STH-V1 Stereo Head
Contents
1. dsp makefile There are several applications see the SVS User s Manual for more information The source code for all applications is included in the distribution The stereo calculation libraries are also included so that user applications can link to them The calibration libraries are not included the 2007 VIDERE DESIGN capability of supplying power and come with an adapter for supplying power to the 1394 cable through a wall transformer 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 5 3 Supplying Power Power to the STH MDCS3 is supplied through the IEEE 1394 cable The IEEE 1394 system must supply this power about 1 Watt There are two typical PC systems desktops and laptops 6 Desktop PCs have either a built in IEEE 1394 port or a PCI card with IEEE 1394 ports In both cases the desktop should supplysufficient power to run the STH MDCS3 e Laptop PCs have either a built in IEEE 1394 port or a plug in PC Card sometimes called a PCMCIA card with several IEEE 1394 ports In both cases the laptop does not supply power to the IEEE 1394 bus and a source of external power must be used see below External power to the IEEE 1394 bus must have the following characteristics 7 to 16 VDC gt 1 5 W The IEEE 1394 spec allows up to 40 VDC on the bus but in practice many devices such as PC C2. e In general keep the gain as low as possible since it introduces additional noise into the system Use it only if the exposure is set to maximum or if the exposure must be kept low to minimize motion blur Indoors the gain is usually set higher because of the lower light levels e Adjust the manual iris of the lens to as small an opening as possible for your application without having to use gain This will increase the depth of field and give better optical performance Indoors the iris usually is fully open Outdoors in bright conditions the iris can be partially closed 2007 VIDERE DESIGN For 320x240 binning will take place on the host PC and the imager The imager will transmit a 640x480 image and the host will bin that down to 320x240 The subsampling must be set with SetSample 1 2 For 1 2 frame rates there are two resolutions 640x480 and 320x240 In both cases the STH MDCS3 transmits the full 640x480 image For 320x240 the SVS interface software uses binning to reduce the image 7 5 Frame Rates Frame rates from the STH MDCS3 C depend on the frame size Table 4 shows the frame rates available for each of the frame sizes Note that a 50 Hz option is available see Section 3 3 7 6 Firmware Parameters There is one firmware parameter that affects the overall behavior of the Resolution Frame Dec on Bin on Frames per Second imager PC 1280 x 960 3 75 75 1024x768 Full no no S Oe ND color only
3. 0 14 6 1 14 6 2 0 niteen aaan 14 6 3 Changin Lense Seeda a ieeeaabiaritaceeacencdes 14 00 14 G5 ila SGI Size sittin eee eee 14 OO SEIN osha eee eas eee ee eee 14 OL Focal TCC t isis dao dorciesleea cha elt A 15 6 8 Range 05001100 15 0090 15 0 7 17 Tal COl aa a nee eine eee nt eee eee ee ee ene 17 7 Gamma COT CUOn ie ai carta tastes teins a A 17 7 3 Video Digitization Parameters cccccccccecceceeeeeeeeeeeeeeeeeeeeeeeees 18 STH MDCS3 USER S MANUAL 2007 VIDERE DESIGN STH MDCS3 USER S MANUAL Figures and Tables Figure 2 1 SVS main program Window cccccccccccccccccececcecceeeeeeeseeeeeeeeeees 5 Figure 3 1 Physical layout of the STH MDCS3 C stereo head 7 Figure 3 2 Schematic of the STH MDCS3 C electronics cceccceeeeeeees 8 Figure 4 1 Host PC low level software structure ccccceeeseeetteeees 10 Figure 5 1 External power supply connections ccccccccccccceceeeeeeeeeeees 13 Figure 6 1 Range resolution in mm as a function of 0150068 15 Figure 7 1 Video Parameters dialog cccessssscccceceeeeeeeeeseeeeessssneeeees i Figure 7 2 Frame size and sampling controls ccccccccccccsccceeeceeeeeeeeeeees 18 Figure 7 3 Firmware parameters dialog 20 Table 1 Frame formats and sizes for the STH MDCS3 C ee 8 Table 2 Bus bandwidth requirements at different frame rates 9 Table 3 Horizontal and v
4. the sampling control has been changed to a simple Frame Division control For the STH MDCS3 there are two possible values 1 full image and 1 2 Refer to Table 4 for a complete list of allowed modes and how the frame size and sampling setting affect the output image Explicit control over the sampling mode is accomplished with the Set Sample function from the SVS API The first four lines of the table are for full frame images At 1280x960 the full image is sent to the host PC and there is no binning At 640x480 there are two choices decimation on the imager or binning on the host the default is decimation on the imager Using SetSample 2 1 means that decimation will take place on the imager which then transmits a 640x480 imager this is the default for full frame images Using SetSample 1 2 means that binning will take place on the host In this case the imager transmits all 1280x960 pixels so the maximum frame rate is lower This is the greyed out line in the table 2007 VIDERE DESIGN accessible from the smallv menubar Choosing this menu brings up the dialog which 18 shown in Figure 7 3 The dialog lists many of the internal parameters of the device which are fixed in the firmware The one changeable parameter is for 50 Hz or 60 Hz operation Section 3 3 The Firmware Parameter dialog is only available after the STH MDCS3 has been opened by pulling down the Video item of the Input chooser To use 50 Hz opera
