Notes(2) on PC164C and 1004X CCD Low Light camera's




From:  "Andrew Schott"  
Date:  Sat Feb 23, 2002  8:26 am
Subject:  Re: [QCUIAG] Re: Finally, the ExView mod revealed!

There's no real "back" to the PC board in the PC164C.  There are four small boards with 
three of them held together in a small 'H' shaped assembly with input (CCD) on one end 
and output on the other.  I've looked at your 1004X mod with the hopes that the conversion 
of the PC164C would be very similar but I find the parts count of the PC164C seems to be 
much higher. There's lots more resistors and caps but that might not be a problem.  I've
taken some half ased shots of all the guts and attached them.  I hope you'll find them 
informative?  Helpful? Blurry?  Since the boards aren't 'flat' I couldn't get any decent 
images on the scanner.  These were shot with a PC23C and I think it was freaking out.  
It probably thought it was witness to a vivisection.
                 
Disassembly instructions:  With proper sized jeweler's style screwdriver, back out the 
four small setscrews visible in the flats machined in the camera housing.  Screw them out 
far enough to disengage the front thread ring and rear connector assembly.  The rear 
connector assembly is simply extracted by carefully pulling the cap off the body, allowing 
the four connectors inside to disengage.  The front thread ring is worked out of the 
threads as best as you can due to the setscrews that have crunched up the threads somewhat.
It might not even be necessary to remove it if you can reach the four screws surrounding 
the CCD window.  My smallest Phillips style screwdriver had a shoulder on it that wouldn't 
allow me to reach these screws directly so I just pulled the ring and had plenty of room.  
After you remove the four screws the inner module will slide out under it's own weight.  
If you remove the four screws first, the module will come out with the rear cap when it is 
extracted from the housing.
                 
Remember, it's best to work over a static free or static grounding padded worksurface to 
avoid damage to the exposed components.  (I know you know but what about the other guy:-)
                 
First the input end....  The chip sits up on top of a 2mm spacer of some kind.  Maybe a 
thermal shield so the middle board won't heat print across the center of the chip?  Arrow
silkscreen in upper left points to top of unit.

                 
Top of middle board.  White blurry thing is crystal reflecting IR from light in kitchen.  
CCD is to the left.

Bottom of middle board. Note white "insulator" under CCD on left. Colors in image caused 
by aliasing in Matrox Marvel capture function.

Rear connector/output board. SMC on both sides, mostly small stuff.

Front of rear board... You know, the side opposite from above... as seen from below... 
awww... more parts.

Top of the front of the rear board... or other half of above....

                 
Finally, the output socket board/cable/iris connector assembly.

                 
                 
                 
 ----- Original Message ----- 

From: Jon Grove 
To: 'QCUIAG@yahoogroups.com' 
Sent: Thursday, February 21, 2002 10:30 AM
Subject: RE: [QCUIAG] Re: Finally, the ExView mod revealed!

Thanks - I think this group is all about sharing experiences and specialised knowledge so 
that more people can do astrophotography 'on the cheap'. Hopefully this mod will be of use 
to some folks!

I would guess the PC164C is similar to the 1004X in terms of circuitry, but the layout will 
be different. It may simply be a case of identifying where to attach wires etc and then 
the rest of the mod would be identical.

Does anyone have a (fairly detailed) image of the back of the PCB that's inside a PC164C? 

                        
Attachment
       
   http://www.nitehawk.com/rasmit/pc164/whole_works.jpg
   http://www.nitehawk.com/rasmit/pc164/business_end.jpg
   http://www.nitehawk.com/rasmit/pc164/mid_board_side_b2.jpg
   http://www.nitehawk.com/rasmit/pc164/midboard_side_a2.jpg
   http://www.nitehawk.com/rasmit/pc164/rear_bulkhead.jpg
   http://www.nitehawk.com/rasmit/pc164/front_bottom_of_rear.jpg
   http://www.nitehawk.com/rasmit/pc164/front_top_of_rear.jpg
   http://www.nitehawk.com/rasmit/pc164/rear_connector_board.jpg
                                                             

From:  "ssb73q"  
Date:  Sat Feb 23, 2002  11:07 am
Subject:  Re: Finally, the ExView mod revealed!

