Allied Vision Technologies AVT Pike Series, Техническое руководство

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Description of the data path
PIKE Technical Manual V5.0.0
174
Deferred image transport is especially useful for multi-camera applications:
Assuming several cameras acquire images concurrently. These are stored in
the built-in image memory of every camera. Until this memory is full, the lim-
iting factor of available bus bandwidth, DMA- or ISO-channel is overcome.
Image transfer is controlled from the host computer by addressing individual
cameras one after the other and reading out the desired number of images.
HoldImg mode
By setting the HoldImg flag, transport of the image over the 1394 bus is
stopped completely. All captured images are stored in the internal
ImageFiFo . The camera reports the maximum possible number of images in
the FiFoSize variable.
Note

Configuration
To configure this feature in an advanced register: See Table
155: Advanced register: Deferred image transport on page
326.
Note

• Pay attention to the maximum number of images that
can be stored in
FiFo . If you capture more images than
the number in FiFoSize , the oldest images are overwrit-
ten.
• The extra SendImage flag is set to true to import the
images from the camera. The camera sends the number
of images set in the
NumOfImages parameter.
• If NumOfImages is 0, all images stored in FIFO will be
sent.
• If NumOfImages is not 0 , the corresponding number of
images will be sent.
• If the HoldImg field is set to false , all images in
ImageFIFO will be deleted. No images will be sent.
• The last image in the FiFo will be corrupted, when
simultaneously used as input buffer while being read
out. In this case read out one image less than max.
buffer size.
• NumOfImages is incremented after an image was read
out of the sensor and therefore stored into the onboard
image FIFO.
• NumOfImages is decremented after the last isochro-
nous packet of an image was handed over to the
IEEE1394 chipset of the camera.