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#apertus IRC Channel Logs

2013/10/31

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23:00
Bertl
yep
23:00
Sasha_C
yeah, I'm also aware of thi
23:00
Sasha_C
*this
23:00
Bertl
maybe we should have some kind of 'active axiom alpha development' link on each of those pages?
23:00
Sasha_C
I think that'd be a pretty good idea
23:00
Bertl
(something flashing or highlighted :)
23:01
Sasha_C
But who would maintain this?
23:01
Bertl
and we should make a central page which has that info
23:01
Sasha_C
yeah, definitely
23:01
Bertl
I guess a single page is easy to maintain for sebastian, and who knows, maybe you or philippe wants to write a section there too every now and then
23:02
Sasha_C
It's like with Gimp. I wish there was a page I could look at on their site that tracked the development progress they're currently making
23:02
Sasha_C
ok, that could work
23:02
Bertl
doesn't have to contain much, shouldn't be longer than a few pages (3-4 at most)
23:03
Bertl
can link to all the nice articles and milestones we already reached
23:03
Bertl
but it should definitely be updated on a weekly basis (maybe sometimes twice a week if something interresting happens)
23:05
Bertl
I think that kind of PR is essential for the upcoming crowd funding
23:06
Bertl
back to the noise/artefacts, can you try to explain to me what you are seeing in e.g. http://vserver.13thfloor.at/Stuff/AXIOM/RAW/colors_500ms.png ?
23:08
Sasha_C
Ok, when I view the image at full res, and I'm looking at the yellow band (as an example)... I can see a subtle pattern of vertical lines
23:08
Bertl
I also see vertical and horizontal lines
23:09
Sasha_C
Yes, forgive me if this isn't sensor pattern noise. I'm not sure what to call it
23:09
Bertl
for me, actually the horizontal lines are more visible
23:09
Bertl
it is a pattern which is too aligned to the sensor orientation to be present in the original motive :)
23:10
Sasha_C
yes, same here, it's just that my IRC window is blocking most of my web browser as I type this, and the vertical lines are easier for me to see
23:10
Sasha_C
yes, exactly
23:10
Bertl
but it might be the result of the debayering, we should look at the raw grey images instead
23:11
Bertl
I also see the 'hot' pixels, which are most likely related to the different discharge times I suspect on a per pixel basis
23:12
Sasha_C
I wasn't sure if they were hot or dead pixels on the defective sensor
23:12
Sasha_C
hey, I'm sorry to be rude, but I have to go have a shower now and then head off to work (starting a little later today...)
23:13
Sasha_C
I'll email Sebastian re: creating a development section on site, updated once to twice per week
23:13
Bertl
no need to be sorry, we'll talk later ...
23:13
Sasha_C
ok, thanks. Have a great one!
23:13
Bertl
thanks, appreciated! you too!
23:40
Sasha_C
left the channel
00:14
troy_s
Greets all.
00:15
troy_s
FergusL: Greets. About to shower then I have a few...
00:16
FergusL
good, troy_s
00:16
FergusL
evening Bertl
00:16
FergusL
shall I read the whole backlog ?
00:16
troy_s
If someone can pastebin I will read when done.
00:17
Bertl
didn't happen much I'd say
00:19
FergusL
troy_s: Bertl and I can easily sum up
00:19
FergusL
basically last night we were looking at the first picture taken by Bertl with the "experimental" setup he has assembled
00:20
FergusL
and quickly we came to matters which I discussed with you : linearization, corrections made to the image
00:21
FergusL
heading to the kitchen for a bit
00:32
FergusL
Bertl: did you continue to investigate about yesterday's issue ?
00:33
Bertl
which one?
00:35
FergusL
the fixed stuck pixels
00:41
troy_s
FergusL: Back
00:41
FergusL
wb
00:41
FergusL
and thanks
00:42
troy_s
FergusL: What in particular regarding linearization?
00:43
Bertl
well, I suspect the pixels (let's call them 'hot pixels' for now)
00:43
troy_s
(and have the primaries been mapped for the sensor yet?)
00:43
troy_s
Bertl: Hrm... I take it this is post debayering?
00:44
troy_s
Bertl: Or pre?
00:44
Bertl
FergusL: are the result of an unusually long exposure time and the fact that pixels discharge at different rates
00:44
Bertl
troy_s: we have pre and post debayering data
00:44
troy_s
Bertl: Correct. The greens fill first.
00:44
Bertl
the .raw8/.raw16 are pre debayering
00:45
troy_s
Bertl: Have you attempted to map the native primaries?
00:45
Bertl
please define what 'native primaries' means
00:45
troy_s
Bertl: The native 'colors' of the R G and B channels.
00:46
troy_s
Are you familiar with the CIE research?
00:46
Bertl
nope, not at all
00:46
troy_s
Oh. Good time to learn a tad about it, but I can give you a condensed notes version if you like.
00:46
FergusL
(say "yes")
00:46
Bertl
yes, that would be appreciated
00:47
Bertl
FergusL: I always say yes to information :)
00:47
troy_s
In 1931 two scientists (Guild and Wright IIRC) concurrently were trying to map the range of average human vision.
00:48
troy_s
There isn't much data on exactly the age or gender of their samples (likely male and younger), but they developed correlating data sets that matched almost perfectly.
00:48
troy_s
With me so far?
00:48
Bertl
yup
00:49
troy_s
Color is much more than wavelengths of light... it is known as a psychophysical phenomenon - it doesn't exist in the real world but is rather how our sensors interpret the data.
00:49
troy_s
It is entirely relative to context and many other phenomenon (hence the psycho in the psychophysical term)
00:49
Bertl
not just the sensors, at some point the brain too
00:50
troy_s
Exactly.
00:50
troy_s
The researchers collected data using a very simple test. They took the most saturated versions of tri color light in red, green, and blue and presented swatches in a 2 degree circle to observers
00:51
Bertl
do you have an url to illustrate this?
00:52
troy_s
Strictly controlled such that the observers could dial in the three lights to match the swatches. The three primaries - or colors of the lights - were carefully selected such that equal parts added to an achromatic color (white if you will, not that white exists per se)
00:52
troy_s
With me?
00:52
Bertl
somewhere on the web, so that I get an idea how they looked like
00:52
troy_s
There isn't a great description of the experiment.
00:52
Bertl
okay, no problem
00:53
troy_s
Only loosely. And I had to actually email Mark Fairchild (_the_ color god) to get some explanation as to what I am about to explain.
00:53
Bertl
so basically they had to figure out the R,G and B values for a saturated color
00:54
troy_s
So if you visualize the data as a plot, we could have a triangle with our red, green, and blue primaries at the points. The observers matched the swatches.
00:54
troy_s
The problem was that there were a good number of colors that the observers could not dial in with the lights - they were beyond the 'gamut' that the three lights could express.
00:54
Bertl
triangle in what color space?
00:54
troy_s
(bear with me :))
00:54
Bertl
okay
00:55
troy_s
Does this make sense so far?
