LUPA-1300 Datasheet, PDF (21/48 Pages) Cypress Semiconductor – 1.3 M Pixel High Speed CMOS Image Sensor

LUPA-1300
Datasheet
3.7 Non-destructive readout (NDR)
The sensor can also be read out in a non-destructive way. After a pixel is initially
reset, it can be read multiple times, without resetting. The initial reset level and all
intermediate signals can be recorded. High light levels will saturate the pixels
quickly, but a useful signal is obtained from the early samples. For low light levels,
one has to use the later or latest samples.
time
Figure 10. Principle of non-destructive readout.
Essentially an active pixel array is read multiple times, and reset only once. The
external system intelligence takes care of the interpretation of the data. Table 6
summarizes the advantages and disadvantages of non-destructive readout.
Table 6: Advantages and disadvantages of non-destructive readout.
Advantages
Disadvantages
Low noise – as it is true CDS.
System memory required to record the
reset level and the intermediate samples.
High sensitivity – as the conversion Requires multiples readings of each pixel,
capacitance is kept rather low.
thus higher data throughput.
High dynamic range – as the results Requires system level digital calculations.
includes signal for short and long
integrations times.
3.8 Operation and signaling
One can distinguish the different signals into different groups:
• Power supplies and grounds
• Biasing and analog signals
• Pixel array signals
• Digital signals
• Test signals
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