CN104332058A - Intelligent traffic light controlling method and system - Google Patents

Abstract

The invention discloses an intelligent traffic light controlling system which comprises a monitoring camera, a traffic signal lamp and countdown lamp, a crossing traffic flow detection microprocessor, a traffic signal timing automatic adjustment and calculation microprocessor, a display driver module, a digital image processor, and an I/O interface. A controller automatically adjusts signal timing of traffic lights to enable utilization rate of green light in each direction of the crossing to increase or decrease along the same trend, compared with the traffic flow, thereby identifying flow state of the crossing in an effective and dynamic manner, adjusting signal timing automatically, and reducing traffic jam.

Description

A kind of Intelligent traffic light control method and system

Technical field

The present invention relates to field of traffic, particularly relate to the intelligent transportation lamp controller in field of traffic.

Background technology

Current, the urban transit system situation of the main big and medium-sized cities of China all allows of no optimist, and vehicle is many, and road blocks up, and emission from vehicles is seriously polluted, and these have become a key factor of restriction socio-economic development to a certain extent.The achievement in research of strategy of sustainable development seminar of Chinese Academy of Sciences expert shows, because of traffic congestion and problem of management, and China's 15 nearly 1,000,000,000 yuan of wealth of city loss every day.In addition, the traffic of blocking up also easily causes the bad mental emotion of driver, adds the probability that traffic hazard occurs.

Advanced technology is used to be the effective way solving current city traffic predicament, by the technology of advanced person, fully can excavate the potential of existing means of transportation, the transport of people as much as possible and thing is born, with the contradiction constantly increased between traffic resource scarcity of transport solution demand with limited traffic resource.Its application in solving urban traffic blocking with effect of getting instant result is exactly install intelligent traffic light at road grade crossing to replace traditional traffic lights.Traditional traffic lights adopts fixing signal period and split, automatically can not regulate according to the dynamic change of crossing traffic flow, often have that the many crossing green light transit times of car are short, without the situation of the crossing but light yellow green light of car or few car, the traffic capacity at crossing has been wasted.And intelligent traffic lamp according to the real-time change of crossing traffic flow, can adopt the parameter of corresponding intelligent control algorithm dynamic adjustments traffic lights, make to be shortened dramatically by the stand-by period of crossing vehicle, the traffic efficiency at crossing is improved.

Although intelligent traffic lamp has attracting advantage like this, researchist has also carried out research to this, design some intelligent traffic lamp control programs, but in present stage, it is not promoted the use of on a large scale, trace it to its cause, mainly existing Intelligent traffic light control method needs the vehicle waiting number detecting crossing direction to the car in real time, this requires two local installation two wagon detectors separated by a distance at stop line rear, every bar track, and by the vehicle data transmission that detects to traffic signal control, its quantities of installing is larger, can impact the traffic of construction section, and likely destroy existing road surface, the fund input needed is also many.Wagon detector mainly contains ultrasound wave, infrared, the type such as microwave radar, ground induction coil, and all kinds of detecting device respectively has quality, and it selects also ununified standard.Above-mentioned all factors make vehicle supervision department be difficult to reach a decision, the unified installation intelligent transportation lamp controller at crossing.

For above-mentioned difficulties, the invention discloses a kind of level-crossing intelligent traffic light scheme, its core concept makes full use of crossing existing hardware equipment, only traffic signal controlling machine need be changed, connect the high-definition camera vision signal at crossing simultaneously, adopt corresponding image procossing and traffic light signals duration dynamic adjustments algorithm, realize the dynamic adjustments of signal lamp.Its transformation only relates to be changed traffic signal controlling machine and is connected crossing camera video signal, can carry out, can not block traffic around the control box in roadside.And the time of installment and debugging is very short, can select to carry on construction work at night.Or daytime constructs, use Mobile traffic light temporary control and education crossing traffic.Its transformation process is convenient and swift, and equipment cost is little.

