©2005 VIDERE DESIGN STOC USER’S MANUAL Stereo-on-a-Chip [STOC] Stereo Head User Manual 1.
©2005 VIDERE DESIGN STOC USER’S MANUAL Table of Contents 1 Introduction .........................................................................................4 1.1 Characteristics of stereo system.....................................................4 1.2 Characteristics of imagers..............................................................4 1.3 General ..........................................................................................5 1.4 Stereo analysis .....................................
©2005 VIDERE DESIGN STOC USER’S MANUAL Figures and Tables Figure 1-1 Stages in STOC processing........................................................ 6 Figure 1-2 Sequence taken by the MT9V022.............................................. 7 Figure 2-1 SVS main program window....................................................... 8 Figure 3-1. Physical layout of the STOC/-C stereo head. ......................... 10 Figure 3-2 Schematic of the STOC/-C electronics ....................................
©2005 VIDERE DESIGN STOC USER’S MANUAL 1.1 1 Introduction Characteristics of stereo system • On-device stereo processing Xilinx Spartan 3 – 1000 processor, 88 MHz 512 KB SRAM The STOC is a new type of device. It functions as a complete vision processor, combining stereo cameras and an embedded processor to produce 3D stereo information. The processor was developed at SRI International’s Artificial Intelligence Lab, for use in real-time vision and robotics projects.
©2005 VIDERE DESIGN STOC USER’S MANUAL Automatic control of black level Manual control of color balance • 50 Hz mode – reduces indoor light interference in countries with 50 Hz electrical line frequency 1.3 General • Stereo calibration information stored on the device • IEEE 1394 interface to standard PC hardware Carries power and commands to device, data to PC DCAM 1.30 compatible • Miniature 12mm diameter or CS-mount lenses, interchangeable |Standard focal lengths 2.1,3.6, and 6.
©2005 VIDERE DESIGN STOC USER’S MANUAL 1.4 rectifiedimages). There is no need to perform any calibration steps – the STOC is ready to start producing range results out of the box. However, you may want to change the lenses at some point, and the device can easily be recalibrated in the field, just like other Videre stereo devices. Stereo analysis The STOC board runs an optimized version of the SRI Small Vision System (SVS) stereo algorithms.
©2005 VIDERE DESIGN STOC USER’S MANUAL 1.5 Global Shutter The STOC has a global shutter. Almost all other CMOS imagers have a rolling shutter. With rolling shutter, each row of pixels is exposed just before it is read out. So each row is exposed at a different time from other rows. This leads to motion blur – a skewing of moving objects from top to bottom. Global shutter, on the other hand, exposes every pixel at the same time.
©2005 VIDERE DESIGN STOC USER’S MANUAL Start the SVS main program, smallv(.exe), on the host computer. You should see a screen as in Figure 2-1. The message window should indicate that the “DCS Digital Stereo Interface” is present. If not, go back to software installation (Section 4.2), and follow the instructions for configuring the correct capture library. 2 Quick Start The STOC/-C normally comes assembled with the lenses mounted.
©2005 VIDERE DESIGN STOC USER’S MANUAL left image plus the disparity (range) image. In the left window there will be the left image from the camera; in the right image, the disparity image produced by stereo processing. If the message “Image timed out” appears, then there is a problem with the IEEE 1394 drivers; please see Section 4. If the images are too light or too dark, you can change the exposure and gain settings (Section 7.4). Images can be saved using the File menu.
©2005 VIDERE DESIGN STOC 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 STOC/-C. Figure 3-1 shows the hardware configuration of the STOC/-C. 3.1 The imager module has a milled aluminum alloy frame that rigidly holds two VGA imagers, separated by a fixed distance of 9 cm.
©2005 VIDERE DESIGN STOC USER’S MANUAL Imager module Left Imager STOC board 8-bit pixels 12 MHz per imager Format Frame size Frame rate (default) Frame rate, 50 Hz option Format 0, Mode 3 YUV 16 bits 640x480 7.5, 15, 30 Hz 6.25, 12.5 25 Hz Right Imager Stereo Processing 1394 imaging commands Table 1 Frame formats and sizes for the STOC/-C. Disparity image Left rectified image The Digital Camera Specification was set up with monocular cameras in mind.
©2005 VIDERE DESIGN STOC USER’S MANUAL Format PROC_MODE_TEST, PROC_MODE_RECTIFIED, PROC_MODE_DISPARITY, PROC_MODE_DISPARITY_RAW }; Submode Format 0, Mode 3 YUV 16 bits Y UV NAME LO RO PROC_MODE_OFF, PROC_MODE_NONE LR RR PROC_MODE_RECTIFIED 3.3 LR D PROC_MODE_DISPARITY LO D PROC_MODE_DISPARITY_RAW TP TP PROC_MODE_TEST The STOC processing board produces a disparity image, which encodes the range to objects in the scene.
©2005 VIDERE DESIGN STOC USER’S MANUAL In sending video information over the IEEE 1394 bus, the STOC device uses 16 bits/pixel: 8 bits/pixel for the left image, and 8 bits/pixel for the disparity image (default mode). Thus, the disparity image must be compressed. For the first implementation of the STOC, the lower two bits are truncated. Future implementations will use companding (lower values are preserved, higher values are compressed) and 24 bit/pixel IEEE 1394 modes. 3.
©2005 VIDERE DESIGN STOC USER’S MANUAL through installation steps for the low-level drivers. You may need your MS Windows OS CD to install some files. 4 Installing the 1394 Host Card and Capture Software The STOC must be powered from the IEEE 1394 bus. Desktop PCs supply power to the bus; laptops do not. See Section 5 for information about cabling and power for the IEEE 1394 bus. The STOC/-C connects to a host computer via a digital 1394 interface.