Andrew, you sure did a lot of good work there, thank you. I was very reluctant to 
disassemble my PC164C, you increased my confidence to proceed. I hope the PC164C is 
amenable to modification.

Regards,
Richard


                   
From:"wlbehrens"  
Date:  Sat Feb 23, 2002  10:54 pm
Subject: Re: Finally, the ExView mod revealed!

Yes,I believe it is a good canadate. First it uses the 1310AQ for the AFE and uses the 
CDX2463 for timing and sync generator. These are the important chips for the mod. The 
supporting "extra parts" are for auto iris and the external controls for other camera 
functions. I assume the camera has external controls for sync, gain, shutter ect,ect. 
Now the bad news is you would more than likely have to remount the "guts" in another 
enclosure for the daughter board and cooling to fit. You could salvage the end pieces 
and just attach them to a cast aluminum project box.

William  


  

From:  "ssb73q"  
Date:  Sun Feb 24, 2002  4:56 am
Subject:  Re: Finally, the ExView mod revealed!


William,

 <> 

Does that camera need to be cooled?  A 1.7 second shutter speed would give 100 times the 
sensitivity, 8.3 seconds 500 times the current sensitivity. Do those shutter times need 
cooling? If the other boards in the PC164C are just for the auto iris, et al., can't 
removing them provide the room for a daughter board???

Regards,
Richard   


Richard,

The daughter board could be cramed into the camera I suspect with some work. When I think 
of making a camera mod I always gravitate (no pun intended) to a cooled unit with long 
exposure capability. With integration software like AstroVideo you wouldn't need to cool 
the camera, but Jon Grove did show that the hot pixels could be reduced a great deal by 
cooling it. By the way do you know what version of the CCD the PC164 has in it? There are 
two 1/3" models the low res and high res.

William



From:  "ssb73q"  
Date:  Sun Feb 24, 2002  4:22 pm
Subject:  Re: Finally, the ExView mod revealed!


William, <>

The spec sheet say "Sony 1/3" Super HAD ExView CCD, NTSC 510(H) x 429 (V).

BTW, see Andrew's post on the temperature rise of his PC23C camera.

Regards,
Richard


From:  "Andrew Schott"  
Date:  Sat Feb 23, 2002  10:55 am
Subject:  Cooling the PC164C.

Now that I've gutted mine and reassembled it to functioning condition, I feel a little 
more inclined to modify it.  Whil'st I wait the verdict from Jon on the electronical mods, 
I'm brainstorming the possibility of cooling this little critter to give it better S/N and 
in general, more stability.
              
None of the internal components are in thermal contact with the outer housing so simply 
chilling the aluminum tube won't be enough to get at the real heat sources inside.  Simple 
fan cooling is tough to accomodate due to the zero clearance design and the small package.  
Small volumes of air could be forced through the unit with a tube/pump but such arrangement
might not provide enough cooling to make much difference.
              
I remember once I saw a cooling arrangement for an experimental computer that used air 
forced through a copper coil immersed in ice to augment the cooling properties.  I guess 
one could use something similar in this device. A small squirrel cage blower, like a dust 
buster, forcing filtered air into a flex hose leading to a big roll of copper tubing in a 
5 gallon bucket or a large cooler filled with ice.  The cold air would then be fed thru 
another flex hose to the camera housing.  One expedient would be to remove the auto-iris 
jack and replace it with a nipple. Since Jon will be using this connector for the long 
exposure/AGC mod I'll probably use the unused tripod mount hole, and run the cooled air 
into the middle of the camera.  I would situate the exhaust so the cooled air would be 
forced out around the CCD escutcheon, cooling the main chip on its way out of the camera.
When used with screw in C mount lenses, the C/CS adapter could be ventilated to allow the 
exhaust out, and when used in a scope, the air would simply flow down the focus tube and 
into the scope.  It remains to be seen whether or not this would effect seeing.  I would 
bet it would so my first workaround would be to use an IR filter to block the flow and 
divert the exhaust elsewhere.
              
