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04:15 | Bertl | off to bed now ... have a good one everyone!
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08:04 | dmj_nova1 | wow that meeting is early
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09:41 | PhilippeJ | Bertl, Hello !, I got a message form Gabe, he will send me what he curently has in term of dng conversion code (python script)
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10:47 | FergusL | cool ! could I see it ? if he's ok
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11:19 | Bertl | morning everyone!
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11:19 | Sasha_C | Morning Bertl
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11:40 | troy_s_ | changed nick to: troy_s
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11:42 | troy_s | FergusL: Answering white balance... if you think of a device referred image as a volume of color points floating in space, the transform (either XYZ scaling, Von Kries, or Bradford) transforms the original point to the new point - stretching / bending the volume such that the values represent the color under the new white.
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11:44 | troy_s | FergusL: It isn't quite this simple when we get into the psychophysical domain as phenomenon happen. Lower luminance levels for example, hand off the color receptors to the monochromatic ones (so your eyes see less to no color at lower luminance) and
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11:44 | troy_s | FergusL: ...metamerism phenomenon where your brain makes up the color seen.
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11:44 | troy_s | etc.
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11:45 | troy_s | eg FergusL - http://wiki.blender.org/index.php/File:Orange.gif
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11:45 | troy_s | Local contrast makes your brain interpret identical values differently
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11:46 | troy_s | (tied to how your brain interprets the scene)
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11:47 | Bertl | well, isn't that more like this one: http://www.businessballs.com/images/shadow-illusion.jpg
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11:47 | troy_s | and this http://wiki.blender.org/uploads/b/b2/Grey-cube-color-squares.jpg
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11:47 | troy_s | where the blue squares on left and yellow squares on right are actually achromatic values
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11:48 | troy_s | http://wiki.blender.org/uploads/thumb/2/2b/Grey-cube-squares.jpg/800px-Grey-cube-squares.jpg
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11:48 | troy_s | Bertl: Yes indeed. Different phenomenon however I believe
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11:49 | troy_s | Bertl: and culture influences perception as well (see Herskavits et al)
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11:49 | troy_s | I believe Mark Fairchild lists all the psychophysical phenomenon in his CIECAM02 paper.
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11:53 | Bertl | in the color squares, the funny part is that the yellow and blue squares are actually the _same_ gray :)
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12:00 | FergusL | http://wiki.blender.org/index.php/User:Sobotka/Color_Management the cyan/green "confusion" is impressive there
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12:05 | FergusL | troy_s: "device referred image" == still bound to the limits of the device space ?
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12:08 | FergusL | I think I get it about white balance it's again a transform
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12:58 | troy_s | FergusL: Display / Device / Output referred - 0 to max (eg sRGB display)
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12:59 | troy_s | FergusL: Scene referred = 0 to theoretical infinity, linear relation.
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12:59 | FergusL | yes
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13:00 | FergusL | shall I think about white balance in an image as : One white reference point (moved around in XYZ with transforms) and all other values in the image relative to this reference ?
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13:31 | troy_s | FergusL: More or less a good summary from the data side.
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13:32 | troy_s | (and remember, not all transforms for white point are equal - Bradford etc.)
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13:39 | FergusL | troy_s: in what aren't they equal ? quality ? or simply the result ?
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13:55 | troy_s | FergusL: 'quality' of the transform.
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13:55 | FergusL | ok
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13:56 | troy_s | Bertl: And to answer your earlier question: I believe profiling the sensor is a prudent choice to at least get a sense of the color gamut and latitude. I wouldn't publish the results, but it is important stuffs for a camera aimed at cinema crafting.
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13:57 | FergusL | why wouldn't you publish the results ?
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13:57 | troy_s | Bertl: The folks that have a hope of being interested in such a device will be deadly interested in the color gamut and latitude. (Namely director of photography archetypes.)
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13:58 | troy_s | FergusL: Because it is too early and likely not 100% optimal / controlled. It would be a great point of reference for development however.
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13:58 | Bertl | well, I don't think there is any reason to hide or hold back information in this regard
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13:59 | FergusL | troy_s: but releasing double checked info with the proper tool later is a good thing, right ? that's what I would do
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13:59 | Bertl | we are not producing/selling the sensor, and if we find out that this specific sensor is not suitable, we simply switch to a different one
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13:59 | FergusL | ^ good to hear
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13:59 | troy_s | Bertl: I wouldn't suggest that either. Merely provide ample caveats and not offer an "official" publish of the results. A simple "additional information".
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13:59 | Bertl | and if somebody misinterprets development results as 'that's how the final image will look like' then they should stay away from development :)
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14:00 | troy_s | And exactly - it would be one more piece of information to see if the sensor is suitable for imaging.
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14:00 | Bertl | we are currently testing with a 'known broken' sensor :)
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14:01 | Bertl | still your 'answer' didn't really answer my question
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14:01 | Bertl | (which basically was: is it worth to do stills of the IT8 chart with known insufficient lighting)
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14:03 | Bertl | we will, for sure, make those images once the prototype is mobile and can be used by sebastian and friends for actual testing
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14:04 | troy_s | Bertl: I think a consistent tungsten image at a few white balance points (tickle registers for this?) would be a magnitude better than where it currently is.
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14:05 | Bertl | regarding publishing findings: I don't think there is any point for us to fund and build a camera which doesn't do what we want :)
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14:06 | Bertl | so if the sensor is insufficient or has bad color rendition, it helps to know that early, because we can save the time and spend it on something more productive
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14:17 | Bertl | off for now ... bbl
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15:19 | se6astian | good evening
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15:23 | FergusL | hello se6astian
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15:45 | se6astian | I just sent the purchase order for the sensor to Cmosis
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16:01 | se6astian | I scheduled a team meeting for Monday the 11th at 12 PM GMT here on IRC, please join us at the time
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16:02 | se6astian | the association general assembly will start 2 hours later at 2PM
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16:03 | se6astian | sorry the meeting is at 12 AM GMT (noon)
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16:20 | FergusL | se6astian: a working one for Bertl ?
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16:23 | se6astian | yes
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17:02 | rexbron | sup troy_s
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17:06 | rexbron | You guys got some coverage over on redshark
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17:11 | se6astian | hi rexbron, yes three articles in the last month :)
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17:49 | troy_s | rexbron: !
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17:50 | troy_s | Bertl: Exactly.
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18:02 | Bertl | back now ...
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19:24 | Bertl | off for a nap ... bbl
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21:15 | se6astian | time for bed
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21:15 | se6astian | goog night!
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