? 2001 VIDERE DESIGN STH-MD1 USER’S MANUAL STH-MD1/-C Stereo Head User’s Manual ? 2001 Videre Design 1
? 2001 VIDERE DESIGN STH-MD1 USER’S MANUAL 7.2 Table of Contents 1 Introduction....................................................................................... 3 2 Quick Start........................................................................................ 4 3 Hardware Overview........................................................................... 6 3.1 Hardware Schematic .................................................................. 6 3.2 Frame Rates...........................
? 2001 VIDERE DESIGN STH-MD1 USER’S MANUAL 1 Introduction The STH-MD1 is a compact, low-power digital stereo head with an IEEE 1394 digital interface. It consists of two 1.3 megapixel, progressive scan CMOS imagers mounted in a rigid body, and a 1394 peripheral interface module, joined in an integral unit. The CMOS imagers are from PixelCam (now a part of Zoran Corporation). They have 1288 H by 1032 V pixels, and come in either monochrome (STH-MD1) or colorized (STH-MD1-C) versions.
? 2001 VIDERE DESIGN STH-MD1 USER’S MANUAL 2 Quick Start The STH-MD1/-C comes assembled, the interface module mounted to the imager module. The module comes without mounted lenses. To set up and test the STH-MD1/-C, you will need the following: 1. Pair of C-mount lenses, for 2/3” or larger imager. 2. Host computer with a 1394 PCI or PCMCIA card, OHCI compliant. 3. 1394 6-pin cable. 4. Capture software or Small Vision System installed on the host computer.
? 2001 VIDERE DESIGN STH-MD1 USER’S MANUAL that software. It is helpful to review Section 6 in conjunction with the SVS documentation.
? 2001 VIDERE DESIGN STH-MD1 USER’S MANUAL video modes (frame size, decimation) will cause the frame rate to change, and this will be reflected in the LED flash rate. 3 Hardware Overview There are no user-settable switches on the STH-MD1/-C. Figure 3-1 shows the hardware configuration of the STH-MD1/-C. 3.1 Hardware Schematic The imager module has a milled Delrin frame that rigidly holds two megapixel imagers, separated by a fixed distance of 9 cm.
? 2001 VIDERE DESIGN STH-MD1 USER’S MANUAL Left Imager Imager module 8-bit pixels 12 MHz per imager Right Imager Interlace Electronics 1394 imaging commands Interlaced pixels 24 MHz 1394 Interface Electronics 1394 module Digital Video Stream 1394 commands 1394 Digital Cable Figure 3-2 Schematic of the STH-MD1/-C electronics.
? 2001 VIDERE DESIGN STH-MD1 USER’S MANUAL small amount of methyl alcohol or similar lens-cleaning solvent, and wipe the imager glass surface gently. Dry with a similar tissue. 4 Lenses 4.3 Imager Size The STH-MD1/-C uses standard C-mount lenses. Good-quality, fixedfocus 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.
? 2001 VIDERE DESIGN STH-MD1 USER’S MANUAL STH-MD1/-C, b is 90 mm, and ? d is 0.46875 um (pixel size of 7.5 um, divided by the interpolation factor of 16). Figure 4-1 plots this relationship for several focal lengths. At any distance, the range resolution is inversely proportional to the focal length. 4.7 Field of View The field of view is completely determined by the focal length. formulas for the FOV in horizontal and vertical directions are: The HFOV ? 2 arctan(4.8 / f ) VFOV ? 2 arctan(3.
? 2001 VIDERE DESIGN STH-MD1 USER’S MANUAL capability of supplying power, and come with an adapter for supplying power to the 1394 cable through a wall transformer. 5 1394 Interface Any 1394 card is suitable, as long as it conforms to OHCI (open host controller interface) specifications. All current cards do, but some older cards may not. Digital image information is transferred from the STH-MD1/-C to the host PC via a 1394 cable.
? 2001 VIDERE DESIGN STH-MD1 USER’S MANUAL 6 two monochrome and one RGB color channel. The color channel corresponds to the left image, which is the reference image for stereo. The color image can be de-warped, just like the monochrome image, to take into account lens distortion (see the Small Vision System User’s Manual). User Controls The CMOS imagers are fully controllable via the 1394 interface.
? 2001 VIDERE DESIGN STH-MD1 USER’S MANUAL problem for stereo processing, but does cause the display to look very dark in low-light areas. You can add gamma correction to the displayed image by choosing an appropriate gamma value in the slider under the right display window (Figure 6-2). 6.3 6.4 Subsampling In many applications it is not necessary to work with the the full 1288 x 1032 pixel array. The CMOS imagers are capable of sampling the pixels in the array.
? 2001 VIDERE DESIGN STH-MD1 USER’S MANUAL Figure 6-2 shows the frame size and subsampling controls on the video capture application. Any x2 or x4 subsampling is allowed, including combined binning and decimation. 6.5 Subwindowing Often the area of interest in an image will be a small portion of the whole image. In this case, there is no need to send all of the image data. The CMOS imagers support subwindowing, where only the pixels from a rectangular subwindow of the image are sent back.
? 2001 VIDERE DESIGN STH-MD1 USER’S MANUAL 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. Table 6-1 shows the frame rates for maximum frame sizes in each of the decimation modes.
? 2001 VIDERE DESIGN STH-MD1 USER’S MANUAL 7.1.2 Linux Hardware and Driver Installation Installing the 1394 Host Card and Capture Software Linux kernels 2.4.x are required for operation. Please see the Videre Design website (www.videredesign.com/support_svslnx.htm) for current information. 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.
? 2001 VIDERE DESIGN STH-MD1 USER’S MANUAL libsvscap.so pixcap.so svspix.dll/lib stereo calculation libraries src/ flwin.cpp svs.h flwin.h samples/ stcap.cpp stdisp.cpp *.dsw, *.dsp, makefile serve as a template for user programs that integrate stereo capture from the STH-MD1/-C. libsvscap.so and svsgrab.lib/dll are the capture libraries for Linux and MS Windows, respectively. These libraries must be set to the correct ones for the MEGA-D. Copy the following files in the bin/ directory: pixcap.
? 2001 VIDERE DESIGN STH-MD1 USER’S MANUAL 8 Interface Software API Please see the Small Vision System manual for information about the software API for capturing and saving images.
? 2001 VIDERE DESIGN STH-MD1 USER’S MANUAL 9 9.1 9.2 Bottom Mounting Diagram for the STH-MD1/-CWide (Rev B) Mounting Diagrams The three holes are threaded for ¼-20 machine screws (standard tripod mounting screw). 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.
? 2001 VIDERE DESIGN STH-MD1 USER’S MANUAL 10 Technical Specifications Format Monochrome, 8 bits / pixel Color, 8 bits / pixel, Bayer pattern 10.1 Geometry Scan mode Progressive Rigid milled Delrin frame Pixel size 7.5 um square 9 cm, fixed Sensitivity 1 lux Housing Baseline Imager size 2/3 inch diagonal Exposure Electronic, 0.1 ms to frame time Lens type C mount, interchangeable Gain 10.
? 2001 VIDERE DESIGN STH-MD1 USER’S MANUAL [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" x 2.5" x 0.
? 2001 VIDERE DESIGN STH-MD1 USER’S MANUAL 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 .
