A spectral imaging system is presented where the color information of an original image is separated by a diffraction grating. The grating is applied on a micro mirror, which is actuated by a fluctuated electrostatic field causing a high frequency oscillation of the device. Due to the vibration different spectral intervals of the diffracted light can be detected by a CCD-line. Altogether 35 spectral intervals in a range between 400 to 740 nm are recorded.The used diffraction gratings are manufactured using three different processes. Besides the classical mechanical scribing of gratings, also standard methods of micro technologies are used like dry and wet etching. The applicability of these gratings depends from their optical properties. Therefore the measurements and their results of the important optical parameters for each grating type are presented.Especially the quality of the spectral reproduction process influences the color accuracy of the presented image capture device (ICD). Therefore spectral properties of an original are measured with the ICD. These characteristics are compared with the spectral properties measured by a spectrometer. Finally a colorimetric characterization of the ICD is done. The color accuracy is evaluated and the size of the color space depending from the different grating types is shown.
Martin Flaspöhler, Andreas Willert, Arved C. Hübler, "Optical and Colorimetric Characterization of a Micro Mirror Based Spectral Image Capturing System" in Proc. IS&T CGIV 2004 Second European Conf. on Colour in Graphics, Imaging, and Vision, 2004, pp 213 - 218, https://doi.org/10.2352/CGIV.2004.2.1.art00044