
2bit Astrophotography with the Game Boy Camera - cremno
http://home.strw.leidenuniv.nl/~pietrow/astrogb.html
======
Jyaif
I doubt the CMOS is only 2 bits, otherwise we wouldn't have such nice
dithering pattern. Somewhere in RAM there's probably at one point a
representation of the image with at least 3 bits per pixel.

~~~
Luc
The camera outputs analog values. I don't know for sure but I bet the
dithering is applied right after the analog pixel is converted to digital...

~~~
objclxt
Yep, here's the technical data sheet for the chip:

[https://people.ece.cornell.edu/land/courses/ece4760/FinalPro...](https://people.ece.cornell.edu/land/courses/ece4760/FinalProjects/f2012/qs44_twc55/qs44_twc55/datasheets/MITSUB_image_sensor.pdf)

~~~
joshumax
Looks like the maximum supported exposure time is ~1 second... That mixed with
the fact that the fact that it has a fairly shallow well depth probably means
that the CMOS would be best suited for LUCKY imaging. Also adding a cooler to
the back of the Gameboy camera may help reduce amp glow. Anyone have the specs
on the ADC chip?

~~~
userbinator
There is some reverse-engineered documentation here:

[https://github.com/AntonioND/gbcam-rev-
engineer/tree/master/...](https://github.com/AntonioND/gbcam-rev-
engineer/tree/master/doc)

The ADC appears to be part of the ASIC which contains most of the circuitry to
interface the sensor to the GB.

------
jacquesm
That's worthy of the term 'hack'. Very neat :)

There should be some silly way of doing this with just a single photo diode
and a speaker to provide one axis of motion and to let the Earth's rotation
provide the other axis.

~~~
orbital-decay
You can do this even without any motion and possibly even with no focusing
optics, just with a single sensor, diffraction grating and a lot of math. This
is called single-pixel imaging and is an ongoing research topic in
computational imaging.

~~~
anfractuosity
Could you explain in laymans terms how that would work? If you're only
obtaining a single value for a single pixel and there's no movement, how does
the pixel value change even if there's a grating in front? Or do you mean the
grating can still move?

~~~
keithpeter
And noise? I used to do long exposure photos of interiors of buildings on film
(~2h) but digital cameras seem challenged to me.

~~~
anfractuosity
That's very interesting re. film. I'd be curious why that is. I've only ever
done exposures less up to around a couple of minutes with film & digital. Do
you have any examples that you shot for 2hr out of curiosity. Was that with
ISO 50 or less, or did you use a darkening filter too?

Edit: I wonder if it is due to reciprocity failure with film -
[https://en.wikipedia.org/wiki/Reciprocity_(photography)](https://en.wikipedia.org/wiki/Reciprocity_\(photography\))
?

~~~
keithpeter
125 asa FP4 roll film (all monochrome and hand developed needless to say, I
used a Rollieflex camera on a tripod when I was playing with this stuff
decades ago).

I found the correction chart below on t'web [1] just now.

I recollect using 2.5x per stop over 1 second which gives slightly longer
exposures than [1], but then I did tend to 'pull' the development a bit
(contrast goes up), so a 2 minute metered exposure would be 2.5^7 seconds (10
minutes) instead of 2^7 seconds roughly. A 10 minute exposure on the meter
corresponds to two hours and a very significant contrast hike - I recollect
printing on grade 1 and grade half filter settings (multigrade paper). I only
used extreme exposure times in old dark interiors e.g. churches in the UK in
November or something. Inside so no need for any filters - not astro.

I'll dig a few prints out and scan them over the weekend. Nowt astounding. See
if you can find a book about Edwin Smith if you are near a library with a very
good photography collection.

I have a fantasy of using 10x8 film with a pinhole camera and just doing
contact prints... but then I remember the darkroom days and the amount of
water that got used up...

[1]
[http://home.earthlink.net/~kitathome/LunarLight/moonlight_ga...](http://home.earthlink.net/~kitathome/LunarLight/moonlight_gallery/technique/reciprocity.htm)

~~~
anfractuosity
That chart looks very interesting, thanks!

Cheers, I'd be very curious to see your prints.

I've just had a little look on google images at some of Edwin Smith's photos,
they look stunning! The light in the photos look amazing.

I still have an old Pentax K1000 film camera I think it is, I'll have to dig
it out again some time :) I'd really like to get a medium format camera, but
they're still not super cheap, I was looking at the Mamiya RZ67 (I'd actually
like to try shooting landscape with it, which could be impractical due to the
weight, but would be fun nonetheless ;).

