[argyllcms] Re: "gamma key" Re: Photocamera calibration questions
- From: Magnus Wallden <magnus.wallden@xxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Mon, 23 May 2011 21:04:15 +0200
Hi !
I trust You, I think I dont need it.
That QP-program works direct from the RAW-file, not from a tif or jpg.
//Magnus
2011/5/23 <yan@xxxxxxxxxxxxxxxxx>
> On Mon, 23 May 2011 12:16:31 +0200, Magnus Wallden wrote:
>
>
>
> Of course, there are a lot of profiling tools. You could use any tool
> suitable for scanner.
>
> By "only one" I mean the only one, that could give normal result, not
> always ideal, but usable. I use them in photography.
>
> I have tried dcp2icc, with colorchecker passport software.
>
> Yes, it possible with dcp2icc utility to make matrix profile and convert
> it to table .icc profile. Why not simple "matrix to matrix" solution? I
> don't know, ask the author.
>
> The result of this conversion is ugly, I could send you an example if you
> want to chek yourself :-)
>
>
>
> Hi !
>
> Not the only one, qpcard202 whit sw, this gives as result an dcp file, and
> it is
> possible to convert this to an icc whit dcp2icc.
>
> http://www.qpcard.se/BizPart.aspx?tabId=31&prod=8&catId=1&tci=151
> http://dcp2icc.sourceforge.net/
>
> //Magnus
>
>
>
>
>
> 2011/5/23 <yan@xxxxxxxxxxxxxxxxx>
>
>> Hello! This would be answer to question 1
>>
>>
>>
>> I understood, that coolproof is not the ideal tool to create profiles
>> from raw sensor. In fact, it's the only one.
>>
>> When you write "by hand" you mean, that I need to write another tool by
>> myself. Of course, it's kind of an aswer :-) But this is rather hard thing.
>> And, on the other hand, I think that only slighter code changes are needed.
>>
>> Coolproof in matrix+gamma mode reads ".ti3" values and try to
>>
>> 1. Guess gamma values;
>>
>> 2. Find matrix for this gamma.
>>
>> The only key I need is "not to guess gamma upon ti3 values, and assume
>> gamma is [some value]". The linearity of camera sensor is quite a good
>> assumption. By analizing this or that real data you get "gamma 2.18" or
>> "gamma 2.21", and this number would be not exactly 2.2 only beacause of
>> camera noise.
>>
>>
>>
>> yan@xxxxxxxxxxxxxxxxx wrote:
>>
>>
>> 1. IS IT POSSIBLE TO SET "GAMMA 2.2" IN INPUT FOR
>> COLPROF UTILITY SOMEHOW, NOT BY MAKING A LOT OF "AUXILIARY COLOR
>> CHARTS"?
>>
>>
>> Hi,
>> I'm not quite sure what you mean by this. colorprof creates a profile
>> that represents the behaviour of the device as sampled by the .ti3 values.
>> You can't "force" the profile model and expect it to be a good fit to the
>> samples.
>> There is no point in doing such a thing - the whole purpose of a profile is
>> to
>> represent the color behaviour of the device.
>>
>> colprof is not the ideal tool to create profiles from raw sensor
>> data that's been converted to samples, since it is doing a "best fit".
>> You are probably better off creating a matrix and curve model "by hand".
>> Note that you (ideally) need both the spectral sensitivity data, and the
>> response data for each sensor. The curves should then translate the sensor
>> responses to linear light, and the matrix convert to XYZ space
>>
>>
>>
>> Graeme Gill.
>>
>>
>>
>>
>
>
>
>
> --
>
> Magnus Wallden
> Klockarevägen 29
> 331 52 Värnamo
>
> +46 (0) 370 10478
> +46 (0)703 33 45 19
> magnus.wallden@xxxxxxxxx
>
>
>
--
Magnus Wallden
Klockarevägen 29
331 52 Värnamo
+46 (0) 370 10478
+46 (0)703 33 45 19
magnus.wallden@xxxxxxxxx
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