Nondestructive/destructive readout

Figure 14. The measuring sequence for combined nondestructive/destructive readout. In nondestructive mode the sequence is cycled as many times as desired to improve signal-to-noise. (Reproduced with permission from Ref. 26. Copyright 1981, J. Auto.

Several methods to avoid destructive readout using fluorescence or infrared absorption as readout signals have been proposed. The fluorescence intensity change between the open- and closed-ring isomers makes it possible to use the change as the readout signal. When the fluorescence can be detected without influencing the ratio of the two isomers, the readout method becomes nondestructive. 

H we compare this method to simple shift and add using destructive readout and double correlated sampling, the advantage is a factor of 3 in speed. Whereas destructive double correlated sampling requires a readout, a reset and a second readout of the pixel intensity, nondestructive readout requires only one readout. Li order to obtain double correlated sampling the previoTis nondestructive readout is subtracted from the current readout. 

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