Summary of the invention

A kind of intelligent transportation lights control scheme, utilizes the existing monitoring camera of road grade crossing, gathers the video information of crossing traffic situation, uses image processing algorithm to obtain the traffic flow data of crossing all directions.Controller is according to the algorithm of these data and setting, and the signal timing dial of adjustment traffic lights, makes the green light utilization factor of crossing all directions compare with wagon flow automatically, and increase by identical trend or reduce, concrete scheme of the present invention is as follows:

A kind of Intelligent Control System for Traffic Lights is set, comprise monitoring camera, traffic lights and countdown lamp, described system also comprises intersection vehicle flux and detects microprocessor, the automatic Adjustable calculation microprocessor of Traffic Signal Timing, driver module, Digital Image Processor, I/O interface:

The video of acquisition is sent to Digital Image Processor by monitoring camera, after Digital Image Processor carries out image procossing, result is exported to intersection vehicle flux and detect microprocessor, described intersection vehicle flux detects microprocessor and obtains information of vehicle flowrate through process and send the automatic Adjustable calculation microprocessor of Traffic Signal Timing to, the automatic Adjustable calculation microprocessor of described Traffic Signal Timing is after process obtains signal timing dial result, call I/O interface and driver module, signal timing dial result is exported to traffic lights and countdown lamp.

Described intersection vehicle flux detects microprocessor and adopts following steps to obtain information of vehicle flowrate:

A) identify in the signal period of traffic lights by the number of vehicles of crossing all directions and vehicle;

B) according to the length ratio of large car and compact car, the kart number of equivalence is converted out;

C) by the number of track-lines of this number divided by this direction, crossing, the vehicle flowrate n in per share track, this direction is obtained _i.

The automatic Adjustable calculation microprocessor (4) of described Traffic Signal Timing adopts the signal timing dial adjusting traffic lights with the following method:

A) remember that the both direction at crossing is respectively x and y, if the signal period of traffic lights is t, containing four phase places, be respectively the craspedodrome of x direction, turning left in x direction, keeps straight in y direction, turn left in y direction, its phase place duration is respectively t ₁, t ₂, t ₃and t ₄, then obtain formula (1):

t=t ₁+t ₂+t ₃+t ₄(1)

B) magnitude of traffic flow number that during establishing each phase place, single track is on average passed through is respectively n ₁, n ₂, n ₃and n ₄, definition green light utilization factor η is the magnitude of traffic flow passed through of single track and the ratio of long green light time, then the long green light time utilization factor of each green light phase place is respectively

$\left\{\begin{array}{c}{\mathrm{\η}}_1=\frac{n_1}{t_1}\\ {\mathrm{\η}}_2=\frac{n_2}{t_2}\\ {\mathrm{\η}}_3=\frac{n_3}{t_3}\\ {\mathrm{\η}}_4=\frac{n_4}{t_4}\end{array}\right.$ (2)

The long green light time average utilization at crossing is

$\stackrel{\‾}{\mathrm{\η}}=\frac{\underset{i=1}{\overset{4}{\mathrm{\Σ}}}{n}_i}{\underset{i=1}{\overset{4}{\mathrm{\Σ}}}{t}_i}$ (3)

Generally, above-mentioned utilization factor is also unequal, namely

${\mathrm{\η}}_1\≠{\mathrm{\η}}_2\≠{\mathrm{\η}}_3\≠{\mathrm{\η}}_4\≠\stackrel{\‾}{\mathrm{\η}}$ (4)

C), at the end of remembering a signal period, during this signal period recorded, traffic parameter is t _i, (i=1,2,3,4) and the then signal duration basic value t of next signal period each phase place _i', (i=1,2,3,4) are

$\left\{\begin{array}{c}{t\′}_{1=\frac{n_1}{\stackrel{\‾}{\mathrm{\η}}}}\\ {t\text{'}}_2=\frac{n_2}{\stackrel{\‾}{\mathrm{\η}}}\\ {t\text{'}}_3=\frac{n_3}{\stackrel{\‾}{\mathrm{\η}}}\\ {t\text{'}}_4=\frac{{\mathrm{\η}}_4}{\stackrel{\‾}{\mathrm{\η}}}\end{array}\right.$ (5)

