CN102270394A - Vessel traffic monitoring method based on laser sensor - Google Patents

Abstract

The invention discloses a vessel traffic monitoring method based on a laser sensor. The method comprises the following steps: 1) acquiring and processing an image; if detecting a vessels passing by, entering the step 2), if not detecting a vessels passing by, repeating the step 1); 2) recording a section, processing the image and filtering, when the vessel leaves, counting, if the vessel does not leave, repeating the step 2). The invention has the advantages that vessel traffic monitoring method can effectively recognize vessels that pass by in the same direction, opposite directions or in a fleet formation.

Description

Vessel traffic quantity monitoring method based on laser sensor

Technical field

The present invention relates to a kind of volume of traffic monitoring method, especially a kind of vessel traffic quantity monitoring method based on laser sensor belongs to the shipping management technical field.

Background technology

Since the eighties in 20th century, laser measuring technique has been widely used in obtaining of detection of obstacles, environment three-dimensional information, and become a kind of important technical that spatial data obtains, be used widely in fields such as geographic survey, satellite orbit tracking, automotive safety driver assistance, military target range finding and indications.

Laser range sensor is the instrument that utilizes laser that the distance of target is accurately measured.Laser range sensor is made of laser generator, optical element and photoelectric device, when work, pass through to penetrate a branch of very thin laser to target, by photovalve receiving target laser light reflected bundle, timer is measured laser beam from being transmitted into the time of reception, calculates from observer's range-to-go and other three-dimensional reciprocal of duty cycle value.

Compare with traditional measurement means, speed is fast, real-time, cost is low, obtain advantages such as data precision height all weather operations but laser range sensor has.What laser range finder collected is depth image, compares with traditional visual pattern, and following 3 advantages are arranged:

(l) be not subjected to the rayed condition influence, light is not required;

(2) be subjected to kind, the texture of scene medium to influence little.Still have good collection effect for medium gray scale environment unified, the texture basically identical;

(3) three-dimensional spatial information of direct feedback target is convenient to set up the position corresponding relation.

The employing laser sensor can be realized the round-the-clock monitoring in 24 hours to the navigation channel volume of traffic substantially, realizes effective monitoring and metering to cruiseway boats and ships flow under the support of analytical calculation module.

Yet; the object that laser range sensor feeds back; three-dimensional space data information such as the outer contour of boats and ships; it is one group of point-like three-dimensional coordinate data that is separated from each other; simultaneously; these data usually are mingled in a large amount of jamming pattern data, how with useful boats and ships profile from wherein separating, discern and forming outline line, be a gordian technique difficult point of this project.

In addition, hour to be under the situation of unit, though the boats and ships amount of passing through of usually average per minute only is 1.25, the peak period can reach 2 or more than.But in actual visual observations, find, still can occur the parallel simultaneously or staggered sight that passes through of 2 above boats and ships on the navigation channel.And also having the ship of 1% quantity nearly in the boats and ships that pass through is that form with towboat team exists, and has in testing process therefore that blocking mutually appears in many boats and ships or because towboat team influences the accuracy of identification of boats and ships quantity continuously.Therefore, how effectively to discern these with in the same way, subtend and the boats and ships that pass through with towboat formation formula, become another gordian technique difficult point that adopts laser sensor observation volume of vessel traffic.

The 3rd, because the data of the underwater portion of navigating ship can not obtain by laser range sensor in the navigation channel, the acquisition of this part data is the 3rd gordian technique difficult points of this project.

Summary of the invention

The objective of the invention is to propose a kind of can boats and ships block mutually or overlapping situation under, effectively identification with in the same way, subtend and the boats and ships that pass through with towboat formation formula, based on the real-time vessel traffic quantity monitoring method of the cruiseway of laser sensor.

In order to realize the foregoing invention purpose, the present invention adopts following technical scheme, may further comprise the steps:

1) step of images acquired and Flame Image Process if having detected boats and ships passes through, enters step 2), if there is not repeating step 1);

2) carry out section record, Flame Image Process and filtering, when boats and ships leave, add up, if do not leave repeating step 2)

Beneficial effect of the present invention is, can effectively discern these with in the same way, subtend and the boats and ships that pass through with towboat formation formula.

