#apertus IRC Channel Logs

so I am not sure, what the problem with longer exposures is then

hmm

currently it counts any two frames that have consecutive frame counts, equal wrsel (in the first corner) and one of them having 0xAA as marker and the other 0x55 as marker as a valid frame pair

well, in that case it should be fine

s/evet/even/

especially if 20ms already works

i.e. duplicates from the same exposure

yeah

but it seemingly doesn't work atall currently, which is confusing

but it should be easy to verify, as we have time calculations in both directions in the snap

Good day

Vup, temperature relationship would be very much worth researching further, your chart shows that noise level dip for 5ms which first puzzled me, but then I realized I did these exposure times first when the sensor was still cooler I assume

yeah

IIRC the on chip sensor temperature of the cmv12000 is in degrees celsius but relative without absolute reference correct?

there are a few in powerboard and zynq IIRC

yes, you want to do a one or better two point calibration for the sensor temperature readings (per sensor)

Well for now just comparing them relative to each other should be enough right?

yeah, nice

https://github.com/rroohhh/cmv12k_color_science ?

let me transfer the repo to the apertus org

se6astian: done https://github.com/apertus-open-source-cinema/cmv12k_color_science

done

welcome! :D

off for dinner now, bbs

good to have you back! :D

yes :)

though I would say we are still at the beginning

(genuine question)

Specifically, on the colour front, we have to ask “What is the goal?”

Oh they will all have challenges.

In the end, it is what it is.

Did anyone ever get the spectral response of the sensor?

That’s uh… about 100 years of research that few retread over.

I’m sure this channel has seen the ridiculous rubbish that happens when someone chases electronics in search of meaning.

It’s worth breaking out a series of data states, and trying to draw lines to meaning.

Folks really struggle with colour here because there are various states of “colour”, and various stages where facets of that “colour” hold different and important considerations.

(Huge gap, and then layer on dozens of more confusing things around the broader ideas of “colour”. Sadly, with the gap, folks also simply forgot or lost the actual research in this domain from the sort of companies like Fuji and Kodak. Hundreds of important papers, totally forgotten for reasons that elude me.)

Nope.

there is some docs over here: https://libera.chat/guides/faq#can-i-connect-with-matrix

anuejn[m]: Does this work for notify?

though my handle is only the anuejn part but my irc client matches also anuejn[m]

What is your background anuejn?

with vup I have built the https://wiki.apertus.org/index.php/AXIOM_Micro

Are either of you two familiar with image / colour subjects?

troy_s1: the extend of what I have done is some basic darkframe and flatfield calibration for astro purposes

we (mostly vup is currently working on it) are currently at the stage of figuring out how to get "clean" (that is noise free + linear) images out of the cmv

Oh... well... that's probably good.

That's a reasonable assumption.

Given you may not recognize the name, David MacAdam was one of the Kodak researchers.

You will find that in the annals of history, most of the significant contributions to colour science and image engineering perhaps unsurprisingly came from Kodak and Fuji. Although we suffer a bit of a language gap, and probably some racism, with respect to the latter.

Note that we should desperately avoid conflating terms. For example, don't call the capture at a sensor an "image".

1. A camera observer senses the incoming visible electromagnetic radiation (hopefully only visible... but another topic) through a series of three monochromatic spectral filtration points.

3. The first goal is to derive a standard observer transformation of the camera observer capture.

I'll try to link to related documents that might help flesh it out.

(also I maybe should have mentiond, but I am studying physics, so thats my main background knowledge)

We can fit known values to unknown values, and derive some magical transformation.

1. Use tristimulus to tristimulus comparison fits. That is, take a captured under fixed conditions and treat the RGB as camera observer sensed linear values, and fit them to the known tristimulus values of the standard observer model in question.

Typically folks will jump down the rabbit hole of lookup tables and what not, but a critical thing to typically try to maintain is the notion of exposure invariance. The TL;DR is that most lookup approaches will fail this test, hence why camera observer to standard observer tristimulus formation matrices are purely 3x3.

Ill read this when I am back home and probably have a bunch of questions then.