The color channels are mounted on the outer rim of the optics frame, up to 4 channels can be added to the system. This allows the collection of images for instance in the Red, Green, Blue and a separate Infrared channel for taking simultaneous true and false color images at the same time In order to achieve high quality color separation, each color channel features a separate lens, a CCD-chip and a high performance color based on non-organic material. The color channels have reduced ground resolution compared to the panchromatic channel and the lenses are looking down in central perspective view. A high performance wide angle lens with high opening f/4 and f =25 mm is combined with a 3k x 2k CCD chip. The resulting overlap of the spectral channels(given in grey bold rectangle) and the panchromatic channel (black thinner lines) is illustrated in figure 4. 2.3. CCD Sensors The CCDs are full frame sensors with high optical fill factor and sensitivity and are manufactured by the Philips company in Eindhoven. Pixel size is 12 um x 12 um, offering a high linear dynamic range 12 bit. The architecture of the CCDs offers 4 readout registers on every corner of the chip This provides high readout rates, which is important for a good S/N ratio of the signals and a repetition rate of the system achieving one image every 2 seconds. The front end electronics, generating the CCD control, timing signals and the digital signal read out circuits are placed directly behind the housing in order to ensure low noise performance of the system. Digitizing of the signals is done with 12 bit resolution. The figure shows the 7k*4k CCD-Chip and the front end electronics. The high resolution CCD-chip is packaged into a customized A1203 housing. Special care has been taken in the development of this housing to ensure very high stability of the geometry during pressure (flying height) and temperature variations. Figure 8. 7k 4k CCD-Chip package and front end electronics 2.4. Radiometric Resolution The high sensitivity of a CCD sensor, along with its wide dynamic range, offers distinct radiometric advantages over film material, as it permits markedly higher contrast to be recorded in the image. In urban areas, in particular, this even enables the recording of heavily obscured structures. Whereas a film generally does not provide a dynamic range of much more than 6 to 7 bits, a CCD chip offers 10 to 12 bits