CN111855693A - Track inspection line scanning imaging control signal generation device and signal generation method - Google Patents
Track inspection line scanning imaging control signal generation device and signal generation method Download PDFInfo
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- G—PHYSICS
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/88—Investigating the presence of flaws or contamination
- G01N21/95—Investigating the presence of flaws or contamination characterised by the material or shape of the object to be examined
- G01N21/9515—Objects of complex shape, e.g. examined with use of a surface follower device
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- B—PERFORMING OPERATIONS; TRANSPORTING
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- B61K9/00—Railway vehicle profile gauges; Detecting or indicating overheating of components; Apparatus on locomotives or cars to indicate bad track sections; General design of track recording vehicles
- B61K9/08—Measuring installations for surveying permanent way
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- G—PHYSICS
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- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P3/00—Measuring linear or angular speed; Measuring differences of linear or angular speeds
- G01P3/64—Devices characterised by the determination of the time taken to traverse a fixed distance
- G01P3/68—Devices characterised by the determination of the time taken to traverse a fixed distance using optical means, i.e. using infrared, visible, or ultraviolet light
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- G01N21/88—Investigating the presence of flaws or contamination
- G01N21/95—Investigating the presence of flaws or contamination characterised by the material or shape of the object to be examined
- G01N21/9515—Objects of complex shape, e.g. examined with use of a surface follower device
- G01N2021/9518—Objects of complex shape, e.g. examined with use of a surface follower device using a surface follower, e.g. robot
Abstract
The invention discloses a line scanning imaging control signal generating device and a signal generating method for a track inspection platform. The rotary axle of the inspection platform drives the marked pattern to rotate; the imaging module images the mark patterns, matches the same mark patterns in the image sequence, calculates the displacement of the mark patterns in unit time and calculates the movement speed of the inspection platform according to the displacement; and generating PWM waves with corresponding frequencies as line scanning control signals according to the motion speed and imaging resolution requirements.
Description
Technical Field
The invention relates to the technical field of rail transit, in particular to a rail inspection line scanning imaging control signal generating device and a signal generating method.
Background
The rail transit is the supporting industry of transportation, and plays a great role in the aspects of national economic development, people's life and travel and the like. The rail serves as the infrastructure of the rail transit, and the performance state of the rail transit is closely related to the operation safety of the rail transit. After the subway runs for a long time, due to various reasons such as train rolling, foundation settlement, material aging and the like, the state of the rail is gradually deteriorated, various diseases such as rail gauge change, rail fracture, fastener failure and the like randomly occur, and if the diseases cannot be found and treated in time, serious traffic accidents such as train derailment and the like can be possibly caused. Therefore, the rail detection and maintenance work is very important for the safe operation management of the subway.
In recent years, large-scale comprehensive inspection vehicles with image processing technology as the core are applied to high-speed rail construction projects at home and abroad. Typical products include a track state inspection system developed by iron institute of China, a TCIS track component imaging system manufactured by ENSCO of America, a V-CUBE track detection system manufactured by MERMEEC of Italy, a TrackImaging track imaging system manufactured by Rial-Vison of England, and the like. The equipment has the technical indexes and partial functions, the working principle and the system structure are different, and a plurality of high-speed cameras are arranged at the bottom of a rail inspection vehicle to continuously shoot sequence images on the surface of a rail, and the sequence images are stored and then are detected to be abnormal by a computer through image processing and mode recognition.
The large-scale comprehensive inspection vehicle is mainly used for completion acceptance of newly-built lines and periodic inspection of important main roads, and has the following outstanding problems in meeting the daily inspection requirements of urban rail transit:
1) the comprehensive detection patrol vehicle data processing timeliness is not strong, and potential safety hazards exist. At present, the data processing mode of the inspection system in the comprehensive inspection vehicle is offline post-processing, after the inspection is finished, inspection data is copied manually, an inspection video is derived, and manual analysis is carried out secondarily. In the actual operation of the comprehensive detection vehicle, the detection result is obtained after the detection is started, the time delay is about 1 day, if a large or serious defect occurs, the first discovery time is missed, and certain potential safety hazards exist.
2) The coverage rate of the driving frequency of the comprehensive detection patrol car is low. At present, the monthly routing inspection frequency of each line of the comprehensive detection inspection vehicle is 1-2 times, the monthly routing inspection coverage rate is only 6%, along with rapid expansion of the operation scale of a wire network, resources of skylight points are very poor, the skylight points are short in time and few in plan, routing inspection of a track of the comprehensive detection inspection vehicle is difficult, and the problem of missed inspection caused by insufficient routing inspection coverage rate is exposed because a plurality of elastic strips of a track fastener are lost in a 10-line golden station in the early stage.