00:55
Bertl
to some extend, but I think I know where this is heading to
00:55
troy_s
So to make the swatches matchable, the researchers added quantities of the primaries to bring them into gamut, making them less saturated.
00:56
troy_s
Once a match was made, they were able to calculate (because all natural light operates radiometrically linear) where their "original" positions on the chart were.
00:56
Bertl
reading up on sRGB, this is what you are referring to, no?
00:56
troy_s
This chart couldn't be named the CIE RGB, as it was beyond the RGB primaries they uses.
00:56
troy_s
It became known as the 1931 2° XYZ color space.
00:57
Bertl
http://en.wikipedia.org/wiki/Chromaticity_diagram
00:57
troy_s
And if you see most horseshoe charts out there, that is a derivative of it known as the xyY chart.
00:57
troy_s
Exactly!
00:57
troy_s
That is the CIE xyY chart
00:58
troy_s
Which, because XYZ is infinitely large (with intensity), is merely a scaled version of XYZ.
00:58
Bertl
okay, understood, so the primaries are 3 points in that space now, yes?
00:58
troy_s
That long rambling description is because THAT colorspace, the XYZ and the xyY model, is used to describe all color.
00:58
troy_s
Exactly.
00:59
troy_s
So when someone asks "what are the camera's native primaries, they are meaning (generally) the xy coordinates in the xyY chart
00:59
Bertl
and how would I go about mapping them?
00:59
troy_s
The unique characteristics of the xyY chart is that the Y represents pure luminance irrespective of color.
01:00
troy_s
To "describe" a color, a simple xy pair can work.
01:00
troy_s
You would shoot a controlled chart
01:00
troy_s
Of known photographic densities
01:01
troy_s
and compare the results to the known values
01:01
Bertl
I see, well, we will hopefully get some charts in the near future
01:01
troy_s
('profiling' the camera)
01:01
troy_s
Is the data off the sensor curved? or lineae?
01:01
Bertl
(not sure those charts are the ones you are referring to, though)
01:01
troy_s
linear?
01:02
Bertl
I'd also need a reference (gray?) chart to say that, no?
01:02
troy_s
(you can use many charts to get a ballpark idea - IT8 or even a Gretag Macbeth chart can give you a rough idea)
01:02
troy_s
A greyscale chart (included on an IT8 IIRC) will show you the TRC
01:02
troy_s
(tone response curve) if it is baked into the data.
01:03
troy_s
Sensors are linear creatures, but sometimes the makers bake a log type curve into the data.
01:03
troy_s
To make it more agreeable to LDR display.
01:03
Bertl
but that should be mentioned in the datasheet, no>
01:03
Bertl
s/>/?
01:04
troy_s
Is your debayered image darkish (linear) or look sort of normal?
01:04
troy_s
SHOULD be estimates. Every sensor would deviate more or less depending on quality.
01:04
FergusL
it looked normal to me
01:05
Bertl
http://vserver.13thfloor.at/Stuff/AXIOM/RAW/colors_500ms.png
01:05
troy_s
FergusL: Direct debayered?
01:05
troy_s
How are you debayering?
01:05
FergusL
after being debayered, "yes"
01:05
troy_s
What algorithm?
01:05
Bertl
it is called 'SIMPLE'
01:05
troy_s
Because the debayer is likely applying a TRC to the data.
01:06
Bertl
okay, give me a few seconds to eliminate the debayering
01:06
Bertl
by just mapping the channels manually
01:06
troy_s
Would be interesting to see... hard to know from that reference shot.
01:07
FergusL
"applying a TRC", like "bending" it ?
01:07
troy_s
Yes.
01:07
troy_s
Exactly.
01:08
FergusL
ok
01:08
troy_s
Of course the bayered image is nothing more than a greyscale, but if you treat those values as raw rgb, the image is probably a linear one. Or it is encoded into a YCbCr signal etc.
01:09
troy_s
What would be _very_ interesting is a shot of an IT8
01:09
troy_s
I could sponsor one for the project probably. Wolf makes decent ones.
01:10
troy_s
http://www.targets.coloraid.de
01:10
FergusL
Ha, that could be great, we were considering ordering one in some way and sending it to Bertl
01:10
troy_s
Easier to just get one shipped directly.
01:11
FergusL
woh
01:11
FergusL
much more complete than a Macbeth
01:11
troy_s
C1
01:11
troy_s
A Macbeth is not ideal for profiling
01:12
troy_s
as there are only 24 swatches
01:12
troy_s
and no greyscale
01:12
troy_s
IT8s are a reference standard. There is another with many more swatches.
01:13
FergusL
there's something I'm wondering, does it come with very specific settings instructions ? like lighting
01:13
troy_s
Some known white point film lighting gear like a Kino would be needed as the white point must be known (and checked if possible using a color meter)
01:14
Bertl
the Macbeth said that lighting doesn't matter (not sure that is true :)
01:14
troy_s
Expose middle geey
01:14
Bertl
uploading composed image now
01:14
troy_s
grey
01:14
troy_s
it does.
01:14
troy_s
largely because to compute the matrix (most sensors are uniform and fall apart near the high and low end)
01:14
troy_s
(spill and noise respectively)
01:15
troy_s
you _must_ know the color of illuminant.
01:15
troy_s
but from that test, you can get a reasonably accurate estimate of the raw data gamut and native white point.
01:15
Bertl
http://vserver.13thfloor.at/Stuff/AXIOM/RAW/colors_500ms_composed.png
01:15
FergusL
we do have Kinos, at least sebastian has access to some
01:16
Bertl
this is after separating the channels, throwing away one green channel and combining them to RGB
01:16
troy_s
Hrm. It looks like it has a TRC applied?!?
01:16
troy_s
Some processor level TRC
01:16
FergusL
hmpf
01:17
troy_s
Odd as hell.
01:17
troy_s
Bertl: Is there a way to pull lower level data?
01:18
troy_s
(I am wondering why and how they would apply a TRC to the bayer sensel data.)
01:18
troy_s
I would also like to know what TRC it is. Are there docs for the sensor? Does it mention log anywhere?
01:18
FergusL
well, in some word the processor is kind of "ours"
01:18
Bertl
no, that is from the basic data directly from the ADCs
01:18
troy_s
(although it sure doesn't look like a log curve)
01:19
FergusL
did you use some algorithm somewhere else in the pipe ?
01:19
Bertl
so whatever curve or transformation happens, it should be the ADC profile
01:19
FergusL
like the "SIMPLE" one
01:19
Bertl
nope, removed
01:19
FergusL
that's going to have to be added to the "errata questions" list I believe :)
01:19
FergusL
Bertl: about the sensor doc, do you have a link to it handy
01:19
FergusL
?
01:23
troy_s
Sorry. Hotel wifi punted me.
01:24
FergusL
looking for the full specs of the sensor
01:24
FergusL
hold on
01:25
troy_s
I suspect then that the ADCs are putting a TRC onto the data for whatever reason.
01:25
troy_s
Still needs to be accurately mapped so that you can invert it (yuck) to get to a scene referred image (or close to it)
01:26
troy_s
Very exciting to see data from the sensor however.
