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Vision Science ProjectNIST has been providing physical measurement standards in photometry and colorimetry over many years, with significant improvements in uncertainties. However, recently, the definitions of photometric and colorimetric units and standards such as the lumen and the V(λ) are increasingly questioned. The discrepancy between measurements and visual perception often reported are one order of magnitude (or more) larger than measurement uncertainties. The units and standards are the basis of physical measurements, and they are based on vision science. To answer these questions, knowledge of vision science as well as physical photometry and colorimetry are required. Such responsibilities to establish or update units and standards have historically been at national laboratories. National Bureau of Standards (former NIST) was once a center of vision science in the world many decades ago and played a key role in the establishment of V(λ) in 1924. But such expertise has been totally lost for many years. Now the world of lighting is changing. The solid state lighting is emerging, and the limitations in existing standards are becoming prominent. The new technologies are requiring new standards. We believed that now is the time for NIST to re-establish vision science program and develop new vision science-based photometric and colorimetric standards to facilitate development of emerging technologies. We received strong support on our plans from the industrial groups and agencies such as NEMA, DOE, FHWA, FAA, as well as CORM. Through a special NIST Director's funding, and with a strong support of Physics Laboratory, the Optical Technology Division is now starting a project "Vision Science as a Basis for Optical Metrology" from FY06. We already have a vision scientist in our staff, and we will develop a state-of-the-art Color Vision Experimental Facility at NIST. The focuses of the project in the first few years will be to develop a new metric for color rendering of light sources (a proposal to replace or supplement CIE Color Rendering Index) and to establish an international standard on effective intensity of flashing lights, both of which are urgent for the industry. We will work closely with the industry and international standardizing bodies such as CIE and ASTM. We plan to develop a real size experimental room with spectrally-tunable light sources using a large number of high power LED clusters at many different peak wavelengths. The sources will simulate spectra of many light sources including traditional lamps and some theoretical spectra such as equal energy, daylight illuminant or blackbody at any temperature, with precise control of chromaticity coordinates. This facility will allow us to perform most systematic and well-controlled vision experiments ever possible in the past. We even plan to have this facility open to researchers outside NIST. We will also build a modern experimental facility for perception of flashing lights. Our future work will include mesopic vision, spectral luminous efficiency functions, and other issues in lighting related to fundamental metrology. Return to Color Rendering of Light Sources For technical information or questions, contact:
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