System and method for monitoring and managing driver attention loads

[0001] The present patent application claims the benefit of U.S. Provisional Patent Application Nos. 60/357,135 filed 19 Feb. 2002 and 60/418,171 filed 15 Oct. 2002. Said applications are expressly incorporated herein by reference in their entireties.

[0002] 1. Field of the Invention(s)

[0003] The present invention(s) relate to systems and methods that facilitate driver safety; and more particularly, to remedies against the effects of drowsiness, distraction and similar compromising conditions to a driver's driving capabilities.

[0004] 2. Background of the Invention(s)

[0005] Drivers of all types of vehicles are often unaware of the effects that drowsiness and distraction have on their own abilities for vehicle control. Humans in general, and particularly as drivers, are poor judges of their own performance capabilities. Typically, a driver's self-impression of his or her capabilities is better than actuality. Even persons who have basically good driving skills, will not perform uniformly at all times when behind the wheel of a vehicle. Furthermore, there are many times during driving trips that very little demand is placed on the driver with respect to execution of driving tasks. As a result, drivers are lulled into states of mind where little attention is being devoted to the driving task. Not surprisingly, driver inattention is a leading cause of vehicular collisions, and especially automotive collisions. According to a Nation Highway and Transportation Safety Administration (NHTSA) study of over two and one-half million tow-away crashes in a year's time, driver inattention is a primary cause of collisions that accounts for an estimated twenty-five to fifty-six percent of crashes. In that study, inattention was defined as having three components: visual distraction, mental distraction (looking without seeing) and drowsiness. Common crash types caused by inattention are: rear-end collisions, collisions at intersection, collisions while lane changing or merging, road departures, single vehicle crashes, and crashes that occur on low speed limit roadways.

[0006] Drowsy drivers are a well known phenomenon. At least one survey has indicated that fifty-seven percent of drivers polled had driven while drowsy in the previous year, and twenty-three percent had actually fallen asleep at the wheel. It is known that fatigue impairs driver performance, alertness and judgment. Collisions caused by drowsiness are a serious road safety problem, and fatigue has been estimated to be involved in as many as twenty-three percent of all crashes.

[0007] From a technological perspective, there is an ongoing and rapid increase of new information systems and functionalities that may be used within vehicles including mobile telephones, navigation aids, the internet, and other types of electronic services. The effect of mobile telephone use on drivers has been foremost in the public eye because of their widespread use, but sales of navigation aids and IT services are also growing fast. Mobile telephones alone have been estimated to have caused 300-1000 fatalities in one years time in the United States, and this is projected to reach 4000 fatalities per year in 2004. Distractions such as handheld telephone use, sign reading, eating food, interaction with other passengers, observing objects and manipulating devices in-the vehicle have the potential for capturing a driver's attention in an excessive way and thus also compromising safety. It is especially important that driving safety not be compromised as these new types of services and activities become more common place in the driving environment.

[0008] Driver workload increases based on utilization of these new functionalities and technologies. In this context, “workload” should be understood to refer to how busy a person is and the amount of effort they need to perform required tasks. When a driver has many things to do and is experiencing high workload, a high attention demand is being made on the driver in that there is much to be done at the same time. Drivers often attend to things that are not related to driver control of the vehicle and are therefore technically irrelevant to the driving situation. These things are often called secondary tasks and are potential distracters from driver attention to primary driving tasks. A secondary task becomes a distraction (including visual-, auditory-, cognitive-, and biomechanical distractions) when the driver's attention is captured thereby to a degree that insufficient attention is left for the primary control tasks of driving. As a result, driving performance such as lane keeping and speed control are compromised as ultimately is safety.

[0009] Driving tasks and secondary tasks overlap in the sense that some secondary tasks are driving related as diagrammatically shown in FIG. 1. Two difficulties arise from this relationship between the driving and secondary tasks. First, it can be difficult to delineate which secondary task information is “irrelevant to the driving situation” and which is not; and second, certain driving related secondary tasks, for instance, looking for a street sign or planning a driving route may also compromise safety as graphically depicted in FIG. 1.