The steady outflow of air around the CCD chip should prevent any dew formation, even here 
in deep in the heart of darkest Florida.  The incoming air itself may actually be dried 
somewhat by the heat exchanger. Hmmmm, this superfluous condensate could cause problems if 
it should gurgle up the pipe and get into the camera. I guess I'll have to rig a "spit 
valve" to dump moisture occasionally.  Not as complex as the Shuttle yet but we're getting 
there.
              
These little cameras do get hot.  Mine climbs to about 105 in less than 30 minutes of 
operation @70 ambient.  That's a 35 heat rise!  On our 95 summer nights here in 
Florida, this thing could get hot enough to melt cheaper barlows!  All that heat can't 
be doing the images any good.


 


From:  Jon Grove  
Date:  Mon Feb 25, 2002  2:39 am
Subject:  RE: [QCUIAG] Re: Finally, the ExView mod revealed!

Thanks Andrew, lots of useful pictures!
                 
Looking at the 'bottom of middle board' picture, there isn't an obvious component connected
to pin 5 of the 2463R. It's possible that with a good lens you could peer underneath the 
chip and see where the track leads from this pin (especially if you've already lifted the 
pin) - alternatively a multimeter (set to resistance measurement) should help to locate a 
component connected to Pin5 (prior to lifting it). I would guess it would be connected to 
a capacitor or a voltage regulator somewhere. Failing that, it may be possible to solder a 
wire to the pad beneath pin 5 once it's lifted, but that would be very fiddly and prone to 
shorting onto other things.
                 
If that stage of the mod can be done, then the rest ought to be pretty straightforward. 
You'd need to locate a +5V supply somewhere on the PCB, and take a ground and +12V from 
the input connectors. Pin 2 on the CCD looks easily accessible, as is Pin 9 if you choose 
to do the amp-off mod.
                 
I'm pretty sure the mod is achievable, with a bit of investigation! The daughterboard 
probably won't fit inside the case as it looks pretty cramped. But I don't think it'd hurt 
to mount it outside on a short cable, if a suitable access hole could be found or made. 
There'd be about 10 wires needing to go through it.
                 
Jon.  


From:  Jon Grove  
Date:  Mon Feb 25, 2002  5:29 am
Subject:  RE: [QCUIAG] Re: Finally, the ExView mod revealed!

No, I've not done any current or temperature measurements (other than feeling the chips 
and thinking "that's warm!"). I wouldn't have thought the basic long exposure would affect 
the CCD temperature, since all it does is disable the charge transfer pulse which is only 
a few microseconds per frame. The amplifier-off mod may have an effect though, since it 
reduces the voltage supplied to the CCD. The specification says the CCD typically draws 
3mA at 15V, which crudely works out at a resistance of 5K. The amp-off mod puts another 
10K in series with it, which will drop the CCD voltage to 5V, and so the heat generated in 
the CCD will drop to 1/9 the 'normal' level. So in principal the amp mod could help the 
CCD run cooler. In practice I think it will be warmed up by all the other components around it.

It would be interesting to measure the current vs supply voltage characteristics of the 
camera as a whole though, since it may help to reduce the temperature by dropping the 
supply a bit.

When I get a chance I'll give it a go. 

Jon. 


                                                                                                         
From:  Jon Grove  
Date:  Wed Feb 27, 2002  1:42 am
Subject:  ExView dark/cooling test

Last night I tried some experiments with the ExView camera to see how cooling it affected 
the dark current/noise characteristics. The results are attached - each swatch is a 
100x100 section from the top left of the full 640x480 frame.

