National Physical Laboratory (NPL), the UK national measurement institute. We discuss the measurement procedure in depth along with the setup of the system in our paper.
The novelty of this approach arises from the fact that we report the measured spectral sensitivities along with the measurement uncertainties. The stated uncertainty values are a combination of camera and calibration uncertainties and are reported per measured wavelength. These values help us understand how close the measured sensitivity values are to the actual camera sensor sensitivity functions. To our knowledge this detailed uncertainty evaluation has not been addressed in other camera calibration methodologies reported in the literature. Prior calibration procedures discussed in the literature follow a much simpler set up, with less controlled conditions that may be easier and faster in practice. The downside of their approach is that they are not in control of the variations and errors of the system and so cannot report the uncertainty of their recovery. One of the motivations for our detailed uncertainty driven approach is that we wish to provide the community with an accurate measured dataset to aid the development of algorithms for spectral sensitivity estimation.
This subject has been published in The Journal of Optical Society of America which can be found here. Also, You can download the paper submitted to Color Imaging Conference here. You can also view the presented poster at this conference.
The measured spectral sensitivity functions from National Physical Laboratory of London are available for download below.