5. H Disparity 2 0 Size none 3D Displa Horopter Window IEN Sample none r Swap 1 xof 4 o H FLR Check Rate 15 x F Color Capable F Multi Scale Figure 2 1 SVS main program window STH MDCS3 USER S MANUAL 2 Quick Start The STH MDCS3 C normally comes assembled with the lenses mounted If you need to change the lenses or if you are supplying your own please see Section 6 1 To set up and test the STH MDCS3 C you will need the following 1 Pair of C mount lenses for 1 2 or larger imager normally included and mounted with the STH MDCS3 C kit 2 Host computer with an IEEE 1394 PCI desktop or PCMCIA laptop card OHCI compliant or a built in IEEE 1394 port 3 IEEE 1394 6 pin to 6 pin cable 4 Small Vision System installed on the host computer Install the IEEE 1394 host card if necessary according to the directions in Section 4 1 Install the Small Vision System software see Section 4 2 If the lenses are not mounted on the device follow the directions in Section 6 1 for installing them Plug one end of the IEEE 1394 6 pin video cable into the 1394 jack on the back of the STH MDCS3 C and the other into an IEEE 1394 port on the host PC Note The STH MDCS3 draws power from the IEEE 1394 bus PCI cards or built in ports for desktop machines normally supply this power For PCMCIA cards PC Cards and laptops with a built in port no power is available In th
6. and standard C or CS mount lenses are screwed into these holders There is an IR cutoff filter with a knee at approximately 680 nm permanently mounted inside the lens holder See Section 6 for appropriate lens characteristics The interface module is mounted on the back of the stereo head One IEEE 1394 port is placed at the back of the module it is inset so that the IEEE 1394 plug does not stick out from the device A status LED indicates video imager activity It will turn on when the device is powered and connected to an IEEE 1394 card on the host computer The LED will begin flashing as soon as images are being acquired by the host computer at 2 the frame rate Changing the video modes frame size decimation will cause the frame rate to change and this will be reflected in the LED flash rate IEEE 1394 port on back Right C CS mount lens Left C CS mount lens indicator Figure 3 1 Physical layout of the STH MDCS3 C stereo head 2007 VIDERE DESIGN Format Frame Frame size rate 60 Hz rate 50 default Hz option Format 0 Mode 3 640x480 3 125 YUV 16 bits 6 25 12 5 Left image on Y right image 25 Hz on UV Format 1 Mode 3 1024x768 5 YUV 16 bits Hz Left image on Y right image on UV Format 2 Mode 0 1280x960 3 75 7 5 Hz YUV 16 bits Left image on Y right image on UV Table 1 Frame formats and sizes for the STH MDCS3 C On the host computer the SVS interface software takes the Y
7. 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 Removing the lens is the reverse process unscrew the lens counter clockwise There will be some initial resistance and then it should unscrew smoothly Normal care should be used in taking care of the lenses as with lenses for any good quality camera 6 4 Cleaning the Ilmagers It should not be necessary to clean the imagers since they are sealed off by an IR filter inside the lens mount If dirt and dust are present on the IR filter surface they can be cleaned in the same manner as a lens Wet a non abrasive optic cleaning tissue with a small amount of methyl alcohol or similar lens cleaning solvent and wipe the imager glass surface gently Dry with a similar tissue 6 5 Imager Size The imager size 1s the largest size of imager that can be covered by the lens For the STH MDCS3 the lens must be 1 2 or greater For some wide angle lenses there will be a little vignetting darkening on the corners of the image Calibration and rectification of the image will usually eliminate this vignetting 6 6 F Number The F number is a measure of the light gathering ability of a lens The lower the F number the better it is at pulling in light and the better the STH MDCS3 will see in low illumination settings For indoor work an F number of 1 8 1s acceptable and 1 4 is even better For out
8. 3 devices can send video information at the same time The bus bandwidth consumed by a device is more than would be expected from just counting the number of bytes in each frame because there are blank cycles on the bus when no data is being transmitted even though the bandwidth is reserved Thus it makes no difference whether the rate is 30 Hz or 25 Hz the bus bandwidth consumed is the same STH MDCS3 USER S MANUAL evenly into this frequency there can be moving horizontal bands of alternating light and dark moving in the output For countries with 60 Hz power such as the United State the frame rates of Table 1 are ideal In many other countries the electrical line frequency is 50 Hz For these countries there is a mode to change the frame rates of the STH MDCS3 to sub multiples of 50 Hz These frame rates are shown in the last column of Table 1 The frame rate mode of the STH MDCS3 device can be changed by using the Firmware Parameter dialog see Section 7 6 3 4 Multiple Devices Multiple STH MDCS3 devices can be attached to the same IEEE 1394 bus When streaming video at the same frame rate they are synchronized so that they capture images at the same time Each IEEE 1394 PC Card or PCI Card defines a separate IEEE 1394 bus The two or three ports on the card all belong to the same bus as does any IEEE 1394 hub connected to these ports Separate PC Cards and PCI Cards cannot be connected to each other The number o