I switched the camera on, uncooled, and took a sequence of three 4-minute exposures with 
the 'lens cap' on. (The front of the camera is a sawn-off film cannister, the lens cap is 
the lid from one but it fits onto the sawn-off end so isn't very positive). As you can see,
the noise levels gradually increased as the camera warmed up, although the hot pixels 
remained largely constant. The background grey level is because the lens cap wasn't very 
light-tight.

I then switched on the Peltier and took another three 4-minute exposures while the camera 
cooled down. as expected, the noise level decreased until it was better than the first 
uncooled frame. Also the hot pixels seemed to improve.

I then realised that light was leaking in to the camera so I turned off the room lights 
and put a cloth over the camera, and took another 4-minute exposure. This looked pretty 
much like the previous one only darker, as expected. So I tried a 10 minute exposure
and whilst there was some noise visible I was quite surprised at how dark the frame was.

Finally I turned off the Peltier (which would allow the CCD to warm up, possibly to a 
higher temperature than it would normally reach because of heat conducted from the hot 
side of the Peltier) and took another 10 minute exposure. This was very noisy as you
can see.

So it appears that it is worth cooling these devices for long exposures - even if only by 
using ambient air. 

It's interesting to note that the noise has a very similar pattern in each of the images, 
which indicates that it might be largely treatable by darkframe subtraction. I may need to 
do some more experiments to determine how much of the 'noise' is random
(thermal) and how much is fixed (dark current).

Food for thought, anyway. 

Jon Grove. 




I think you're right - you could probably go to about 5 mins uncooled and use postprocessing
to reduce the effects of dark current.
You'd have a higher noise level on top of the dark current, which you couldn't get rid of 
(other than by stacking/summing/averaging multiple exposures). But I need to do some more 
experiments to work out how much random noise there is in the warm vs cold exposures.

Good point about the flatframe generator - I hadn't thought of it like that! 

Jon. 

> 
> Jon, very interesting experiments, thank you very much. I find the 
> very early pixel saturation of the ExView HAD interesting, cooled or 
> uncooled. You experiment confirms my conjecture about an uncooled 
> ExView camera being useful with dark frame subtraction to ~5 minutes. 
> If the cooled camera only gives 2-3 times the uncooled exposure, is 
> the effort and complexity of the peltier cooling the camera worth it? 
> 
> Again, thank you for your time doing these experiments, it is very 
> useful work that allows us to make decisions based on knowledge, not 
> wishful thinking. 
> 
> BTW, it looks like your "light leaking cap" makes a nice flat frame 
> for testing exposure intensity as a function of time. That test may 
> be useful for estimating CCD sensitivity linearity. 
> 
> Regards, 
> Richard 
> 
> 

From:  Jon Grove  
Date:  Wed Feb 27, 2002  5:23 am
Subject:  RE: [QCUIAG] Re: ExView dark/cooling test

Hi Gene [and in spite of your misspelling my name, I won't comment on the sound of that 
greeting as I'm sure you've heard it too many times ;-)  ]

I don't know how cold the CCD gets yet. I bought a cheapo digital indoor/outdoor thermometer
and one day will attach the sensor to the cold finger near the CCD, but I haven't tried it 
yet. A layer of frost forms fairly quickly most of the way up the cold finger, but I've 
never noticed it forming near the CCD. So I'd guess it runs at a bit above freezing, but 
not much. I'm not running the Peltier at full power though, since the PSU I'm using won't 
supply enough juice.

Regarding noise levels, I just did some quick'n'dirty experiments with the dark images I 
took yesterday. I averaged them all (except the last one) to produce a 'master dark frame' 
with, I hoped, less thermal noise than any of the individual frames. I then scaled and
subtracted it from image 3 (warm) and image 7 (cold), adjusting the scaling so that the 
result was as flat as possible. It was done by eye so was rather approximate. Naturally 
the warm image required a bigger multiple of the darkframe to be subtracted than the cold
one did, by a factor of about 3. The residual noise had an amplitude of around 10-15 in 
the warm image and about 5 in the cold.