©2005 VIDERE DESIGN STOC USER’S MANUAL In MSW Windows, execute the file bin\setup_dcs.bat. This will copy svsdcs.dll/lib as the interface libraries. only way to run the SVS calibration procedures is through the smallvcal(.exe) application. Under Linux, copy the following file in the bin/ directory: smallv(.exe) is a GUI-based application that allows the user to exercise the capture and stereo functions of the STOC/-C. It is described in earlier sections of this document. dcscap.so -> libsvscap.
©2005 VIDERE DESIGN STOC USER’S MANUAL capability of supplying power, and come with an adapter for supplying power to the 1394 cable through a wall transformer. 5 IEEE 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 STOC/-C to the host PC via a 1394 cable.
©2005 VIDERE DESIGN STOC USER’S MANUAL Figure 5-1 shows the two configurations for supplying power. A wall transformer converts line voltage to 12 VDC, and is plugged into a hub or the PC Card. PC Card with power port IEEE 1394 hub with power port IEEE 1394 Cable IEEE 1394 Cable IEEE 1394 Cable to PC Power – 12 VDC, >3W Power – 12 VDC, >3W Figure 5-1 External power supply connections. On the left is power supplied to a PC Card with a power port.
©2005 VIDERE DESIGN STOC USER’S MANUAL The STOC/-C uses either 12mm diameter miniature lenses, or CS-mount locking lenses. Miniature lenses are screwed into integral lens-holders milled into the aluminum chassis. The lenses are focused at the factory, and firmly glued into place. There are no adjustments to be performed on the lenses. It is possible to change both types of lenses, although changing the miniature lenses is not recommended; see Section 6.7 and 6.8 below.
©2005 VIDERE DESIGN STOC USER’S MANUAL 6.6 Table 4 plots this relationship for several focal lengths. At any distance, the range resolution is inversely proportional to the focal length. Range Resolution Range resolution is the minimum distance the stereo system can distinguish. Since stereo is a triangulation operation, the range resolution gets worse with increasing distance from the stereo head. The relationship is: 6.
©2005 VIDERE DESIGN STOC USER’S MANUAL while watching the video. You should be able to get a good, sharp image. Screwing down too much past the point of good focus can damage the internal IR filter, so be careful here. Once the threads are engaged, continue screwing it on until it seats firmly. You can snug it down, but do not tighten it excessively, since this can damage the lens and the lens holder threads. Once you have found a good focus, unscrew the lens until its barrel is almost out.
©2005 VIDERE DESIGN STOC USER’S MANUAL inputs. The default submode, left rectified image and disparity image, is set by using Function->Stereo and turning Warp on. By default, this is done when the STOC is first opened. Setting Function->None turns off stereo processing, and outputs the right rectified image in place of the disparity image. Turning off Warp will output both original images. Table 5 summarizes these settings. Note that it is not possible to invoke the Test Submode from smallv.
©2005 VIDERE DESIGN STOC USER’S MANUAL produce an image that is overall neutral (called white balance). The STOCC provides manual color balance by allowing variable gain on the red and blue pixels, relative to the green pixels. Manual balance is useful in many machine vision applications, because automatic white balance continuously changes the relative amount of color in the image. Both imagers are treated in exactly the same manner. It is not possible to set a different exposure or gain on each imager.
©2005 VIDERE DESIGN STOC USER’S MANUAL • 50 Hz operation motion blur. Indoors, the gain is usually set higher because of the lower light levels. • This parameter can be changed by using the Firmware Parameter dialog, which is only available from the smallvcal menubar. Choosing this menu brings up the dialog, which is shown in Figure 7-3. Adjust the manual iris of the lens to as small an opening as possible for your application, without having to use gain.
©2005 VIDERE DESIGN STOC USER’S MANUAL Figure 7-3 Firmware parameters dialog.
©2005 VIDERE DESIGN STOC USER’S MANUAL Firmware dialog. A file chooser dialog will appear, allowing you to select the FPGA configuration file. The chooser should be at the bin/ directory; if it is not, navigate to this directory. Then choose one of the following files: 8 Redoing Calibration Whenever the lenses are changed, or the focus or iris is adjusted, it is recommended to perform a re-calibration of the STOC device. This requires the following steps: 1.
©2005 VIDERE DESIGN STOC USER’S MANUAL 9 Interface Software API Please see the Small Vision System manual for information about the software API for capturing and saving images.
©2005 VIDERE DESIGN STOC USER’S MANUAL 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. 10 Physical Diagram Dimensions and Mounting The diagram below shows the physical dimensions for the STOC/-C.
©2005 VIDERE DESIGN STOC USER’S MANUAL Exposure 1 line time to full frame 11 Technical Specifications Gain 0 – 12 dB (1x – 4x) 11.1 Specifications Sensitivity 4.8 V/lux-sec (monochrome) STOC processor S/N > 60 dB, no gain Power Imagers and FW interface: 1.45 W STOC board: 0.84 W Total: 2.29 W Synchronization Internal: pixel-locked External: 60 us Lens 3.6 mm miniature lenses standard Other lenses optional (2.1 to 16 mm) Size 1.725” high x 5.2” long x 1.
©2005 VIDERE DESIGN STOC USER’S MANUAL 11.2 Imager Response - Color 11.
©2005 VIDERE DESIGN STOC USER’S MANUAL 11.
©2005 VIDERE DESIGN STOC USER’S MANUAL 12 Technical Support For technical support, please contact Videre Design by email or FAX. Videre Design 865 College Avenue Menlo Park, CA 94025 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.
