Caltrans’ New Technology and Research Program
Instructor: Kevin Almeroth
June 14, 2001
In support of this project, I developed an animated computer simulation of the robotic incident response system that is envisioned by the ATON researchers. This will provide a way to quickly and concisely present the basic idea of the project to anyone interested in learning about, or possibly providing additional funding for, the project. Using a program called Maya, from Alias Wavefront, I modeled the system as a two-car monorail that travels on the concrete median, or “K-rail,” of a freeway to the site of an incident. Upon its arrival, the system deploys a CMS (Changeable Message Sign) to alert motorists of the incident, ODVS and rectilinear cameras to allow remote operators to closely monitor the incident site, and wireless-controlled miniature vehicles carrying expandable cones to cordon off the area of the incident. The animation is about a minute in length and shows the process happening from various “camera angles,” or virtual points of view. Figures 1-A through 1-J below show selected frames from the animation in order to give an idea of how it looks.
Figure 1 - A
Figure 1 - B
Figure 1 - C
Figure 1 - D
Figure 1 - E
Figure 1 - F
Figure 1 - G
Figure 1 - H
Figure 1 - I
Figure 1 - J
Inductive Loop Signatures Embedded in Video
Another Caltrans funded project being worked on at UCSB involves a technique known as “Data Hiding,” where a digital file is embedded into a digitized video stream and can later be extracted. This can be used for security applications, but it is also convenient for automatically correlating data with a corresponding video clip. Caltrans’ idea is to use this technology to provide files for automated vehicle identification using both machine vision and inductive loop signature technologies. Caltrans is looking for ways to automatically identify and re-correlate vehicles on a given stretch of highway. This ability can be used to detect incidents and congestion and to determine up-to-the-minute travel times. Therefore, the data to be “hidden” in a video clip of a specific vehicle is that vehicle’s corresponding inductive loop signature.
A conventional inductive loop detector consists of an insulated wire, which is coiled and embedded in the pavement, and an electronic detector card. The detector card is physically connected to the coiled wire, typically through a cable in an underground conduit, and sends alternating current through the coil. This arrangement is basically an LRC circuit, where the coil of wire is the inductor, or “L,” in the circuit. This circuit can be tuned to resonate at a certain frequency. When a vehicle passes over the coiled wire, its metal provides and easier path than air for the magnetic field induced by the current in the wire to travel through. This causes a shift in the resonant frequency of the circuit, which can be used to measure the change in inductance of the wire coil. In conventional applications such as traffic signals, the detector card provides a bivalent (“on” or “off”) output to a micro-processor based traffic controller when the inductance has changed above a settable threshold. Hence, the only information provided is whether there is a vehicle on top of the wire coil. In a “speed trap” configuration, the speed of a vehicle can be determined using two loop detectors, with the two wire coils placed close together in the same lane. The controller can then be programmed to measure the time between “on” signals from the two detector cards and divide this number into the distance between the two wire coils.
Recently, detector cards have been developed with electronics that run fast enough to measure changing inductance values many times as a vehicle passes over the loop. By storing the measured values, an “inductive signature” is produced that is characteristic of certain classes of vehicles, or, given enough measurements, even individual vehicles. These measurements can also be used to determine the speed of a vehicle passing over a single loop by determining the “slew rate,” or rate of change in inductance values during the leading and trailing edges of the signature (See Figure 2). The loop signatures that the New Technology and Research Program have obtained from its industry partner have a “sample rate” of 4 Khz (i.e. there is a discrete inductance measurement every 0.25 milliseconds). It is hoped that through this research project, and others like it, techniques will be developed to gather and fuse enough information in the field to allow remote processing centers to automatically identify and re-correlate vehicles on a given stretch of highway.
During the Winter 2001 quarter, we moved our off-campus facility to a temporary location, and this past Spring 2001 quarter, we finally moved it to its permanent location at 6950 Hollister Avenue. Because the office building into which we moved is new, there were no interior walls; it was basically a shell, and our lease included an architect and contractor to design and build our new office space. I worked with these people during the planning and construction phases to specify the floor plan and the layout of the electrical circuits and communications outlets (See Figure 3). I also worked with UCSB communications services to specify lines we needed pulled from the building’s main communications room to the UCSB/Caltrans communications room (room number 1 in Figure 3). One of these lines was a multi-mode fiber cable to accommodate an OC-3 SONET (synchronous optical network) circuit from Cox Communications that is used to link our on campus LAN in 3432 South Hall with the LAN at our new office (See Figure 4 in the next section). Another line is a “D-screen” cable containing two shielded twisted pairs that will be used for our ISDN PRI (primary rate interface) line. This line consists of a T-1 line, which provides the layer one protocol, and ISDN signaling, which is transmitted on channel 24 of the T-1 line and provides the layer two protocol. This allows the line to be switched through the phone company just like a POTS (“Plain Old Telephone Service”) line, instead of being just a point-to-point connection like a conventional T-1 line. The terminal equipment for this line is an Ascend MAX 6000 IMUX (Inverse Multiplexer) which, in turn, connects to a PictureTel Concorde 4500ZX video Conferencing system. Finally, a copper pair cable was pulled for our POTS and ISDN BRI (basic rate interface) lines.