So it looks as though, roughly speaking, cooling the thing cuts the repeatable dark current
and the random thermal noise to about a third, maybe less if I do the analysis more accurate
ly. Reducing noise levels to a third would also be achievable by stacking 9 images, so the 
question of whether it's worth cooling maybe boils down to whether you have the patience to
take 9 times longer per imaging session.

Personally, I'd rather use the cooler, since it's already built! But it's probably worth 
investigating less invasive methods of cooling the CCD such as sucking cold air around it, 
or cooling the metal lens-holder that comes with the camera, or even making a snug-fitting 
cooled metal clamp that fits to the ends of the chip.


From:  Jon Grove  
Date:  Fri Mar 1, 2002  2:06 am
Subject:  RE: [QCUIAG] Not enough images in astrostack

Surely it's not possible to give a hard and fast rule of the form "Using the best x% of 
your frames will give the best resulting image".

If you have very stable seeing then the main difference between each image will be noise. 
In that case, stacking a large number of images will reduce noise, and leave the image 
detail unchanged (since the same detail is present in the same place in all the images)

If the seeing is variable, as is more often the case, then the best image might contain 
good detail, but as you select more of the 'next-best' images the true detail will be both 
blurred and displaced relative to the best image. As more of these images are stacked, 
noise will decrease as before, but so will image detail - because the underlying 
(noise-free) image is of poorer quality than the best one. Even slight movement of features 
caused by turbulence will have a blurring effect on the result after stacking.

I feel it is a subjective thing. In a given set of raw images, you can choose how to trade 
off noise against detail. If the seeing was excellent you may be able to tip the balance 
heavily towards detail, by stacking more images. If it was variable then you'll have to put 
up with more noise to keep the detail, and stack fewer images.

Wonder if it would be possible to have a program which, given a sorted (either manually 
or automatically) set of raw images would start with the best, and keep stacking images, 
monitoring the 'quality' of the result, until that quality started to deteriorate. The 
'quality' metric would have to be supplied by the user, as a tradeoff between noise and 
detail. Of course it's hard for a program to tell the difference between noise and detail, 
so it may require human guidance.

Could be an interesting project! 

Jon Grove. 


From:  Jon Grove  
Date:  Fri Mar 8, 2002  9:18 am
Subject:  RE: [QCUIAG] ExView 1004X

Hi Adam, 

How are you monitoring the output from the camera? Are you viewing it on a TV/monitor, or 
are you capturing it on your PC?
I found that using a TV I would always see the 'bright' frame (except on very rare occasions,
<1% when the timing was just wrong). Using a capture card in preview mode you may well not 
be seeing all the frames, and so the magic one might not be displayed. If you can capture
an AVI at 25 [30 US] fps without dropping any frames then you ought to see the magic one 
in there somewhere!

Jon. 

> -----Original Message----- 
> From: vilarestil [mailto:hodsonfamily@madasafish.com] 
> Sent: 08 March 2002 17:09 
> To: QCUIAG@yahoogroups.com 
> Subject: [QCUIAG] ExView 1004X 
> 
> 
> Dear ExView users, 
> 
> When testing out stage 1 of the mod, I discovered that the 'magic 
> white frame' is not being generated every time I reclose the switch. 
> I tried to ascertain whether it was releated to time but it doesn't 
> seem to be the case. It's random whether I reclose the switch after 2 
> or 10 seconds. 
> Have any of you experienced the same thing i.e. sometimes it 
> integrates, other times it doesn't? 
> I have checked my wiring so I don't think it's a loose connection! 
> 
> Many thanks, 
> 
> - Adam 

From:  Jon Grove  
Date:  Tue Mar 12, 2002  1:44 am
Subject:  RE: [QCUIAG] "good frame" in 1004X mod.

Sorry, been away from my PC for a few days! 