01:26
FergusL
yes
01:26
FergusL
but agreeing on "yuck"
01:26
FergusL
I still have hope for something else going on
01:27
Bertl
sec, it should be on github
01:27
troy_s
FergusL: It is entirely possible there is a register to poke to get the raw data.
01:28
Bertl
https://github.com/apertus-open-source-cinema/alpha-hardware/blob/master/Datasheets/datasheet_CMV12000%20v8.pdf
01:28
troy_s
FergusL: My worry is that (and yes it has happened) that some sensor manufacturer out of China or wherever is applying a transform to yield colors they like or think looks "right"
01:28
FergusL
absolutely, yes
01:29
troy_s
FergusL: And to prove my depressing point... read this...
01:30
troy_s
From the Cinematography mailing list http://pastebin.com/8kr06ckr
01:32
Bertl
but I guess it should be trivial to check for linearity by taking samples with linear exposure times, no?
01:32
FergusL
oh god, when was that on CML ?
01:32
Bertl
lear incresing exposure times that is
01:34
Bertl
*linear
01:34
FergusL
hm...
01:34
FergusL
what would that give ?
01:34
FergusL
higher values ?
01:34
FergusL
but bent in the same way
01:34
FergusL
(my take on it)
01:34
Bertl
what I mean is, I put up a white piece of paper
01:35
Bertl
and configure exposure times from e.g. 5ms to 500ms in 5 ms intervals
01:35
Bertl
then I make a histogram of each sample (from the center area to remove the pixel defects)
01:36
Bertl
and then I plot the centers of the to be expected bell curve in a linear plot
01:37
troy_s
LOL. "Spectral response: Not available yet."
01:37
Bertl
that should show the response curve of the pixels
01:37
FergusL
I'm not sure if I understand right
01:37
FergusL
well in fact I think I see
01:38
troy_s
Bertl: You can probably get a good idea of the curve if you have a series of reflective swatches at half stop increments or quarter stops.
01:38
Bertl
well, I don't have any swatches atm :)
01:38
troy_s
It just doesn't look linear (not knowing what the test tape looked like)
01:38
troy_s
Light meter?
01:38
Bertl
nope
01:38
troy_s
Balls.
01:39
troy_s
LOL
01:39
Bertl
yes, I juggle :)
01:39
troy_s
And we don't really know the primaries, so we are seeing an sRGB dump of the RGB channels.
01:39
troy_s
Did you shoot the pattern?
01:40
Bertl
I do not shoot, not even pattern :) but yes, I captured the image
01:40
Bertl
so, any flaws you can find in my reasoning regarding detecting any non linear transfer function?
01:41
troy_s
The bottom line is that to make the data useful, this will need to be tackled soon. Largely also because the target audience will also find said information very useful.
01:41
troy_s
Hrm.
01:41
Bertl
(by linearily increasing the exposure time and capturing a histogram?)
01:42
troy_s
I am unsure.
01:43
troy_s
Because we are talking about the response curve in a single image. If we do exposure slices I fear that we will always be grabbing the "middle" value. But I have never tried anything like that so I am simply uncertain.
01:43
FergusL
what troy_s just said about the "target audience" is very important, I think we're atm discussing points that will have to be put forward in our documentation
01:43
troy_s
Try it perhaps? If the result is a curve, then the test is perhaps working.
01:43
Bertl
hehe :)
01:43
troy_s
The gamut of that sensor is pretty darn important for sure. But the curve is deadly important.
01:43
Bertl
well, that would be selecting the test to support your argument :)
01:44
Bertl
i.e. biasing the information ... but I do not see any flaw in the reasoning
01:44
troy_s
If they are baking some nonstandard curve in merely to present the data in a "nice" fashion, it makes the data useless if we can't reverse it.
01:45
troy_s
To store as a native DPX on a storage device or even a purely linear EXR for example.
01:45
Bertl
i.e. if there is a linear relation between light and read out values, then we should get a linear relation between the sampled/mean values for linear exposure steps, no?
01:45
troy_s
Bertl: Well if it is linear and the image clearly isn't, the test failed. If it is curved, then it likely is working to a degree. Not much room for bias I can see?
01:45
Bertl
and if it isn't linear, then we should see the curve
01:46
Bertl
the bias is, that you say it failed if it doesn't support your assumption, and it might have worked if it does
01:46
Bertl
that is like when I say, let's plot this data to see if it is linear
01:46
troy_s
And given that you don't have the means to do a proper chart test (or toggle the register to get raw linear) then I guess it is better than nothing.
01:46
Bertl
and you say, well, if it fits a curve, your plot is wrong
01:47
troy_s
Well not quite
01:47
troy_s
a linear image is deadly easy to see
01:47
troy_s
and it almost certainly doesn't feel close to a linear image being displayed on an sRGB close device.
01:47
troy_s
(but a face would be easier perhaps)
01:47
Bertl
I don't see how you could see a linear image from single colors
01:48
troy_s
A linear representation in data looks wholly "crunched" down
01:48
Bertl
there are no gray values in this image, except from the change of light (which falls from one side)
01:48
troy_s
Very "dark" to use a low level guess.
01:48
troy_s
the bright region (and notably yellow) would likely be much more crunched.
01:49
FergusL
very dark with only the highly exposed areas of the image shining through
01:49
troy_s
Exactly
01:49
FergusL
taht's roughly what a "linear image" looks like, even though that doesn't make much sense
01:49
Bertl
I think this assumption might hold on a real world scene, but I do not see how it applies to this artificial image
01:49
troy_s
FergusL: Can you quickly invert an srgb curve on that image and post it?
01:50
troy_s
Bertl: It is tape on a wall correct?
01:50
FergusL
let me do this
01:50
Bertl
tape on a white paper (A4)
01:51
troy_s
Bertl: I have looked at a few images in my time, and that is how I can roughly guess what it likely looks like in the physical scene.
01:52
troy_s
I _may_ very well be incorrect, but the telltale falloff on the yellow tape
01:52
troy_s
from bottom to top
01:52
troy_s
suggests a gradient that is almost certainly not a linear representation dumped to an sRGB display curve.
01:52
troy_s
FergusL: Agree?
01:53
FergusL
hm, agreed yes
01:54
Bertl
so why not figure how we can 'measure' it with what we(I) currently have available?
01:54
troy_s
Bertl: Because I am not as clever as you?
01:54
troy_s
If you place a light source close
01:54
troy_s
and measure it
01:55
troy_s
the measurement of X distance (near left edge perhaps) should be 1/4 the rgb values at 2x
01:55
troy_s
1/d^2 of course
01:55
troy_s
(assuming a simple pinpoint tungsten fixture, that SHOULD hold roughly true. EG No reflector or diffuse source)
01:56
troy_s
so given light from lamp to left edge as X
01:56
Bertl
okay, so I get a small lamp which can be considered a point source
01:56
troy_s
lamp to right edge as a ratio of x
01:56
troy_s
the rgb values, if linear, should hold according to 1/d^2
01:56
Bertl
put it nearby the paper and take a picture, yes?
