DVC DVC-1412 - Multi-Spectral Option; Software Issues; Figure 7.10-1: Cooled (Left) and Non-Cooled (Right) Multi-Spectral Cameras

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7.10 MULTI-SPECTRAL OPTION

Figure 7.10-1: Cooled (left) and non-cooled (right) multi-spectral cameras.

A module equipped with a four-position multi-spectral filter wheel is integrated within a modified

monochrome DVC-1412 camera housing (both TE-cooled and non-cooled versions are available).

The filter module, can be supplied with high-quality CLEAR/IR-CUT, RED, GREEN, BLUE

optical filter elements or with special application set. It is designed such that the filter elements

can easily be removed and replaced with the users choice of standard 1” filters. The entire module,

comprising of the wheel, filters, motor and electronics can easily be removed from the camera

housing, to facilitate the use of different multispectral filter sets to match the user’s applications. A

tool is provided to facilitate the removal and replacement of filter elements on the wheel.

The wheel is indexed to the "Home" position, which nominally coincides with the CLEAR/IR-CUT

optical filter. A serial command set is used to step the filter wheel through its four positions, which

place one of the four filter elements in the optical path of the CCD. Once a particular optical filter

is positioned in front of the CCD, the user may invoke any of the camera modes (discussed in this

manual) to set up parameters such as gain, offset, exposure and mode. This allows users to set up

sequential multi-spectral exposures to match the requirements of the application.

7.10.1 Software issues

In R-G-B color applications, three individual color plane images are taken sequentially; these color

plane images are usually superimposed via software to create a high-resolution full-color image.

There are several factors in taking good images with such a sequential system:

7.10.1.1 Image Registration

The images in the three color planes should be precisely aligned; mis-registration of the color

planes will result in image artifacts ranging from loss-of-resolution to mis-aligned edges. The

camera should be firmly clamped in position while the wheel is being moved to prevent mis-

registration.