Cooling the CCD and reading it out slowly dramatically reduces the noise level but has no effect on the maximum signal that the CCD can store. The grading of a CCD relates to the number of defects present in its structure. These defects occur during the manufacturing process and manifest themselves as small blemishes in images recorded by the system. Contact Pix Cellent for more details about these CCDs. The accompanying table gives information regarding the quality of the CCDs offered by Pix Cellent .
Clusters are a grouping of adjacent pixel defects.
Columns are a grouping of pixel defects along a single column. It is important to appreciate that each CCD manufacturer uses a different scheme for specifying and counting defects in a CCD so the figures given in the table are not quite as directly comparable as they might appear. A great variety of pixel numbers, pixel sizes and sensitivities are available. Please refer to the Imaging system selection guide to help you choose the best device for your application. The graphs with the CCD data sheets show the spectral response curves produced by a few of the CCDs offered by Pix Cellent .