01:56
troy_s
Does that make sense?
01:56
troy_s
Yes
01:57
troy_s
raking along the paper
01:57
troy_s
in a gradient
01:57
troy_s
bright to dark
01:57
troy_s
whatever the distance ratio is
01:57
troy_s
should hold up in data according to the inverse square law
01:57
Bertl
sounds reasonable
01:58
troy_s
so if say, the distance from left edge is 2x
01:58
troy_s
then 1/4 values can be estimated.
01:59
troy_s
(you can probably cheat the source to get you more easily calculated values too.)
01:59
troy_s
Just avoid reflectors like light hoods etc.
02:00
Bertl
let me see what lamps I can find
02:01
troy_s
it is also plausible that they encode some form of a curve in the data that maximizes the data capture range similar to a log curve.
02:02
troy_s
(that is effectively a form of compression)
02:02
Bertl
I actually doubt that
02:02
troy_s
Well it isn't unheard of. Most commercial cameras offer a log mode.
02:03
troy_s
For just that reason. A purely linear image 'wastes' many data values in terms of image collection)
02:03
Bertl
sure, but the specification of a sensor for medical imaging should at least give a hint
02:03
troy_s
Yeah
02:04
troy_s
I am no sensor guru on that front however.
02:04
troy_s
I am surprised they don't document all of this stuff if it is for some form of precision medical use.
02:05
troy_s
I glanced at the HDR line skipping technique etc, and I would have expected more documentation on how to interpret the blasted data.
02:06
FergusL
regarding HDR there is more than just line skipping
02:06
FergusL
on this sensor, that is
02:07
FergusL
(hu... I'm on the wrong computer right now, I don't have much to work with images)
02:07
FergusL
(I'm tempted to just try with nuke)
02:08
troy_s
Egads I would love to shoot with that sensor if it worked and had a decent bit of proper workflow output footage.
02:09
troy_s
FergusL: It does a window mode and a line skip mode.
02:09
troy_s
Where it appears to read two separate readings at intervals for window mode.
02:09
FergusL
you consider it's not working ?
02:13
troy_s
Not at all.
02:13
troy_s
I was just looking at the data sheet for the HDR modes.
02:14
troy_s
Anyways... must sleep. Pleasant to finally see an image!
02:14
FergusL
thanks for your help !
02:14
troy_s
G'nite folks. Poke me via PM for anything to avoid getting buried in the scrollback buffer.
02:14
troy_s
Bertl: G'nite.
02:14
troy_s
(email works too)
02:16
FergusL
going to sleep too, btw
02:16
Bertl
have a good sleep
02:17
FergusL
thanks, I'll be there hopefully "earlier" tomorrow
02:17
FergusL
maybe we can talk ("work" ?)
02:18
Bertl
yeah, I'll do some tests with the lamp
02:19
FergusL
cool, night !
07:40
Sasha_C
joined the channel
08:10
se6astian
joined the channel
08:10
se6astian
morning!
08:10
Sasha_C
Good morning Sebastian. I'm moments away from sending out an email to the team, based on a discussion Herbert and I had earlier today
08:11
Sasha_C
How are you feeling? Still stressed?
08:20
Sasha_C_
joined the channel
08:20
Sasha_C
left the channel
08:20
Sasha_C_
changed nick to: Sasha_C
08:31
se6astian
hi, a bit less stressed today :)
08:32
Sasha_C
good to hear :D
08:57
dmj_nova
Bertl: FergusL: If I remember correctly, what the sensor documentation *claims* it does is provide up to 3 regions with different slope.
08:58
dmj_nova
I think each region is supposed to be linear.
08:58
dmj_nova
This could bear checking, however.
09:04
se6astian
Sasha_C, replied
09:04
Sasha_C
Thanks, I can see it
09:04
se6astian
dmj_nova, you refer to the PLR HDR mode right?
09:04
Sasha_C
just about to reply back ;)
09:05
dmj_nova
se6astian: yes
09:05
dmj_nova
I'm not sure if this is being used
09:05
dmj_nova
but that could explain non-linearity
09:05
se6astian
the name carries the answer: piecewise LINEAR response mode ;)
09:06
se6astian
explain which nonlinearity, did I miss everything again during the night?
09:07
dmj_nova
yes
09:08
dmj_nova
this image: http://vserver.13thfloor.at/Stuff/AXIOM/RAW/colors_500ms_composed.png
09:09
dmj_nova
troy_s claimed it appeared to have a TRC applied.
09:09
dmj_nova
and they were discussing how to test the response curve of the camera
09:10
se6astian
"TRC"?
09:11
dmj_nova
I'm not familiar with the acronym but from context, I think it's a curve applied to the data that makes it not linear light response
09:26
se6astian
hmm, I dont really follow
09:27
se6astian
Sasha_C, did you summarize any of the recent developments for the article yet?
09:27
se6astian
maybe we can get the new article done today
09:32
Sasha_C
I haven't added last night's developments yet
09:33
Sasha_C
But I can try to have it done by the end of this night
09:36
se6astian
it was a google doc right?
09:36
se6astian
can you give me what you have so far and I put it into the article layout for now
09:36
Sasha_C
well, the google doc only has the text that I've copied and pasted from my IRC window
09:37
Sasha_C
Give me fifteen minutes and I'll have it ready for you
09:40
se6astian
thanks
09:58
Sasha_C
Sebastian, here's the link to the google doc: https://docs.google.com/document/d/1AtexpX8avHEXORvTlnYrDMPn69FQv-uwM62DHqtSXok/edit
10:03
se6astian
thanks
10:25
se6astian
creating floorpln animation of the FPGA now
10:25
Sasha_C
great. Out of curiosity, who is the anonymous pumpkin, coyote and duck in the google doc?
10:27
se6astian
random names google generates
10:27
Sasha_C
i know, but I'm trying to figure out who else in this IRC room is looking at the doc
10:27
mars_
its me ^^
10:28
Sasha_C
Thanks Mars
10:28
Sasha_C
Sebsatian, what else would you like me to add to the document?
10:52
se6astian
https://www.apertus.org/axiom-alpha-opens-eyes
10:53
se6astian
well now we need to add the first captured image
10:53
se6astian
and then the second one that fixes most of the problems in the first one ;)
10:55
Sasha_C
Just read the article, looking FANTASTIC!
10:55
Sasha_C
Nice video :D
10:57
se6astian
:)
11:14
Sasha_C
Hey, I'm currently afk. I'll be back in 30mins
11:50
se6astian
lunchtime
12:09
FergusL
hi here
12:18
se6astian
back
12:18
se6astian
hi FergusL
12:19
se6astian
slightly updated: https://www.apertus.org/axiom-alpha-opens-eyes
12:19
se6astian
continuing to expand the article now
12:36
se6astian
ok I have the basic layout finished
12:36
se6astian
I think I will add a picture of the prototype assembly when I am at home as well
12:36
Sasha_C
I'm back
12:42
se6astian
renamed the article
12:42
se6astian
https://www.apertus.org/axiom-alpha-first-images
12:42
se6astian
anything else we should add?
