CN102030016A - Structured light vision-based track irregularity state detection method - Google Patents

Abstract

The invention discloses a method for detecting track irregularities based on structured light vision. Based on the structured light method, as the vehicle moves, the imaging sensor senses the geometric position between the reference light segment 310 and the reference light segment 210. change to know the geometric deviation of the two-dimensional plane space of the measured track 100 under dynamic load conditions; two sets of detection systems on the vehicle can be used more widely to detect the track geometric deviation of the left and right two tracks, so as to obtain the left and right two Orbit-related planar geometric deviation information. The present invention has more information than light spot detection, can not only obtain the height irregularity information of the rail surface in the vertical direction, but also obtain the rail direction irregularity information along the horizontal direction of the track, and has high detection accuracy, good real-time performance, easy installation Convenience, the advantage of being easy to engineer.

Description

Track irregularity detection method based on structured light vision

technical field

The invention relates to the field of structured light visual measurement technology and rail traffic safety detection technology, in particular to a high-speed visual detection method for railway track irregularities based on structured light.

the

Background technique

Track irregularity exists on the contact surface of wheel and rail, which will increase the dynamic effect of wheel and rail, and at the same time further increase the track irregularity, forming a vicious circle. Excessive track irregularities will lead to severe vibration of the wheel-rail system, shorten the service life of vehicles and track components, reduce the stability of driving, and endanger driving safety in severe cases. Routine testing cannot affect the normal transportation of high-speed railways, and efficient means must be used. For the detection of track irregularities, most domestic and foreign detection systems based on the principle of inertial reference are currently used. However, the strapdown inertial system is expensive and bulky, so it is limited in large-scale application. Vision measurement technology has also been applied and developed rapidly in track inspection system. Southwest Jiaotong University in China has carried out relevant research. Lasers and linear array CCDs are respectively installed at the front and rear wheel axles. The lasers directly illuminate the CCD, and the method of directly detecting the offset of the laser spot on the imaging surface is used to detect the state of the track; since only the spot is measured This method can only obtain one-dimensional spatial information. Different from the above-mentioned visual measurement method, the present invention adopts the structured light visual measurement method, uses two line lasers to irradiate the rail surface respectively, obtains two structured light segments, and obtains the relative distance change and angle change of the two light rays through a CCD visual imaging device The two-dimensional spatial characteristics of the track are used to detect the track's height irregularity, track direction irregularity, horizontal irregularity, and triangular pits.

Contents of the invention

In view of the above shortcomings of the prior art, the object of the present invention is to provide a track irregularity detection method based on structured light vision, which has the advantages of low cost, high-speed measurement, high measurement accuracy and easy implementation, and the system device is easy to install.

The purpose of the present invention is achieved by the following means.

A method for detecting track irregularities based on structured light vision, characterized in that a line light source 200 is set above the track and perpendicular to the plane of the track 100 to be measured, and the line light source 200 emits light that is perpendicular to the track plane and on the track plane Projected as a straight line light section perpendicular to the track length direction, the line light section is the reference light section 210; another line light source 300 is set above the track at a distance L from the line light source 200 and parallel to the track plane. The light source 300 emits a reference light segment 310 projected on the track plane and parallel to the reference light segment 210 with a distance of D; an imaging sensor device is arranged near the line light source 200 to sense the distance change between the reference light segment 210 and the reference light segment 310; The line light source 200, the line light source 300 and the imaging sensor device are fixedly arranged on a vehicle that slides along the track, and as the vehicle moves, the imaging sensor device senses the geometric position between the reference light segment 310 and the reference light segment 210 The geometric deviation of the two-dimensional plane space of the measured track 100 under dynamic load conditions can be obtained.

Based on the method of structured light, as the vehicle moves, the imaging sensor device obtains the two-dimensional plane space geometry of the measured track 100 under dynamic load conditions by sensing the change in the geometric position between the reference light segment 310 and the reference light segment 210 Deviation; more widely used. Two sets of detection systems on the vehicle can detect the orbit geometric deviation of the left and right tracks respectively, so as to obtain the plane geometric deviation information related to the left and right tracks.

A more convenient way to realize the object of the present invention is: the railway locomotive is regarded as a vehicle, the near-infrared laser line light source 200 and the line light source 300 are arranged on the axle boxes of the front and rear axles of the same bogie of the locomotive, and the imaging sensor device is arranged on the line light source Around 200. Two near-infrared lasers are used, and they are respectively installed on the axle boxes of the front and rear axles of the same bogie of the train. The laser emits a line light source, and the angle of the laser is adjusted so that the laser beams are all irradiated on the rail surface near the front wheel axle, and the two laser lines are irradiated on the same rail, forming two light projections. Two high-speed imaging devices are used (CMOS or CCD chips can be used as sensors), installed on the axle box of the front wheel axle of the same bogie, and symmetrical along the track length direction. Two high-speed imaging detectors are used to acquire images projected by two rays on the rail surface. Since both the laser and the imaging detector are installed on the axlebox of the same bogie of the train, their relative positions are fixed. There is a rigid connection between the axle box and the wheels of the train. When the train is running, if the track is not smooth, the front and rear two sets of wheels will have a small displacement in the left and right directions or in the up and down direction. At this time, since the two lasers are respectively installed on the front and rear axles, the relative distance and angle between the two laser beams irradiated on the rail surface will change. The two imaging devices acquire the images of the two light rays on the rail surface, and detect the change of the track irregularity by calculating the amount of change. Installing two identical systems on the left and right axles of the train respectively can make judgments on the comprehensive irregularities of the track, such as horizontal irregularities and triangular pits.

