Colour conversion matrices - Tutorial by Andy Rowlands

[alanr0]

Given the recent posts on colour conversion topics, this tutorial from Andy Rowlands might be of interest.

Not my area of expertise, but at first glance it looks like a useful introduction.

https://www.spiedigitallibrary.org/...ras-a-tutorial/10.1117/1.OE.59.11.110801.full

Open access, with the option for a PDF download.

Rowlands' "Physics of Digital Photography" was discussed here, along with his treatment of equivalence theory from 2018.

--
Alan Robinson

 

[Jack Hogan]

Nice to see such information collected in one place.

 

[J A C S]

Thank you for posting this.

I did not read the whole paper, just a remark on what I see on pp. 8-9 there. A variation of the standardized method B of ISO 17321-1 there involves (1) computing a color matrix T by eq. (14) which is a standard way to find an approximate solution of a system which may not be even solvable (least squares) and (2) optimize T by minimizing ΔE using the nonlinear optimization technique recommended by ISO 17321-1. The latter publication is behind a paywall and my university does not seem to be subscribed.

One may wonder if the optimization above is done with a good choice of an L^2 product. On the other hand, (2) probably takes care of this.

 

[alanr0]

Thank you for posting this.

I did not read the whole paper, just a remark on what I see on pp. 8-9 there. A variation of the standardized method B of ISO 17321-1 there involves (1) computing a color matrix T by eq. (14) which is a standard way to find an approximate solution of a system which may not be even solvable (least squares) and (2) optimize T by minimizing ΔE using the nonlinear optimization technique recommended by ISO 17321-1. The latter publication is behind a paywall and my university does not seem to be subscribed.

One may wonder if the optimization above is done with a good choice of an L^2 product. On the other hand, (2) probably takes care of this.

I don't have any more details of the ISO 17321-1standard.

FWIW, Keith Borrino (GoPro, with co-authors from Rochester Institute of Technology) has published a sensitivity analysis comparing the results of the test chart based method and the spectral characterisation method from ISO 17321-1.

https://www.researchgate.net/publication/313232184_Sensitivity_analysis_applied_to_ISO_recommended_camera_color_calibration_methods_to_determine_how_much_of_an_advantage_if_any_does_spectral_characterization_of_the_camera_offer_over_the_chart-based_ap