9. 480 HFOV 2arctan 3 28 f VFOV 2arctan 2 46 f where f is in millimeters For example a 3 5 mm lens yields a horizontal FOV of 95 3 degrees for monochrome devices This is about the smallest practical focal length for the STH MDCS3 VAR The following table shows the FOV for some standard focal lengths Lens focal length Horizontal FOV deg Vertical FOV deg color color color color ao lee a a Lee 35mm 953 607 862 789 as 0 702 Table 3 Horizontal and vertical field of view for different lens focal lengths 16 2007 VIDERE DESIGN two monochrome and one or two RGB color channels The primary color channel corresponds to the left image which is the reference image for stereo The right image color channel is also available The color images can be de warped just like the monochrome images to take into account lens distortion see the Small Vision System User s Manual Color information from the camera is input only if the Color button is pressed on the main window Figure 2 1 Because the typical color camera uses a colorizing filter on top of its pixels the color information is sampled at a lower resolution than a similar non colorized camera samples monochrome information In general a color camera has about 4 the spatial resolution of a similar monochrome camera The cameras have on imager binning from 1280x960 to 640x480 Whenever the 640x480 frame size is requested binning is automa
10. 640 x 480 3 15 ore erro 320x240 Fu_ yes 3 75 7 5 15 30 640 x 480 jf no 3 15 75 15 30 320 x 240 3 75 7 5 15 30 Table 4 Subsampling modes and frame rates for the STH MDCS3 The greyed out line is a non default mode accessible with the SetSample function 19 STH MDCS3 USER S MANUAL 7 4 Subsampling In many applications it is not necessary to work with the the full 1280 x 960 image The CMOS imagers are capable of sampling the pixels in the array Sampling allows the video stream to send less data for faster frame rates or less bus activity A sampled image shows the same scene as the original image but it uses fewer pixels to do so and has less detail Binning is a subsampling technique in which several adjacent pixels are averaged into one Binning reduces video noise sometimes quite substantially Binning is available on the host PC the larger image is first transferred on the IEEE 1394 bus then binned down The binning 18 color aware for the STH MDCS3 C so that pixels of like color are combined Sampling differs from subwindowing which picks a rectangular portion of the image but doesn t change its resolution The STH MDCS3 has one subwindow mode in which the center 640x480 subwindow of the imager is chosen Using the subwindow has the effect of zooming the image by a factor of 2 Figure 7 2 shows the frame size and subsampling controls on the video capture application With SVS version 3 2b
11. Lab again see the SVS User s Manual smallvcal exe is the same as smallv with the addition of a calibration package for calibrating a stereo rig Use this application to perform calibration on your stereo system stcap exe is 8 simple application that connects to the stereo head and displays images It can serve as a template for user programs that integrate stereo capture from the STH MDCS3 C stdisp exe is a simple application that connects to the stereo head grabs images and performs stereo analysis and displays the results It can serve as a template for user programs that integrate stereo capture and computation from the STH MDCS3 C 1 STH MDCS3 USER S MANUAL In MSW Windows execute the file bin setup dcs bat This will copy svsdcs d11 1ib as the interface libraries Under Linux copy the following file in the bin directory descap so gt libsvscap so LINUX You can check that the correct interface library is installed by looking at the information text when the capture application is started It should say DCS digital stereo interface If not the wrong interface library is installed in svsgrab dllorlibsvscap so The directory structure for the software is piny smallv exe smallvcal exe smallvmat exe svsgrab dll lib libsvscap so interface libraries stereo calculation libraries sxrc 6 image 10 SVS sii flwin h samples smalls Cpp 3 CPP 8
