Automated spectroradiometer applying computer analysis of spectral data.

An automated scanning spectroradiometer has been constructed for the measurement of color-vision test stimuli and various types of luminescence. A Jarrell-Ash 0.25-n, f/3.6 Ebert type monochromator is employed in combination with photoelectric detection. Recorder and paper tape data output have been provided. Processing of the spectral information is performed by a CDC 3300 computer. The spectral sweep range can easily be set by electromechanical registers, as can the number of required sweeps. Photon numbers are integrated by the counter over 5-nm blocks, and this procedure sets the limit of resolution. The spectral range is between 250 nm and 800 nm. By computer several spectra can be added when they are faint. Mean spectra are listed and plotted. Smoothing can be performed for spectra where noise is predominant. A novel method of correction by computer has been introduced to get rid of stray-light and grating ghosts in the monochromator. A program has been written for colorimetric analyses of light sources, spectral filters, and pigmented surfaces. The dominant wavelength and the excitation purity are computed and given in CIE chromaticity coordinates.