T _i' and t _ibetween relation meet

$\mathrm{\Σ}{t\text{'}}_i=\mathrm{\Σ}\frac{n_i}{\stackrel{\‾}{\mathrm{\η}}}=\frac{\mathrm{\Σ}{n}_i}{\stackrel{\‾}{\mathrm{\η}}}=\mathrm{\Σ}{t}_i$ (6)

D) according to the actual conditions at crossing, each phase place should have a minimum green time mutually, is designated as t _gmin, according to above-mentioned t _i' and t _gmincomparative result, the setting of each signal duration of next signal period is considered in two kinds of situation:

（1）t _i'3t _gmin,(i=1,2,3,4)

Get t _i' be the signal duration of next signal period each phase place, new signal period time-preserving, and the green light utilization factor desired value of each phase place is identical, is

(2) at least there is a phase j, { 1,2,3,4} meets t' to j ∈ _j<t _gmin

T will be less than _gmint _i' value is adjusted to t _gmin, its time of using shares other phase place equably, for this reason, first by t _i' (i=1,2,3,4) by ascending sequence, new sequence is designated as s _i, according to s _iwith t _gminrelation, adjust accordingly.

the ultimate principle of technical scheme

1, general structure

Intelligent transportation lamp controller described in this method, comprise the module such as intersection vehicle flux detection, the automatic Adjustable calculation of Traffic Signal Timing, display driver, overall framework is as shown in Figure of description 1.In figure, camera uses crossing, crossing monitoring camera, without the need to extra installation; DSP(Digital Image Processing) processor and intersection vehicle flux detect microprocessor according to image information, calculates vehicle flowrate to the automatic Adjustable calculation microprocessor of Traffic Signal Timing; Microprocessor performs the automatic adjustment algorithm of signal timing dial of the present invention, drives traffic lights and the countdown lamp at crossing, and is provided with corresponding I/O port.

2, vehicle Flow Detection

Conventional traffic flow detecting method has the technology such as ground induction coil, ultrasound wave, microwave, video.In the technical program, traffic flow detecting device makes full use of crossing existing equipment, to reduce cost and installation difficulty.Consider that the main intersection of Current City Road is all equipped with monitoring camera, therefore this method adopts video car flow amount detection technique, by the mounted camera in crossing, uses image processing algorithm to obtain information of vehicle flowrate.Image processing function completes on one piece of custom-designed Digital Image Processing (DSP) circuit board, and it receives crossing vision signal, carries out image procossing, obtains information of vehicle flowrate, and send microprocessor to.

During image procossing, first identify in the signal period of traffic lights by the number of vehicles of crossing all directions and vehicle; Secondly, according to the length ratio of large car and compact car, the kart number of equivalence is converted out; Finally, by the number of track-lines of this number divided by this direction, crossing, obtain the vehicle flowrate n in per share track, this direction _i.

3, signal timing dial automatic adjusting method

For the most universal cross level-crossing, the both direction at note crossing is respectively x and y, if the signal period of traffic lights is t, containing four phase places, be respectively the craspedodrome of x direction, turning left in x direction, keeps straight in y direction, turn left in y direction, its phase place duration is respectively t ₁, t ₂, t ₃and t ₄, then

t=t ₁+t ₂+t ₃+t ₄

The magnitude of traffic flow number that during each phase place, single track is on average passed through is respectively n ₁, n ₂, n ₃and n ₄, definition green light utilization factor η is the magnitude of traffic flow passed through of single track and the ratio of long green light time, then the long green light time utilization factor of each green light phase place is respectively

$\left\{\begin{array}{c}{\mathrm{\&eta;}}_1=\frac{n_1}{t_1}\\ {\mathrm{\&eta;}}_2=\frac{n_2}{t_2}\\ {\mathrm{\&eta;}}_3=\frac{n_3}{t_3}\\ {\mathrm{\&eta;}}_4=\frac{n_4}{t_4}\end{array}\right.$

