KelSolaar on lut_inversion
Improve LUT inversion support. (compare)
KelSolaar on lut_inversion
Improve LUT inversion support. (compare)
KelSolaar on develop
Ensure that chromatic adaptatio… Fix example in "colour.contrast… Code formatting. and 1 more (compare)
KelSolaar on v0.4.0
Code formatting. (compare)
KelSolaar on v0.4.0
Fix example in "colour.contrast… (compare)
KelSolaar on v0.4.0
Update "requirements.txt" file. Merge branch 'feature/v0.4.0' i… Add Saransh Chopra (@Saransh-cp… and 4 more (compare)
Hi Dani!
Concluding from the documentation, does those function take samples of colours and trying to interpolating the colours to create 3D LUT?
Not quite, depending on the variant they either do a linear transformation via a 3x3 matrix that wil rotate and scale the colours to the best fit, or do something similar but using a 3xn polynomial to distort the space to the best fit
eotf_sRGB
to decode
>>> colour.models.eotf_sRGB(colour.utilities.as_float_array([122, 122, 122]) / 255)
array([ 0.19461783, 0.19461783, 0.19461783])
thanks,
yeah, I also got to that conclusion after seeing examples and comments from different places.
I ended up just using the reference colors from 'colour' since I could see my x-rite chart was from January 2014:
D65 = colour.CCS_ILLUMINANTS['CIE 1931 2 Degree Standard Observer']['D65']
REFERENCE_COLOUR_CHECKER = colour.CCS_COLOURCHECKERS['ColorChecker24 - Before November 2014']
REFERENCE_SWATCHES = colour.XYZ_to_RGB(
colour.xyY_to_XYZ(list(REFERENCE_COLOUR_CHECKER.data.values())),
REFERENCE_COLOUR_CHECKER.illuminant, D65,
colour.RGB_COLOURSPACES['sRGB'].matrix_XYZ_to_RGB)
Based on the example from https://github.com/colour-science/colour-checker-detection/blob/develop/colour_checker_detection/examples/examples_detection.ipynb
I also tried converting the reference I previously had from X-rite by doing what you said (I had also tried the cctf_decoding()/encoding() as in the example above) and I could see that the values where quite close but not really an exact match...
Is that because of all the colorspace conversions (xyY->XYZ->RGB)?
read_spectral_data_from_csv_file
. Are there any other types other than sekonic and UPRTek that were already implemented that I can have a look at? If not, where should I fit the new parser?
it is indoors sports the illumination won't change, so I expected that doing the calibration once (like I already do for white balance and exposure) would work...
Yes! This is almost the ideal scenario, ideally you would sample the illumination with a spectrometer, e.g. Sekonic C7000, measure the chart reflectances with another one, e.g. X-Rite I1 Pro, from there you could generate the reference chart values under the illumination of the location and calibrate the camera against that.