12:42
se6astian
next steps maybe
12:42
Bertl
morning everyone!
12:42
Sasha_C
Sebastian, I just want to edit one sentence in the first paragraph. It'll be a minor change.
12:43
Sasha_C
morning Bertl
12:53
se6astian
hi Bertl
12:53
se6astian
go ahead Sasha_C
13:06
FergusL
Hi Bertl
13:10
Bertl
hey, it looks like the sensor data is linear after all :)
13:10
Bertl
http://vserver.13thfloor.at/Stuff/AXIOM/RAW/linear_2.svg
13:10
Sasha_C
Done, and looking great (if I say so myself): https://www.apertus.org/axiom-alpha-first-images
13:14
FergusL
does this look linear to you ?
13:14
Bertl
yes, nice article! good work everyone!
13:14
Bertl
FergusL: yes, the curves are what we expect assuming a linear sensor
13:15
Bertl
i.e. light will behave like the dark curves
13:15
FergusL
(linear is not always what we think it is)
13:15
Bertl
and the more colorful curves are what we measure
13:15
FergusL
yes
13:15
Bertl
http://vserver.13thfloor.at/Stuff/AXIOM/RAW/linear_1.svg
13:16
Bertl
here is measured divided by expected
13:16
FergusL
I see
13:16
Bertl
i.e. a horizontal line means constant factor
13:16
FergusL
yes, I can get that
13:16
FergusL
but hm...
13:17
FergusL
in the other image, the dark lines are the "ideal" behaviour ?
13:17
FergusL
like, physically rigorous
13:17
Bertl
yes, that would be according to physics, the curve a linear system would show
13:17
Bertl
basically 1/squar-distance corrected by lambert
13:18
FergusL
okay
13:18
FergusL
I'm still missing some points of the theory, even after troy_s explained it to me countless times
13:19
FergusL
because "visually", the dark lines certainly don't look linear
13:19
FergusL
linear as in 1 + 1 = 2
13:22
FergusL
Bertl: as troy_s mentioned too, what we're discussing right now is what many users will want to know and trust, so I could suggest to write an article about this at some point
13:23
FergusL
it would clearly target an educated audience but could also sum up about the theory lying behind at the same tie
13:23
FergusL
time*
13:23
FergusL
CC se6astian ^
13:25
se6astian
we can add it to this article if we want
13:25
se6astian
is there anything else you think should be added
13:25
se6astian
I want to cover next steps briefly
13:25
se6astian
and add a picture of the prototype assembly which I have on my home pc
13:27
FergusL
I'm assuming you want to release this article asap, Bertl's/our investigations regarding linearity can still use some time I think, basically it can wait
13:29
Bertl
yes, and don't forget, it is not a precise measurement or calibration, it is just a quick test to check the data
13:29
FergusL
yes, too
13:29
FergusL
from what I understood, we could get an IT8 chart thanks to troy_s
13:29
FergusL
maybe wait until then
13:31
Sasha_C
Good decision. And on that note, I have to go get some sleep so I can wake up on time for work tomorrow :(
13:31
FergusL
there was a very short discussion on cml recently about Axiom
13:32
Bertl
Sasha_C: make that! thanks again and have a good night!
13:32
FergusL
thanks Sasha_C, bonne nuit !
13:32
Sasha_C
left the channel
13:32
se6astian
cml?
13:33
FergusL
cinematography mailing-list, I've already talked about it, I think
13:36
se6astian
ah great
13:38
FergusL
I think cml rules include that mails are not to be published outside of the mailing list but basically there were some doubts expressed about the modular desing
13:43
FergusL
especially regading power connections : if the battery is at the back and the camera at the front, that makes several connections in series, which isn't great
13:43
FergusL
that's a valid point I believe
13:44
se6astian
interesting to see a discussion on such a level there, good signs :)
13:44
FergusL
absolutely, I'm still monitoring cml for more mails about Apertus, I'll make sure to report to the community
13:45
se6astian
great
13:45
se6astian
about the power lines we already had a discussion in Brussels when we were in the train back to the airport
13:46
se6astian
there are several options IIRC like having the power go in a loop from battery to parts and from battery to head and from there back again
13:46
se6astian
Bertl will surely remember more of the technical details
13:46
FergusL
there could also be a single cable directly connection, also that doesn't fit entirely in the modular paradigm
13:46
FergusL
I see
13:48
Bertl
yes, power management and distribution will be something we have to design and test carefully in the modular concept
13:48
Bertl
worst case scenario is a primitive power plug on every module, directly connected to a battery pack :)
13:50
Bertl
the main problems with power is the distribution, for example, it would be very efficient (power consumtion wise) to generate the required voltages in one place (e.g. 1.8V, 2.5V, 3.3V, 5V)
13:50
FergusL
http://www.afcinema.com/-2014-.html ever heard about the AFC ? it's basically BSC or ASC in France, they hold a show every year
13:50
FergusL
maybe some day we could have a booth there
13:50
Bertl
OTOH, when we transport 5V over 5 modules, we will get like 3V at the end, if all those modules consume a certain amount of power
13:51
FergusL
I see
13:51
Bertl
(unles we use super conductors :)
13:51
Bertl
*unless
13:52
FergusL
it's the same effect that makes looong unshielded cables weak ?
13:52
FergusL
like, over 10 meters you lose X volts ?
13:53
Bertl
yup
13:53
Bertl
it is called resistance
13:54
Bertl
http://en.wikipedia.org/wiki/Electrical_resistance
13:54
FergusL
ha yes, because even a wire has a resistor value, it's insignificant in most case but becomes important in longer distance
13:55
Bertl
not just distance, it also depends on the power
13:55
Bertl
or to be precise, on the current
13:56
Bertl
http://en.wikipedia.org/wiki/Ohm%27s_law
13:56
Bertl
so basically if you have 10V at 1A (on the receiving side)
13:57
Bertl
this equals a 'resistance' of 10 Ohm
13:57
Bertl
now if the wire adds 1 Ohm, you already need 11V at the provider
14:03
FergusL
I'm more used to using Ohm's law as U = RI, because most of the time R is known
14:05
Bertl
well, that's fine here, the R = Rwire + Rconsumer
14:05
Bertl
and they build a voltage divider
14:06
FergusL
yes, I'm aware of these concepts
14:06
Bertl
where the voltage at the consumer is Rconsumer/R
14:06
Bertl
times the provider voltage
14:07
FergusL
how are connectors treated in this matter ? like wires touching each other
14:07
FergusL
as an equivalent resistance ?
14:09
Bertl
they have a resistance, yes
14:09
FergusL
I get it
14:09
Bertl
they also cause strange effects because different metals are involved
14:10
FergusL
I do some electronics, Arduino and stuff, but I'm more into controllers, specifically controllers for music making
14:10
Bertl
mostly thermoelectric effects
14:10
FergusL
I see, didn't know that
14:13
Bertl
http://en.wikipedia.org/wiki/Seebeck_effect#Seebeck_effect
14:16
FergusL
do you have knowledge about audio in electronics ? amplification, signal path and power
14:16
Bertl
somewhat
14:20
FergusL
I have as a project to build a small amplificator board (and maybe including an USB dac as well) that would be portable and go with small embedded Linux systems... but... that's off-topic !
