Image Processing Reference
In-Depth Information
8-channel output CMOS sensor, respectively. There is an example of a CMOS sensor with
128 channel parallel outputs
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by 64 channel outputs at the top and bottom, respectively. It
should be considered that fixed-pattern noise is apt to be caused as output differences due
to the variation of the output channel characteristics independent of the sensor type, and
countermeasures are necessary.
7.3.1.2 Column-Parallel ADC-Type Sensor
This type of sensor is described in detail in Section 5.3.3.2.2. As mentioned there, various types
of column converter ADC sensors are reported and a high-rate output performance of gigapix-
els per second is achieved. Continuous progress is expected in accordance with its applications.
7.3.1.3 Burst-Type Sensor
All the sensors described thus far have continuous output with continuous capturing. In con-
trast, in a burst-type sensor, on-chip frame memories are equipped to store captured image
signal charges for giving priority to higher frame rate by avoiding output operation at each
frame, which needs driving and output time. The first one is burst CCD,
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proposed in 1996.
A two-by-two pixel configuration is shown in Figure 7.9; signal charges generated in the
PD are collected and stored in the potential well under the G1 gate. They are transferred in
series into the serial-parallel register of the pixel to detect successive frames by way of the G3
gate channel. The signal charges of the following frame are also transferred into the serial-
parallel register. After the serial-parallel register is filled with the signals of five frames,
the charge signals are transferred in parallel from the serial-parallel register to the parallel
Serial-parallel register
Parallel register
D
G2
G1
G3
D
G2
G1
G3
PD-11
PD-12
D
G2
G1
G3
D
G2
G1
G3
PD-21
PD-22
Output serial register
Output
FIGURE 7.9
Pixel configuration of burst-type CCD (serial-parallel memory).