In order to solve the problems, the chinese patent CN201910331806.1 proposes a detachable trolley for rail inspection, which carries a visual imaging module to image the rail, so as to realize daily inspection of the rail. However, such rail inspection trolleys require "night maintenance window periods". And the night detection window period is very important for track inspection and maintenance. How to realize the daily inspection of the track and not occupying the night maintenance window period is an important effort direction for improving the inspection level of the urban track.
In order to meet the daily inspection requirement and not occupy the night maintenance window period, the vision imaging system in the patent CN201910331806.1 needs to be transplanted to an electric bus. The visual imaging system facing the track inspection comprises a linear array camera or a 3D camera, and is usually a linear array scanning imaging system by referring to the prior art such as 'vehicle-mounted track inspection system development based on computer vision', patent 201910356927.1 and the like. Adopt linear array scanning imaging system to carry out 2D or 3D formation of image to the rail surface, generally speaking, the formation of image resolution interval of linear array scanning is 1mm, consequently, need carry out once imaging to the track surface when electric passenger train moves 1mm, this imaging process needs a TTL pulse to control. A photoelectric encoder is usually adopted on a track inspection vehicle and an inspection robot to encode the rotation angle of the vehicle to generate mileage pulse, and the mileage pulse is used for triggering imaging of a vision system.
The mile pulse requirement for visual imaging control is to generate 1 pulse per 1mm or 2mm of train movement. However, the vision system is mounted on the daily-running electric bus, and there is no mileage pulse signal meeting the requirement for the vision imaging system, and because of safety factors or management process constraints, a photoelectric encoder meeting the mileage pulse resolution requirement of the vision imaging system cannot be mounted on the electric bus. Therefore, the visual intelligent inspection system for the track mounted on the train has to solve the problem of how to acquire a high-precision mileage pulse signal under the condition that a photoelectric encoder cannot be installed.
Disclosure of Invention
In order to solve the problems in the background art, the invention provides a robust track inspection line scanning imaging control signal generator. The device can independently acquire high-precision mileage pulse signals of any motion state of the train under the conditions that a photoelectric encoder is not required to be installed and a train signal system is not required to provide the speed of a train body.
In order to achieve the purpose, the invention adopts a technical scheme that:
the utility model provides a line scanning formation of image control signal generating device is patrolled and examined to track, carries on patrolling and examining the platform, and this signal generating device contains:
the marking pattern is fixed on the surface of the axle of the inspection platform and is a spot or mottled pattern with randomly changed brightness, which can also be called as a speckle pattern;
a light source for imaging module illumination;
the imaging module consists of an imaging lens and an image sensor and is used for imaging the marking pattern;
the data processing and signal generating module is an embedded system based on FPGA or DSP or ARM, is in communication connection with the imaging module, and is used for driving the imaging module, acquiring an imaging image of a marked pattern, processing the imaging, calculating the motion speed of the inspection platform and generating an imaging control pulse; and
and the fixing box is used for installing the light source, the imaging module and the data processing and signal generating module and is fixed at the bottom of the inspection platform.
Further, imaging module's formation of image optical axis with it is perpendicular to patrol and examine the axletree axis of platform, preferably, imaging optical axis passes the axletree center.
Furthermore, the imaging module is a linear array camera and consists of an imaging lens and a linear array image sensor; or
The area array camera consists of an imaging lens and an area array image sensor.
Further, the sampling frequency of the linear array camera is 10-120 KHz.
The invention adopts another technical scheme that:
a signal generating method of the track inspection line scanning imaging control signal generating device comprises the following steps:
the axle of the inspection platform rotates with the marked pattern;
the imaging module images the rotating mark pattern to obtain an image sequence; and
the data processing and signal generating module receives the image sequence, obtains the moving speed of the inspection platform after processing, generates PWM waves with corresponding frequency according to the moving speed of the inspection platform and the imaging resolution requirement, and outputs the PWM waves as line scanning control signals.
