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NOTE This website covers the aspects of the Virtual Cable™ technology that have been published in our patent applications. Subsequently, we have made design breakthroughs that significantly reduce the size of the Virtual Cable™ hardware and allow greater flexibility in the shape of the display enclosure. Information on these innovations can only be released under a non-disclosure agreement.
The Virtual Cable™ car navigation technology consists of a unique human-machine interface (HMI) and a breakthrough true-3D engine hardware making this interface commercially feasible today.
In this section, we describe the hardware and software components of the Virtual Cable™ technology. The HMI component is explained in the Virtual Cable™ section of this website and, in great detail, in our patent applications, where we also show how the Virtual Cable™ can be used for speed control, tailgating avoidance, POI alerts, alternate route presentation, collision avoidance, and off-road navigation.
True 3D is our technology to display stunningly "out-there" 3D images at any distance in front of the car - as close or as far as needed.
Our images are immersed into the landscape itself, making them as natural and non-distracting as trees and houses, providing enduring comfort and an effortless, instinctive situation awareness to the driver. We achieve this by creating volumetric images and then projecting them to the driver using our specialized head-up display (HUD).
Volumetric displays are in their own league among various 3D imaging technologies. They are the only displays capable of showing 3D images so realistic that no viewer (and even no optical instrument) can determine if the observed 3D object is really where it appears to be or if this is just an image projection.
Of course we can't demonstrate full capabilities of our true-3D technology on a flat computer screen. However, one of its most important features can still be shown here. Our true-3D engine can produce 3D images that appear completely stationary to the ground:
Animation 1. Our true-3D engine can show images that are stationary to the ground and appear to be part of the landscape.
Since the Virtual Cable™ is projected in a fixed position over the road, its perspective view changes in complete agreement with the surrounding landscape. This gives the viewer surprisingly good depth perception even on a flat computer screen! And because our 3D engine adds all the other depth cues that can't be shown in a flat imge (like biocular stereoscopy, focus, motion parallax, etc.) its depth projection can be stunningly compelling.
To make the accurate depth perception even stronger, the Virtual Cable™ can have some uniform features (in this case gaps) that may help some drivers understand and use the interface quicker. Such features are added only through software and therefore can easily be made controllable by the end user.
Our breakthrough in the volumetric engine design made our true-3D technology inexpensive and robust enough to be used in the automotive environment. Many other applications (military, transportation, aviation, marine, etc.) will also benefit from our 3D engine.
Unlike all other existing and proposed automotive 3D HUD designs, our true-3D imaging technology:
In addition, our 3D engine can produce high-definition images that are smooth, elegant, and, when needed, bright enough to be visible against a sunny sky.
The Virtual Cable™ image that guides the driver is produced by a unique, volumetric head-up display (HUD) device located behind the dashboard of a car. We call this HUD the Virtual Cable™ display.
The Virtual Cable™ display avoids the usual design problems associated with the existing automotive HUDs:
The Virtual Cable™ display does not alter the appearance of the car. As shown in the following illustration, the only hint of its presence is a fine mesh embedded in a transparent panel (1) in the dashboard in front of the driver. The color of the mesh may be set to match the appearance of the dashboard.
The Virtual Cable™ display must be factory-installed in a car and can be integrated with ANY method of route planning, including:
The Virtual Cable™ display is built from existing and proven components currently employed in applications unrelated to navigation. These components meet the usual requirements for automotive applications (longevity, safety, reliability, etc.), even under extreme environmental conditions.
Routine engineering work is required to get the Virtual Cable™ display ready for mass-production at market-acceptable costs. The research phase has been completed. We've developed a project plan to produce a detailed technical design suitable for mass production.
Animation 2. The Virtual Cable™ display design basics.
This animation is the second part of the introduction to the Virtual Cable™ display design. It explains the workings of its key component, the primary volumetric display. Please make sure that your computer's audio is on.
Animation 3. The primary volumetric display in motion.
All of the Virtual Cable™ display hardware is housed in a single enclosure. The arrangement and size of the internal hardware components (and therefore the shape and size of the enclosure) can be modified to accommodate a variety of vehicle designs.
The following animation illustrates one possible outline of such an enclosure, specifically designed to have a minimum impact on the existing structural design of an existing car model (Chrysler Sebring). As has been shown in Fig. 1, the Virtual Cable™ display enclosure will be hidden behind the dashboard, so this animation shows a car with the dashboard removed.
Animation 4. The Virtual Cable™ display in an existing car design. Note the minimum impact on the existing structural design of the car.
Our patent applications describe all of the possible designs of the Virtual Cable™ display. Here we briefly outline only one potential design (and without the technological innovations mentioned in the NOTE above). Also, for the sake of clarity, we purposely avoid most of the technical details and specifications, which can be found in the patent applications.
The major components of this design can be categorized as follows:
NOTE The components are not drawn to scale and the drawings are only schematic representations.
Our unique volumetric display consists of the primary volumetric display and the viewing optics. The viewing optics relay the real optical image produced by the primary volumetric display and, utilizing the vehicle's windshield as a head-up-display (HUD) combiner, present it to the driver as a 3-dimensional Virtual Cable™, positioned within the outside scenery in front of the vehicle.