12. STH MDCS3 USER S MANUAL 2007 VIDERE DESIGN STH MDCS3 C Stereo Head User s Manual September 2007 2007 Videre Design 2007 VIDERE DESIGN TA 10 erreen nn ee ee nee Table of Contents T5 Frame Rafes ee ee erie reread tect T aweanadniaiaiveates 4 1O SPAREN BUG Parameters ainni taii eens een oe 1 1 Characters tiC S rene ea A e E i 4 8 Interface Software 4 Quick Sfar senses scessavsiassscsecsessasuasssbesecsiasssuens E 5 9 Physical Dimensions and Mounting 19130173 171 Hardware 16 7 10 Technical 7 Sali 0 einser i a taints tiareeoanstanies 7 TO 0 miaaegnesswhe Mamevoeaneteabentouse 3 2 Frame Formats atid Rates cerniera ieia EG 7 10 2 Imaget Response 0 eee are PO IA OP era ON mian sae ease tin ease 8 10 3 Imager Response Monochrome sccsesessroveeoveeeoseness 3 4 Multiple WEE OTR 9 10 4 Filter Transmittance ccccccccccccccccccccccceccccccccceccccccccccccccccecccecce Installing the 1394 Host Card and Capture Software cs00 10 11 Technical 4 1 1394 Hardware and sissies coke sc ohiee a a 10 4 1 1 MS Windows Hardware Installation 10 4 1 2 Linux Hardware and Driver 1518118110 10 4 2 S3 SOLWALC aniraa A a OR RTG 10 TEEE 1394 InterfaA C soesoenan noioa aieia aaa aiis 12 5 1 PIEBE 1094 AIG inagaana 12 32 JEEE 1394 H st Inter lace 3 eit bearded a eee ns 12 5 3 POWET sirrini iia eee ec 12
13. UV stream and parses it into the left and right images making them available as separate images in computer memory It also performs color processing for the STH MDCS3 C converting the Bayer pattern into full color RGB images Smaller frame sizes are also available using on host binning Binning averages neighboring pixels to produce a smaller image with improved noise characteristics The STH MDCS3 also has a subwindow mode in which only the center portion of the image is returned See Section 7 4 for full information on the modes and resolutions for the STH MDCS3 3 3 50 Hz Operation Indoor lighting especially from fluorescent fixtures can oscillate at the frequency of the electrical supply If the image frame rate does not divide STH MDCS3 USER S MANUAL 8 bit pixels 12 MHz per imager Imager module Interlace Electronics 1394 Interlaced imaging pixels commands 24 MHz 1394 1394 Interface a Electronics module Digital 1394 Video commands Stream 1394 Digital Cable Figure 3 2 Schematic of the STH MDCS3 C electronics data type sending the left stereo image in Y and the right image in the UV pixels Each image from the stereo camera has 8 bit pixels In the case of the color version STH MDCS3 C the color information is encoded as a Bayer pattern in the same 8 bit pixel image 2007 VIDERE DESIGN simultaneously For example at 15 Hz and 640x480 resolution a maximum of 3 STH MDCS
14. and Drivers Before installing the software interface the PC must be equipped with a 1394 port If there is one already present a built in port then you can skip this section Otherwise you have to install a PCI or PCMCIA card The card must be OHCI compliant which all current cards are 4 1 1 MS Windows Hardware Installation For the most up to date information about installation please see the Videre Design website www videredesign com support_svsmsw htm MS Windows 2000 or XP is required For a PCI card insert the card into a free PCI slot with the computer power off and start the computer With a PCMCIA card insert it into the PCMCIA slot In either case the New Hardware wizard will walk you 1394 To video user stream program Low level STH MD1 PC 1394 interface Hardware driver software Figure 4 1 Host PC low level software structure 2007 VIDERE DESIGN only way to run the SVS calibration procedures is through the smallvcal exe application smallv exe is a GUlI based application that allows the user to exercise the capture and stereo functions of the STH MDCS3 C It is described in earlier sections of this document smallvmat exe is similar to smallv with the addition of a MatLab interface for sending images and stereo information to MatLab You must have installed the R13 release of MatLab to run this program There is also a version of SVS that can be invoked directly from Mat
15. ards will fail if a voltage higher than 16 VDC or so is used We recommend using a 12 VDC source Power can be supplied to the bus through an IEEE 1394 hub or PC Card with an external port Most hubs have such a port most PC Cards do not The PC Card supplied by Videre has a power port The format of the power plug can vary with the hub or PC Card so please check the specifications for the device Generally the positive terminal of the plug is on the inside and the negative is the outside cylinder 12 STH MDCS3 USER S MANUAL 5 IEEE 1394 Interface Digital image information 15 transferred from the STH MDCS3 C to the host PC via a 1394 cable The cable sends a video stream from the imagers to the PC and sends commands from the PC to the stereo head to control exposure subsampling etc The cable also supplies power to the stereo head 5 1 IEEE 1394 Cable The STH MDCS3 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 The port on the STH MDCS3 is recessed so that the IEEE 1394 cable plug will not stick out from the camera The distance between the stereo head and the PC can be extended by using a 1394 repeater Several 1394 enabled devices can be connected together as long as the connection topology doesn t have any loops The STH MDCS3 C can be connected at any point in