[0010] It should also be appreciated that the driver is often unaware of the effects of distraction on the driving task. Also, drivers cannot reliably determine when they are impaired by fatigue to the point of having a serious vigilance lapse or uncontrolled sleep attacks. The attention management systems outlined herein are intended to increase safety by assisting the driver in drowsy, distractive, and/or high workload situations.

[0011] The attention management systems and methods disclosed herein have as an objective to increase safety by assisting drivers in drowsy, distractive, and/or high workload situations. Functional specifications are provided for a number of attention management systems that can be characterized to include drowsiness managers, distraction managers, managers for distraction adaptation of forward collision and lane change warning systems, and workload managers that are at least in part controlled based on driving demand estimations observed or deduced from visual behavior of the driver. A hardware system that can be suitably employed to perform these driver attention management tasks is also described. A “platform” for development of the instant drowsiness and distraction manager based on Human Machine Interaction (HMI) is also disclosed, as is description of continuous and post-trip attention feedback systems. The HMI approach has as an objective thereof to counteract driver inattention by providing both imminent collision warnings, as well as attention-feedback to cause positive behavioral change.

[0026] In at least one embodiment, the present invention provides a system and method that enables the implementation of attention management concepts in a vehicle, including exemplary hardware upon which the inventive functionalities can be accomplished. Several basic questions and goals are addressed herein, including: what visually derived support do drivers need and how should it be conceptualized to achieve acceptance; how can real-time recognition of driver visual behavior be applied to reduce driving errors and prevent accidents; what is the commercial feasibility of implementation. Functional descriptions are provided for exemplary drowsiness managers; distraction managers, distraction adaptation of forward collision and lane change warning systems; and workload managers. Systems and methods for implementing driving demand estimation from visual behavior are also included.

[0027] One or more of these systems and methods are individually, as well as collectively, described as making-up a so-called attention management system. One possible component of these systems, as well as a component of the several inventions described herein, is the attention support demonstrator that can be used to implement these systems and methods for demonstration and testing. Examples of driving demand estimation from visual behavior are also described herein.

[0028] In one embodiment, the attention management system includes hardware for (1) sensing, (2) computation, (3) HMI, and (4) electrical supply. The units or functional modules can be exemplarily configured (interrelated) as illustrated in FIG. 2, and are suitable for implementation in such vehicles as automobiles and trucks.

[0029] A visual behavior sensor is employed such as that which is available from the company, SeeingMachines, and which can be adapted to be installed in a vehicle. This type of system can include (1) a stereo camera head, (2) a personal computer (PC), and (3) appropriate driving software. A visual behavior sensor such as that produced and sold under the trade name SMARTEYE may also be optionally employed.

[0030] Vehicle performance signals can be acquired from the CAN bus. A steering wheel angle sensor can also utilized, as well as lane tracking hardware and software. An annotation box and video recording hardware is utilized. An onboard personal computer, or similarly capable computing device is utilized. Alternatively, and especially to facilitate testing and implementation, a laptop computer can be employed that exemplarily runs such software as “Director” and “Simulink.” An xPC can also be installed and utilized. From a hardware perspective, LED controller hardware is employed. Audio HMI (warning sounds, recorded messages) are provided for via the computing device. A touch-screen for user input can also be utilized. It should be appreciated that some of these embodiments are suitable for product development and facilitate system testing, but when commercialized, the several components are integrated directly into the vehicle.

[0031] A seat vibration arrangement or similar driver alert can be included. In a preferred embodiment, a LED HUD (heads up display) is employed. A LED array (display), controlled by a LED controller can also be utilized. An electrical supply for the entire system can be tapped from the carrying vehicle.

[0032] A drowsiness manager can be implemented in two configurations. In a first example, it is entirely PC based; that is, no external hardware or external communication capabilities are required. This embodiment is scenario based; that is, tracking of a drowsiness episode based on real PERCLOS (analysis that considers scan patterns, number and length of fixations, saccade latency and the like) data rather than in real-time. The hardware functionality stimulates the driver via such stimuli as a visual display such as LED-based or HUD, or physical stimulation such as seat vibration. In another embodiment, HMI hardware and Simulink communication is implemented.

