Multispectral Image Capturing System Based on a Micro Mirror Device with a Diffraction Grating.

Although the color reproduction of RGB-based image capturing systems is sufficient for many tasks, there are some critical color matching applications like digitizing of high quality illustrated books, artwork imaging or catalogue selling. Due to the known theoretical limitations of RGB-techniques, multi-channel methods of image capture have been introduced in the recent years, typically based on a multitude of color filters. In this paper 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 an 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. As a first step 35 different spectral intervals of each pixel are measured. The gamut of the resulting color space compared to standard RGB-based image capturing systems is shown. Finally, experimental results are discussed dealing with the limits of resolution of this micro mirror based multispectral device.