16. doors higher F numbers are fine In any case it is useful to have a manual iris for high light situations While the imagers can have electronic exposure and gain control to automatically compensate for different light conditions the 14 STH MDCS3 USER S MANUAL 6 Lenses The STH MDCS3 C uses standard C or CS 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 6 1 Locking Lenses Some lenses come with thumbscrew locks for holding the focus and iris settings We recommend these locking lenses for all applications in which the device is moving or in which people or objects may touch the lens Locking lenses are available from Videre 6 2 Cand CS Mount Lenses The STH MDCS3 will accommodate either C or CS mount lenses CS mount lenses have a mounting distance of 12 5 mm from the imager C mount lenses have a mounting distance of 17 5 mm Normally 1 2 format lenses are of the C mount variety They require a 5 mm spacer to focus properly This spacer is shipped with the STH MDCS3 it is the round silver part on the lens holder To use CS mount lenses unscrew the spacer before mounting the lens 6 3 Changing Lenses Standard C CS mount lenses have a 1 diameter 28 threads per inch screw on their back end The screw mates with the
17. dual streams into a single pixel interlaced stream at 24 MHz The interlaced stream contains one byte from the left imager then the corresponding byte from the right imager then the next byte from the right imager and so on The interlaced video stream is transferred to the IEEE 1394 interface module which communicates to the host PC over an IEEE 1394 digital cable The module also accepts commands from the host PC over the cable and uses these commands to control imaging modes such as exposure or subwindowing The IEEE 1394 interface module can communicate at the maximum IEEE 1394 data rate 400 MBps 3 2 Frame Formats and Rates The IEEE 1394 interface electronics on the STH MDCS3 supports a maximum rate of 24 megapixels per second At this rate there is no need for large buffer memories to hold video data on the stereo device The STH MDCS3 C conforms to the IIDC version 1 30 camera specification Frame rates and frame sizes are set by this standard The STH MDS C implements the formats shown in Table 1 The Digital Camera Specification was set up with monocular cameras in mind To conform to this specification the STH MDS C uses the YUV STH MDCS3 USER S MANUAL 3 Hardware Overview Figure 3 1 shows the hardware configuration of the STH MDCS3 C The imager module has a milled aluminum alloy frame that rigidly holds two megapixel imagers separated by a fixed distance of 9 cm Lens mounts are an integral part of the frame
18. e drivers for the STH MDCS3 C for MS Windows 2000 XP and for Linux 2 4 and 2 6 kernels 2007 VIDERE DESIGN Start the SVS main program smallv exe or smallvcal 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 Pull down the Input chooser and select the Video option If everything has been set up correctly the SVS interface will recognize and configure the stereo head and a success message will appear in the info text window If not the Input chooser will go back to None and an error message will appear in the info window Please see Section 4 for troubleshooting To view stereo video press the Continuous button Left and right images should appear in the application windows 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 open the manual iris of the cameras or change the exposure and gain settings W SRI Smally Stereo System Joj xj Fie Device Wideo Video Buffer byvindow librate Debug Rate 0 0 T Left F Color 55 version 3 08 DCS Digital Stereo Interface Right l Color 1 00 Gamma Input None Function None gt Cont afii2
19. eo 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 an upgrade from those in the STH MDCS They are MT9MO01 monochrome or MT9TOO1 color sensors from Micron Semiconductor They are 1 2 format with a resolution of 1280 H by 1024 V pixels and come in either monochrome STH MDCS3 or colorized STH MDCS3 C versions These imagers have excellent dynamic range sensitivity anti blooming and noise characteristics They are fully controllable via the 1394 interface the user can set exposure gain decimation etc They have better noise sensitivity and crosstalk characteristics than the previous sensors The STH MDCS3 C uses standard C mount lenses for user changeable optics Wide angle to telephoto options are available depending on the application The variable baseline version of the STH MDCS3 C uses the same imagers but has a separate IEEE 1394 interface for each imager It has similar characteristics to the STH MDCS3 C please see the STH MDCS3 VAR C manual for more information SRI s Small Vision System SVS software has an interface to the STH MDCS3 C and is included with each stereo head You can simply and automatically calibrate the stereo head perform stereo correlation and view the results as a 3D point set The SVS software includes softwar
