XI-V

Earth pictures from XI-V #1

2005
Nov 22, C4, 59.2% Nov 28, C7, 38.1% Dec 3, C6, 20.9% Dec 9, C5, 51.8%
Over the Amazon North America South Vietnam Bolivia

XI-V pictures data's downlink are performed now ONLY during the pass over Japan.
And I am in ground wave range of the command station.

I first receive these ascii data by using TunaTerm.exe (Japanese), and secondly
analyze these ascii files by using ImageDecoder.exe (Japanese) program.

The frequency is 437.345MHz, 1200bd AFSK, and KEPS is "28895U 05043F".

Nov 22, C4, 59.2%
S.Lat 3.4762 / W.Lon 50.1559 : Over the River Amazon
Nov 28, C7, 38.1%
N.Lat 42.1774 / W.Lon 61.2517 : Over the Atlantic Ocean near North America
Dec 03, C6, 20.9%
N.Lat 9.2543 / E.Lon 110.0230 : Over the Pacific Ocean near South Vietnam
Dec 09, C5, 51.8%
S.Lat 19.7855 / W.Lon 66.7326 : Over the land of Bolivia

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JE9PEL / Mineo Wakita wrote:

Q1. What are the specifications of the camera on XI-V?
A1. CMOS digital camera
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Q2. What is the pixel resolution (x pixels wide / y pixels high)?
Bit Depth?
A2. GS of University Tokyo / Enokuchi Akito wrote:
CMOS Color image sensor (15360 pixels, RGB, 5bit/color)
Focal length : 6mm, F number : 1.8
The onboard camera resolution is VGA format (640x480 pixels)
with bayer pattern. But we window only 128x120 pixels for saving
memory storage. Pixel size is around 7 um.
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Q3. Is the image downloaded in jpeg or raw format?
A3. Not jpeg. Downloaded data are the ascii as the following A4.
These ascii data can be received by using TunaTerm.exe (Japanese),
and I analyze these ascii files by using ImageDecoder.exe (Japanese).

GS of University Tokyo / Enokuchi Akito wrote:
Not exactly, but nearly raw format.
We don't release our CubeSat's image format to the public.
Therefore, everyone who'd like to analyze packets needs to use
software ImageDecoder, only for Japanese.
---
Q4. What is the format you receive data in?
A4. Ascii data, Received example:
JQ1YGW>JQ1YCX [12/09/05 22:36:35] <UI>:
C5..tCw\8T............~..............t.|..|..?..~...........
JQ1YGW>JQ1YCX [12/09/05 22:36:37] <UI>:
C5..Cw2.....T~D;r;r..u?..d~L?d~L?....l.\.l.;.;.3zCw2..\.S..=
---
Q5. Is the ASCII format for images published?
A5. The ascii format for images is not published in detail.
The output data from the camera are RGB (each 8 bits),
and these data are compressed without each low 3 bits.
After attaching both of the header and parity, these data
are downloaded to the ground.
---
Q6. Seems like vertical image smearing occurs.
How is the image read from the CCD?
A6. GS of University Tokyo / Enokuchi Akito wrote:
XI's onboard camera is not CCD, but CMOS.
So we don't expect annoying vertical noise is Not smear noise,
but variation of performance of CDS circuits, which are installed
on every column of CMOS sensor. Currently, we guess this variation
occurs due to the CMOS sensor at very low temperature, like -20 degC.
Anyway, we'll soon publish reports about this problem and solution on
our website and/or a kind of articles.
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How to decode XI-IV/V using ImageDecoder
http://www.ne.jp/asahi/hamradio/je9pel/xivimgdc.htm