Further, the method for obtaining the movement speed of the inspection platform comprises the following steps:
taking the t1 th frame and the t1-k1 th frame images I (t1) and I (t1-k1) in the image sequence, and performing distortion correction on I (t1) and I (t1-k1) according to an imaging model of the imaging module to respectively obtain I '(t 1) and I' (t1-k1), wherein t1 is an image frame number, k1 is a processing image frame number interval, and the value range of k1 is 1-1000;
taking the central point of I' (t1) as a reference position, and taking pixels in the first neighborhood as a template image;
determining the optimal matching position of the template image in I' (t1-k1) by adopting a template matching method;
calculating the difference value between the optimal matching position and the reference position in the I' (t1) to obtain the axle rotation displacement, and calculating the actual physical length of the axle rotation displacement according to the imaging model;
calculating the actual rotating length of the wheel of the inspection platform according to the diameter proportional relation between the axle of the inspection platform and the actual physical length of the rotating displacement of the axle; and
and calculating the ratio of the actual rotation length of the wheels of the inspection platform to the sampling time interval of the t1 th frame image and the t1-k1 th frame image, and obtaining the movement speed of the inspection platform.
Further, when the imaging module is an area-array camera, the first neighborhood is (w1 × w1), and the value range of w1 is 3-100.
Further, when the imaging module is a linear array camera, the first neighborhood is [ -w2, w2], and the value range of w2 is 3-100.
Further, the template matching method is selected from any one of SAD, NCC and NCC + FFT.
Further, when the imaging module is a linear array camera, the method for obtaining the movement speed of the inspection platform comprises the following steps:
caching the b +1 frame image in a time sliding window mode, and performing position matching on the 0 th frame image and the b th frame image in the cached image, wherein the value range of b is 3-50;
matching the current frame image I (t2) with the t2-k2 frame image I (t2-k2) to obtain a displacement d 1;
matching the current frame image I (t2) with the t2-k3 frame image I (t2-k3) to obtain a displacement d 2;
matching the current frame image I (t2) with the t2-k4 frame image I (t2-k4) to obtain a displacement d 3;
when d1/k2 is d2/k3 is d3/k4 and the values are all smaller than a threshold value q1, the inspection platform is judged to be static, PWM pulses are stopped to be generated, and the value range of q1 is 0.5-1;
when d1/k2> d2/k3+ q2 and d2/k3> d3/k4+ q2, judging that the inspection platform is accelerated, and estimating the motion speed of the inspection platform by using d1/k 2;
when d1/k2< d2/k3+ q2 and d2/k3< d3/k4+ q2, judging that the inspection platform decelerates, and estimating the movement speed of the inspection platform by using d1/k 2;
when the inspection platform moves at a constant speed (d1/k2-d2/k3) < q3, (d2/k3-d3/k4) < q3 and d1/k2> q1, estimating the movement speed of the inspection platform by using the mean values of d1/k2, d2/k3 and d3/k 4;
wherein, k2< k3< k4, and k2, k3 and k4 all have the value range of 1-100.
Furthermore, the method for buffering b + 1 frame images in a time sliding window mode is realized by adopting an FIFO memory.
Compared with the prior art, the invention has the beneficial effects that:
1. the invention adopts a non-contact vehicle movement speed measuring method, which comprises the steps of setting a mark pattern on a rotating axle, shooting the mark pattern through a photoelectric imaging sensor, calculating the rotation displacement of the axle through an image matching method, and calculating the vehicle movement speed according to the diameter proportional relation of the axle and wheels. Compared with certain displacement measurement methods based on specific pattern shapes, the speckle pattern has natural anti-pollution capacity and cannot be interfered by outdoor pollution, and a measurement system is ensured to work stably and normally.
2. The invention uses the linear array image sensor, has very high sampling rate, can quickly distinguish the change of the high-speed rotating axle and realizes the high-resolution measurement of the minimum displacement.
3. The invention uses an area array image sensor, and can eliminate the position deviation caused by vibration.
4. According to the invention, the b +1 row of pixels are subjected to template matching in a time sliding window mode, and through mileage integration, noise can be eliminated, the accuracy of template matching is increased, and the displacement estimation precision is improved.
5. The invention adopts the NCC method to carry out template matching, can well track the change of the rotating speed of the axle, thereby being suitable for any speed state of the carrying platform.