Description of drawings

The present invention is further illustrated below in conjunction with accompanying drawing.

Fig. 1 is the schematic flow sheet synoptic diagram of the present invention's invention.

Embodiment

The detection of the detection of boats and ships contour feature value and navigation direction and speed

1.1 the laser data coordinate system transforms

For the contour feature value (length etc.) that accurately records boats and ships by laser and the navigation direction and the speed of boats and ships, need carry out the conversion of coordinate system to the laser measurement data that record by the two-dimensional laser sensor, set up the space polar coordinate system of laser sensor, the launching site of definition laser beam is the coordinate system limit, straight line with the 0th section laser scanning line place is a pole axis, the coordinate figure of arbitrary measured point is (R in this coordinate system, a), wherein, R is the distance value of point, and a is the angle value of point.

Simultaneously, set up the rectangular coordinate system in space of laser sensor, the definition laser beam launching site be coordinate origin, the coordinate of any point P under rectangular coordinate system that laser sensor measures for (x, y).Obtain after the data of sensor acquisition, carry out the conversion of polar coordinate system to rectangular coordinate system: the conversion formula of each measured point under two coordinate systems is as follows:

1.2 the water surface clutter data processing of laser

In order correctly to be identified in each ship that navigates by water in the water, what at first will realize is detection and Identification to the water surface.Be different from solid, the water level in the navigation channel changes, and need dynamically obtain.Laser presents special reflection characteristic for water simultaneously.

When measuring the water surface, all have only some discrete points, cause such measurement result that two reasons are arranged:

(l) for most of Measuring Object, as mountain, body of wall etc., the laser major part can reflect.Laser is after entering water body, and most of light directly refraction enters water body, propagates to the water surface is following, and a part of in addition light presents direct reflection, presents another direction of mirror image angle directive with former absorption light, has only very little a part of laser to reflect.Therefore, only at the river surface of close laser sensor, laser light reflected intensity just is enough to return signal.

(2) water body itself presents uncalm situation, and the appearance of wave can allow the water surface in a certain moment present the inclination angle, thereby increases the weight of the total reflection of laser, makes measurement image discontinuous straight line occur.In another time test, the tranquil nothing wave of a certain moment river surface, according to expectation is such, of short duration straight line signal occurred.Through practical operation, the result who directly adopts this method to obtain can not recover actual outline line, thinks by analysis, and the information that laser sensor returns occurs intermittently, is not the noise that fluctuates up and down.This direct least square fitting method is also inapplicable, must adopt the mode that combines with cluster analysis, promptly obtains the roughly line segment classification of image earlier, carries out linear regression again.

Through above computing, we can obtain stable water surface coordinate.

1.3 boats and ships profile scan

In the actual detected of boats and ships flow quantity detecting system, the two-dimensional laser sensor place the river course directly over the top, thereby realized substantially the nothing of ship is blocked measurement, laser back and forth rotates along vertical (river course xsect) direction, angle is to be 0 degree vertically downward, maximum angle 84 degree.Every horizontal scanning once obtains a cross section of current boats and ships.

Form one group of profiled outline data of whole piece ship thus, we can the reasonable assumption boats and ships outer contour and other crucial outline line such as deck inside and outside contour line, it all is continuous line, so can adopt polynomial expression to describe these outline lines, thus with computing machine draw corresponding boats and ships digital model and obtain the critical size of the boats and ships relevant with volume of vessel traffic.In addition, in some cases, we can also adopt the way similar to water surface coordinate to discern outer contour and other crucial outline line of boats and ships.

1.4 the measurement of speed of the ship in metres per second

, adopt and arrange 1 mini laser rangefinder along the river apart from 100 meters of iron tower by speed for boats and ships, back and forth rotation on surface level is in order to measure the passage rate of passing ships.

1.5 boats and ships block recall rate

Fixedly hang on the laser sensor on the mid-channel line, when current ship carries out scanning survey on to river surface, the situation that boats and ships block mutually may take place, cause that measurement data is imperfect.