[0033] A “platform” upon which several drowsiness manager countermeasures may be implemented is desirable, and upon which tests may be conducted. An exemplary platform for such implementation is schematically illustrated in FIG. 3.

[0034] The illustration of FIG. 3 may be considered to depict a director program. Such an arrangement is easy to change with respect to different HMI components; for instance, to provide (1) continuous information streaming to the driver, to provide (2) cautionary warnings, (3) eminent danger warning alarms, (4) driver response tests, (5) post trip summary information, and (6) operator input set-up menu(s).

[0035] In one embodiment of the invention, a caution warning to the driver is provided. The driver is able to choose between warning versions, but is not able to completely disable the warning. Exemplarily, a beep followed by an optional voice message warning can be played to the driver such as “<automated insertion of drowsiness cause>, ‘take a break.’” An icon can be alternatively displayed to the driver either individually, in conjunction with an audible warning, or together with a printed version of the warning.

[0036] Exemplary icon warnings are shown in FIGS. 4(a)-(d) for (a) large eye closure detection, (b) inconsistent steering detection, (c) inconsistent lane-keeping detection, and (d) driver drowsiness detection. One or more of these icons can be simultaneously displayed depending upon detected driver conditions.

[0037] In another embodiment, a microphone is included so that the driver can record or supply his or her own warning much like in a telephone answering machine and other customizable audio play-back devices.

[0038] In still another embodiment, driver physical-stimulation warnings are applied. Preferably, the driver can choose between warning-types in the set-up menu, but in at least one embodiment the operator is prevented from completely disabling the physical warning. An example of such a physical stimulation would be seat vibration.

[0039] In another version, a flashing “HUD” LEDs may be used to sharply stimulate the driver; again, alone or in conjunction with the other types of warnings described herein. In a preferred embodiment, capabilities are provided to the driver for enabling up to three of the described warning types to be simultaneous presented when active.

[0040] A driver response functionality; that is, reaction-time to a signal, is also provided. With regard to this functionality, the driver is able to both enable and disable, as well as choose between warning versions in the set-up menu.

[0041] In a predetermined amount of time, for example five to eight seconds post-warning, a driver response function operates. Exemplarily, there will be a beep, with text “Press” under a button presented on a touch screen as illustrated in FIG. 5. If the driver does not react within the prescribed amount of time, or according to some other reaction time based algorithm, then an alarm warning will issue. This continues until the driver stops the vehicle, becomes alert and this fact is system-detected, or the driver turns the function off.

[0042] In order to provide customizing capabilities to the operator, exemplary options that may be selected via the HMI components are illustrated below:

[0043]

	HMI Component	Option(s)
	(1) Continuous	Continuous
	drowsiness	feedback on/off
	feedback	Choice of one
		of several versions
	(2) Caution	Voice message
	Warning	on/off
		Default
		message on/off
		User supplied
		message on/off
		Use multiple
		icons or Use
		default icon
	(3) Alarm/	Choice of following
	Stimulation	(at least one
	Warning	must be checked)
		Seat
		vibration
		on/off
		Sound on/off
		HUD visual
		warning on/off
		Fan (not
		implemented in
		iteration 1)
		Scent (not
		implemented in
		iteration 1)
		Cut gas (not
		implemented in
		iteration 1)
		Drive to roadside
		(not implemented
		in iteration 1)
		Use multiple
		icons or Use
		default icon
	(4) Driver Response	Driver response on/off

[0044] A distraction manager can be exemplarily implemented in two embodiments. In a first embodiment, the distraction manager is entirely PC based with no external hardware or communication capabilities. It is scenario based; that is, a timeline of a distraction episode is given rather than in real-time. The hardware functionality is simulated. A second embodiment is based on a hardware implementation that includes the capability of real time communication.