6. The method for caching pixels and performing multi-level matching measurement has better robustness.
Drawings
FIG. 1 is a schematic diagram of a signal generator according to an embodiment of the present invention;
FIG. 2 is a diagram illustrating the effect of a marking pattern;
FIG. 3 is a diagram showing the imaging effect of the linear array speckle pattern in embodiment 1;
FIG. 4 is a graph of luminance curves obtained from the pixels in the 5 th row and the pixels in the 10 th row in the captured image in example 3;
FIG. 5 is a graph of the axle rotational arc length speed calculated according to the NCC method in example 5;
the system comprises a patrol platform, wheels, axles, a marking pattern, an imaging module, a data processing and signal generating module, a fixing box, a light source irradiation plane, an imaging plane and an axle wire, wherein the patrol platform is 1-2-wheels, the axles are 3-4-marking pattern, the imaging module is 5-6-data processing and signal generating module, the fixing box is 7-8-light source, the light source irradiation plane is 9-10-imaging plane, and the axle.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention.
The imaging images of the area camera and the linear array camera are respectively an area image and a linear array image, which are represented by frames, wherein the area image is represented by w x h, h is more than 1, the linear array image is represented by w x h, and h is 1; where w is the image width and h is the image height.
Example 1
The utility model provides a platform line scanning formation of image control signal generating device is patrolled and examined to track, the schematic structure is shown in fig. 1, the mount is patrolled and examined on platform 1, this signal generating device contains:
the mark pattern 4 is fixed on the surface of the axle 3 of the inspection platform, is a spot or mottle pattern with randomly changed brightness, and can also be called as a speckle pattern, as shown in fig. 2;
a light source 8 for imaging module illumination;
the imaging module 5 consists of an imaging lens and an image sensor and is used for imaging the marked pattern, the imaging optical axis of the imaging module 5 is vertical to the axle central axis 11 of the inspection platform, and the imaging optical axis penetrates through the center of the axle 3;
the data processing and signal generating module 6 is an embedded system based on FPGA or DSP or ARM, is in communication connection with the imaging module, and is used for driving the imaging module, acquiring an imaging image of a marked pattern, processing the imaging image, calculating the motion speed of the inspection platform and generating an imaging control pulse; and
and the fixing box 7 is used for installing the lighting source, the imaging module and the data processing and signal generating module and is fixed at the bottom of the inspection platform.
In this embodiment, the imaging module 5 is a linear array camera, and is composed of an imaging lens and a linear array image sensor; the imaging plane 10 of the linear array camera is perpendicular to the central axis of the axle 3, the imaging plane 10 samples the speckle pattern in a single line to obtain a line of image, when the axle 3 rotates, the speckle pattern is driven to rotate, and the projection of the speckle pattern in the imaging plane also rotates along with the rotation, so that the effect diagram shown in fig. 3 is generated. From the effect diagram of fig. 3, it can be seen that when the axle rotates with the mark pattern, the stripes in the linear array image also rotate along with the mark pattern, so that the translation distance of the stripes can be found through matching of adjacent pixel rows in the image, and the measurement of the rotation arc length of the axle is realized.
The method for generating the line scanning imaging control signal comprises the following steps:
the linear array camera carries out single-line imaging on speckle patterns at a fixed frequency of 10-120KHz to obtain an image sequence, adjacent pixel rows in the image sequence are searched and matched, the offset is calculated, then the actual physical size is converted according to an imaging model of the linear array camera, the moving arc length of an axle in unit time can be calculated, the running speed of an inspection platform can be calculated according to the proportional relation between the axle and the diameter of wheels, and pulse signals with corresponding frequencies are generated to serve as line scanning control signals according to the running speed of the inspection platform and the resolution requirement of a linear array scanning imaging system.
The specific method for acquiring the speed of the inspection platform comprises the following steps:
taking the t1 th frame and the t1-k1 th frame images I (t1) and I (t1-k1) in the image sequence, and performing distortion correction on I (t1) and I (t1-k1) according to an imaging model of the imaging module to respectively obtain I '(t 1) and I' (t1-k1), wherein t1 is an image frame number, k1 is a processing image frame number interval, and the value range of k1 is 1-1000;
taking the central point of I' (t1) as a reference position, and taking pixels in [ -w2, w2] neighborhood as a template image, wherein the value range of w2 is 3-100;
determining the optimal matching position of the template image in I' (t1-k1) by adopting a template matching method;
calculating the difference value between the optimal matching position and the reference position in the I' (t1) to obtain the axle rotation displacement, and calculating the actual physical length of the axle rotation displacement according to the imaging model;
calculating the actual rotating length of the wheel of the inspection platform according to the diameter proportional relation between the axle of the inspection platform and the actual physical length of the rotating displacement of the axle; and
and calculating the ratio of the actual rotation length of the wheels of the inspection platform to the sampling time interval of the t1 th frame and the t1-k1 th frame to obtain the movement speed of the inspection platform.