Now, at the end of the Spring quarter, we’ve finally moved in all of our furniture and have Internet, phone and video conferencing connectivity to our new office.
CalREN-2 is short for California Research and Education Network, and links various California Universities and research institutions via high speed OC-12 and OC-48 fiber optic connections. During the Spring quarter, I helped establish an OC-3 (155 mbps) VC (Virtual circuit) from our facility at 6950 Hollister Avenue to the Computer Vision and Robotic Research Laboratory at UCSD. This link uses the CalREN-2 infrastructure from the UCSB switch-room to UCSD.
The first step in doing this was to relocate one of our ATM switches and re-patch some fiber pairs and jumpers. In our previously existing setup (See Figure 4-A), the Fore ASX200BX switch sat in our South Hall lab on campus. I needed to connect a port on this switch to one on the “CENIC” (Corporation for Education Network Initiatives in California) switch (Cisico Light Stream 1010), which is the gateway to CalREN-2. The CENIC switch sits in the UCSB switch-room along with the Positron fiber MUX that provides our link to the Cox Communications SONET ring and, thus, links our on campus LAN with the LAN in our off campus facility at 6950 Hollister Avenue. Ideally, I would have used one of the muli-mode fiber pairs in a six pair cable that runs from South Hall to the switch-room, but as can be seen in Figure 4-A, all six pairs were used. Therefore, I had to move the ASX200BX to the switch-room so I could connect it to the CENIC switch with a fiber jumper (See Figure 4-B). I used another fiber jumper to connect the ASX200BX to the Positron fiber MUX. This freed fiber pair 5 & 6, which I used to connect the ASX200BX to our Fore 2810 Ethernet-to-ATM hub, which remains in the South Hall lab. Finally, I installed an ATM NIC in a PC and connected a fiber jumper from the NIC to a port on the ASX1000 switch at 6950 Hollister Avenue.
Once the physical connections were in place, it was time to configure the logical ones. The goal was to establish an IP connection between the PC at 6950 Hollister and a PC in the CVRR lab at UCSD. Host PCs connected to the ES-3810 at 6950 Hollister and the ES-2810 in 3432 South Hall are logically bridged through a LANE (LAN Emulation) VLAN configured on the Fore ATM switches. The PCs at the CCVR Lab to which we needed to connect are attached through an Ethernet module to a 3COM Cellplex 7000 ATM switch, which also runs the LANE VLAN protocol. Unfortunately, the CENIC switch and other CalREN-2 equipment don’t support virtual LAN protocols. Therefore, I configured the ATM NIC at 6950 Hollister to run the RFC 1577 classical IP (CLIP) over ATM. In this configuration, the IP addresses of the ATM NIC and an interface on a Cisco 7500 router at the UCSD end of the virtual circuit are statically assigned (i.e there is no ARP server). I then configured a PVC (permanent virtual circuit) from the port on the ASX1000 into which the ATM NIC plugged, to the port on the ASX200BX that was jumpered to the CENIC switch. I set the VCI (virtual channel identifier) and VPI (virtual path identifier) numbers to match the ones on the PVC that the CalREN-2 netwrok guy had configured to exit the CENIC switch. At the UCSD end, the PVC exits CalREN2 at a Cisco 8540 ATM switch and continues to a CLIP interface on the Cisco 7500 router. The Cisco 7500 converts IP packets from the CLIP protocol to the LANE VLAN and passes them through the interface connected to the 3COM Cellplex 7000 ATM switch in the CVRR lab.
I can now ping a PC in the CVRR lab at UCSD from the aforementioned PC at 6950 Hollister, and we now have a high-speed dedicated link over which we can exchange IP data with the researchers at UCSD.
Figure 4 - A
Figure 4 - B