CN101777261B - Method for measuring vehicle speed based on CMOS digital camera with roll-type shutter - Google Patents

Abstract

The invention provides a method for measuring a vehicle speed based on a CMOS digital camera with a belt-type shutter, which comprises the following steps of: by utilizing the characteristic of distortion of image of a moving object when he CMOS digital camera with the belt-type shutter is used for shooting, calibrating the central pixel of the distorted image by using a CMOS digital camera calibration technique; determining the specific coordinates of the central pixel; substituting the specific coordinates into a formula for calculating a speed to obtain a speed value corresponding to a moving vehicle image; and comparing the speed value with a set vehicle running speed threshold value to judge whether a vehicle is overspeed or not. The method can be implemented by the CMOS digital camera with the belt-type shutter and a computer monitoring terminal only. Compared with the conventional devices for detecting the speeding of a vehicle, the method has the advantages that: a conclusion is obtained based on the analysis of the image, the precision error of the calculated speed value is within 2.5 percent, and the method facilitates the post development of other functions, and the calling of images of a computer monitoring center.

Description

Measure the method for car speed based on the cmos digital camera of belt-type shutter

Technical field

The present invention relates to measure based on the cmos digital camera of belt-type shutter the method for car speed.

Background technology

Fast development along with China's road traffic, traffic safety problem becomes the problem of people's primary concern, and to travel be the one of the main reasons that causes traffic accident to produce always and exeed the regulation speed, therefore, must take effective means, the serious phenomenon of travelling that exeeds the regulation speed of administering.Existing highway is measured the overspeed of vehicle device and usually is divided into two classes, and a class is radar trap (comprising hand-hold type and fixed), and a class is the moving-coil type velometer that is laid on the road surface.Their operation principle is all by the time difference finding speed.The patent No. is in 200520081899 the Chinese invention patent, relate to a kind of Doppler speedometer, below supersonic generator, be respectively equipped with shield and dash receiver with both sides, close wherein dash receiver place is provided with laser, be respectively equipped with baffle plate and oriented tube below the dash receiver, two dash receivers respectively are connected with a photocell, photocell successively with high pass filter, casacade multi-amplifier, the frequency meter serial connection, two groups of stringers are connected to data processor by frequency meter, be located at supersonic generator thermometer on one side and also be connected to data processor, data processor connects respectively display and gate circuit.This system has found car speed zero point over the ground by the cooperation of a series of designs.According to the dash receiver of actual conditions designs, thereby realize that measuring car speed is by traditional qualitative average to quantitative instantaneous transformation.But carrying out there is incomplete place when bicycle road or instantaneous velocity are measured, its main drawback performance is that this device can only record interior average speed of a period of time but not instantaneous velocity, and the relevant information of the vehicle that can't provide timely and effectively exeeds the regulation speed travels can not help traffic control department to administer traffic.

Summary of the invention

In order to solve the deficiency of prior art, the invention provides the method for measuring car speed based on the cmos digital camera of belt-type shutter.This is a kind of instantaneous velocity detection method that more accurately reflects vehicular traffic.

The method of measuring car speed based on the cmos digital camera of belt-type shutter provided by the invention.It is that the cmos digital camera of using belt-type shutter is taken the characteristics that produce distortion to moving object, as shown in Figure 1-Figure 3, in the cmos digital camera of belt-type shutter, its time for exposure of the pixel of every delegation is identical with the moment, but for different pixel columns, its time for exposure is identical, but successively difference is but arranged the time of exposure, and this will cause the one-tenth image distortion of sports car.The direction of the cmos digital camera motion of the direction of motion of automobile and belt-type shutter not simultaneously, the picture of the automobile that becomes just has different variations.During the cmos digital camera motion of the direction of motion of automobile and belt-type shutter identical or opposite, the picture of automobile will be elongated or be shortened; When both were angled, the image that becomes just had certain angle of inclination.The movement velocity of automobile is certain, and frame frequency is certain, and then exposure cycle is longer, become anamorphose more serious.When image is analyzed, adopt the camera calibration technology that the fault image center pixel is demarcated, determine its concrete coordinate, be brought in the formula (1) of computational speed, obtain velocity amplitude that should the sports car image.Fig. 4 is the projection of moving object on three dimensions.

Cmos digital camera based on belt-type shutter provided by the invention is measured the method for overspeed of vehicle, and concrete steps and condition are as follows:

The cmos digital camera that 1) will have a belt-type shutter working method be fixed on the highw ay m onitoring crossing the road surface the top and with the road surface 30 degree angles are arranged, be used for taking the Vehicle Driving Cycle process;

2) the DSP embedded treatment system exploitation that utilizes cmos digital camera with belt-type shutter working method to combine detects software, the packing of the detection software program finished is integrated in the program development bag of cmos digital camera of belt-type shutter, and downloads in the cmos digital camera with belt-type shutter working method;

The cmos digital camera that will have the belt-type shutter working method is transferred to output image data by optical fiber and wired or wireless passage the monitor terminal of Surveillance center; According to following formula (1) computational speed value;

3) carry out following workflow:

