Re: Did Huygens send JPEGS?

From: Mark Adler (madler_at_alumni.caltech.edu)
Date: 01/22/05 

To: sci-space-tech@moderators.isc.org
Date: 21 Jan 2005 21:57:14 -0800

Henry Spencer wrote:
> Nobody sends unprocessed bitmaps, or even losslessly-compressed
> bitmaps, from planetary probes any more. Images are invariably
> compressed using JPEG, or variations thereon, before transmission.

The MER rovers routinely send losslessly compressed images. This is
most common with the microscopic images. Early in Spirit we
accidentally sent a few unprocessed bitmaps that were not compressed at
all, because the wrong option was used on the command (lossless
compression was what was intended). Most of the images are indeed
lossily compressed, using a wavelet (not JPEG DCT) based technique.
-
mark

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