ACS-I1024-CPGA Photon Vision Systems, Inc., ACS-I1024-CPGA Datasheet - Page 18

• Manufacturer Part Number: ACS-I1024-CPGA
• Description: High Performance Area CMOS Image Sensor
• Manufacturer: Photon Vision Systems, Inc.

continued signal accumulation for optimal image contrast. The “sensing” of the pixel signal is a key advantage over
CCDs.
Electronic shutter allows video to be temporarily stored on the Hold capacitor. The sequence starts with the Hold FET
and the Reset FET turned “on” to bias both the Hold capacitor and the pixel to the same level. The Reset FET and the
Hold FET are turned “off”. The pixel is allowed to integrate. The Hold FET is selected, the video on the pixel is
sampled, and the Hold FET is turned “off” or deselected. When the row is selected for reading, the Row FET is
selected and the stored video is read. Then, the Rest FET and Hold FET are selected, re-biasing the pixel to the reset
value and both are turned off. The rest value is sampled and subtracted for pattern noise free video.
The “Adaptive Exposure Control” method describes Non Destructive Read Out ( NDRO) for ACS sensors. The pixels
are biased to the reset value by selecting and deselecting the Hold FET and Reset FET as previously described. The
pixels are allowed to integrate. The Hold FET is selected and deselected for sampling the pixel value. The value is
read for optimal signal levels. If more integration is desired the pixels are allowed to integrate longer and pixel value
is re-sampled by selecting and deselecting the Hold FET. When the desired signal level has been achieved, a row is
selected for reading by selecting the Select FET and sampling the video by selecting and deselecting the Hold FET.
The Hold and Bias FETs are then Selected and deselected to re-bias the pixels the reset value and the back ground.
These are the standard methods allowed and controlled internally by the ACS sensors series. If the imager is operated
in the slave mode, greater operator control allows more flexibility, to minimize the number of operations performed
per frame of Video and potentially reduce the associated noise generated.
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Photon Vision Systems, Inc. 1999, 2000
Product DATASHEET ACS-I XXX Rev. 10/31/00 Subject to change without notice. Page 18 of 26
PRELIMINARY