20. ertical field of view Error Bookmark not defined Table 4 Subsampling modes and frame rates ccccccceceeeeeeeeeeeeeeeeeees 19 2007 VIDERE DESIGN 1 1 Characteristics e Micron 1791001 monochrome or MT9TOOI color Megapixel Sensors 1280 x 960 maximum image size High sensitivity low noise Low pixel cross talk Rolling shutter e Fully synchronized stereo left and right pixels are interleaved in the video stream 6 Monochrome or Bayer Color e High frame rates 30 Hz for 640x480 15 Hz for 1024x768 color only 7 5 Hz for 1280x960 o On chip decimation full frame 640x480 and 320x240 modes e Electronic zoom mode center 640x480 subwindow e Extensive control of video parameters Automatic or manual control of exposure and gain Automatic control of black level Manual control of color balance o 50 Hz mode reduces indoor light interference in countries with 50 Hz electrical line frequency e Stereo calibration information can be stored on the device and downloaded automatically to the PC o IEEE 1394 interface to standard PC hardware carries power and commands to device data to PC e Standard C CS mount lenses interchangeable focal lengths from 3 5 mm to 50 mm e Fixed 9 cm baseline 6 Anodized aluminum alloy chassis high rigidity STH MDCS3 USER S MANUAL 1 Introduction The STH MDCS3 is a revision of the STH MDCS digital stereo camera It is a compact low power digital ster
21. f devices that can simultaneously send video is determined by the maximum bandwidth of the bus for isochronous transfers 32 MB s This rate cannot be exceeded by the combined video streams on the bus Table 2 shows the bandwidth requirements for the STH MDCS3 in various modes and for various frame rates Using this table it is possible to determine the maximum number devices that can stream 0 Frame Bus MB per 30 25 15 12 5 7 5 6 25 3 75 size frame Hz Hz Hz 3 125 Hz stereo 640x480 0 683 MB 20 5 MB 10 2 MB 5 12 MB 2 6 MB 1280x960 2 73 MB 20 5MB 10 2 MB Table 2 Bus bandwidth requirements at different frame rates 2007 VIDERE DESIGN through installation steps for the low level drivers You may need your MS Windows OS CD to install some files The STH MDCS3 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 4 1 2 Linux Hardware and Driver Installation Linux kernels 2 4 or 2 6 kernels are required for operation Please see the Videre Design website www videredesign com support_svsInx htm for current information GCC 3 x 18 recommended as the compiler there is a separate SVS distribution for GCC 2 95 x but it is not as reliable 4 2 STH MDCS3 Software The STH MDCS3 C comes with the SVS stereo software and several sample applications including the GUI application described in this manua
22. horizontal and vertical directions are For monochrome HFOV 2arctan 3 84 f VFOV 2arctan 2 88 f For color 1280x960 or 640x480 15 STH MDCS3 USER S MANUAL gt Figure No 1 File Edit Window Help Range Resolufion for Three Different Lenses 120 100 80 60 40 Range Resolution mm 20 0 1 2 3 4 5 6 7 8 9 10 Distance to Object m Figure 6 1 Range resolution in mm as a function of distance for several different lens focal lengths acceptable illumination range can be extended by mechanical adjustment of the lens opening 6 7 Focal Length The focal length is the distance from the lens virtual viewpoint to the imager It defines how large an angle the imager views through the lens The focal length is a primary determinant of the performance of a stereo system It affects two important aspects of the stereo system how wide a field of view the system can see and how good the range resolution of the stereo is Unfortunately there s a tradeoff here A wide angle lens short focal length gives a great field of view but causes a drop in range resolution A telephoto lens long focal length can only see a small field of view but gives better range resolution So the choice of lens focal length usually involves a compromise In typical situations one usually chooses STH MDCS3 USER S MANUAL 2007 VIDERE DESIGN HFOV 2arctan 2 05 f VFOV 2arctan 1 54 f For color 1280x960 or 640x
23. is case external power must be supplied see Section 5 3 The PC operating system will normally recognize the STH MDCS3 and install the correct system drivers Please see the Videre support web pages www videredesign com support htm for specific information about installation for your OS At this point you should check to see that the STH MDCS3 has been recognized by the system 2007 VIDERE DESIGN STH MDCS3 USER S MANUAL Section 7 3 Images can be saved using the File menu A more complete description of the video capture program is in Section 7 The SVS programs are described in the SVS User s Manual and the SVS Calibration Addendum documentation that comes with that software It is helpful to review Section 7 in conjunction with the SVS documentation 2007 VIDERE DESIGN There are no user settable switches on the STH MDCS3 C 3 1 Hardware Schematic Figure 3 2 shows the design of the internal hardware of the STH MDCS3 C In the stereo imager module two CMOS imagers each of size 1280 x 1024 pixels digitize incoming light into a digital stream The imagers operate in progressive mode only that is each line is output in succession from the full frame The maximum video rate is 12 megapixels per second from each imager The imagers are synchronized to a common clock so that the corresponding pixels from each imager are output at precisely the same time Special interlace electronics convert the indivi