[0045] Another aspect of the invention is safety threshold based distraction warnings. Warnings are provided that inform the driver of safety compromising distractive behavior. As appreciated hereinabove, drivers are often unaware of the effects of their distraction on their driving capabilities. Thus a goal of the safety based distraction warnings is to give the driver feedback about driving control task performance decrements. That is, if distraction is detected (i.e. glance behavior is over an appropriate safety threshold and/or vehicle performance deteriorates during glance behavior), the system provides one or more of the following alerts. A sound such as a simple beep or a performance-specific voice message referring to which performance decrements have been detected may be provided. For example, if glance behavior is above glance safety threshold standards (e.g. EU recommended 4 glances or 2 second single glance duration, US AAA recommended 10 second total glance duration), then the message “Visual Distraction Detected” or “Eyes off road extensively” can be issued. If steering is deviant during secondary task glance behavior, then the message “Inconsistent steering during visual distraction” can be issued. If lane keeping is deviant during secondary task glance behavior, then a message such as “Inconsistent lane-keeping during visual distraction” can be provided. If large_speed_reduction is detected during secondary_task_glance_behavior, then a message such as “Large speed reduction during visual distraction” can be issued. If multiple_causes are detected, then a generic message such as “Visual distraction detected” can be issued. If control task intrusion is detected during secondary task glance behavior, during different road types or different demand levels, then a corresponding warning is issued. The form(s) of the warnings can include a driver recorded or provided message, a seat vibration in a front part of seat or gaze redirection as described hereinbelow.

[0046] The present invention disclosure includes a new concept of “gaze redirection” that is illustrated in FIG. 6. Therein, an interface directs the driver' eyes to the forward driving scene (i.e.; through the front windshield) if driver distraction is detected. Exemplarily, a wave of light following one or more of the three LED “lines” (left, center, or right) will be initiated depending on where the drivers' gaze detected. After a wave of light, a large circle may optionally light up and then the central line of LEDs will light up; each purposed to more clearly focus the driver's attention where needed. The exact placement and timing of the several LED lights is not critical, nor is the color. In fact, the timing may be subliminal; that is, so fast that they are not consciously perceived. Alternatively, the appropriate lights may be first slowly flashed and the driver evaluated by the system to determine if corrective behavior has taken place. If not, the flash timing, as well as light intensity may be increased.

[0047] The set-up menu for distraction feedback may have exemplary logic as shown below:

[0048]

	HMI Component	Option(s)
	(1) Continuous	Continuous
	distraction	distraction
	feedback	feedback on/off
	(2) Safety	Voice message on/off
	threshold	Performance specific message on/off
	based	Default/multiple cause message on/off
	distraction	User supplied message on/off
	warning	Seat vibration on/off
		Gaze redirection on/off

[0049] In another aspect, the present invention incorporates the concept of workload management with driving demand estimation derived from visual behavior of the driver. In general, the concept of a “workload manager” is a prioritization system that categorizes information and potentially delays presentation of the information to the driver until his or her workload is sufficiently low to avoid risk associated with the information's reception. The interfaces of integrated, in-vehicle information systems can be adapted to ensure that proper attention is being given to the driving task. The output from the distraction management algorithms referenced herein can be used as input to workload managers.

[0050] Workload managers of the type disclosed herein accurately measure driver workload using the driving demand visual activity measure of driving demand. Exemplarily, this is a non-bodily contact, on-board measure of how “visually active” a driver is; that is, head and eye movement (rotation) variability. This measure of head and eye movement is described in greater detail in U.S. Provisional Patent Application No. 60/418,171 filed 15 Oct. 2002, the disclosure of which is expressly incorporated herein by reference, including the “visual activity” algorithm described therein. Furthermore, the driving demand visual activity measure also enables new functionality in the Workload Manager HMI, disclosed herein.

[0051] One aspect of the workload manager is to pause dialogue of audible conversation or information. As examples, this includes system-initiated or auto-initiated information (e.g. text-to-speech email and non-critical navigation system information) and randomly-initiated spoken dialogue (e.g. incoming and outgoing telephone conversations) can be paused during periods of high visual activity.

[0052] As an example, a series of emails can be being delivered to the driver, for example, ten new emails from memory that are being “read” out loud by a text-to-speech system. During the course of such audio transmission, a period of high driver visual activity is detected by the management system. In response, the system pauses the audio transmission to avoid increasing the driver's attention load beyond pre-selected levels; such levels exemplarily corresponding to attention loads beyond which driving capabilities are compromised. Optionally, the management system can include an audible indication to the driver of such interruption via a tone or the like which may also serve as notice to the driver of the high attention load condition. The audible transmission can be resumed based on driver initiation or system initiation that is dependent on the system's detection of a sufficient reduction in attention load to a pre-selected level exemplarily corresponding to safe conditions for driver receipt of such audible information.