The long green light time average utilization at crossing is

$\stackrel{\&OverBar;}{\mathrm{\&eta;}}=\frac{\underset{i=1}{\overset{4}{\mathrm{\&Sigma;}}}{n}_i}{\underset{i=1}{\overset{4}{\mathrm{\&Sigma;}}}{t}_i}$

Generally, above-mentioned utilization factor is also unequal, namely

${\mathrm{\&eta;}}_1\&NotEqual;{\mathrm{\&eta;}}_2\&NotEqual;{\mathrm{\&eta;}}_3\&NotEqual;{\mathrm{\&eta;}}_4\&NotEqual;\stackrel{\&OverBar;}{\mathrm{\&eta;}}$

This method is by the above-mentioned t of dynamic adjustments _i, (i=1,2,3,4) reach and make η _i, (i=1,2,3,4) and n _i, the object that (i=1,2,3,4) increase by identical trend or reduce.At the end of remembering a signal period, during this signal period recorded, traffic parameter is t _i, (i=1,2,3,4) and the then signal duration basic value t of next signal period each phase place _i', (i=1,2,3,4) are

$\left\{\begin{array}{c}{t\&prime;}_{1=\frac{n_1}{\stackrel{\&OverBar;}{\mathrm{\&eta;}}}}\\ {t\text{'}}_2=\frac{n_2}{\stackrel{\&OverBar;}{\mathrm{\&eta;}}}\\ {t\text{'}}_3=\frac{n_3}{\stackrel{\&OverBar;}{\mathrm{\&eta;}}}\\ {t\text{'}}_4=\frac{{\mathrm{\&eta;}}_4}{\stackrel{\&OverBar;}{\mathrm{\&eta;}}}\end{array}\right.$

Obviously, t _i' and t _ibetween relation meet

$\mathrm{\&Sigma;}{t\text{'}}_i=\mathrm{\&Sigma;}\frac{n_i}{\stackrel{\&OverBar;}{\mathrm{\&eta;}}}=\frac{\mathrm{\&Sigma;}{n}_i}{\stackrel{\&OverBar;}{\mathrm{\&eta;}}}=\mathrm{\&Sigma;}{t}_i$

According to the actual conditions at crossing, each phase place should have a minimum green time mutually, is designated as t _gmin, according to above-mentioned t _i' and t _gmincomparative result, the setting of each signal duration of next signal period is considered in two kinds of situation.

（1）t _i'3t _gmin,(i=1,2,3,4)

Now, t is got _i' be the signal duration of next signal period each phase place, obviously, new signal period time-preserving, and the green light utilization factor desired value of each phase place is identical, is

(2) at least there is a phase j, { 1,2,3,4} meets t' to j ∈ _j<t _gmin

Now, t will be less than when determining the basic ideas of new timing duration _gmint _i' value is adjusted to t _gmin, its time of " using " shares other phase place equably.For this reason, first by t _i' (i=1,2,3,4) by ascending sequence, new sequence is designated as s _i, according to s _iwith t _gminrelation, adjust accordingly.

The comprehensively situation of above-mentioned (1) and (2), corresponding to a signal period signal timing dial algorithm overall flow as shown in Figure 2.

4, the realization of the automatic adjustment algorithm of signal timing dial

Main and the cumulative sum division of the computing that the automatic adjustment algorithm of signal timing dial relates to, and need to use multiple timer; Suitable with a signal period of signal lamp for the time of implementation algorithm, generally about hundred seconds tens of second to one, very abundant.Automatic adjustment algorithm is realized by microprocessor, and in addition, display driver, I/O interface also need microprocessor to manage (see figure 1), and thus, microprocessor selects speed not high but the product that peripheral hardware aboundresources, reliability are high.

field conduct step

After the good traffic light controller of described principle design, its in-site installation is simple, the controller that the position only need installing traffic light controller in roadside more renews, connect the video monitoring signal at crossing to controller, connection control machine output signal to signal lamp, initial parameter is set, just can have brought into operation, as shown in Figure 3.