14:30
FergusL
back to the topic, Bertl, your experiment would suggest that the images coming from the sensor are linear ? did you test pre or post debayer ?
14:31
FergusL
pre, I believe ?
14:31
Bertl
everything on the raw data, so no debayering or similar
14:31
Bertl
all I did was split up the data according to the channel
14:32
Bertl
(4 channels, 1 red, 1 blue, 2 green)
14:33
FergusL
I see
14:34
FergusL
do you have the code somewhere for that "SIMPLE" debayer algorithm ?
14:35
FergusL
I might just be wasting your time if I'm wrong but I'm suspecting it's not linear
14:35
Bertl
sure, but it wasn't used
14:36
FergusL
of course it wasn't, yes
14:36
FergusL
am just curious of what it does, especially regarding tone curve correction
14:37
Bertl
https://github.com/jdthomas/bayer2rgb
14:38
Bertl
https://github.com/jdthomas/bayer2rgb/blob/master/bayer.c line 569
14:40
FergusL
(
14:41
FergusL
https://github.com/jdthomas/bayer2rgb/blob/master/bayer.c#L569 <- this works :)
14:41
FergusL
oh noes, bit shifting, why why why é_è
14:51
Bertl
well, AFAICT, it's a perfectly fine integer division with rounding
14:51
Bertl
(a + b + 1) >> 1
14:52
FergusL
yes yes, it's just an old fear of mine
14:52
Bertl
as the resulting data is not further processed in any way, it is probably as good as it gest
14:52
Bertl
*gets
14:55
FergusL
you're refering to the debayer there, right ?
14:55
FergusL
apparently, no, it's not processing in any way
14:57
Bertl
yep
14:59
se6astian
any thoughts on the apertus° association accepting bitcoins for donations in the future?
15:01
Bertl
why not
15:02
FergusL
I'm all for it
15:04
FergusL
I'm all for anything that would put us more in the path of things we believe in: transparency, independance and unbound honesty
15:06
se6astian
agreed
15:08
FergusL
ultimately that'd also include leaving Google, Facebook, Paypal, capitalism, "agressive business model"
15:08
FergusL
(I'm not saying we have an agressive business model)
15:11
FergusL
Bertl: did you check the assumed bayer pattern is the right one ?
15:11
FergusL
hm, nevermind, that would be obvious if you didn't
15:12
Bertl
yep, actually I tried all of them and took the one which looked the least ugly :)
15:13
FergusL
it wouldn't hurt to write our own debayer
15:13
FergusL
well, it would do the same exactly
15:14
Bertl
originally I wanted to use dcraw, because it is kind of famous in the community
15:15
FergusL
yes
15:15
Bertl
but I didn't manage to get it working with real raw data (i.e. bayer mosaic data)
15:15
FergusL
I'm interested in investigating in this side
15:15
Bertl
and the folks I asked told me, it would be best to write my own 'raw' importer for dcraw, to read the raw files :)
15:16
FergusL
it's even possible to compute the debayering as a node system in Blender or else
15:16
Bertl
so it seems that dcraw cannot read 'raw' after all, it can only read the various proprietary formats the companies call 'raw'
15:16
FergusL
(maybe that could be a good think to make it easy to understand to people)
15:17
FergusL
what's the "format" you get ? is it a standard of some sort ?
15:18
Bertl
go crazy, you have the 'real raw' data, give it a try and see how it looks, if it's fine and can be pipelined in an efficient way, I can use it
15:18
Bertl
the 'format' is the one I described on the dev mailing list
15:19
Bertl
basically 12 bit padded to 16bit gray values in big endian, arrange in the RGGB bayer pattern
15:19
FergusL
it's also rather trivial to write it for ImageMagick with Python
15:20
FergusL
RGGB, got it
15:20
Bertl
no headers, no additional metadata yet
15:21
Bertl
although I will probably dump the registers in the near future at the end
15:21
Bertl
i.e. just dump out all the sensor registers one after the other for later processing
15:21
se6astian
gabe said he is working on a DNG converter
15:21
Bertl
yep, I hope it will become useful soon
15:22
FergusL
very useful to make it usable in decent application for further checking and investigation
15:22
FergusL
linear formats would be cool be cool at some point too, dpx or exr
15:22
Bertl
well, I can't believe that photoshop and friends cannot read bayer data as gray image
15:22
FergusL
Bertl: I'm not sure I understand, how different would this dump be from the raw data you get ?
15:23
Bertl
it would be what we have now <raw image data> plus <register dump> appended at the end
15:23
FergusL
Blender should, if you mark the input colorspace as... hm.. what it it called ? "none" or something
15:23
Bertl
so instead of 4096x3072x2 bytes, there would be additional 128*2 bytes register values
15:23
FergusL
ohhh, the registers, absolutely, that'd be metadata, right ?
15:24
Bertl
for post processing, just remove the last 256 bytes or ignore them
15:24
Bertl
and for analysis, just read the last 256 bytes and you know exactly what the sensor was configured for
15:25
FergusL
ok, I get it, thanks
15:25
Bertl
np
15:32
FergusL
opencolorIO and openimageIO (http://opencolorio.org/index.html https://sites.google.com/site/openimageio/home) are good tools to look into as well
15:32
FergusL
it's like imagemagicks made particularly for our field
15:36
se6astian
going home from my office now
15:36
se6astian
see you
15:36
se6astian
left the channel
15:39
FergusL
Bertl: what was used for the export to .png ?
15:39
Bertl
okay, just added that register dump feature to my tool
15:39
FergusL
cool
15:39
FergusL
is that code somewhere ?
15:39
Bertl
I'm using ImageMagick for almost everything
15:39
FergusL
I see
15:39
Bertl
I haven't uploaded it yet, but I will upload it soon
15:39
FergusL
github ?
15:41
Bertl
http://vserver.13thfloor.at/Stuff/AXIOM/cmv_snap.c
15:41
Bertl
here you go :)
15:42
FergusL
thanks
15:44
FergusL
my C is like my german, I'm still working on it
15:52
FergusL
what are the mmap() for ?
15:52
FergusL
is is the step writing to registers ?
15:52
FergusL
though it's also writing to registers later
15:53
Bertl
everything on the arm cortex platform is somewhere in memory
15:53
Bertl
the sensor registers, the data collected from the sensor, etc
15:53
Bertl
the mmap maps this physical memory to a virtual memory region
15:54
Bertl
(so that it can be directly accessed)
15:56
Bertl
http://vserver.13thfloor.at/Stuff/AXIOM/cmv_train.c
15:56
Bertl
this is the code to train the LVDS channels
17:15
FergusL
Bertl: train ? they need to train ?
17:15
FergusL
like, otherwise, we're back to NTSC ?
