Noise fixed pattern

Because the spatial area with higher temperature on the catalyst surface of one of the samples of the library is very small the detection of catalytic activities through temperature measurement cannot be carried out by direct temperature measurements but only by non-contact methods such as pyrometry or IRT. The IR video camera used here measures the emission at every point of the library in parallel. The detector consists of a 256x256 pixel array of Pt-silicide-IR-sensors. Each pixel delivers a voltage-signal that depends on the infrared radiation and the sensitivity of that pixel (fixed pattern noise). 

Figures 14-18 are examples of the computer plots of selected data. These spectra have had dark current and fixed pattern noise subtracted "on-the-fly". (Both of these items are inherent in PDA s, the correction for which represents trivial implementation in terms of software and hardware). In some of the printouts, the individual diode levels can be seen representing 25 urn spatial resolution across the focal plane. The ordinate is quantified to only 12 bits while the PDA s themselves have a dynamic range of 14 bits. This was done for expediencey only.

The CID-11 is a multiplexed device having two separate video outputs. The multiplexer switching signal couples into the video outputs in such a way as to introduce a fixed pattern signal (also referred to as "fixed pattern noise") which is easily corrected (9). Fixed pattern signal subtraction is accomplished as follows ... 

The first one is a coded mask telescope of 1.5m length. The mask would have a size of 70 X 70cm and elements of 1X Imm. A detector of 35 X 35cm would be needed, consisting of 36 XMM CCD wafers, to provide a field of view of 24°. In order to use it for continuous scanning, a new reconstruction method has been developed (direct backprojection of each photon) which very effectively smoothes the fixed pattern noise. The scientific requirements are met very well, in particular at the high energy part of the band, for X-... 

DB Chase. Raman spectroscopy from the laboratory to the process Orientation studies of polymeric fibers under draw—Fixed pattern noise in CCD detection. In SA Asher, PB Stein, eds. Proceedings of the XVth International Conference on Raman Spectroscopy. Chichester Wiley, 1996, pp 1072-1073. 

The effect of ambient lighting, another source of fixed pattern noise, on tissue Raman spectra should also be considered. 

An often neglected source of fixed pattern noise is that caused by instrument alignment and calibration errors. Unwanted information about the performance of the Raman instrument is added to the Raman spectrum. Calibration drift errors should therefore also be considered. 

Imagers, both infrared and visible, must produce pictures that are acceptable to the human eye, and are not typically used to collect scientific dafa. Imagers are very tolerant of global and low spatial frequency offsets. They are not, however, tolerant to low-level salt and pepper variations and fixed pattern noise across an image. 

Figure 7.23 Nonuniformity of the nonlinearity of pixels can cause fixed pattern noise, or streaking, at flux points between the calibration points.

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