To capture a frame it is currently necessary that software can 'see' every frame as it is 
generated. It only needs to select the exposed ones to store in an AVI. I have a 
preliminary program that does all this work, and compiles an AVI consisting only of 
exposed frames. When the program has had a bit more testing, and if there is sufficient 
interest, I will make it generally available.

Jon Grove. 


From:  Jon Grove  
Date:  Mon May 13, 2002  8:06 am
Subject:  RE: [QCUIAG] Re: Why is on-camera integration superior to off cam era integration?

From the online description of the 1268 Mintron 

                 http://www.mintron.com/HTM/News/HTM/Alpha.htm, 
it uses 'Star Light' technology.

On a Mintron Q&A site 

          http://www.mintron.com/HTM/Q&A/Htm/Star%20light%20mode.htm,

I found the following info on StarLight mode (admittedly a different model camera):

                =============================================== 
Star light mode will make a CCD camera able to see clear color image under very low 
lighting situation such as 0.0002 lux illumination level. 

All CCD sensors were designed to work on 1/50,1/60 ~1/2000 sec. shutter speeds, hence the 
minimum illumination level or so called sensitivity  is then limited on 3 to 6 lux  with a 
F1.2 lens on 5600k Mintron proprietary DSP can drive CCD shutter speed to as low as 
1 sec ~ 10 sec. As a fundamental of physics the longer the shutter is open, the more 
photons the CCD will capture, hence increased the sensitivity to 100 ~ 600 times more 
then a legacy camera.

Mintron V series camera's are having 4 times better sensitivity on legacy mode then other 
camera's . Plus it will multiply light by 128X on the socalled star light mode, all these 
make V series camera's  512 times more sensitivities then all other camera on the market. 
 

Jaguar MTV-63W1 is also equipped with a 64X star light mode.  
How does the Star light mode kick in?
Is it automatically ? How can I activate it? 

The user can turn on the Star light mode ( slow shutter frame integration mode  ) 
On model  6318 / 6368 by the Dip switch No 8, and on the advanced models  V and W series 
such as 63V1 and 63W1 the user can turn on the Star light mode by OSD screen and an
interactive push bottom.

If a camera has the Star light mode turned on as above, while the incoming light is getting 
weaker, the camera will automatically increase AGC gain to bring video level back to 100 
IRE. After the AGC has pulled up to the maximum and the system still can not maintain 
100 IRE, the frame integration feature will automatically kick in, the shutter speed will 
start to drop from 1/60 to 1/30, 1/15, 1/8 1/4 1/2,  1, 2 ,4 ,8 ... and all the way down 
to 1~10 sec. Due to the manufacturing methods of CCD sensors , most of the CCDs will have 
too much dark current noise on 64X multiply  or 1 sec shutter speed. hence the 6318 and 
6368 have max 64x integration. The new V series camera 63V1 / 63V0 use  better selected 
CCD's and adaptive noise cancellation circuits , it's can go further up to 128X 
multiplication or 2 sec. slow shutter. hence it will add two times better sensitivity. 
In V series an even more advanced feature is added 

                =============================================== 

From this description, it sounds very much as though StarLight mode actually does keep 
the shutter open for several frames, rather than integrating multiple 'normal' frames. 
In particular, the sentence about the custom DSP driving the CCD shutter speed to 
1-10 seconds seems very indicative of on-chip integration.

Thoughts, anyone? 

Jon. 


     
   http://www.sel.sony.com/semi/PDF/CXA1310AQ.pdf
   http://www.sel.sony.com/semi/PDF/CXD2463R.pdf



From:  Jon Grove  
Date:  Wed May 15, 2002  1:14 am
Subject:  RE: [QCUIAG] Re: Why is on-camera integration superior to off cam era integration?

Hi Rein, 

You are largely correct in what you say below. For the sake of clarity I'll assume we're 
working with a 50Hz field (25 frames per second), and I'll describe the reasoning behind 
the 1004x mod. I guess this is similar to the Mintron, except that they have the
luxury of designing their own version of the 2463R.