Example 2
Compared with embodiment 1, the imaging module 5 in this embodiment is an area-array camera, and is composed of an imaging lens and an area-array image sensor.
The specific method for acquiring the speed of the inspection platform comprises the following steps:
taking the t1 th frame and the t1-k1 th frame images I (t1) and I (t1-k1) in the image sequence, and carrying out distortion correction on I (t1) and I (t1-k1) according to the imaging model of the imaging module to respectively obtain I '(t 1) and I' (t1-k1), wherein t1 is an image frame number, k1 is a processing image frame number interval, and the value range is 1-1000;
taking the central point of I' (t1) as a reference position, and taking (w1 w1) pixels in the neighborhood as a template image, wherein the value range of w1 is 3-100;
determining the optimal matching position of the template image in I' (t1-k1) by adopting a template matching method;
calculating the difference value between the optimal matching position and the reference position in the I' (t1) to obtain the axle rotation displacement, and calculating the actual physical length of the axle rotation displacement according to the imaging model;
calculating the actual rotating length of the wheel of the inspection platform according to the diameter proportional relation between the axle of the inspection platform and the actual physical length of the rotating displacement of the axle; and
and calculating the ratio of the actual wheel rotation length of the inspection platform to the sampling time interval of the t frame and the t-k frame images to obtain the movement speed of the inspection platform.
Example 3
Compared with the embodiment 1, the method for acquiring the speed of the routing inspection platform is different, and specifically comprises the following steps:
caching b +1 line of pixels, performing position matching on the 0 th frame image and the b th frame image in the cached image, wherein the value range of b is 3-50, as shown in fig. 4, the obvious displacement deviation can be seen by taking the brightness regions of the 5 th line of pixels and the 10 th line of pixels in fig. 3;
matching the current frame image I (t2) with the t2-k2 frame image I (t2-k2) to obtain a displacement d 1;
matching the current frame image I (t2) with the t2-k3 frame image I (t2-k3) to obtain a displacement d 2;
matching the current frame image I (t2) with the t2-k4 frame image I (t2-k4) to obtain a displacement d 3;
when d1/k2 is d2/k3 is d3/k4 and the values are all smaller than a threshold value q1, the inspection platform is judged to be static, PWM pulses are stopped to be generated, and the value range of q1 is 0.5-1;
when d1/k2> d2/k3+ q2 and d2/k3> d3/k4+ q2, judging that the inspection platform is accelerated, and estimating the motion speed of the inspection platform by using d1/k 2;
when d1/k2< d2/k3+ q2 and d2/k3< d3/k4+ q2, judging that the inspection platform decelerates, and estimating the movement speed of the inspection platform by using d1/k 2;
when the inspection platform moves at a constant speed (d1/k2-d2/k3) < q3, (d2/k3-d3/k4) < q3 and d1/k2> q1, estimating the movement speed of the inspection platform by using the mean values of d1/k2, d2/k3 and d3/k 4;
wherein, k2< k3< k4, and k2, k3 and k4 all have the value range of 1-100;
the method for buffering b + 1 frame images in a time sliding window mode is realized by adopting an FIFO memory.
The advantage of this embodiment of caching b +1 rows of pixels is: when the electric bus is slow in movement speed, the difference of pixels of adjacent lines is small, real displacement is difficult to find through template matching, error results are easy to generate, after multiple lines are cached, noise can be eliminated through mileage integration, accuracy of template matching is improved, and displacement estimation precision is improved.
Example 4
The template matching method in examples 1 to 3 employed the SAD method.
Example 5
In embodiments 1 to 3, the NCC method is used for the template matching method, and fig. 5 is a result of displacement estimation performed on the data acquired in fig. 2 by using the NCC method, where the vertical axis in the figure is arc length displacement and the horizontal axis is a time axis.
Example 6
The template matching method adopts a frequency-dependent NCC method and is accelerated by FFT.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various changes and modifications can be made without departing from the inventive concept of the present invention, and these changes and modifications are all within the scope of the present invention.
Claims (10)
1. The utility model provides a line scanning formation of image control signal generating device is patrolled and examined to track, carries on patrolling and examining the platform, and its characterized in that, this signal generating device contains:
the marking pattern is fixed on the surface of the axle of the inspection platform and is a spot or mottled pattern with randomly changed brightness;
a light source for imaging module illumination;
the imaging module consists of an imaging lens and an image sensor and is used for imaging the marking pattern;
the data processing and signal generating module is an embedded system based on FPGA or DSP or ARM, is in communication connection with the imaging module, and is used for driving the imaging module, acquiring an imaging image of a marked pattern, processing the imaging image, calculating the motion speed of the inspection platform and generating an imaging control pulse; and
and the fixing box is used for installing the light source, the imaging module and the data processing and signal generating module and is fixed at the bottom of the inspection platform.
