SpectroCAL MKII is an affordable, high-performance reference spectroradiometer for vision scientists. The instrument has a cross-platform USB interface and is designed to make it extremely simple to measure the Spectral Power Distribution of computer display devices like CRT and LCD monitors over an extended range (350nm-1000nm). The supplied CRS Colour Toolbox for MATLAB provides all the necessary tools for a working in a wide variety of colorimetric and physiological based color spaces.

Unlike a colorimeter, the instrument does not use filters to approximate colour matching functions, so it can make extremely accurate colorimetric measurements such as luminance and chromaticity over the entire spectrum, even of narrow band sources. SpectroCAL does this by accurately measuring the spectral power distribution of the light source and calculating the appropriate value. A wide range of standard measurements can be made using routines provided by the CRS Colour Toolbox for MATLAB.

The compact instrument uses an innovative laser system to project a circular target that defines the area being measured. This novel point-and-measure feature allows extremely rapid and accurate alignment of the instrument with the display.

The SpectroCAL Measurement Control Panel initialises and automatically controls all the parameters of the spectroradiometer, including the exposure time. Just align the SpectroCAL with the display and a single click is all that is required to make and display a measurement of spectral radiance, luminance and chromaticity. The radiance measurements of each phosphor can be exported directly to the MATLAB workspace for subsequent visualisation and manipulation by the CRS Colour Toolbox for MATLAB, or your own routines.

The CRS Colour Toolbox for MATLAB provides a plethora of functions for scientists interested in light and colour. The colorimetry tools provide support for almost all known CIE colour measurement standards, while the vision science tools are especially designed to simplify the use of physiologically based colour spaces (e.g. SML, DKL). Not only are routines provided to make measurements, but also to precisely define colour parameters for visual displays. The tools are fully compatible with the ViSaGe, Bits#, Bits++ and the popular PsychToolbox.

Of course SpectroCAL is not limited to measuring just display devices. The instrument can be used to measure the luminance and radiance of any extended source. The supplied cosine filter allows direct measurements of illuminance and irradiance. The uniquely compact form factor makes it ideal for applications in the field: a laptop and the SpectroCAL can be conveniently carried in a small briefcase.

Useful Information

The Color FAQ

The Light Measurement Handbook