1. Field of the Invention
This invention relates to a warning system and a warning method, more particularly to a vehicular warning system and a vehicular warning method.
2. Description of the Related Art
A conventional vehicular warning system for use with a vehicle comprises a driver surveillance module for capturing images of a driver of the vehicle, and a processing module electrically connected to the driver surveillance module for determining, based on the captured images, a duration of shutting of an eye of the driver or changes in position of the driver's head so as to identify whether the driver is dozing off or distracted. However, the abovementioned system is apt to misjudge when the driver moves.
Another conventional vehicular warning system for use with a vehicle comprises an operation information generating module for generating operation information associated with operation of the vehicle, including, for instance, a lateral acceleration and a steering angle of the vehicle, and a processing module electrically connected to the operation information generating module for establishing a transfer function according to the operation information received therefrom so as to determine a state of a driver of the vehicle, e.g., whether the driver is dozing off. However, false determinations may arise if abrupt changes occur in the driver's driving behavior, such as when the driver makes a sudden change of lanes. Additionally, computational complexity of such warning system involving transfer functions is relatively high.
Therefore, an object of the present invention is to provide a vehicular warning system and a vehicular warning method capable of alleviating the above drawbacks of the prior art.
According to an aspect of this invention, a vehicular warning system comprises an image information generating module, an operation information generating module, a processing module, and an alert module. The image information generating module is for generating image information associated with at least one of a driver of a vehicle and a position of the vehicle. The operation information generating module is for generating operation information associated with operation of the vehicle. The processing module is electrically connected to the image information generating module and the operation information generating module for respectively receiving the image information and the operation information therefrom. The processing module determines a first risk value with reference to the image information, determines a second risk value with reference to the operation information, further determines a risk index indicative of a degree of risk with reference to the first and second risk values, and generates an alert-triggering signal when the risk index reaches a predetermined index threshold. The alert module is electrically connected to the processing module for receiving the alert-triggering signal therefrom, and generates an alert signal of one of sound, light and pictures in response to the alert-triggering signal.
According to another aspect of this invention, the vehicular warning method comprises the steps of:
a) configuring a processor to obtain image information associated with at least one of a driver of a vehicle and a position of the vehicle;
b) configuring the processor to obtain operation information associated with operation of the vehicle;
c) configuring the processor to determine a first risk value with reference to the image information and to determine a second risk value with reference to the operation information;
d) configuring the processor to determine a risk index indicative of a degree of risk with reference to the first and second risk values; and
e) configuring the processor to enable an alert to warn the driver of potential danger when it is determined that the risk index reaches a predetermined index threshold.
Other features and advantages of the present invention will become apparent in the following detailed description of the preferred embodiment with reference to the accompanying drawings, of which:
Referring to
The image information generating module 2 generates image information associated with at least one of a driver (not shown) of the vehicle 9 and a position of the vehicle 9. The image information generating module 2 includes a driver surveillance camera 21 for monitoring the driver of the vehicle 9, a forward surveillance camera 22 for monitoring a view ahead of the vehicle 9, and a processing unit 23 coupled electrically to the driver surveillance camera 21 and the forward surveillance camera 22 and generating the image information based on monitoring results of the driver surveillance camera 21 and the forward surveillance camera 22. The processing unit 23 determines from the monitoring result of the driver surveillance camera 21 a dozing degree indicative of whether shutting of an eye of the driver continues for a predetermined duration, and further determines from the monitoring result of the forward surveillance camera 22 a lane departure degree indicative of a position of the vehicle 9 within a current lane and a front barrier degree indicative of a position of the vehicle 9 relative to a barrier ahead of the vehicle 9. The image information is composed of at least one of the dozing degree, the lane departure degree and the front barrier degree.
The operation information generating module 3 generates operation information associated with operation of the vehicle 9. The operation information generating module 3 includes a lateral acceleration sensor unit 31, a steering angle sensor unit 32, and a steering torque sensor unit 33. The lateral acceleration sensor unit 31 is to be mounted on the vehicle body 91 of the vehicle 9 for detecting a lateral acceleration of the vehicle body 91, the steering angle sensor unit 32 is to be mounted on the vehicle body 91 for detecting a steering angle of the vehicle body 91, and the steering torque sensor unit 33 is to be mounted on the handling module 92 for detecting a steering torque of the handling module 92. The operation information generated by the operation information generating module 3 is composed of the lateral acceleration of the vehicle body 91, the steering angle of the vehicle body 91 and the steering torque of the handling module 92. In this embodiment, the operation information generating module 3 further includes a velocity sensor unit 34 to be mounted on the vehicle body 91 for detecting a velocity of the vehicle body 91, which also forms a part of the operation information herein.
In an implementation, the lateral acceleration sensor unit 31 may be capable of detecting a lateral acceleration of the vehicle body 91 and generate an output in the form of a voltage, the steering angle sensor unit 32 may be capable of detecting a steering angle of the vehicle body 91 and generate an output in the form of a voltage, and the steering torque sensor unit 33 may be capable of detecting a steering torque of the handling module 92 and generate an output in the form of a voltage.
