kac-9617 ETC-unknow, kac-9617 Datasheet - Page 17

• Manufacturer Part Number: kac-9617
• Description: Kodak Kac-9617 Cmos Image Sensor
• Manufacturer: ETC-unknow

IMAGE SENSOR SOLUTIONS
Functional Description
5.5
In some cases it is desirable to reduce the time during which the
pixels in the array are allowed to integrate incident light without
changing the frame rate.
This is known as Partial Fame Integration and can be achieved
by resetting pixels in a given row ahead of the row being
selected for readout as shown in Figure 20. The number of Hclk
clocks required to process a partial frame is given by:
Where:
The Integration time is subject to the following limits:
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Progressive Scan
Interlace
Sub-Sampled
RN
I
time
Row n
Partial Frame Integration
Hclk
Mode
is the number of Hclk clock cycles required to
process & shift out one row of pixels.
is the number of rows ahead of the current row
to be reset. (See the Integration Time High and
Low registers).
New I
of the first frame after the UpdateSettings bit is
set in the UPDATE register.
Frame
Delay
FP
time
Hclk
values only take effect at the beginning
= RN
Row 0
I
I
I
time
time
time
Hclk *
<= SWN
<= 2* (SWN
<= 0.5 * (SWN
Row 1
I
(continued)
time
Programmable Row Delay
Programmable Row Delay
rows +
Limit
Figure 20. Partial and Full Frame Integration
rows +
F
rows +
Row 2
delay
F
delay
F
delay
)
)
Partial Frame Integration
Full Frame integration
Full Integration Time
17
Frame N
Row x
Row CDS, Reset Row x+∆ & Shift
Row CDS, Reset Row x & Shift
5.6
The electro-optic transfer curve of the pixel array is linear. While
a linear response is satisfactory for capturing images containing
similar brightness levels, it is not always satisfactory for captur-
ing images with a large variation of brightness levels.
For a fixed integration time, pixels capturing bright areas of a
scene will saturate much faster than pixels capturing darker
regions. When there is a large variation in the light intensities
between the dark and light regions it is not possible to simulta-
neously capture the detail in both regions. One would have to be
sacrificed.
Since the response of the human eye to light is non-linear, a
non- linear response such as that shown with the dashed curve
in figure 21 would allow the detail in both the light and dark
regions of the image to be captured and seen.
The timing and control circuit built into the KAC-9617 allows the
linear response of the electro-optic response to be modified into
a piece-wise linear response (approximate gamma)
Partial Integration
Figure 21. Linear & Non Linear Transfer Responses
Modification of Linear Response Curve
Time
BP1
Row x+∆ Row n
Saturation level
BP2
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Frame
Delay
Illumination (Lux)
Row 0