This method combines structured light and visual measurement technology, and obtains track state changes by analyzing the relative position changes of laser lines irradiated on the track surface. In actual use, the present invention has the following advantages: the position and structure of all devices are fixed after installation, and there is no scanning device; the two-dimensional change information of the track under dynamic load is obtained through the laser line imaging method, because the laser line has more The amount of information can not only obtain the height irregularity information of the rail surface in the vertical direction, but also obtain the track direction irregularity information along the horizontal direction of the track. The invention can not only measure the changes of the irregular state of the left and right tracks respectively, but also can make a comprehensive judgment to obtain the state changes of the horizontal irregularity and the triangular pit along the track. In addition, the present invention can use a CMOS imaging device, and the output is a digital image signal, which does not require digital acquisition, saves the traditional process of converting analog signals into digital signals using CCD imaging methods, and can improve the real-time performance of the system. The invention uses equipment with low cost, convenient installation and engineering.

Description of drawings

Fig. 1 is a schematic diagram of the method of the present invention.

Fig. 2 is a schematic diagram of the positional relationship between the laser and the camera in the method of the present invention.

Fig. 3 is a schematic diagram of track irregularity detection by the method of the present invention.

Fig. 4 is a schematic diagram of unevenness detection by the method of the present invention.

Fig. 5 is a schematic diagram of double-track composite irregularity detection by the method of the present invention.

Fig. 6 is the overall working block diagram of the method of the present invention. the

Detailed ways

The embodiments of the present invention will be further described below in conjunction with the accompanying drawings.

1 and 2, the present invention takes the installation and use of a railway locomotive as a vehicle as an example. The line light sources 200 and 300 are line lasers in two near-infrared bands, respectively, and the imaging sensors are respectively composed of two high-speed imaging devices 220 and 230 serve as the laser beams emitted by the two lasers to irradiate the rail surface to form laser lines 210 and 310 . Install the near-infrared laser 300 on the axle box 420 of the rear wheel axle of the train bogie, the laser emits a line light source, adjust the angle of the laser, so that the beam line is irradiated on the rail surface near the front wheel 411 wheel-rail contact surface to form a reference light segment 310 , with a small distance (such as 3 cm) from the light bar 210 . The size of the interval should meet the following conditions: the two laser lines can be completely and clearly imaged in the imaging detector under the detection condition. Install the near-infrared line laser 200 and two CMOS (or CCD) imaging devices 220 and 230 on the axle box 410 of the front wheel axle of the train bogie, respectively on both sides of the laser 200, and symmetrically along the length direction of the track 100. Acquire images of two light segments on the orbital surface. The laser 200 emits a line laser beam, which irradiates the track surface at a vertical angle, and the formed reference light segment 210 is perpendicular to the length direction of the track. In order to accurately calculate the relative position of the two light segments, the camera lens needs to be calibrated precisely. The calibration process can be carried out before the camera is installed. In actual operation, only the calibration parameters need to be brought into the calculation, which will not affect the real-time performance of the system. As shown in FIG. 2 , the laser 200 is perpendicular to the rail surface. When the train is running, the imaging position of the reference light segment 210 in the two cameras is fixed, which is used as the reference line. Both the laser and the imaging detector are installed on the axle box of the train bogie, and their relative positions are fixed.

The laser light emitted by the two lasers irradiates the rail surface to form laser lines. In the actual operation of the train, the background light irradiated on the rail surface may be strong, which will cause great interference to the imaging light. The present invention uses a laser in the near-infrared band and installs a filter in front of the imaging lens, which can eliminate the strong background light band. The interference from the laser line is enhanced to enhance the contrast of the laser line image, thereby reducing the post-image processing steps and improving the real-time and measurement accuracy of the system measurement.

When the track is uneven, the relative position of the front and rear axles of the train in the vertical direction changes, thereby changing the distance between the characteristic lines. For example: the initial height of the front and rear wheel axles relative to the track is both H, and during operation, the position of the rear wheel axle corresponding to the track has a slight increase Δd, then the position of the reference light section 210 irradiated by the laser 200 on the track is basically unchanged, while the position of the laser 300 irradiated on the track is basically unchanged. The distance between the position of the reference light segment 310 of the track and the reference light segment 210 is increased from D1 to D2 (as shown in FIG. 3 ). By analyzing the variation of the spacing, a judgment can be made on the dynamic unevenness of the monorail. In addition to the change of the distance D between the two light segments, the change of the parallelism between the light segments can also be detected. If the track at the corresponding position of the two wheel shafts is slightly bent laterally and the parallelism between the light segments changes, the angle corresponding to the two light lines will change ( As shown in Figure 4), by analyzing the change of the angle, the track irregularity can be analyzed.