[0053] In another aspect, continuous and/or post-trip attention load feedback is enabled via the disclosed management system. This aspect has been enabled pursuant to the fundamental human behavior characteristic commonly referred to as the feedback principle; such principle generally holding that feedback enhances performance. This is true for both task/skill learning (e.g. learning to drive safely) and for job motivation. As appreciated hereinabove, drivers are typically poor judges of their own performance. The degree to which direct, accurate, immediate, and continuous information on task/skill performance is available is a key element in enhanced driver performance and motivation. Attention feedback constitutes a form of intrinsic driving feedback that has heretofore been otherwise unavailable to the driver. The approach is one of positive behavioral adaptation and lifestyle change rather than imminent collision warning. For example, some researchers believe that the main mechanism for increased alertness is “decision influence.” The concept of decision influence stipulates that information of this nature (driver attention load and state-of-alertness) will influence a driver' decision about whether to stop for rest, drink coffee, reduce alcohol consumption or change other such behaviors.

[0054] An objective of attention feedback is thus to encourage positive behavior change over one or more of a plurality (multiple) of time-frames, for instance: (1) immediate (e.g. short-term compensatory behaviors like changing posture or aborting a complicated task); (2) trip (e.g. stopping for a nap, turning off mobile phone); (3) day-to-day (sleeping more after a low attention day, removing video screen from front seat); (4) and long-term (adoption of a different sleep lifestyle or distraction attitude). This feedback increases driver self-awareness of inattentive behavior and enables better self-management.

[0055] Two main feedback types are considered. The first is continuous in-vehicle feedback that provides the driver with real-time attentive performance information, for example information presented while driving. This information is communicated in a way that, in itself, does not jeopardize safety. The concept is to provide a sort of attention-meter, alertness meter (alert-o-meter), or safe/unsafe driving performance meter. The second feedback type is post-trip feedback that provides the driver with more detailed attentive performance information once driving has stopped.

[0056] Saving post-trip feedback “to file” further allows fleet-based safety feedback to focus on source behaviors as opposed to outcome measures such as accident incidents. One option, perhaps contributing to driver acceptance, is the provision of a tiered system. In such a tiered system, drivers have continuous access to data, fleet managers have access to summarized data, and regulating agencies can be granted access to summary data. Therefore, in the instance of fleet drivers, the invention can be better enjoyed as a helpful tool, without necessarily having to induce driver apprehension about employer-reporting characteristics.

[0057] To be able to give attention feedback, the management system has to be operationalized. Inattention may be seen as being comprised of drowsiness/impairment, distraction, and high workload factors. Therefore, and as illustrated in FIG. 7, an integrated model considering each type of inattentiveness is preferred. Therein, one system model configured according to the present invention is shown that can selectively consider driver inattention, workload, and personal characteristics such as drowsiness and distraction.

[0058] In another aspect of the present invention, unique ways are provided for displaying various information or feedback to the driver. In the instance of continuous attention-feedback, FIGS. 8(a)-(c) demonstrate various “active” graphical displays for displaying real-time driver information that has been sensed or generated by the management system. As an example, the display can be of a “generic” or synthesized attention feedback quantity such as the level of attention/inattention as a combined measure of drowsiness, distraction, and workload. In the instance of FIG. 8(a), a simple stack of lights with no trend information is exemplified. In the instance of FIG. 8(b), an “aircraft radar type” display is utilized in which a box is positioned around the current level and trend information in the form of “fading out” is enabled. FIG. 8(c) demonstrates a histogram in which instantaneous “real time” information is shown as an elongating/retracting bar (relatively wide) on the right, with aggregate statistical values (average, median, and the like) for periods of pre-selected duration represented by the more narrow bars on the left. In this manner, trend information is demonstrated. In the illustrative example of FIG. 8(c), five previous periods are represented. It should be appreciated that any previous periods may be displayed according to the control logic for the display and memory capacity.