10x8 film would be awesome to play with!

~~~
keithpeter
Well I did say fantasy - a sheet of 10 x 8 film is the same cost as a _roll_
of 35mm (similar area if you think of a contact sheet).

A 35mm camera on a tripod with shutter release would allow experimentation and
allow you to decide about weight and carrying for hiking. I used the long
exposures mainly in buildings in a city.

My images are not on Edwin Smith's level by any means, but the movement of the
Sun direction over an hour does make a sort of smoothing of the light.

------
makmanalp
In case anyone here knows - where can one buy an "old-school" low-res /
monochrome / dithered camera module that produces images this one, for easy
use with a raspberry pi or arduino or something? All I get is weird
electronics company websites with "request more info" buttons - nothing that
gives me pricing and a "buy" button.

Or alternatively, what's a way to transform high-res images to look like that?

~~~
joshvm
Bin the image from a raspberry pi camera by a factor of.. 8 or so (maybe 16 if
you need smaller)? Load the image as grayscale and divide the counts by 64 to
get 2-bit values.

Kinda difficult to buy crappy low resolution detectors these days because
nobody makes them and you'd need to build the readout electronics yourself.
You might as well just use a decent detector and make it look bad.

~~~
anfractuosity
You can also interestingly get the raw sensor data from the Pi camera too, as
in before the demosaicing is applied.

I wonder, this may be silly, but could you not potentially get a slightly
higher resolution image, if you just created a pixel for every sensel. Than if
you were to apply the demosaicing algorithm then convert to grayscale.

~~~
kqr
> I wonder, this may be silly, but could you not potentially get a slightly
> higher resolution image, if you just created a pixel for every sensel. Than
> if you were to apply the demosaicing algorithm then convert to grayscale.

That's along the lines of what the Leica Monochrom promises. One drawback of
doing it with a regular Bayer sensor is that the colour filters eat light, so
while the number of pixels will increase significantly, the spatial resolution
may not be that much better.

~~~
joshvm
You'd get the same resolution because colour cameras interpolate
(demosaicing). If you converted to grayscale you might get problems because
each pixel has a different colour response with the bayer filter. You'd still
need to do some intensity correction.

The performance of the Leica Monochrom is due to this - you don't get more
pixels per sensor, but you get proper intensity values at each pixel. This
corresponds to better effective spatial resolution _in most cases_. All
they're doing is selling you an identical sensor and pretending it's something
fancy and new...

When you buy industrial cameras, the colour and mono versions are identical,
but one is filtered (they use the same detector). We use mono in industry
often because image quality tends to be much better than colour, and you have
a third of the bandwidth requirements (or you want to filter a specific
waveband).

------
tbabb
Very cool.

I'd be very curious to see what happens if you do exposure stacking-- in
principle, you could get a lot more bit depth!

~~~
throwaway1572
Came here to say exactly this! In addition, you could stack and them once you
have something that's at least 8 bits per pixel use Photoshop to clean things
up.

I guess instead of making an HDR image from SDR images you'd be making an SDR
image from LDR images. :-)

------
zokier
The images are remarkably good, considerning the general quality of GB camera
images. I suppose this demonstrates that if you stuff enough glass in front of
a camera, you can get half-decent images even from the worst of sensors.

------
djhworld
Really fun read, thanks

Next step, find the Gameboy Printer and print out your shots!

------
app4soft
CASIO WQV-1 is would be much better choice for 2-bit astrophotography.[1]

[0] ftp://ftp.casio.co.jp/pub/watch/wc/WQVLink_Manual_K.pdf

[1]
[http://www.3wheelers.com/elvis/body_wqv-1.html](http://www.3wheelers.com/elvis/body_wqv-1.html)

~~~
ljf
Man I loved that watch - I still have it in my watch box somewhere, but it
miss behaves now. I regret not buying the black plastic versions for spares
when they were about £12 each. Ho hum!

~~~
app4soft
In 2007 my friend got working WQV-1. I tried it and for me it was something
like "007" artifact. Think, if I could buy one sometime - I will buy it
immediatly!

~~~
ljf
They still come up on ebay, but the prices are higher now. But still much less
than the £200 it cost in 2001 or whenever I got it.

------
faragon
Super-resolution [1] using the Game Boy Camera: any taker?

[1] [https://en.wikipedia.org/wiki/Super-
resolution_imaging](https://en.wikipedia.org/wiki/Super-resolution_imaging)

------
owobeid
If you guys don't have the original Game Boy Camera and would like to try, I
wrote an iPhone app a while ago to get a similar effect. Sorry for the
shameless plug :P

[https://itunes.apple.com/us/app/pixl8r/id981531620](https://itunes.apple.com/us/app/pixl8r/id981531620)

------
kregasaurusrex
Neat stuff! I wouldn't have thought that old of a digital sensor would have
the sensitivity to see distant dim objects like this. And being able see the
same thing in Stellarium by matching up the coordinate view with the actual
photo is also cool.

------
phpnode
Is this the most Hacker News title of the year so far?