5 and 6, the present invention installs two sets of detection systems with the same configuration in FIG. The track geometry deviation of the right track 110 is detected with the high-speed imaging units 250 and 260 . The irregularity information of the left and right tracks is comprehensively processed, and the related plane geometric deviation information of the left and right tracks is calculated, so as to obtain the composite irregularity state information along the track. The image processing and data processing units 500 and 510 shown in FIG. 6 respectively preprocess the image data acquired by the left and right tracks, such as: image filtering, lens distortion correction for the acquired image, feature line extraction and data filtering processing. The single-track irregularity calculation units 600 and 610 perform data analysis respectively, calculate the relative distance and angle variation of the two characteristic lines in real time, and judge the irregularity of the left and right tracks respectively, and the results can be transmitted to the output interface unit in real time 800, to store or display data. The calculation results of the two single-track irregularity calculation units 600 and 610 are sent to the dual-track composite irregularity comprehensive calculation unit 700 to judge the dual-track composite irregularity and send the result to the output interface unit 800 for data storage or display.

Based on the above statements, the present invention has the following characteristics: 1). The present invention adopts the structured light method, and under the dynamic load situation, obtains the laser line image irradiated onto the rail surface, calculates its spacing and relative angle changes, and solves the problem of track irregularities. Real-time dynamic detection. The method has the characteristics of simple structure, convenient installation, no manual intervention, and real-time measurement. 2). The present invention uses laser lines as characteristic lines to obtain its changes in two-dimensional plane space, which has more abundant information than laser spots. By analyzing the relative spacing and angle changes of two laser characteristic lines, the irregularity of the height and direction of a single track can be detected. 3). The present invention can not only detect the irregularities of the left and right rails respectively, but also detect the composite irregularities such as horizontal irregularities and triangular pits through comprehensive analysis. 4). The present invention uses a near-infrared band line laser source, a filter corresponding to the wavelength, and an imaging sensor with high sensitivity in the near-infrared band to obtain a high-contrast laser line image, which can adapt to outdoor strong background light conditions.

What has been stated above is only the preferred implementation of the method of the present invention, it should be pointed out that under the premise of not departing from the essence of the method of the present invention, some changes can be made in actual implementation (such as changing the angle at which the laser used is irradiated onto the rail surface , height; or change the height and angle of the high-speed imaging device; or change the wavelength band range of the laser, optical filter and imaging detector, etc.), in addition, the present invention can be used for real-time detection of track irregularities, and can also be used for analyzing wheel The defect of the rail contact surface; the vehicle can be a railway locomotive or other special patrol car, which should be included in the protection scope of the present invention.

Claims (6)

1. track irregularity condition detection method based on structural optical sight, it is characterized in that, the side is provided with a line source (200) with institute's survey track (100) plane vertical direction in orbit, described line source (200) launch vertical with orbit plane and on orbit plane the projection be one with the perpendicular straight line light section of track length direction, described straight line light section is reference light section (210); In the track of range line light source (200) one segment distance L top and parallel the position with orbit plane another line source (300) is set, line source (300) is launched and is incident upon on the orbit plane and parallels with reference light section (210) and at a distance of being the reference light section (310) of D; Near line source 200, be arranged to the variable in distance of image-position sensor (comprising component driving circuit) sensing reference light section (210) and reference light section (310); Line source (200), line source (300) and described imaging sensor spare are fixedly installed on the means of delivery that slides along track, with described means of delivery motion, imaging sensor spare is known the two dimensional surface space geometry deviation of institute's survey track (100) under the dynamic load situation by the variation of geometric position between sensing reference light section (310) and reference light section (210).

2. the track irregularity condition detection method based on structural optical sight according to claim 1, it is characterized in that the variation of geometric position comprises that the intersegmental distance D of two light changes and the intersegmental parallelism of light changes between described reference light section (310) and reference light section (210).

3. the track irregularity condition detection method based on structural optical sight according to claim 1, it is characterized in that, on the described means of delivery two cover checking system respectively to about the track geometry deviation of two tracks detect, by two track correlation plane geometrical deviation information about COMPREHENSIVE CALCULATING, thus the compound irregularity status information of acquisition track.

4. the track irregularity condition detection method based on structural optical sight according to claim 1, it is characterized in that, with the railway locomotive is means of delivery, near infrared band laser line source (200), line source (300) are arranged on the axle box of forward and backward wheel shaft of the same bogie truck of locomotive, and imaging sensor spare (220,230) is arranged near the line source (200).

5. the track irregularity condition detection method based on structural optical sight according to claim 4 is characterized in that described imaging sensor spare is CMOS or CCD imaging device, and this imaging sensor can adopt surface array device or line array.

6. the track irregularity condition detection method based on structural optical sight according to claim 5 is characterized in that, is provided with filter before the imaging lens of described imaging device.

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