>This sounds good if you are archiving scans for storage. However, if you are
>trying to make scans quickly available for viewing, then jpeg (lossy) or
>gif(lossless) is probably the best way to go.
JPEG is designed for compressing photographic images. It does a
poor job on sharp edges, such as those found on monochrome schematics. It just
kills me to see people use JPEGs on monochrome images, as it smears out all the
edges.
GIF is good (the compression is as good or better than JPEG on
monochrome images, I believe), but as I recall it doesn't have a 1
bit-per-pixel format, so you are probably bloating up your files.
But you are right, it's great for viewing. I think Zonn was mostly looking to
decrease the space the scans were taking up on the server, though.
As a test, I made a 830x603 pixel monochrome BMP file. The BMP file
was 61K (as would be expected for an uncompressed image). The JPEG file (with
minimum compression) was 20K. If you increased the compression, the JPEG
file could get much smaller, but the lines started smearing around
13K. The GIF version of the file was about 5K. The BMZ (Zonn's compression)
version was... 652 bytes!
Zonn - that compression algorithm looked interesting, but I couldn't
quite grok it from looking at the source code. Is the IEEE journal you got it
from online anywhere? I'm too lazy to look for it myself, I guess ;)
Drew
Received on Fri May 15 10:03:33 1998
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