Designing Color Filters that Make Cameras MoreColorimetric

03/27/2020
by   Graham D. Finlayson, et al.
0

When we place a colored filter in front of a camera the effective camera response functions are equal to the given camera spectral sensitivities multiplied by the filter spectral transmittance. In this paper, we solve for the filter which returns the modified sensitivities as close to being a linear transformation from the color matching functions of human visual system as possible. When this linearity condition - sometimes called the Luther condition - is approximately met, the `camera+filter' system can be used for accurate color measurement. Then, we reformulate our filter design optimisation for making the sensor responses as close to the CIEXYZ tristimulus values as possible given the knowledge of real measured surfaces and illuminants spectra data. This data-driven method in turn is extended to incorporate constraints on the filter (smoothness and bounded transmission). Also, because how the optimisation is initialised is shown to impact on the performance of the solved-for filters, a multi-initialisation optimisation is developed. Experiments demonstrate that, by taking pictures through our optimised color filters we can make cameras significantly more colorimetric.

READ FULL TEXT
research
04/26/2020

Designing a physically-feasible colour filter to make a camera more colorimetric

Previously, a method has been developed to find the best colour filter f...
research
05/13/2020

Designing a Color Filter via Optimization of Vora-Value for Making a Camera more Colorimetric

The Luther condition states that if the spectral sensitivity responses o...
research
06/24/2020

Unifying Optimization Methods for Color Filter Design

Through optimization we can solve for a filter that when the camera view...
research
11/06/2018

Embedded polarizing filters to separate diffuse and specular reflection

Polarizing filters provide a powerful way to separate diffuse and specul...
research
04/28/2022

Inverse-Designed Meta-Optics with Spectral-Spatial Engineered Response to Mimic Color Perception

Meta-optics have rapidly become a major research field within the optics...
research
03/26/2021

Tuning IR-cut Filter for Illumination-aware Spectral Reconstruction from RGB

To reconstruct spectral signals from multi-channel observations, in part...
research
10/07/2021

Direct design of biquad filter cascades with deep learning by sampling random polynomials

Designing infinite impulse response filters to match an arbitrary magnit...

Please sign up or login with your details

Forgot password? Click here to reset