Step 1: the automobile driving speed threshold value that begins and arrange regulation;

Step 2: the running car image that shows institute's monitor area at the liquid crystal display equipment screen of Surveillance center;

Step 3: detected target and entered in the field range, the cmos digital camera with belt-type shutter is taken the running car image, and captured image is passed to the DSP embedded treatment system;

Step 4: the car of taking is travelled the velocity amplitude V of image and threshold ratio:

To the image taken according to following formula (1) computational speed value:

From image, appoint and get 12 characteristic points and be made as P, in the formula,

Be the antisymmetric matrix of sports car angular velocity vector Ω, I is 3 * 3 unit matrixs, P _i=[X _i, Y _i, Z _i] ^TBe the three-dimensional coordinate of the automobile image frame that is taken,

R and T are respectively the peaceful vectors that moves of rotation matrix between the cmos digital camera picture of the automobile that is taken and belt-type shutter, make m=[u, v] ^TThe projection of P point on image, order

Then the pass between P and m is:

$s\tilde{m}=K\left[\begin{array}{cc}R& T\end{array}\right]\tilde{P}---\left(2\right)$

In the formula, S is scale factor at random, and τ is the time interval of two image lines exposures;

$k=\left[\begin{array}{ccc}{\mathrm{\α}}_u& 0& u_0\\ 0& {\mathrm{\α}}_v& v_0\\ 0& 0& 1\end{array}\right]$

K is the inner parameter of the cmos digital camera of belt-type shutter;

Characteristic point P in image coordinate under world coordinate system is brought in the above-mentioned formula calculates, just can obtain speed V by formula (1);

The speed V value that obtains and the comparison of predefined threshold speed; If this speed V value then continues execution in step 2 less than the threshold speed that sets, display shows the road conditions in detected zone; If this speed V value is greater than the threshold speed that sets, then execution in step 5;

Step 5: the monitor terminal that image and the speed data thereof of taking the photograph over-speed vehicles is transferred to Surveillance center is shown same alarm by optical fiber;

Step 6: directly be kept in the computer monitor terminal memory overspeed of vehicle image, velocity amplitude and the time parameter taken for subsequent use;

Step 7 is got back to step 2; Go round and begin again, repeat above detection.

Beneficial effect: the invention provides the method for measuring car speed based on the cmos digital camera of belt-type shutter, gather multi-function in integral whole, cost is lower than the hypervelocity monitoring product of like product, be the traffic control department effective monitoring equipment of providing convenience, extremely favourable help the serious traffic law of traffic control department, administer traffic accident, apply powerful pressure for the drivers that travel that exeed the regulation speed, improved the present situation of road traffic.Native system has the ability of scene evidence taking simultaneously, the relevant information that can effectively assist traffic control department to distinguish and trace the vehicle of driving against traffic regulations according to the image scene record, thus greatly improve the working rate.Auxiliary with the automatic speed-measuring function in the recording process at the scene, make native system under the condition that does not need operating personnel to intervene, realize automatic speed-measuring and recording image to moving target, the using value of Effective Raise native system alleviates people's labour intensity.Also can utilize modern high technology, the situation of driving against traffic regulations is in time recorded and promptly be sent to the position of appointment by various communication networks, realize Long-distance Control.

The present invention is based on the method for the belt-type shutter mensuration overspeed of vehicle of cmos digital camera, is the image-based speed-measuring method, only need to just can finish with cmos digital camera and the computer monitor terminal of belt-type shutter.Compare with traditional mensuration overspeed of vehicle device, the present invention is based on the conclusion that the analysis to image draws, and calculates the accurate mistake of velocity amplitude in 2.5%, and is convenient to exploitation and the computer monitoring center calling graph picture of other functions of later stage.

Description of drawings

Fig. 1, Fig. 2 and Fig. 3 are moving object image-forming principle schematic diagrames under the belt-type shutter mode.

Fig. 4 is the perspective view of moving object on three dimensions.

Fig. 5 is software flow pattern

Embodiment

Embodiment 1 is provided by the invention to measure the method for overspeed of vehicle based on the cmos digital camera of belt-type shutter, and concrete steps and condition are as follows:

The cmos digital camera that 1) will have a belt-type shutter working method be fixed on the highw ay m onitoring crossing the road surface the top and with the road surface 30 degree angles are arranged, be used for taking the Vehicle Driving Cycle process;

2) the DSP embedded treatment system exploitation that utilizes cmos digital camera with belt-type shutter working method to combine detects software, the packing of the detection software program finished is integrated in the program development bag of cmos digital camera of belt-type shutter, and downloads in the cmos digital camera with belt-type shutter working method;

The cmos digital camera that will have the belt-type shutter working method is transferred to output image data by optical fiber and wired or wireless passage the monitor terminal of Surveillance center; According to following formula (1) computational speed value;

3) carry out following workflow:

Step 1: the automobile driving speed threshold value that begins and arrange regulation;

Step 2: the running car image that shows institute's monitor area at the liquid crystal display equipment screen of Surveillance center;