Our primary volumetric display (PVD) can be broadly classified as a laser scanned swept volume type display. The job of the PVD is to produce a primary Virtual Cable™ image - a small, 3-dimensional, volumetric real optical image. To produce the primary Virtual Cable™ image, the laser beam is scanned obliquely from the laser projector (described later) onto the front surface of the projection screen (5), which is mounted on the voice-coil actuator (6). The graphic mode used is a 3-D vector mode, with a variable spot size and profile. The scan refresh rate is normally a flicker-free 60 Hz.
The radius of the rim of the projection screen is 35 mm and the range of its motions is less than 3 millimeters. These dimensions define the working volume of the PVD, i.e. the volume swept by the projection screen surface in its motions, and thus the volume within which the primary image is contained.
The projection screen (5) is mounted on the voice-coil actuator (6). It has a special coating to give it: heat-resistance; lambertian diffusion characteristics; and low absorption at visual and near IR wavelength yet high emissivity at far (thermal) IR. The screen actuator (6) uses a voice coil motor similar to a bass-midrange acoustic speaker, except for the heat hardened surround and the above mentioned optical coating of its (concave) single piece cone. Additionally, it has a screen position sensor used for control purposes (not shown). In normal operation, the screen is actuated with a complex signal. This signal depends on the currently displayed shape of the Virtual Cable™. The laser, focuser, scanner and the screen are all actively, synchronously, controlled by the electronics module (11) to draw a 3-D line with a finely controlled thickness and brightness profile.
The laser projector is a PVD subsystem consisting of a light source, light beam focuser and profiler, scanner and accompanying optics. Its job is to focus and scan the light beam onto the moving projection screen.
The light source for the PVD is a laser module (10), employing an edge emitting semiconductor laser diode, producing modulated output of up to 30 mW (continuous) at about 635 nm wavelength, with a single mode round truncated-gaussian beam of about 3 mm in diameter.
The laser beam focus and its profile (i.e. its spherical aberration) are independently adjustable in real time while the beam is scanned by the focuser/profiler (9). This device employs two small lenses axially mounted on voice coil actuators. The mechanical beam scanner (8) can be either a pair of x-y galvanometers, or a tip-tilt mirror (shown). When a tip-tilt mirror is used, the additional beam expanders and compressors are employed to fill the working aperture of the deflector with the beam (7), as shown. These are not generally needed if the galvanometers are used. The required bandwidth of the scanner is less than 2 kHz, with the most power needed at the lower end of the spectrum.
The Viewing Optics is the last major system component of our Virtual Cable™ display. Its job is to convert the real optical image from the primary volumetric display into a virtual image in front of the vehicle.
We employ a high magnification, 2 stage. viewing optics. The first stage is a relay lens group (4) with an entrance pupil radius of 36 mm, working at an object numerical aperture of 0.35 and a 2.3 magnification. It is followed by a second stage, a large (about 155 mm radius) ocular optics group (2). The system exit pupil (a "biocular eyebox") of 100 mm diameter is adjustably positioned to the driver's face, typically allowing the driver 160 mm of head movement without blanking out the image. The 160 mm is sufficient; it is more than twice the typical distance between the human eyes.
The large transversal magnification of the viewing optics results in a generous binocular horizontal field of view of at least 27 degrees (i.e. the field of view comprising the field seen together by both eyes (in 3-D) as well as flanking left and right fields seen only by the right and left eye, respectively).
We have devised a method to test this field of view in a moving car and we have found it adequate for effective and comfortable navigation in normal driving situations. If desired, the field of view can be enlarged even further by combining two or more of the Virtual Cable™ displays (as described in our patent applications).
The longitudinal magnification of the viewing optics is even larger. The viewing optics are focused on the back limiting surface of the working volume of the primary display (i.e. the farthest from the entrance pupil of the viewing optics). This means that the light originating from any point on this surface is imaged at infinity (i.e. is collimated). In contrast, the front limiting surface of the working volume is conjugated to the optical distance of approximately 10 meters. In other words, the viewing optics are employed at a very large, to extreme, longitudinal magnification and optically translate the working volume of the primary display into the volume-of-view stretching from 10 meters to infinity. Because of such longitudinal magnification of the optics, the Virtual Cable™ image can stretch for hundred of yards inside the cone-of-view within the 3-D space in front of the car.
We use molded polycarbonate aspherics to achieve satisfactory correction of the system with a small number of optical elements. We also employ folding mirrors (3) to package the optics into an enclosure with an acceptably small footprint, and an additional optical element (not shown) for windshield curvature correction (see our patent applications for details).
We leverage the monochromaticity of the laser source to provide protection of the display unit from direct solar irradiation by using a narrowband filter as a top cover (1). This dark-ruby covering filter will also conceal the inner components of the display device (for esthetic reasons). A fine mesh (embedded in a transparent panel) can also be added. The color of the mesh may be set to match the appearance of the dashboard (see Fig. 1).
