no further improvement is possible.
Save all images in lossless PICT format. Then select all images, and drop them at once onto PTAverage icon. You will be asked for a result file name. Then PTAverage reads one file after the other, and creates the final image.
TODO: provide non copyrighted images and example for now see 
current version of PTAverage is 220.127.116.11 2001/12/02 provided by Helmut Dersch with his last distribution of PanoTools bundle.