24. l For the most up to date information about installation please see the Videre Design website www videredesign com support_svsmsw htm To install the software under MS Windows execute the file svsXXX exe If you have installed a previous version of SVS the installation wizard will ask you if you want to un install the old version It is best to uninstall the old version then start the installation file again and install the new one The installation process will add the relevant interface and application software To install the software under Linux untar the file svsXXX tgz in a new directory which will become the top level directory of the software You should also set the environment variable SVSDIR to this directory and add bin to your LD LIBRARY PATH variable libsvscap so and svsgrab 1lib dl1l1 are the capture libraries for Linux and MS Windows respectively These libraries must be set to the correct ones for the STH MDCS3 10 STH MDCS3 USER S MANUAL 4 Installing the 1394 Host Card and Capture Software The STH MDCS3 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 4 1 The STH MDCS3 C comes with interface software for either MS Windows 2000 XP or Linux 4 1 1394 Hardware
25. lens holder opening To insert a lens place its back end on the lens holder opening as straight as possible and gently turn it clockwise looking down at the lens until it engages the threads of the lens holder If you encounter a lot of resistance you may be cross threading the lens Forcing it on will damage the lens holder or lens threads 2007 VIDERE DESIGN the focal length based on the narrowest field of view acceptable for an application and then takes whatever range resolution comes with it 6 8 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 1s 2 r Ar Ad bf where b is the baseline between the imagers f is the focal length of the lens and Ad is the smallest disparity the stereo system can detect For the STH MDCS3 C b is 90 mm and Ad is 0 325 um pixel size of 5 2 um divided by the interpolation factor of 16 Error Reference source not found plots this relationship for several focal lengths At any distance the range resolution is inversely proportional to the focal length 6 9 Field of View The field of view is completely determined by the focal length and the image size The color and monochrome versions have slightly different imagers and so the calculation depends on the imager type The formulas for the FOV in
26. ochrome a ei 8 intemal Transmittance 40 T E h Lil E E a ro Gao a a er Wavelength inm 200 300 400 00 600 rod 300 900 1000 1100 Wierelength in mim 24 2007 VIDERE DESIGN 25 STH MDCS3 USER S MANUAL 11 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
27. ram The diagram below shows the physical dimensions for the STH MDCS3 0 videra be grn 50 999 6708 Fax 0 bag STH 5 REV 4 Delrin and 4Slurminum Vf4 20 center mounting hole sas 0 31 offset mounting holes FFF r peu 123 liom 22 STH MDCS3 USER S MANUAL 2007 VIDERE DESIGN 1 7257 high x 95 2 long x 1 3 deep Size excluding lenses 190 g 6 7 oz without lenses 71 g 2 5 oz for 6 0 mm lenses 10 Technical Specifications Weight 10 1 Specifications Linux kernel 2 4 2 6 MSW 2000 and XP 2 format CMOS Micron MT9M001 1280x960 active area Progressive scan SVS software Imagers Color or monochrome Digital Camera Specification Version 1 30 1280x960 1024x768 color only Formats 640x480 10 2 Imager Response Color 8 bit monochrome or Bayer color pattern 3 75 7 5 15 30 HZ Quantum Efficiency Color 3 125 6 5 12 5 25 HZ Blue Max 7 5 Hz at 1280x960 Green Max 15 Hz at 1024x768 l DEE Red WAYS Synchronization Internal pixel locked i External 60 us 6 0 mm F 1 4 C mount included 3 5 mm 8 mm 12 mm and 16 mm lenses optional Frame Rates 5 4 2 i Lil E 5 Wavelength nm 23 STH MDCS3 USER S MANUAL 2007 VIDERE DESIGN 10 3 Imager Response Monochrome 10 4 Filter Transmittance Thickness in mir 7 Quantum Efficiency Mon
28. s may input color images STH MDCS3 C only set video digitization parameters exposure gain red and blue balance and subsampling modes All of these parameters can be set with the SRI Small Vision System They are also accessible to user programs through the capture API Section 8 User controls for frame size and sampling modes are on the main capture window dialog Video digitization controls are accessed through a dialog invoked with the Video menu item Figure 7 1 shows the dialog 7 1 Color Color information from the stereo digital head STH MDCS8S3 C only is input as raw colorized pixels and converted by the interface library into DER a Video Parameters Gamma Fed Blue fo fe Figure 7 1 Video Parameters dialog 2007 VIDERE DESIGN There are automatic modes for both exposure and gain In auto mode gain and exposure are controlled by the host PC which samples the incoming image and sends commands to the stereo device The auto algorithm will try to reduce gain as much as possible while still maintaining overall light levels in the image Auto mode for gain and exposure can be set separately For the STH MDCS3 it is recommended to use a manual mode for gain and auto mode for exposure Indoors set the gain to a higher value outdoors set it to a low value With exposure in auto mode the light on the image will be adjusted by changing the exposure Te SRI SVS Stereo Sys