We use DSP based digital electronics. We integrate position estimator functions, Virtual Cable™ shape calculations and scanner/laser/focuser/screen controllers onto one circuit board (11) located within the Virtual Cable™ display enclosure. The GPS receiver, inertial sensors and communication devices are located outside the enclosure.
The control software utilizes data streams from GPS and inertial sensors together with the map data and requested route data to calculate the current shape and position of the displayed segment of Virtual Cable™. This process produces the data stream for the scanner/laser/focuser/screen drivers. It involves position estimator functions (e.g. a Kalman filter for fusing the GPS and inertial data, and map matching), Virtual Cable™ shape calculations (including coordinates transformation and scaling), projector signal calculations (including e.g. viewing optics optical distortion compensation) and self-calibration.
The control software uses optimizing algorithms to drive the laser, focuser/profiler, scanner and projection screen with lowest-bandwidth signal compatible with the current refresh rate and Virtual Cable™ complexity. The perceived look of the Virtual Cable™ depends solely on the shape (trajectory) of the line and its integrated brightness, not on how fast the spot was moved while drawing a given line section. This phenomenon is leveraged to limit as much as possible the scanner or screen maximum acceleration as when drawing a sharp bend in the Virtual Cable™.
In the device controllers, we combine closed loop for quick mitigation of random disturbances with feed-forward control for maximizing the devices performance.
The system provides a continuously updated and stabilized volumetric view of the Virtual Cable™. It estimates the vehicle position and orientation 60 times per second and uses this real-time data, together with the 3-D geographical (route) data, to re-calculate and re-draw the Virtual Cable™ with this frequency.
The position/orientation information is obtained from both the GPS and on-board inertial sensors. The two streams are combined ("fused") mathematically, together with the road network information, resulting in a continuously available and sufficiently accurate estimate of the vehicle position, orientation, speed (linear and angular) and acceleration (also linear and angular).
Based on this current data, the system obtains map data from the local data storage (periodically, as needed). It then calculates a digital representation of the three-dimensional shape and position and orientation of the Virtual Cable™ that will be displayed during the next refresh cycle of the display device. Then (using coordinate transformation calculations), the digital representation of the perspective view of the Virtual Cable™ (from the driver viewpoint) and a set of distances from the driver to all the points of the Virtual Cable™, are calculated. Since such a data directly relates to the geometry of the image that needs to be generated inside the primary volumetric display, it is used to calculate the signals to the controllers of the laser and the display actuators for the next display refresh cycle.
The brightness and the thickness data (of the line painted onto the screen) is needed to achieve the desired apparent thickness and brightness of the Virtual Cable™. It is calculated for each point of the visible Virtual Cable™. Knowing the projector geometry, the system calculates the laser power, position of the scanner and the screen and the setting of the focuser, for each such point. The brightness calculations take into account the current data from the ambient light sensor, resulting in the dynamically adjusted optimum Virtual Cable™ brightness based on the current light conditions.
Correction to counter the optical distortions of the viewing optics is included and an optimization algorithm is applied to lessen the demand on the relatively slow mechanical devices. This new digital data is then used by the device controllers to generate specific analog signals to steer the laser, focuser, scanner and the actuated screen to paint the desired image.
The scanners receive feedback signals from their respective devices (for closed loop control and calibration), and the scanner controller also receives the accelerometer data directly, to immediately compensate for any wobble or jarring (e.g. from the vehicle hitting a pothole) and provide a stable Virtual Cable™ image.
The Virtual Cable™ is essentially a one-dimensional line positioned in three dimensional space in front of the driver. The map data required by the Virtual Cable™ display (at any given time) needs only to describe the segment of the line currently visible to the driver. For the same traveled distance, the amount of map data required by the Virtual Cable™ display is much smaller than the amount of data needed for the traditional map displays.
The map data required by Virtual Cable™ display is commercially available today. Because the Virtual Cable™ is displayed high above the roadway, the strict accuracy requirements of "line on the road" displays are substantially relaxed. The map data currently being introduced to the market allows to render a 3D Virtual Cable™ with more than sufficient degree of accuracy (for example, NEXTMap® mapping effort by Intermap Technologies).
Our Virtual Cable™ could be also be used with less accurate 2D data widely available today. Our "aligned with the driver's head" data fusing method, described in our patent applications, can ensure satisfactory image correlation with the road for a reasonable distance in front of the driver.
The Virtual Cable™ displays for trucks and buses work just the passenger car units. The only major difference is their location in a vehicle, above the driver's head instead of uder the dashboard.
Unlike in cars, the Virtual Cable™ display do not have be factory-installed in a truck. After-market installation can be easy. The units can be seamlessly integrated with the current fleet management systems.
We have applied for patents on the Virtual Cable™ technology in the United States, European Union and in Japan. These applications cover:
Our applications were prepared by Ron Slusky, a recognized authority on the art of patent claims design and a former head of the patent department at Lucent Technologies.
The Virtual Cable™ patent applications in US, EU and Japan are based on our international PCT application, International Publication Number WO 2005/121707 A2, filed under the international Patent Cooperation Treaty (PCT) with the World Intellectual Property Organization (WIPO).
The priority date for all of the Virtual Cable™ patent applications is June 3, 2004.