Described content be only the present invention conceive under basic explanation, and according to any equivalent transformation that technical scheme of the present invention is done, all should protection scope of the present invention be belonged to.

figure of description explanation

Fig. 1 Intelligent Control System for Traffic Lights frame construction drawing

Fig. 2 corresponds to the signal timing dial automatic adjusting method of a signal period

Fig. 3 in-site installation implementing procedure figure

Fig. 4 green light utilization factor compares

The incoming flow vehicle of each phase place in Fig. 5 crossing and wait in line the comparison of vehicle number

Embodiment

According to said method, carry out corresponding emulation on computers.Emulate the crossing considered containing four signal phases, be designated as A, B, C and D respectively, incoming flow vehicle produces at random by Poisson distribution, and 50 signal periods have been carried out in emulation altogether.

Fig. 4 is that the total green light utilization factor in crossing compares, and green light utilization factor corresponds in formula (3) .Visible, after adopting this method, its green light utilization factor is improved.

Fig. 5 is the incoming flow vehicle of each phase place in crossing and waits in line the comparison of vehicle number.As seen from the figure, when not adopting this method (timing timing scheme), the queuing vehicle of crossing B and crossing D continues to increase, and formation is blocked up, and then incoming flow vehicle is few for A phase and C phase, and green light transit time is underutilized; Adopt after this method, the queuing vehicle base of crossing B and crossing D this without, crossing A and crossing C has vehicle queue to wait once in a while, but just disappears immediately.Visible, adopt after this method, can the traffic conditions at effective Dynamic Recognition crossing, automatic regulating signal timing, reduces to block up.

cost and benefit is estimated

(1), cost

For a crossing, it is only change Traffic signal control machine that the transformation that implementing this method needs drops into, and the camera video signal at crossing is sent to traffic grade machine simultaneously, and overall input can be controlled within thousands of yuans.

(2), benefit

Its benefit is mainly reflected in vehicle and reduces by the minimizing (environmental benefit) of the reduction (economic benefit) of oil consumption during crossing, exhaust emissions, the raising going out line efficiency and corresponding driver's bad mental emotion traffic safety factor lifting (social benefit) brought.Wherein social benefit is difficult to provide and assesses accurately, only does a rough calculating to economic benefit and environmental benefit here.

1, economic benefit

Economic benefit derives from the vehicle oil consumption saved, and this is relevant with the magnitude of traffic flow at crossing.The magnitude of traffic flow at crossing is subject to the impact of the factor such as road width, traffic time section, as shown in table 1.The 12h magnitude of traffic flow of main roads and secondary road in table is added, the 12h magnitude of traffic flow at crossing can be obtained.Consider that the magnitude of traffic flow at night is fewer than daytime a lot, the magnitude of traffic flow of getting 12h at night is here 10% of daytime, and therefore, the 24h magnitude of traffic flow is multiplied by coefficient 1.1 by the 12h magnitude of traffic flow and obtains, the mean value that can calculate the 24h magnitude of traffic flow thus is further 16579, as shown in table 2.

Table 1 intersection traffic flow standard

Table 2 crossing 24h magnitude of traffic flow standard

After installing intelligent transportation lamp controller, if each car decreases 5 seconds in the average latency at crossing, the magnitude of traffic flow of crossing every day is by 16579, then amounting to T.T. is 82895 seconds.The oil consumption of picking up the car during a parking waiting is 0.8 l/h, then the fuel oil saved every day is about 18.4 liters, about 6716 liters every year.With the calculation of price of 7.94 yuan of/liter of, No. 93 gasoline price of Nantong (in the March, 2013), amount to Renminbi 53325.04 yuan, single from direct economic benefit, enough make up the improvement expenses at this crossing.

2, environmental benefit

The carbon emission coefficient of gasoline is 2.361kgCO ₂/ L, according to result of calculation above, the fuel oil of crossing saving in a year is about 6716 liters, and the carbon emission amount of minimizing should be 3.361 × 6716=22.57(ton mutually), if be generalized to a large size city, or the whole nation, its enormous amount, environmental benefit is very remarkable.

