Princeton Digital (USA) 4411-0062 User Manual
93
Appendix
E
Virtual Chip Mode
Introduction
Virtual Chip mode (a WinView/32 option) is a special fast-acquisition technique that
allows frame rates in excess of 100 fps to be obtained. For the Virtual Chip selection to
be present, it is necessary that:
allows frame rates in excess of 100 fps to be obtained. For the Virtual Chip selection to
be present, it is necessary that:
• the system be a PentaMAX, I-PentaMAX, MicroMAX (1 MHz or 5 MHz) or
ST-133,
• that the camera have a frame transfer chip and,
• that the file WXvchip.opt be present in the same directory as the executable
• that the file WXvchip.opt be present in the same directory as the executable
WinView/32 program. Contact Technical Support for information regarding the
availability of Wxvchip.opt.
availability of Wxvchip.opt.
This method of data acquisition requires that the chip be masked as shown in Figure 31.
Masking can be achieved by applying a mechanical or optical mask or by positioning a
bright image at the ROI against a dark background on the remainder of the array.
Masking can be achieved by applying a mechanical or optical mask or by positioning a
bright image at the ROI against a dark background on the remainder of the array.
In operation, images are continually piped
down the CCD at extraordinarily high frames
per second (FPS). The mini-frame transfer
region is defined by an ROI as illustrated in
Figure 31. The charge from this ROI is
shifted under the frame-transfer mask,
followed by a readout cycle of an ROI-sized
region under the mask. Since the ROI is far
from the serial register, the stored image is
just shifted repeatedly with the readout and
the first few images collected will not
contain useful data. After the readout period,
the next frame is shifted under the mask and
another ROI sized frame is read out. The net
result is a series of images, separated by
spacer regions, streaming up the CCD under
the mask. Refer to Table 9 for a listing of
virtual chip sizes with their respective
readout times and FPS.
down the CCD at extraordinarily high frames
per second (FPS). The mini-frame transfer
region is defined by an ROI as illustrated in
Figure 31. The charge from this ROI is
shifted under the frame-transfer mask,
followed by a readout cycle of an ROI-sized
region under the mask. Since the ROI is far
from the serial register, the stored image is
just shifted repeatedly with the readout and
the first few images collected will not
contain useful data. After the readout period,
the next frame is shifted under the mask and
another ROI sized frame is read out. The net
result is a series of images, separated by
spacer regions, streaming up the CCD under
the mask. Refer to Table 9 for a listing of
virtual chip sizes with their respective
readout times and FPS.
Shift Register
ROI
Virtual
Chip
Frame Transfer Mask
Virtual Chip Mask
Virtual
Chip
Mask
Figure 31. Virtual Chip Functional diagram