The SUB pulse is of duration Td < 20ms, so that the interval between the end of the SUB 
pulse and the CT (charge transfer) pulse determines the exposure time. The 2463 can 
generate exposure times at certain discrete values, between 1/10000 and 1/50 second.

The shutter speed is determined by a voltage that's derived from the previous frame, by 
integrating the brightness in a particular area of the image (the area is selectable from 
various patterns in order to allow for backlight compensation, etc.). Also, the video 
signal is sent through an AGC which allows finer control than shutter speed alone would 
give.

So as a video image gets brighter and brighter, the AGC pregresively attenuates it until 
the unattenuated signal reaches a level where the 2463R decides to switch to a shorter 
shutter speed - at which point the AGC will compensate by increasing the gain - and 
so on.

The SUB pulse can be disabled by applying +5V to pins 20 and 21 of the 2463R - this makes 
the shutter effectively fully open all the time, which is what is required for long 
exposures. 

Then the only requirement is to disable the CT pulses. These are also generated 
by the 2463R, and are derived from the +15V input at pin 5. (The SUB pulse is also derived 
from this voltage). So disconnecting pin5 disables the CT pulses. 

When pin 5 is reconnected, the next field will transfer charge from all the CCD array into a single 
field - adjacent lines are binned into one line in order to generate a field with half the 
number of scanlines as are present in the sensor array. Depending on whether an odd or 
even field is being generated, the binning is either lines 1, 2+3, 4+5, 6+7, ...
or 1+2, 3+4, 5+6, ... 

This allows the full area of the CCD to be used each field, whilst preserving some of 
the resolution of the full array. Unfortunately it's not the behaviour that we want 
when reading out a full resolution long exposure, since reading (and binning) the lines 
removes the charge and there's nothing left for the alternate field - 
we get a frame in which every other line is a long exposure made from two lines of the 
CCD sensor.

The solution to that problem was to prevent one of the sets of lines from being 
transferred when pin 5 was re-enabled. Fortunately the CT pulses for odd and even 
CCD lines are presented separately so we can disable, say, the odd lines CT by 
shunting the pulse to ground through a diode. Then when pin 5 is enabled, the even 
lines will be read out (and the CCD will try to bin them with the odd lines but the odd 
data  will not be there). 

Subsequently we can re-enable the odd lines and they will be read out (and binned with 
absent even-lines) at the next field. So the whole array can be read out at full resolution,
no binning, in two separate fields. It's a little bit complicated, but it works.

Hope that's clear! 

Jon Grove. 


From:  Jon Grove  
Date:  Fri May 17, 2002  1:28 am
Subject:  RE: [QCUIAG] Re: Why is on-camera integration superior to off cam era integration?

Hi Rein, 

Some of your questions have already ben answered, but I'll answer the ones about the 1004x 
operation. 

The binning of adjacent scanlines is performed inside the CCD chip. Depending on whether an 
odd or even video field is being generated, the CCD bins in one or other of the patterns I 
mentions (1, 2+3,... or 1+2, 3+4...). The only way to get unbinned data is to fool the CCD
into binning data lines with blank lines, which is what the mod does. When, for example, 
even data lines are prevented from being transferred to the shift register, the CCD will 
produce a field consisting of only odd data lines. However this field may be presented as 
an odd OR even field. The iCatch program knows which set of data lines it has requested, 
and when it receives a frame in which alternate lines are bright and dark it keeps the 
bright lines (which can be odd or even lines) and then requests the other set of data lines 
in a new frame.
Again it grabs the brightest set of lines from that frame, and reinterlaces the two sets 
to produce a full-resolution image.

It's complicated to descibe, but not too hard to write the program. Are you a programmer 
yourself? If you can grab the two frames into an AVI then you don't have to use iCatch to 
re-interlace them, it can be done manually with a graphics package. But it's a bit 
laborious!

What sort of device is your Snappy - is it a USB or a PCI (internal) capture device? 

Jon.