User manual

Small Vision System User Manual 12
/dev/fg1 (if there are two). Check the device names for your installed devices, and make soft links to the
SVS names, e.g., for Matrox Meteor cards, use the command
ln -s /dev/mmetgrab0 /dev/fg0
The framegrabber interface used by smallv under MS Windows or Linux is indicated in the message
window at startup.
There are some limitations in framegrabber drivers that should be noted. First, there are currently no
fast framegrabbers for portables, although this could change if they take advantage of the PC card 32-bit
interface. The maximum frame rate for the VideoPort Pro, one of the better cards, is about 15 fps at 320 x
120; this frame rate uses all of the CPU to do the I/O transfers.
The Video for Windows interface has limitations that prevent it from working in Windows NT. Even
in Windows 95, it is inefficient, since there is no way to specify field mode captures, and the fields are
extracted by SVS after a full frame has been shipped to memory. We recommend using a Matrox or
Imagenation card under MS Windows.
When using the Imagenation PXC200 cards with PC104+ form factor under Linux, an additional
initialization call is necessary. The variable svsIsPXC_PC104 should be set to 1, which will be done
automatically if the environment variable SVS_PXC_PC104 is defined.
2.1.3 IEEE 1394 (FireWire) Framegrabber
The SVS has an interface to digital stereo heads from Videre Design via the IEEE 1394 serial bus.
Any OHCI-compliant IEEE 1394 PCI or PCMCIA card can be used, under MS Windows 98/2000 or
Linux. Please check the stereo head manual for instructions on installing the 1394 card and drivers. The
relevant DLL for MS Windows is svspix.dll, and the shared library for Linux is libpix.so.
2.1.4 Selecting Video Format
The Video Format menu lets you tell the SVS library what kind of video input you are using. This
section should be ignored if you are using the IEEE 1394 digital interface with a Videre Design digital
head, which has a fixed format.
There are three choices:
1. Line interlace [default]. This is the mode for the STH-V3 line interlace stereo head. Any
framegrabber can be used in this mode.
2. Dual framegrabbers. This mode uses two framegrabbers, with one framegrabber per camera.
Check Table 2-1 for supported framegrabbers.
3. RG components. This mode uses the Matrox Meteor RGB or Meteor II, and inputs one
camera video stream on the R channel, and one on the G channel.
Single
video
stream
Left camera
field
Right
camera field
Interlaced
field
Figure 2-3 Line-interlaced stereo cameras (STH-V1 stereo head). Alternate
lines from each camera are interlaced into a single video stream.