[0059] In another aspect, the present invention also provides real-time driver feedback in a comparative format against an indication of an optimal level of attention. An exemplary embodiment of such a display is illustrated in FIG. 9 where a driver may observe his or her degree of distraction or overload relative to optimum attentiveness.

[0060] In still another aspect, the invention may be used to measure detected periods of driver inattention, with notification of the state provided. The driver may then “ask” (e.g. by touching a screen, for instance) what the problem was and receive an explanation of the basis for the detected increased workload/inattention level. Such feedback can exemplarily be provided in the form of verbal messages and/or graphically as shown in FIG. 10. Therein, three graphic representations of drowsiness, distraction, and workload are depicted on the right, and a combination of the effects is demonstrated on the left where relative driver attentiveness is indicated.

[0061] As explained above, the aspect of trip-reporting can be highly advantageous for the driver' learning and behavior modification. Therefore, inventive ways to provide on-screen post-trip feedback are disclosed and exemplarily illustrated in FIG. 11. In this illustrative example, a menu choice from a display screen has been selected for post-trip feedback and the associated display of such measured characteristics as percent eye-closure, steering consistency and the like have been displayed in a historical format. Of course, this same information can advantageously be logged for later analysis and use.

[0062] The driver capabilities that have been discussed above can also be utilized for distraction adaptation of other vehicle systems such as forward-collision, rear-collision and lane-change collision warning (FCW, RCW and LCW)_systems. Rear-end collisions account for approximately twenty-eight percent of automotive crashes. Because driver inattention is a contributing factor in more than sixty percent of these collisions, collision warning and avoidance systems are important tools for reducing crashes and saving lives. One objective of the present attention management systems is to detect the co-occurrence of inattention and safety critical events in the traffic environment; for example, sudden braking of a lead vehicle and driver eyes-off-road conditions. Two examples of this can be used as visual behavior information to adapt forward collision—and lane change—warnings.

[0063] Integration of detection of quantified secondary tasks (e.g. by detecting button presses or eye movements) greatly enhances the collision warning system by dynamically adjusting the collision warning threshold according to whether the driver is engaged with a potentially distracting device or other type task. For example, the collision warning system could generate a warning earlier if it is detected that the driver is involved in a cellular telephone conversation. An early collision warning helps the driver react more quickly and avoid more collisions compared to late warning, or no warning at all. If the driver is inattentive with respect to a certain aspect of the driving task, for example looking away from forward when a likelihood of forward collision is detected, or has not looked sideways when a possible lane change collision is detected, then warnings of such conditions are initiated earlier. Studies have shown that even a one second earlier warning when drivers are looking away is highly effective for avoiding collisions.

[0064] If it is detected that the driver is attentive, then the warnings can be delayed or even cancelled. A delay in warning presentation allows more time for the forward collision and lane change warning algorithms to more certainly ascertain that a warning is needed, thereby reducing false alarms. Still further, driver cancellation wherein the driver chooses not to have collision warnings active when looking at the road or side mirrors would also eliminate annoying false alarms.

[0065] As an implementation strategy, in a first stage, such warnings may be “soft,” but increasing in intensity as conditions worsen and a crash becomes more imminent. In the instance of forward collision warning, a heads-up or screen display warning may first be called up, but later being joined by an audible warning sounded as crash conditions intensify. An example of such a warning and its control parameters (which may or may not be displayed to the driver) are depicted in FIG. 12 regarding forward collision situations and FIG. 13 regarding lane-change collision situations.

[0066] The detection features described hereinabove with regard to driver characteristics may be utilized in other environments and for other purposes than expressly described. The detection features may also be integrated for employment in other in-vehicle systems. For instance, as a passive safety feature, a “smart” airbag may be enabled that detects when the driver'/passenger' head is not in a proper position to receive a deployed airbag. Responsively, deployment of the airbag may be modified to accommodate the sensed head position.

[0067] In another capacity, sensed behavior could be used to identify the driver, or at least rule out that an authorized driver is behind the wheel thereby facilitating theft protection. The head and eye sensors could also be used to automatically configure mirrors, seat positions and the like. Mouth tracking can be used to enhance speech recognition accessories. Filters for oncoming headlights can be adapted, as can displays for the driver based on eye position and motion.