List of references

[1] CCTV. expert claims China's 15 urban traffic blockings to lose 1,000,000,000 yuan of [EB/OL] .http: //news.xinhuanet.com/fortune/2012-08/23/c_123621201.htm, 2013-03-23. every day

[2] Wen Zhida, Liang Guirong, Chen Biming, Gao Suping. based on the Intelligent Control System for Traffic Lights [J] of vehicle flowrate. automatic technology and application, 2009,28 (6): 115-118.

[3] horse great writing, Chen Songli, Chen Zhiguo, Li Jian. a kind of novel radio crossroad access lamp Intelligent Dynamic induction control system [J]. Small heparin, 2009,30 (4): 62-66.

[4] Zhang Wenpu. road traffic detects [M]. Beijing: People's Transportation Press, 2010.

[5] Xu Jianmin. traffic administration and control [M]. Beijing: People's Transportation Press, 2007.105-106.

[6] Environmental monitoring in Jiangsu Province net [EB/OL] .http: //www.jsem.net.cn/jshjjc/InfoDetail/ InfoID=b628bcc8-62ac-483d-b88f-f6c63f838de5 & CategoryNum=026007,2013-03-26.

Claims (6)

1. an Intelligent Control System for Traffic Lights, comprise monitoring camera (1), traffic lights and countdown lamp (2), it is characterized in that: described system also comprises intersection vehicle flux and detects microprocessor (3), the automatic Adjustable calculation microprocessor (4) of Traffic Signal Timing, driver module (5), Digital Image Processor (6), I/O interface (7):

The video of acquisition is sent to Digital Image Processor (6) by monitoring camera (1), after Digital Image Processor (6) carries out image procossing, result is exported to intersection vehicle flux and detect microprocessor (3), described intersection vehicle flux detects microprocessor (3) and obtains information of vehicle flowrate through process and send the automatic Adjustable calculation microprocessor (4) of Traffic Signal Timing to, the automatic Adjustable calculation microprocessor (4) of described Traffic Signal Timing is after process obtains signal timing dial result, call I/O interface (7) and driver module (5), signal timing dial result is exported to traffic lights and countdown lamp (2).

2. an Intelligent Control System for Traffic Lights as claimed in claim 1, is characterized in that:

Described intersection vehicle flux detects microprocessor (3) and adopts following steps to obtain information of vehicle flowrate:

A) identify in the signal period of traffic lights by the number of vehicles of crossing all directions and vehicle;

B) according to the length ratio of large car and compact car, the kart number of equivalence is converted out;

C) by the number of track-lines of this number divided by this direction, crossing, the vehicle flowrate n in per share track, this direction is obtained _i.

3. an Intelligent Control System for Traffic Lights as claimed in claim 1 or 2, is characterized in that:

The automatic Adjustable calculation microprocessor (4) of described Traffic Signal Timing adopts the signal timing dial adjusting traffic lights with the following method:

A) remember that the both direction at crossing is respectively x and y, if the signal period of traffic lights is t, containing four phase places, be respectively the craspedodrome of x direction, turning left in x direction, keeps straight in y direction, turn left in y direction, its phase place duration is respectively t ₁, t ₂, t ₃and t ₄, then obtain formula (1):

t=t ₁+t ₂+t ₃+t ₄(1)

B) magnitude of traffic flow number that during establishing each phase place, single track is on average passed through is respectively n ₁, n ₂, n ₃and n ₄, definition green light utilization factor η is the magnitude of traffic flow passed through of single track and the ratio of long green light time, then the long green light time utilization factor of each green light phase place is respectively

$\left\{\begin{array}{c}{\mathrm{\&eta;}}_1=\frac{n_1}{t_1}\\ {\mathrm{\&eta;}}_2=\frac{n_2}{t_2}\\ {\mathrm{\&eta;}}_3=\frac{n_3}{t_3}\\ {\mathrm{\&eta;}}_4=\frac{n_4}{t_4}\end{array}\right.$ (2)

The long green light time average utilization at crossing is

$\stackrel{\&OverBar;}{\mathrm{\&eta;}}=\frac{\underset{i=1}{\overset{4}{\mathrm{\&Sigma;}}}{n}_i}{\underset{i=1}{\overset{4}{\mathrm{\&Sigma;}}}{t}_i}$ (3)