The processing module 4 is electrically connected to the image information generating module 2 and the operation information generating module 3 for respectively receiving the image information and the operation information therefrom. The processing module 4 determines a first risk value with reference to the image information, further determines a second risk value with reference to the operation information, and further determines a risk index indicative of a degree of risk with reference to the first and second risk values. The processing module 4 generates an alert-triggering signal when the risk index reaches a predetermined index threshold.
In this embodiment, the processing module 4 determines the first risk value by giving each of the dozing degree, the lane departure degree, and the front barrier degree a respective predetermined weight parameter, and taking a maximum of the weighted dozing degree, the weighted lane departure degree, and the weighted front barrier degree. The processing module 4 determines the second risk value by performing fuzzification and defuzzification on the lateral acceleration, the steering angle, the steering torque and the velocity with reference to a predetermined set of membership functions (shown in
The alert module 5 is electrically connected to the processing module 4 for receiving the alert-triggering signal therefrom, and generates an alert signal of one of sound, light and pictures in response to the alert-triggering signal. In this embodiment, the alert module 5 is a buzzer.
Referring to
In step S02, the processor is configured to obtain operation information associated with operation of the vehicle 9. The operation information is composed of a lateral acceleration L(t) of the vehicle body 91, a steering angle A(t) of the vehicle body 91 and a steering torque H(t) of the handling module 92. As discussed above, the operation information of this embodiment further consists of a velocity V(t) of the vehicle body 91.
In this embodiment, steps S01 and S02 are performed substantially simultaneously.
In step S03, the processor is configured to determine a first risk value with reference to the image information. In this embodiment, the first risk value is determined by giving each of the dozing degree, the lane departure degree, and the front barrier degree a respective predetermined weight parameter, and taking a maximum of the weighted dozing degree, the weighted lane departure degree, and the weighted front barrier degree.
Specifically, the first risk value is defined according to the following equation.
In Equation (1), σ1(t) represents the first risk value at time t, KL(t) denotes the lane departure degree at time t in the form of a distance indicative of the position of the vehicle 9 within the current lane in this embodiment, the distance being the greater of a distance between a left side of the vehicle 9 (say, represented by the left front wheel) and an edge of a current lane in a corresponding side and a distance between a right side of the vehicle 9 (say, represented by the right front wheel) and an edge of the current lane in a corresponding side, KF(t) denotes the front barrier degree at time t in the form of a distance indicative of the position of the vehicle 9 relative to a barrier ahead of the vehicle 9 in this embodiment, the distance being a distance between the front side of the vehicle 9 (say, a front bumper of the vehicle 9) and the barrier ahead, KD(t) denotes the dozing degree at time t and is set to be 1 when shutting of an eye of the driver at time t has continued for the predetermined duration, which is defined as 5 seconds herein, and is set to be 0 otherwise, max_KL denotes a predetermined threshold for the lane departure degree, max_KF denotes a predetermined threshold for the front barrier degree, and PL, PF, PD denotes three predetermined weight parameters respectively corresponding to the lane departure degree, the front barrier degree and the dozing degree. Herein, max_KL is in the form of a predetermined distance between a side of the vehicle 9 and an edge of a standard-sized lane in a corresponding side when the vehicle 9 is centered in the standard-sized lane, and is defined to be 100 cm since the standard-sized lane is approximately 4 m in width and a standard-sized vehicle is approximately 2 m in width, and max_KF is in the form of a predetermined distance that varies with the velocity of the vehicle 9 and is a standard distance to be kept between the vehicle 9 and another vehicle ahead so as to keep safety. For instance, if the velocity of the vehicle 9 is 80 km/hr, max_KF is set as 40 m. In addition, PL, PF, PD may be predetermined based on experimental data, and are respectively defined as 1, 1, and 0.8 herein.
For example, when the lane departure degree KL(t) is equal to 50 cm, the front barrier degree KF(t) is equal to 10 m, the dozing degree KD(t) is 1, and the velocity V(t) is 80 km/hr, the first risk value is determined to be 0.8 by Equation (1) as follows while max_KF is set based on the velocity V(t).
In step S03, the processor is further configured to determine a second risk value by performing fuzzification and defuzzification on the lateral acceleration L(t), the steering angle A(t), the steering torque H(t) and the velocity V(t) with reference to a predetermined set of membership functions (see
In the following, an example of how the processor performs fuzzification and defuzzification will be illustrated. Referring to
where h3 is the right bound of the triangular fuzzifier (M), and h2 is the center of the triangular fuzzifier (M) and the lower bound of the trapezoidal fuzzifier (L).