17:35
Bertl
well, yes, the process of adjusting the bitstreams (delay wise) is called training
17:43
FergusL
I see
17:44
FergusL
do I have the time to do some tests on Nuke hm..
17:57
dmj_nova
left the channel
18:18
troy_s
Bertl: Tested? I recommend OIIO compiled with OCIO and iv tool.
18:18
FergusL
ding ding :)
18:18
troy_s
Bertl: OCIO allows a well documented transform on both the TRC (tone response curve) and the primaries.
18:19
Bertl
if you can elaborate on the acronyms, maybe I can comment :)
18:19
FergusL
this is the linked I put there earlier
18:19
FergusL
open <foo> IO
18:19
troy_s
Bertl: Would be good to see if the vendor will supply native primaries. I could do up a LUT configuration.
18:20
troy_s
Bertl: OCIO = Sony (Jeremy Selan's) OpenColorIO
18:20
troy_s
Bertl: OIIO = Sony (Larry Gritz's) OpenImageIO
18:21
troy_s
Bertl: TRC = Tone Response Curve (aka Transfer Curve) (aka the wrong term Gamma)
18:21
troy_s
Back to work... ping and I will check from time to time.
18:21
Bertl
okay, well, we probably can do that at some point when we have test charts
18:22
Bertl
troy_s: what's your comment on the linearity? :)
18:32
tonsofpcs
left the channel
18:32
tonsofpcs
joined the channel
18:35
troy_s
Bertl: I trust your math. Did you try the test we discussed via lamp?
18:36
troy_s
Bertl: Can you yank a shot of a generic scene with hots and darks in it?
18:37
troy_s
Bertl: It is possible the tape was overexposed all to hell... but the image sure looked "normal", which suggests it wasn't linear. Could be subject matter of course.
18:38
troy_s
Bertl: I only suggested OCIO and OIIO as they are reference baseline motion picture libs. OCIO is in Nuke, Silhouette, etc. Both OCIO and OIIO are in many post houses. Further, it is great if everyone gets to know DPX and EXR as well.
18:42
dmj_nova
joined the channel
18:47
se6astian
joined the channel
19:02
Bertl
troy_s: everything is possible regarding exposure
19:02
Bertl
I just took the first image where I could clearly see the tapes and colors
19:02
Bertl
and yes, I did the discussed lamp test
19:03
Bertl
http://vserver.13thfloor.at/Stuff/AXIOM/RAW/linear_1.svg
19:03
Bertl
http://vserver.13thfloor.at/Stuff/AXIOM/RAW/linear_2.svg
19:04
Bertl
(details were posted on the devel mailing list)
19:06
Bertl
regarding generic scene, I can probably take photo or centerfold and capture that :)
19:08
FergusL
Right now you can't bring the prototype at a window and snap a picture there, right ?
19:09
Bertl
correct
19:09
FergusL
I was wondering, at this point, can apertus have interns ?
19:09
Bertl
we will be able to do that once the case is finished though
19:10
Bertl
I guess, if they work for free, we can have interns :)
19:13
FergusL
I'm looking for an internship, actually
19:14
FergusL
Did you take a look at ocio and oiio ?
19:15
Bertl
check with se6astian what might be possible and what not (wikipedia says, in france labor law requires a minimum payment)
19:17
FergusL
(facts say, in France it's very likely you might remain unpaid as an intern, applies to any field)
19:19
se6astian
well the company is in Belgium
19:19
se6astian
I have no idea about the law status there or what the requirements would be
19:19
se6astian
if you just need a signed paper I guess that should be possible
19:19
FergusL
I don't care about a payment, actually, what I want is bridging the gap between cinema and programming
19:20
Bertl
that's the spirit!
19:20
se6astian
but I have to warn you, we are very strict, mean and demanding bosses, this is kindergarden compared to being an intern in apertus: https://lh3.ggpht.com/-jfb2AXC6x6o/TmRIJOnCnsI/AAAAAAAACv4/Ds7nRMJLTdU/s400/galley%2Bslaves.jpg
19:21
FergusL
I just need a signed paper, indeed, I'll look into the details
19:24
se6astian
thanks, of course we need to wait for oscars OK as he owns the company
19:24
FergusL
Uh. I'm going to Red then.
19:25
Bertl
:)
19:25
se6astian
but if it does not mean additional work or expenses for him I guess it should be fine
19:25
se6astian
I bet Red is much cooler, you will surely get Ocley eyewear and regular rides in the company helicopter!
19:26
se6astian
possibly they will even let you create their entire next product on your own, I only heard that they managed to make the scarlet worse than the Red One :)
19:27
Bertl
you have to adapt to consumer demands
19:27
se6astian
added prototype picture and oscars cava picture as link to the article: https://www.apertus.org/axiom-alpha-first-images
19:27
se6astian
indeed, the customer is king ;)
19:28
Bertl
ah, cool!
19:35
dmj_nova
se6astian: isn't the scarlet supposed to be like the stripped down model?
19:37
se6astian
yes but of the epic, not the red one
19:38
dmj_nova
that said I've never used any of them
19:38
dmj_nova
of course the scarlet changed so many times before it was released
19:48
se6astian
what do you think of this prototype progress ad banner: https://www.apertus.org/axiom-alpha-hardware-complete ?
20:10
Bertl
besides the fact that it links to a 'Latest News' page which shows news from 3 weeks ago as 'latest' it looks really nice
20:11
se6astian
that ARE the latest public news :)
20:12
se6astian
about the prototype
20:12
Bertl
well, that _is_ sad :)
20:13
se6astian
a catastrophe!
20:13
Bertl
next news point will be 'crowd funding completed!' :)
20:18
se6astian
hopefully! and not "failed"
20:22
se6astian
would you suggest to mix Axiom and Alpha prototype news?
20:22
se6astian
currently its strictly seperated
20:24
Bertl
well, if it can be labeled accordingly then I guess it would make sense
20:26
se6astian
people tend to mix up the two already so we have to label them quite cleverly
20:27
se6astian
I dont know how many times I have seen people on forums complain that Axiom will only have a nikon mount for example....
20:27
Bertl
how about a logo/icon?
20:28
Bertl
something which goes left of the title text or even over the associated image?
20:28
Bertl
like for example an 'alpha' or the greek letter maybe?
20:31
se6astian
like the sony alpha camera? https://upload.wikimedia.org/wikipedia/commons/0/00/Sony-Alpha-A700-Front.jpg
20:31
se6astian
might get us sued :)
20:32
se6astian
but a symbol is a good idea
20:32
Bertl
I don't think that a letter can be registered or trademarked (yet)
20:33
se6astian
the "geschmacksmuster" most likely is protected
20:33
dmj_nova
also one can have an 'alpha' that doesn't look like the Sony one
20:33
Bertl
otherwise microsoft would have one half of the alphabet and apple the other :)
20:33
se6astian
what if we used the prototype assembly as a kind of "icon" (like on the left of: https://www.apertus.org/sites/default/files/axiom-alpha-progress-update-ad_0.jpg)
20:33
se6astian
I like that it looks so "prototypical" with PCBs, cables, etc.