Step 3: detected target and entered in the field range, the cmos digital camera with belt-type shutter is taken the running car image, and captured image is passed to the DSP embedded treatment system;

Step 4: the car of taking is travelled the velocity amplitude V of image and threshold ratio:

To the image taken according to following formula (1) computational speed value:

From image, appoint and get 12 characteristic points and be made as P, in the formula,

Be the antisymmetric matrix of sports car angular velocity vector Ω, I is 3 * 3 unit matrixs, P _i=[X _i, Y _i, Z _i] ^TBe the three-dimensional coordinate of the automobile image frame that is taken,

R and T are respectively the peaceful vectors that moves of rotation matrix between the cmos digital camera picture of the automobile that is taken and belt-type shutter, make m=[u, v] ^TThe projection of P point on image, order

Then the pass between P and m is:

$s\tilde{m}=K\left[\begin{array}{cc}R& T\end{array}\right]\tilde{P}---\left(2\right)$

In the formula, S is scale factor at random, and τ is the time interval of two image lines exposures;

$k=\left[\begin{array}{ccc}{\mathrm{\α}}_u& 0& u_0\\ 0& {\mathrm{\α}}_v& v_0\\ 0& 0& 1\end{array}\right]$

K is the inner parameter of the cmos digital camera of belt-type shutter;

Characteristic point P in image coordinate under world coordinate system is brought in the above-mentioned formula calculates, just can obtain speed V by formula (1);

The speed V value that obtains and the comparison of predefined threshold speed; If this speed V value then continues execution in step 2 less than the threshold speed that sets, display shows the road conditions in detected zone; If this speed V value is greater than the threshold speed that sets, then execution in step 5;

Step 5: the monitor terminal that image and the speed data thereof of taking the photograph over-speed vehicles is transferred to Surveillance center is shown same alarm by optical fiber;

Step 6: directly be kept in the computer monitor terminal memory overspeed of vehicle image, velocity amplitude and the time parameter taken for subsequent use;

Step 7 is got back to step 2; Go round and begin again, repeat above detection.

Claims (1)

1. measure the method for overspeed of vehicle based on the cmos digital camera of belt-type shutter, it is characterized in that step and condition are as follows:

The cmos digital camera that 1) will have a belt-type shutter working method be fixed on the highw ay m onitoring crossing the road surface the top and with the road surface 30 degree angles are arranged, be used for taking the Vehicle Driving Cycle process;

2) the DSP embedded treatment system exploitation that utilizes cmos digital camera with belt-type shutter working method to combine detects software, the packing of the detection software program finished is integrated in the program development bag of cmos digital camera of belt-type shutter, and downloads in the cmos digital camera with belt-type shutter working method;

The cmos digital camera that will have the belt-type shutter working method is transferred to output image data by optical fiber and wired or wireless passage the monitor terminal of Surveillance center; According to following formula (1) computational speed value;

3) carry out following workflow:

Step 1: the automobile driving speed threshold value that begins and arrange regulation;

Step 2: the running car image that shows institute's monitor area at the liquid crystal display equipment screen of Surveillance center;

Step 3: detected target and entered in the field range, the cmos digital camera with belt-type shutter is taken the running car image, and captured image is passed to the DSP embedded treatment system;

Step 4: the car of taking is travelled the velocity amplitude V of image and threshold ratio:

To the image taken according to following formula (1) computational speed value:

From image, appoint and get 12 characteristic points and be made as P, in the formula,

Be the antisymmetric matrix of sports car angular velocity vector Q, I is 3 * 3 unit matrixs, P _i=[X _i, Y _i, Z _i] ^TBe the three-dimensional coordinate of the automobile image frame that is taken, R and T are respectively the peaceful vectors that moves of rotation matrix between the cmos digital camera picture of the automobile that is taken and belt-type shutter, make m=[u, v] ^TThe projection of P point on image, order Then the pass between P and m is:

$s\tilde{m}=K\left[\begin{array}{cc}R& T\end{array}\right]\tilde{P}---\left(2\right)$

In the formula, S is scale factor at random, and τ is the time interval of two image lines exposures;

$k=\left[\begin{array}{ccc}{\mathrm{\α}}_u& 0& u_0\\ 0& {\mathrm{\α}}_v& v_0\\ 0& 0& 1\end{array}\right]$

K is the inner parameter of the cmos digital camera of belt-type shutter;

Characteristic point P in image coordinate under world coordinate system is brought in the above-mentioned formula calculates, just can obtain speed V by formula (1);

The speed V value that obtains and the comparison of predefined threshold speed; If this speed V value then continues execution in step 2 less than the threshold speed that sets, display shows the road conditions in detected zone; If this speed V value is greater than the threshold speed that sets, then execution in step 5;

Step 5: the monitor terminal that image and the speed data thereof of taking the photograph over-speed vehicles is transferred to Surveillance center is shown same alarm by optical fiber;

Step 6: directly be kept in the computer monitor terminal memory overspeed of vehicle image, velocity amplitude and the time parameter taken for subsequent use;

Step 7 is got back to step 2; Go round and begin again, repeat above detection.

Images