Similarly, further referring to
where a3 is the right bound of the triangular fuzzifier (Z), and a2 is the center of the triangular fuzzifier (Z) and the lower bound of the trapezoidal fuzzifier (P);
where l3 is the right bound of the triangular fuzzifier (Z), and l2 is the center of the triangular fuzzifier (Z) and the lower bound of the trapezoidal fuzzifier (P);
where v1 is the left bound of the triangular fuzzifier (M), and v2 is the center of the triangular fuzzifier (M) and the lower bound of the trapezoidal fuzzifier
Subsequently, the processor is configured to perform defuzzification on the membership degrees using the weighted average defuzzification technique with reference to the predetermined set of fuzzy rules (see Table 1 below) so as to determine the second risk value.
First of all, fuzzy intersection operator is applied to the membership degrees for the steering torque H(t), the steering angle A(t), the lateral acceleration L(t) and the velocity V(t) for each of the rules R1 to R16, i.e., the minimum value of the membership degrees for H(t)=2.6, A(t)=20, L(t)=0.15, V(t)=80 in this example is taken for each of the rules R1 to R16. The results are listed as follows.
W1=min{M(H(t)),Z(S(t)),Z(L(t)),S(V(t))}=0.2
W2=min{L(H(t)),Z(S(t)),Z(L(t)),S(V(t))}=0.1
W3=min{M(H(t)),P(S(t)),Z(L(t)),S(V(t))}=0.25
W4=min{L(H(t)),P(S(t)),Z(L(t)),S(V(t))}=0.1
W5=min{M(H(t)),Z(S(t)),P(L(t)),S(V(t))}=0.2
W6=min{L(H(t)),Z(S(t)),P(L(t)),S(V(t))}=0.1
W7=min{M(H(t)),P(S(t)),P(L(t)),S(V(t))}=0.33
W8=min{L(H(t)),P(S(t)),Z(L(t)),S(V(t))}=0.1
W9=min{M(H(t)),Z(S(t)),Z(L(t)),M(V(t))}=0.2
W10=min{L(H(t)),Z(S(t)),Z(L(t)),M(V(t))}=0.1
W11=min{M(H(t)),P(S(t)),Z(S(t)),M(V(t))}=0.25
W12=min{L(H(t)),P(S(t)),Z(L(t)),M(V(t))}=0.1
W13=min{M(H(t)),Z(S(t)),P(L(t)),M(V(t))}=0.2
W14=min{L(H(t)),Z(S(t)),P(L(t)),M(V(t))}=0.1
W15=min{M(H(t)),P(S(t)),P(L(t)),M(V(t))}=0.67
W16=min{L(H(t)),P(S(t)),Z(L(t)),M(V(t))}=0.1
where Wi denotes the output of the fuzzy intersection operator for rule i.
According to the weighted average defuzzification technique, the second risk value is a weighted average of outputs of the rules, and is defined as Equation (2):
where σ2(t) represents the second risk value at time t, Wi denotes the output of the fuzzy intersection operator for rule i, and Bi represents a weight associated with rule i.
Subsequently, the weight Bi associated with rule i is determined. Referring to Table 1 and
In step S04, the processor is configured to determine a risk index indicative of a degree of risk with reference to the first risk value and the second risk value by Equation (3) that combines the first risk value at time t multiplied by a first predetermined weight and the second risk value at time t multiplied by a second predetermined weight as follows:
S(t)=w1σ1(t)+w2σ2(t) (3)
where S(t) represents the risk index, and w1 and w2 respectively denote the first predetermined weight and the second predetermined weight.
In this embodiment, the first and second predetermined weights are respectively defined to be 0.7 and 0.3, and may be varied depending on the situation as long as the first and second predetermined weights are in negative correlation. Consequently, the risk index at time t in this example is calculated to be 0.774 as follows.
S(t)=0.7×0.8+0.3×0.713=0.774
In step S05, the processor is configured to enable an alert to warn the driver of potential danger when it is determined that the risk index S(t) reaches a predetermined index threshold.
It is noted herein that the processing module 4 of the vehicular waning system as shown in
To sum up, since the vehicular warning system and method of the present invention take into consideration information related to a state of a driver of a vehicle 9 (i.e., whether the driver is dozing off), to a position of the vehicle 9 in relation to the environment (i.e., whether the vehicle 9 is drifting off a current lane, and whether the vehicle 9 is too close to a barrier ahead), and to an operating state of the vehicle 9 (i.e., the lateral acceleration, the steering angle and the steering torque of the vehicle 9) in determining whether to alert the driver of potential danger, the present invention is able to provide more accurate alerts than the prior art. In addition, by implementing fuzzy logic for the determination of the second risk value, instead of using transfer functions, computation complexity is reduced and the present invention is able to provide alerts in a more effective way.
While the present invention has been described in connection with what is considered the most practical and preferred embodiment, it is understood that this invention is not limited to the disclosed embodiment but is intended to cover various arrangements included within the spirit and scope of the broadest interpretation so as to encompass all such modifications and equivalent arrangements.
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Number | Date | Country | |
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20130162791 A1 | Jun 2013 | US |