29. such a topology At a maximum it will need about 60 of the bandwidth of a 400 MBps connection 5 2 IEEE 1394 Host Interface The host computer must have an available 1394 port Some portables and desktops come with built in ports If these are 6 pin ports they can be connected directly to the STH MDCS3 C Sony laptops also support an alternative 4 pin 1394 cabling which has the signal pins but no power There are adapters that convert from 4 pin to 6 pin styles these adapters use an external power supply transformer If the host PC doesn t have a built in 1394 port one can be added by installing a 1394 PCI card or PCMCIA card for laptops 1394 PCI cards have 6 pin ports and supply power PCMCIA cards do not have the STH MDCS3 USER S MANUAL 2007 VIDERE DESIGN 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 IEEE 1394 hub power port IEEE 1394 with power port IEEE 1394 Cable Cable IEEE 1394 Cable to PC Power Power 12 VDC gt 150 12 VDC gt 150 Figure 5 1 External power supply connections On the left is power supplied to a PC Card with a power port On the right power is supplied through a hub with a power port Power should be 7 to 16 VDC at gt 1 5 W Check the PC Card or hub for the type of power connector 13 2007 VIDERE DESIGN Once the threads are engaged continue screwing it
30. tem Video Butter File Device ideo Horopter Window 4 gt xott 4 H Multi Scale Swap F Color Capable Frame size Gamma correction Sampling mode Figure 7 2 Frame size and sampling controls in the main capture window 18 STH MDCS3 USER S MANUAL STH MDCS3 C do not necessarily have gamma correction This is not a 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 7 2 7 3 Video Digitization Parameters The CMOS imagers have electronic exposure and gain controls to compensate for varying lighting conditions The exposure can vary from a maximum of a full frame time to a minimum of one line time Gain is an additional amplification of the video signal for low light situations It is settable from 0 to 18 dB 1x to 8x Both imagers are treated in exactly the same manner It is not possible to set a different exposure or gain on each imager Digitization control can operate in either manual or automatic mode Refer to Figure 7 1 for the controls in the video capture program Both manual and automatic modes are available for the STH MDCS3 C devices In manual mode the user program sets the exposure and gain The exposure and gain are based on a 0 to 100 scale Here are some tips for setting exposure and gain
31. tically performed on camera and all the pixels are used For 320x240 frame sizes binning is performed by the SVS software The relative amounts of the three colors red green blue affects the appearance of the color image Many color CCD imagers have attached processors that automatically balance the offsets among these colors to produce an image that is overall neutral called white balance The STH MDCS3 C provides manual color balance by allowing variable gain on the red and blue pixels relative to the green pixels Manual balance 15 useful in many machine vision applications because automatic white balance continuously changes the relative amount of color in the image The manual gain on red and blue pixels is adjusted using the Red and Blue controls on the Video Parameters dialog For a particular lighting source try adjusting the gains until a white area in the scene looks white without any color bias 7 2 Gamma Correction To display properly for human viewing most video images are formatted to have a nonlinear relationship between the intensity of light at a pixel and the value of the video signal The nonlinear function compensates for loss of definition in low light areas Typically the function is x where y is 0 45 and the signal is called gamma corrected Digital cameras such as the 17 STH MDCS3 USER S MANUAL 7 User Controls The CMOS imagers are fully controllable via the 1394 interface User program
32. tion check the box and then press the Save button This choice is downloaded and stored in the device and will cause 50 Hz operation every time the STH MDCS3 is accessed To change back to 60 Hz uncheck the box and again save it to the device It 1s also possible to clear any calibration parameters that are saved on the STH MDCS firmware If the calibration parameters are present the Clear Calibration button will be activated Pressing this button will clear the parameters See the SVS Users Manual for information on saving and loading calibration parameters on the device 20 STH MDCS3 USER S MANUAL STH MDCS3 e 50 Hz operation This parameter can be changed by using the Firmware Parameter dialog Sets Device Type Fi Version 0204 Camera Version 3 Camera Imager 1 Device Type Steren m Firmware Parameters Color Capable yes Device ID ao 6 Device Parameters Max Width 0 Max Height 0 Lettered Figure 7 3 Firmware parameters dialog STH MDCS3 USER S MANUAL 2007 VIDERE DESIGN 8 Interface Software API Please see the Small Vision System manual for information about the software API for capturing and saving images 21 STH MDCS3 USER S MANUAL 2007 VIDERE DESIGN C The larger hole is threaded for a 7 20 machine screw standard tripod mounting screw The two smaller holes are threaded for 6 32 machine 9 Physical Dimensions and Mounting SCTEWS Diag
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