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Introduction
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H-compress Performance
Following is a table of LASCO H-Compress statistics that I
compiled last week. I have also indicated movies
with the results of the tests if you would like to
see the images. Since July 25 we have roughly been
running C2 and C3 alternating Rice and H-Compress.
For C2 we have been using H-Compress 5 (compression
factor 7.6) and for C3 H-Compress 3 (compression
factor 6.2).
General Impressions:
1. H-Compress works great for C1-C2-C3 (no EIT testing done yet).
The images look good at significant compression factors and
the algorithm itself is fast.
2. For lossless compression Rice provides a better compression
factor and is faster than lossless H-compress.
[Ed Note. Ground testing showed lossless H-compress to be
faster than Rice but not as good at compression. ]
3. With the same H-Compress Scale Factors C1 compresses better
than C3 which compresses better than C2.
4. With H-compress as you raise the compression factor the
compression time gets considerably faster so it is
possible to reach an equilibrium between processing time
and image downlink time.
Compression Statistics using H-Compress (July 24-25 '97)
------------------------------
C3 - 1024x1024 full-resolution see $MVIS/hcompress_c3.mvi
------------------------------
H-Compress Scale Compression time to compressed time to downlink
IP Step Factor Factor process (sec) size (bits) (@ 7.9 kbps)
---------- ------ ----------- ------------- ----------- ----------------
Rice 2.4 275 5,774,304 731
0 0 2.3 378 6,381,392 808
1 8 3.5 274 4,324,448 547
2 16 4.5 243 3,375,904 427
3 32 6.2 212 2,440,256 309
4 48 7.8 193 1,924,704 244
5 64 9.6 182 1,566,192 198
------------------------------
C2 - 1024x1024 full-resolution see $MVIS/hcompress_c2.mvi
------------------------------
H-Compress Scale Compression time to compressed time to downlink
IP Step Factor Factor process (sec) size (bits) (@ 7.9 kbps)
---------- ------ ----------- ------------- ----------- ----------------
Rice 2.3 290 6,726,880 851
0 0 2.2 308 7,165,632 907
1 8 3.1 303 5,040,624 638
2 16 3.9 267 4,044,992 512
3 32 5.2 234 3,048,896 386
4 48 6.4 215 2,444,704 310
5 64 7.6 204 2,060,112 261
6 96 10.2 1,538,688 195
7 128 13.6 173 1,159,360 147
8 192 21.5 162 730,560 93
9 256 28.3 155 555,648 70
------------------------------
C1 - 768x640 full-resolution see $MVIS/hcompress_c1.mvi
------------------------------
H-Compress Scale Compression time to compressed time to downlink
IP Step Factor Factor process (sec) size (bits) (@ 7.9 kbps)
---------- ------ ----------- ------------- ----------- ----------------
Rice 2.3 122 2,065,008 261
0 0 2.2 140 2,391,088 303
1 8 4.6 110 1,428,720 180
2 16 6.4 96 1,028,784 130
3 32 10.1 84 657,472 83
4 48 12.9 79 512,160 65
5 64 15.6 75 424,912 54
------------------------------
C1 - 768x640 2x2 LEB-Binned
------------------------------
H-Compress Scale Compression time to compressed time to downlink
IP Step Factor Factor process (sec) size (bits) (@ 7.9 kbps)
---------- ------ ----------- ------------- ----------- ----------------
Rice 2.3 44 756,128 96
1 8 2.8 49 615,408 78
2 16 3.4 45 504,384 64
3 32 4.4 42 396,192 50
4 48 5.2 40 332,224 42
5 64 5.9 39 293,664 37
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