[argyllcms] Re: [argyllcms] lookup table based profiles
- From: Nikolay Pokhilchenko <nikolay_po@xxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Thu, 06 Oct 2011 18:46:04 +0400
Khan Gul wrote:
I am experimenting with generating lookup table based ICC profiles.
I know it is a difficult task but I want to generate simple lookup tables.
I have the following queries regarding this.
1- What is the purpose of input and output curves in AToB0 and AToB1 Tags
(lut16type)?This curves helps to oprimize the transfer of device data into the
LUT and LUT data into PCS values. Input curves usualy accounts device
non-linearity and even more, optmizes the link between LUT and device data.
Such optimisation increases the precision of LUT operation. So, the input and
output curves can be realated to TRC of the device or to device linearization
but they not obliged to.
2- Are the input curves used for gray balancing ? Can you devise how can I
experiment for this purpose.You can use curves for any purposes. Input curves
modify the data before sending them to the LUT. Output curves modifys the data
after the LUT, before profile output.
3- I generated CLUT for AToB1 by measurements, chromatic adaption to D50,
normalizing and converting to fixed point.
How can I generate similar for BToA1 (the reverse, XYZ to RGB) ? I think it
is not simple inverse.Yes. The computing of reverse XYZ->RGB LUT spents the
most of computing power.
Other related posts:
- » [argyllcms] Re: [argyllcms] lookup table based profiles - Nikolay Pokhilchenko