Generally, above-mentioned utilization factor is also unequal, namely

${\mathrm{\&eta;}}_1\&NotEqual;{\mathrm{\&eta;}}_2\&NotEqual;{\mathrm{\&eta;}}_3\&NotEqual;{\mathrm{\&eta;}}_4\&NotEqual;\stackrel{\&OverBar;}{\mathrm{\&eta;}}$ (4)

C), at the end of remembering a signal period, during this signal period recorded, traffic parameter is t _i, (i=1,2,3,4) and the then signal duration basic value t of next signal period each phase place _i', (i=1,2,3,4) are

$\left\{\begin{array}{c}{t\&prime;}_{1=\frac{n_1}{\stackrel{\&OverBar;}{\mathrm{\&eta;}}}}\\ {t\text{'}}_2=\frac{n_2}{\stackrel{\&OverBar;}{\mathrm{\&eta;}}}\\ {t\text{'}}_3=\frac{n_3}{\stackrel{\&OverBar;}{\mathrm{\&eta;}}}\\ {t\text{'}}_4=\frac{{\mathrm{\&eta;}}_4}{\stackrel{\&OverBar;}{\mathrm{\&eta;}}}\end{array}\right.$ (5)

T _i' and t _ibetween relation meet

$\mathrm{\&Sigma;}{t\text{'}}_i=\mathrm{\&Sigma;}\frac{n_i}{\stackrel{\&OverBar;}{\mathrm{\&eta;}}}=\frac{\mathrm{\&Sigma;}{n}_i}{\stackrel{\&OverBar;}{\mathrm{\&eta;}}}=\mathrm{\&Sigma;}{t}_i$ (6)

D) according to the actual conditions at crossing, each phase place should have a minimum green time mutually, is designated as t _gmin, according to above-mentioned t _i' and t _gmincomparative result, the setting of each signal duration of next signal period is considered in two kinds of situation:

（1）t _i'3t _gmin,(i=1,2,3,4)

Get t _i' be the signal duration of next signal period each phase place, new signal period time-preserving, and the green light utilization factor desired value of each phase place is identical, is

(2) at least there is a phase j, { 1,2,3,4} meets t' to j ∈ _j<t _gmin

T will be less than _gmint _i' value is adjusted to t _gmin, its time of using shares other phase place equably, for this reason, first by t _i' (i=1,2,3,4) by ascending sequence, new sequence is designated as s _i, according to s _iwith t _gminrelation, adjust accordingly.

4. an Intelligent traffic light control method, it is characterized in that: comprise monitoring camera (1), traffic lights and countdown lamp (2), described system also comprises intersection vehicle flux and detects microprocessor (3), the automatic Adjustable calculation microprocessor (4) of Traffic Signal Timing, driver module (5), Digital Image Processor (6), I/O interface (7):

The video of acquisition is sent to Digital Image Processor (6) by monitoring camera (1), after Digital Image Processor (6) carries out image procossing, result is exported to intersection vehicle flux and detect microprocessor (3), described intersection vehicle flux detects microprocessor (3) and obtains information of vehicle flowrate through process and send the automatic Adjustable calculation microprocessor (4) of Traffic Signal Timing to, the automatic Adjustable calculation microprocessor (4) of described Traffic Signal Timing is after process obtains signal timing dial result, call I/O interface (7) and driver module (5), signal timing dial result is exported to traffic lights and countdown lamp (2).

5. an Intelligent traffic light control method as claimed in claim 4, is characterized in that:

Described intersection vehicle flux detects microprocessor (3) and adopts following steps to obtain information of vehicle flowrate:

A) identify in the signal period of traffic lights by the number of vehicles of crossing all directions and vehicle;

B) according to the length ratio of large car and compact car, the kart number of equivalence is converted out;

C) by the number of track-lines of this number divided by this direction, crossing, the vehicle flowrate n in per share track, this direction is obtained _i.