20:34
Bertl
yeah, well, it is probably too delailed to work as icon
20:34
dmj_nova
Bertl: how much of the FPGA resources are used at present?
20:34
dmj_nova
for the very basic functionality it has now
20:35
se6astian
lets continue this discussion soon, I think we are on the righ track
20:35
se6astian
gotta go afk for a bit
20:36
se6astian
ah not for another 15 minutes ;)
20:36
Bertl
dmj_nova: http://vserver.13thfloor.at/Stuff/AXIOM/utilization.rpt
20:37
Bertl
we will free up a little when I switch to the Zynq Serdes (which is on my todo list)
20:39
dmj_nova
Serdes?
20:42
Bertl
SERial/DESerializer
20:43
dmj_nova
Bertl: hmm...that's really not that much
20:48
Bertl
yes it is quite efficient if you leave out all that xilinx IP stuff :)
20:50
dmj_nova
haha
20:51
se6astian
good news: another electronics engineer just emailed us and wants to help
20:53
Bertl
hehe, you don't say :)
20:53
se6astian
note, you only email your reply to team@aper...
20:53
se6astian
*emailed
20:54
Bertl
yeah, the mailing list is obviously sending the wrong headers
20:55
Bertl
Reply-To: apertus-team@googlegroups.com
20:56
se6astian
yes, well the website form sends all enquiries to the google group
20:57
Bertl
you might want to add the reply-to header to the envelope
20:58
se6astian
in the google group settings or for the websites contact form?
20:58
Bertl
probably in the contact form, unless google groups strip that information
20:59
se6astian
there are no settings like that in drupal
20:59
Bertl
check if the google-groups settings force a reply to?
20:59
se6astian
you can only select the target address
21:00
Bertl
I just googled for the issue and it seems there is an option
21:01
se6astian
http://picpaste.com/googlegroups-FyhIasLL.jpg
21:02
Bertl
I guess the last one would be the proper setting, but I have to test it
21:02
se6astian
its a strange option to let the user decide, where should they decide when they receive an email?
21:03
Bertl
well, it is how the headers are formulated
21:03
Bertl
I can hit reply, or reply-group for example
21:03
Bertl
where reply would reply to the sender
21:03
Bertl
just give it a try and send a message via the form
21:04
Bertl
say that you are looking for a well payed job :)
21:05
se6astian
"replying only to sender" is also not a good idea as people will then reply only to the other member who posted to the group but nobody else will get the reply if people are not careful
21:05
Bertl
as I said, let the user decide sounds correct to me
21:05
Bertl
i.e. it will not force the reply-to header
21:06
Bertl
you can always add the group in the cc reply
21:06
se6astian
https://support.google.com/groups/answer/2648318?hl=en
21:06
se6astian
Users decide where replies are sent - Replies to posted messages are decided on a per-member level.
21:07
se6astian
to me it sounds like any group meber can set it individually
21:07
se6astian
lets give it a try
21:09
Bertl
looks good to me
21:09
Bertl
now just add the dev group to the cc, like the team one
21:10
se6astian
hmm, the test mail I sent doesnt work
21:10
Bertl
hmm?
21:10
se6astian
it still replies to the group only by default
21:10
Bertl
that is probably your mail client, but here it works fine
21:10
Bertl
(i.e. I presume your mail client has a default set to the group)
21:11
se6astian
gmail webclient
21:11
Bertl
I'm sure it can be configured somewhere, I don't use gmail
21:12
se6astian
checking...
21:12
Bertl
probably an option like 'list reply' or reply to mailing list or something like that
21:12
se6astian
but if it works for you now I will leave the setting and we will just see if the problem is gone for most people
21:13
Bertl
yep, works fine for me, thanks
21:14
se6astian
great
21:14
se6astian
ok now I really gotta go
21:14
se6astian
afk<-
21:15
Bertl
cya
21:18
troy_s
Bertl: Is there a public repo of the apertus mailing list?
21:20
Bertl
https://www.apertus.org/mailinglists
21:20
Bertl
I don't think so
21:21
Bertl
but we probably could/should make axiom-dev public in the near future
21:22
troy_s
Bertl: Is there a copy of your results from the low tech test?
21:22
[1]se6astian
joined the channel
21:23
Bertl
give me you e-mail (pm) and I'll bounce it to you
21:24
[1]se6astian
I can also add you to the list if you plan to contribute/hang around in the future?
21:25
se6astian
left the channel
21:25
[1]se6astian
changed nick to: se6astian
21:39
troy_s
se6astian: Sure.
21:44
se6astian
pm me your email address please
21:53
troy_s
I am not going to lie... that is an impressive test there Bertl. I don't quite understand the axes, but pretty impressive nonetheless.
21:56
Bertl
it is rather simple (the graphs) basically x is the inverse distance from the projected point light source
21:57
Bertl
i.e. the light is on the right side
21:57
Bertl
and y is the measured/calculated intensity
21:58
Bertl
in he curvy graph it is plotted as is, in the more horizontal graph one divides the other
21:58
Bertl
i.e. horizontal line would be a perfect match
21:59
Bertl
I think the peaks at the left end are due to back level noise
21:59
troy_s
So at 800 if the value is 50 (arbitrary fake value) then at 400 it should be 1/4 that?
21:59
Bertl
well, not exactly, we 'forgot' the cosine law yesterday
22:00
troy_s
Bertl: Sensors should fall apart near the edges of the sensitivity ranges. There is likely a good test there for sampling the color primaries as which values to toss out.
22:00
Bertl
i.e. the light hits the paper at an angle, which affects the intensity seen from the camera proporional to the cosine of the angle between light source and normal
22:00
troy_s
Hrm?
22:01
Bertl
think about it like this, if you hit a unit square from the top, it will be well illuminated
22:01
troy_s
Gosh that wikipedia article uses the word luminance for perceptual lightness / brightness. Yuck.
22:02
troy_s
(Luminance strictly means the radiometrically correct value (Y), where luma is the TRC luminance (Y'))
22:02
dmj_nova
ah yes, shading models
22:02
troy_s
Bertl: Gotcha.
22:02
Bertl
so we assume an ideal diffuse paper here, which I think is a good approximation
22:03
troy_s
Bertl: I usually am holding a diffuse meter when using the inverse square... not looking via a spot meter.
22:03
Bertl
and in contrary to our test setup, you are probably pointing it to the light source as well :)
22:03
Bertl
but for the given setup, it has to be accounted :)
22:05
troy_s
Bertl: I am still worried that the test shot of the DVD cover looks TRCd.
22:05
Bertl
so yes, I probably over exposed the color band image
22:05
troy_s
Bertl: Was that image augmented in some way such as exposure or?
22:05
Bertl
no, but the DVD cover was without the IR/UV cutoff
22:06
Bertl
so you are basically seeing a lot of IR as well
22:06
troy_s
Because there is no way in hell that a linear typical image will resolve correctly on an LDR display. (Granted, it is an LDR paper source and jacking the exposure would likely bring it into range)