The STH-MD1/-C uses standard C-mount lenses for user-changeable optics. Wide-angle to telephoto options are available, depending on the application. The wide baseline version of the STH-MD1/-C has exactly the same characteristics as the STH-MD1/-C, with the exception of range resolution and mounting diagrams.
Plug one end of the 1394 6-pin video cable into either 1394 jack on the STH-MD1/-C, and the other into a 1394 port on the host PC. Note: for PCMCIA cards, and laptops with a 4-pin Sony iLink port, an external power supply and adapter are necessary to convert to a 6-pin (signal + power) 1394 plug.
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STH-MD1 U ’ 2001 V ANUAL IDERE ESIGN that software. It is helpful to review Section 6 in conjunction with the SVS documentation.
Either port can be used as a connection to the host PC. The two ports allow daisy-chaining of the 1394 cable to other devices. Use only one port to connect the STH-MD1/-C to the host computer! A status LED indicates video imager activity.
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Left imager Imager Imager module Interlace Electronics 1394 Interlaced imaging pixels commands 24 MHz 1394 Interface 1394 Electronics module Digital Video Stream 1394 Digital Cable Figure 3-2 Schematic of the STH-MD1/-C electronics. Right Imager 1394 commands 2001 V IDERE ESIGN...
STH-MD1 U ’ ANUAL 4 Lenses The STH-MD1/-C uses standard C-mount lenses. Good-quality, fixed- focus lenses with low distortion and high light-gathering capability are best. Lenses are characterized optically by imager size, F number, and focal length. Following subsections discuss the choice of these values.
5.1 1394 Cable The STH-MD1/-C must be connected to the host PC via a 6-pin male-male IEEE 1394 cable. The maximum length for such a cable is 4.5 m (about 15 feet). The cable supplies both signals and power to the stereo head.
STH-MD1 U ’ ANUAL 6 User Controls The CMOS imagers are fully controllable via the 1394 interface. User programs may input color images (STH-MD1-C only), set video digitization parameters (exposure, gain, red and blue balance), subsampling modes, and region-of-interest (subwindowing). All of these parameters can be set with the included capture application, or with the SRI Small Vision System.
Binning is superior to subsampling in that it reduces video noise, sometimes quite substantially. However, binning does not cut down on the video stream data rate for the STH-MD1/-C, since the binning is done on the host PC.
Vergence is important when viewing close objects, because it allows the object to be centered in each image. The STH-MD1/-C supports electronic vergence, which simulates mechanical vergence. In electronic vergence, the horizontal offset of the left subwindow differs from that of the right.
The vergence control is on the Video Parameters dialog (Figure 6-1). 6.8 Frame Rates Frame rates from the STH-MD1/-C depend on two factors: decimation and the number of image lines in a subwindow. It does not depend on the length of a line, since the CMOS imagers always use the same time to output a line, no matter how many pixels it contains.
7 Installing the 1394 Host Card and Capture Software The STH-MD1/-C connects to a host computer via a digital 1394 interface. The host PC must have a 1394 port, and software to interface to the video stream from the camera. This interface software presents the video stream from the 1394 hardware as a set of stereo frames to the user program (see Figure 7-1).
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GUI-based application that allows the user to exercise the capture functions of the STH-MD1/-C. It is described in earlier sections of this document. smallv(.exe) is similar to smallvcap, with the addition of SRI’ s stereo calculation libraries for realtime depth analysis.
STH-MD1 U ’ 2001 V ANUAL IDERE ESIGN 8 Interface Software API Please see the Small Vision System manual for information about the software API for capturing and saving images.
STH-MD1 U ’ ANUAL 9 Mounting Diagrams 9.1 Bottom Mounting Diagram for the STH-MD1/-C. The larger hole is threaded for a ¼-20 machine screw (standard tripod mounting screw). The two smaller holes are threaded for 6-32 machine screws. 9.2 Bottom Mounting Diagram for the STH-MD1/-C- Wide (Rev B) The three holes are threaded for ¼-20 machine screws (standard tripod...
STH-MD1 U ’ ANUAL 10 Technical Specifications 10.1 Geometry Housing Rigid milled Delrin frame Baseline 9 cm, fixed Imager size 2/3 inch diagonal Lens type C mount, interchangeable 10.2 Interface Type Digital 1394 [Firewire], OHCI compliant Speed Maximum 20 megapixels / second Host interface Any 1394 OHCI card Host OS...
STH-MD1 U ’ ANUAL [Subwindowed frames are proportionally faster, e.g., N x 640 images at no decimation are 15 Hz] 10.5 Physical Power 2 watts Cabling Single 6-pin 1394 cable (power and signal) Stereo module size 5" x 1.75" x 1" 1394 module size 3.5"...
STH-MD1 U ’ 2001 V ANUAL IDERE ESIGN 11 Technical Support For technical support, please contact Videre Design by email or FAX. Videre Design P.O. Box 585 Menlo Park, CA 94026-0585 Fax: (650)323-3646 Email: support@videredesign.com Technical information about stereo algorithms and stereo calibration can be found at www.ai.sri.com/~konolige/svs .