6. the Intelligent traffic light control method as described in claim 4 or 5, is characterized in that:

The automatic Adjustable calculation microprocessor (4) of described Traffic Signal Timing adopts the signal timing dial adjusting traffic lights with the following method:

A) remember that the both direction at crossing is respectively x and y, if the signal period of traffic lights is t, containing four phase places, be respectively the craspedodrome of x direction, turning left in x direction, keeps straight in y direction, turn left in y direction, its phase place duration is respectively t ₁, t ₂, t ₃and t ₄, then obtain formula (1):

t=t ₁+t ₂+t ₃+t ₄(1)

B) magnitude of traffic flow number that during establishing each phase place, single track is on average passed through is respectively n ₁, n ₂, n ₃and n ₄, definition green light utilization factor η is the magnitude of traffic flow passed through of single track and the ratio of long green light time, then the long green light time utilization factor of each green light phase place is respectively

$\left\{\begin{array}{c}{\mathrm{\&eta;}}_1=\frac{n_1}{t_1}\\ {\mathrm{\&eta;}}_2=\frac{n_2}{t_2}\\ {\mathrm{\&eta;}}_3=\frac{n_3}{t_3}\\ {\mathrm{\&eta;}}_4=\frac{n_4}{t_4}\end{array}\right.$ (2)

The long green light time average utilization at crossing is

$\stackrel{\&OverBar;}{\mathrm{\&eta;}}=\frac{\underset{i=1}{\overset{4}{\mathrm{\&Sigma;}}}{n}_i}{\underset{i=1}{\overset{4}{\mathrm{\&Sigma;}}}{t}_i}$ (3)

Generally, above-mentioned utilization factor is also unequal, namely

${\mathrm{\&eta;}}_1\&NotEqual;{\mathrm{\&eta;}}_2\&NotEqual;{\mathrm{\&eta;}}_3\&NotEqual;{\mathrm{\&eta;}}_4\&NotEqual;\stackrel{\&OverBar;}{\mathrm{\&eta;}}$ (4)

C), at the end of remembering a signal period, during this signal period recorded, traffic parameter is t _i, (i=1,2,3,4) and the then signal duration basic value t of next signal period each phase place _i', (i=1,2,3,4) are

$\left\{\begin{array}{c}{t\&prime;}_{1=\frac{n_1}{\stackrel{\&OverBar;}{\mathrm{\&eta;}}}}\\ {t\text{'}}_2=\frac{n_2}{\stackrel{\&OverBar;}{\mathrm{\&eta;}}}\\ {t\text{'}}_3=\frac{n_3}{\stackrel{\&OverBar;}{\mathrm{\&eta;}}}\\ {t\text{'}}_4=\frac{{\mathrm{\&eta;}}_4}{\stackrel{\&OverBar;}{\mathrm{\&eta;}}}\end{array}\right.$ (5)

T _i' and t _ibetween relation meet

$\mathrm{\&Sigma;}{t\text{'}}_i=\mathrm{\&Sigma;}\frac{n_i}{\stackrel{\&OverBar;}{\mathrm{\&eta;}}}=\frac{\mathrm{\&Sigma;}{n}_i}{\stackrel{\&OverBar;}{\mathrm{\&eta;}}}=\mathrm{\&Sigma;}{t}_i$ (6)

D) according to the actual conditions at crossing, each phase place should have a minimum green time mutually, is designated as t _gmin, according to above-mentioned t _i' and t _gmincomparative result, the setting of each signal duration of next signal period is considered in two kinds of situation:

（1）t _i'3t _gmin,(i=1,2,3,4)

Get t _i' be the signal duration of next signal period each phase place, new signal period time-preserving, and the green light utilization factor desired value of each phase place is identical, is

(2) at least there is a phase j, { 1,2,3,4} meets t' to j ∈ _j<t _gmin

T will be less than _gmint _i' value is adjusted to t _gmin, its time of using shares other phase place equably, for this reason, first by t _i' (i=1,2,3,4) by ascending sequence, new sequence is designated as s _i, according to s _iwith t _gminrelation, adjust accordingly.