CN104802799A - Guidance method for reversing track - Google Patents

Abstract

The invention is suitable for the automotive field, and provides a generation method for a reversing track line. A system comprises a vehicle-mounted navigator, a rear-view camera, a gyroscope and a whole-vehicle CAN (controller area network) monitor, wherein reference objects are arranged at intervals at a preset distance; the rear-view camera takes photos of the reference objects; the position information of the reference objects is extracted from feature points from the taken photos; the reversing track line is drawn out on a display based on a camera image-forming principle according to car body parameters, the parameter of the rear-view camera and the position information of the reference objects; the track line changes with the change of the steering of a steering wheel, so that the guidance method for the reversing track can more vividly and more accurately help a driver to judge that whether a vehicle collides an obstacle or not in order to effectively reduce incidents in reversing the vehicle and to assist the driver to reverse the vehicle easily.

Description

A kind of backing track guidance method

Technical field

The present invention relates to automotive field, be specifically related to a kind of backing track guidance method.

Background technology

Along with popularizing of vehicle, the growing tension on parking stall, reversing aid system is welcome all the more using the system as a kind of safety reversing; Especially for the new hand lacked experience that moves backward, reversing aid system efficiently avoid the reversing potential safety hazard caused not in place.

The parking guide mode the most often used at present coordinates alarming sound mixer for utilizing proximity sensor, informs the rough distance of driver and obstacle with the length change of sound.Some meetings increases video camera and telltale provides driver to move backward picture, makes driver can know situation arround car.If but driver's technology is not or the said apparatus place that cannot detect, automobile still cannot stop to preposition by driver smoothly, also may with arround obstacle produce and collide.

Summary of the invention

The object of the present invention is to provide a kind of backing track guidance method, utilize gyroscope and the parameter of camera measured by sensor, after being supplied to control setup computing, and on display screen, indicate the backing track that predetermined parking space puts, guide steerman by this and fast and safely move backward.

The technology of the present invention solution:

A kind of backing track guidance system, comprise automatic navigator, rearview camera, gyroscope and car load CAN networking detector, the parameter collected is outputted to MCU by CAN network by gyroscope, and MCU goes out reversing induction trajectory by calculating and plotting and the navigating instrument screen display that is added to the vision signal that rearview camera collects.

A kind of backing track guidance method, comprises the following steps:

A. measure and obtain vehicle body preset parameter;

B. according to camera imaging principle and geometric relationship, by rearview camera, calibration position object of reference is taken pictures, to obtain ground coordinate to screen coordinate conversion formula coefficient;

C. set up ground backing track math modeling, according to a, the parameter coefficient of b step gained substitutes into ground backing track formula and obtains the displaing coordinate position of backing track on screen, is then superimposed upon on screen with rearview camera picture and shows.

In described step a, vehicle body preset parameter can by tape measure out.

In described step b, coordinate transformation coefficient can be adjusted out by solving quadratic equation with one unknown at ground specified point placement object of reference.

Beneficial effect of the present invention:

Predetermined parking space is put backing track by method of calculating and is marked on display screen by the present invention, trajectory can change with rotating of steering wheel, can chaufeur be helped to judge whether to touch obstacle more intuitively, more exactly like this, effectively reduce the generation of reversing accident, auxiliary car owner easily moves backward.

Accompanying drawing explanation

Fig. 1 is the realization flow figure of backing track line generation method of the present invention.

Fig. 2 is backing track line ground trace schematic diagram of the present invention.

Fig. 3 is parameter tuning schematic diagram of the present invention.

Fig. 4 is that the one of backing track line of the present invention specifically generates example.

Detailed description of the invention

The present invention is set forth further below in conjunction with the drawings and specific embodiments.

As shown in Figures 1 to 4, backing track guidance method, comprises the following steps:

A. use tape measure to go out the intrinsic parameter of vehicle body, the physical length of actual measurement has: wheel base L, rear axle width W, camera are to rear axle horizontal throw D, and camera is apart from floor level h.

B. by rearview camera, calibration position object of reference is taken pictures, to obtain ground coordinate to screen coordinate conversion formula coefficient; Derived by Formula of Coordinate System Transformation coefficient and know, need to provide two groups of ground coordinate y and corresponding screen coordinate Ys, Formula of Coordinate System Transformation coefficient can be obtained.We put two in the position that the dead aft of the car distance tailstock is respectively 1 meter and 2 meters and are parallel to car rear axle object of reference as shown in Figure 3.The unit relating to physical length assuming that all is rice, by straight line mobile on screen, Ys=Ys1 is overlapped with the ground straight line y=1 that screen shows, Ys=Ys2 overlaps with the ground straight line y=2 that screen shows, obtain ground and screen two respective coordinates groups (1, Ys1), (2, Ys2).

By obtain , , according to derive coefficient solution formula:

Separately , ,

Solve and obtain coefficient and be respectively:

、

C. set up backing track math modeling by experience in conjunction with geometry, rear shaft center's equation of locus is: (wherein , l=1 during right-hand rotation, l=-1 during left-hand rotation), then when time represent off-side wheel sub-trajectory, time represent nearside wheel sub-trajectory.

D. parameter and tuning coefficient are substituted into formulae discovery and go out screen coordinate corresponding to ground coordinate, on screen, then draw out reversing guide rail trace.

Claims (4)

1. a backing track guidance method, comprises the following steps:

A. measure and obtain vehicle body preset parameter;

B. according to camera imaging principle and geometric relationship, by rearview camera, calibration position object of reference is taken pictures, to obtain ground coordinate to screen coordinate conversion formula coefficient;

C. set up ground backing track math modeling, according to a, the parameter coefficient of b step gained substitutes into ground backing track formula and obtains the displaing coordinate position of backing track on screen, is then superimposed upon on screen with rearview camera picture and shows.

2. the method for claim 1, is characterized in that: in described step a, vehicle body preset parameter by tape measure out.

3. the method for claim 1, is characterized in that: in described step b, coordinate transformation coefficient is adjusted out by solving quadratic equation with one unknown at ground specified point placement object of reference.

4. the method as described in one of as any in claims 1 to 3, is characterized in that: described method specifically comprises the following steps:

A. use tape measure to go out the intrinsic parameter of vehicle body, the physical length of actual measurement has: wheel base L, rear axle width W, camera are to rear axle horizontal throw D, and camera is apart from floor level h;

B. by rearview camera, calibration position object of reference is taken pictures, to obtain ground coordinate to screen coordinate conversion formula coefficient; Derived by Formula of Coordinate System Transformation coefficient and know, need to provide two groups of ground coordinate y and corresponding screen coordinate Ys, Formula of Coordinate System Transformation coefficient can be obtained;

Put two in the position that the dead aft of the car distance tailstock is respectively 1 meter and 2 meters and be parallel to car rear axle object of reference; The unit relating to physical length assuming that all is rice, by straight line mobile on screen, Ys=Ys1 is overlapped with the ground straight line y=1 that screen shows, Ys=Ys2 overlaps with the ground straight line y=2 that screen shows, obtain ground and screen two respective coordinates groups (1, Ys1), (2, Ys2);

By obtain , , according to derive coefficient solution formula:

Separately , ,

Solve and obtain coefficient and be respectively:

、

C. set up backing track math modeling by experience in conjunction with geometry, rear shaft center's equation of locus is: (wherein , l=1 during right-hand rotation, l=-1 during left-hand rotation), then when time represent off-side wheel sub-trajectory, time represent nearside wheel sub-trajectory;

D. parameter and tuning coefficient are substituted into formulae discovery and go out screen coordinate corresponding to ground coordinate, on screen, then draw out reversing guide rail trace.