Image from CT data downloaded from http://graphics.stanford.edu/data/voldata/
Okay, this is a bit gruesome, but I’ve been dusting off some old papers that I never really understood on Fourier Volume Rendering, and testing my understanding by writing some simple code that takes in a volume dataset and uses the fast Fourier transform to convert it into simulated X-ray pictures. The data set that this picture was generated from was downloaded from this webpage at Stanford, and consists of CT scan data of a cadaver. The basic code works! Given a bit more work, I should be able to do arbitrary orthographic views.
The math for all this is described quite admirably by Tom Malzbender’s paper Fourier Volume Rendering.
I still check my WSPR station logs each morning when I wake up. This morning I spotted the callsign E51EME, coming from grid square BG08. I’ve come to realize that many of these spots which include only a four element grid designator are spurious bad decodes, and I didn’t recognize the prefix (I’m not much of a DX-er). But still, it decoded multiple times:
Timestamp
Call
MHz
SNR
Drift
Grid
Pwr
Reporter
RGrid
km
az
2009-08-12 12:16
E51EME
10.140137
-22
0
BG08
5
K6HX
CM87ux
7649
30
2009-08-12 11:44
E51EME
10.140136
-20
-1
BG08
5
K6HX
CM87ux
7649
30
2009-08-12 11:32
E51EME
10.140137
-18
0
BG08
5
K6HX
CM87ux
7649
30
2009-08-12 11:24
E51EME
10.140136
-17
0
BG08
5
K6HX
CM87ux
7649
30
2009-08-12 11:14
E51EME
10.140137
-15
0
BG08
5
K6HX
CM87ux
7649
30
2009-08-12 11:06
E51EME
10.140135
-12
0
BG08
5
K6HX
CM87ux
7649
30
2009-08-12 10:56
E51EME
10.140137
-12
0
BG08
5
K6HX
CM87ux
7649
30
2009-08-12 10:44
E51EME
10.140135
-10
0
BG08
5
K6HX
CM87ux
7649
30
2009-08-12 10:32
E51EME
10.140137
-11
0
BG08
5
K6HX
CM87ux
7649
30
2009-08-12 10:12
E51EME
10.140137
-11
0
BG08
5
K6HX
CM87ux
7649
30
2009-08-12 10:04
E51EME
10.140136
-14
0
BG08
5
K6HX
CM87ux
7649
30
2009-08-12 09:56
E51EME
10.140137
-17
0
BG08
5
K6HX
CM87ux
7649
30
2009-08-12 09:44
E51EME
10.140136
-18
-1
BG08
5
K6HX
CM87ux
7649
30
2009-08-12 09:34
E51EME
10.140137
-18
0
BG08
5
K6HX
CM87ux
7649
30
2009-08-12 09:24
E51EME
10.140136
-20
-1
BG08
5
K6HX
CM87ux
7649
30
2009-08-12 09:16
E51EME
10.140137
-19
0
BG08
5
K6HX
CM87ux
7649
30
2009-08-12 09:04
E51EME
10.140136
-19
-1
BG08
5
K6HX
CM87ux
7649
30
2009-08-12 08:52
E51EME
10.140136
-19
0
BG08
5
K6HX
CM87ux
7649
30
A quick trip to QRZ.com verified that this was indeed a real call, Bob Sutton from Raratonga, in the Cook Islands. Very cool.