2. The apparatus of claim 1, wherein an imaging optical axis of the imaging module is perpendicular to an axle central axis of the inspection platform.
3. The apparatus of claim 1 or 2, wherein the imaging module is a line camera, which is composed of an imaging lens and a line image sensor; or
The area array camera consists of an imaging lens and an area array image sensor.
4. A signal generating method of the track inspection line scanning imaging control signal generating device according to any one of claims 1 to 3,
the method is characterized by comprising the following steps:
the axle of the inspection platform rotates with the marked pattern;
the imaging module images the rotating mark pattern to obtain an image sequence; and
the data processing and signal generating module receives the image sequence, obtains the moving speed of the inspection platform after processing, generates PWM waves with corresponding frequency according to the moving speed of the inspection platform and the imaging resolution requirement, and outputs the PWM waves as line scanning control signals.
5. The method of claim 4, wherein the method of obtaining the speed of movement of the inspection platform comprises:
taking the t1 th frame and the t1-k1 th frame images I (t1) and I (t1-k1) in the image sequence, and performing distortion correction on I (t1) and I (t1-k1) according to an imaging model of the imaging module to respectively obtain I '(t 1) and I' (t1-k1), wherein t1 is an image frame number, k1 is a processing image frame number interval, and the value range of k1 is 1-1000;
taking the central point of I' (t1) as a reference position, and taking pixels in the first neighborhood as a template image;
determining the optimal matching position of the template image in I' (t1-k1) by adopting a template matching method;
calculating the difference value between the optimal matching position and the reference position in the I' (t1) to obtain the axle rotation displacement, and calculating the actual physical length of the axle rotation displacement according to the imaging model;
calculating the actual rotating length of the wheel of the inspection platform according to the diameter proportional relation between the axle of the inspection platform and the actual physical length of the rotating displacement of the axle; and
and calculating the ratio of the actual rotation length of the wheels of the inspection platform to the sampling time interval of the t1 th frame image and the t1-k1 th frame image, and obtaining the movement speed of the inspection platform.
6. The method of claim 5, wherein when the imaging module is an area-array camera, the first neighborhood is (w1 w1) and w1 has a value in the range of 3-100.
7. The method of claim 5, wherein when the imaging module is a line camera, the first neighborhood is [ -w2, w2], and w2 has a value in the range of 3-100.
8. The method of claim 5, wherein the template matching method is selected from any one of SAD, NCC + FFT.
9. The method of claim 4, wherein when the imaging module is a line camera, the method for obtaining the moving speed of the inspection platform comprises:
caching the b +1 frame image in a time sliding window mode, and performing position matching on the 0 th frame image and the b th frame image in the cached image, wherein the value range of b is 3-50;
matching the current frame image I (t2) with the t2-k2 frame image I (t2-k2) to obtain a displacement d 1;
matching the current frame image I (t2) with the t2-k3 frame image I (t2-k3) to obtain a displacement d 2;
matching the current frame image I (t2) with the t2-k4 frame image I (t2-k4) to obtain a displacement d 3;
when d1/k2 is d2/k3 is d3/k4 and the values are all smaller than a threshold value q1, the inspection platform is judged to be static, PWM pulses are stopped to be generated, and the value range of q1 is 0.5-1;
when d1/k2> d2/k3+ q2 and d2/k3> d3/k4+ q2, judging that the inspection platform is accelerated, and estimating the motion speed of the inspection platform by using d1/k 2;
when d1/k2< d2/k3+ q2 and d2/k3< d3/k4+ q2, judging that the inspection platform decelerates, and estimating the movement speed of the inspection platform by using d1/k 2;
when the inspection platform moves at a constant speed (d1/k2-d2/k3) < q3, (d2/k3-d3/k4) < q3 and d1/k2> q1, estimating the movement speed of the inspection platform by using the mean values of d1/k2, d2/k3 and d3/k 4;
wherein, k2< k3< k4, and k2, k3 and k4 all have the value range of 1-100.
10. The method of claim 9 wherein the buffering of b +1 frame pictures in a time sliding window manner is implemented using a FIFO memory.
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