For the ease of understanding, we are as follows to following nominal definition:

In full force and effect blocking:Two ships that refer to equidirectional navigation with the cabin parallel fully and almost constant speed by measurement zone, simultaneously because the relative position relation between relative position and two ships and navigation channel causes laser beam can't obtain the situation of effective computational data of the ship that is blocked between two ships.

Part is effectively blocked:Two ships that refer to equidirectional or relative direction navigation cause laser beam can't obtain the situation of effective computational data of the ship that is blocked because of the relative position relation between relative position between two ships and two ships and navigation channel by measurement zone the time simultaneously.

Partial occlusion:Two ships that refer to equidirectional or relative direction navigation are by full measurement zone the time, cause laser beam can't directly obtain the data of outer contour and other crucial outline line of the ship that is blocked because of the relative position relation between relative position between two ships and two ships and navigation channel simultaneously, but can calculate the situation of outer contour and other crucial cross-sectional data of the ship that is blocked indirectly by the mirror image Calculation Method.

We are according to the relevant regulations and the actual observation statistics of the relevant inland navigation craft size of country and cruiseway standard, and the size and the sailing condition of the boats and ships discussed are below done following basic assumption:

1) the average wide 8 meters of boats and ships, long 35 meters, dried up plane, deck average height is 3 meters (3 meters of freeboards) when unloaded, dried up plane, deck average height is 0.5 meter (0.5 meter of freeboard) during heavy duty, minimum distance to go is 0 meter between two ships of parallel sailing, and on average at the uniform velocity passes through measurement zone with 8 kilometers/hour speed;

2) cruiseway is wide 80 meters, and by mid-channel line left-right symmetric;

3) laser range sensor is positioned at 15 meters, mid-channel line top;

4) boats and ships all have high about 1.5 a meters cabin on the quarter, and its width is to be slightly less than 7 meters of boats and ships width, and length is about about 1/10th 3 meters of boats and ships length overall.

5) boats and ships that navigate by water on the inland river are even shape distribution and at the uniform velocity pass through measurement zone (in fact, under observation we find, all boats and ships are below by the bridge that laser range sensor has been installed the time, because be subjected to the constraint of bridge, with the mid-channel line is that certain distribution is done at the center laterally, and promptly near more mid-channel place density is big more):

Under above assumed condition, we do following discussion to the recall rate of blocking at the boats and ships of cruiseway navigation:

Under the situation directly over laser sensor is positioned at middle of fairway, the far-end that maximum situation of effectively blocking occurs in observation station takes place, promptly when two ships near, and be in relative position (outer low and inner high) situation of navigation in the same way or in opposite directions that is positioned at lower heavily loaded ship inboard with higher lightship.In the navigation channel with above-mentioned two ships near the ship of form navigation, along with dwindling of the distance of relative middle of fairway, lightship is just few more to blocking of heavily loaded ship, until not blocking.

In addition, in the above under the situation of Tao Luning, if the distance between two ships is greater than certain value, block also and can not take place, prove that easily the size of this distance is relevant with the relative position of two ships in the navigation channel, promptly two ships are the closer to middle of fairway, this distance is more little, and more away from center line, this distance is big more.

In fact, when two ships are in following time of situation of this kind situation, we in most of the cases can directly obtain the appearance profile size or calculate the appearance profile size by calculating by laser data, and are as follows by the necessary condition that calculates the appearance profile size:

1) the length and width size of acquisition nacelle top;

2) the outermost freeboard coordinate of heavily loaded ship;

We just can calculate the appearance profile size of the heavily loaded boats and ships that are positioned at the outside by mirror image processing like this.

Below we to minority because two ship relative positions are crossed near or cross long-range guided missile apart from middle of fairway causes heavily loaded ship and too much blocked so that can't satisfy the situation of the appearance profile size (part is effectively blocked) that the mirror image computing obtains heavily loaded boats and ships and discuss:

At first, if navigation in opposite directions, because the ship that passes through under the laser beam of vertical scanning can be done repeatedly vertical cutting by laser beam, consider in the navigation that a ship between two ships stays the distance more than 2 meters to I haven't seen you for ages, distinguish that easily we necessarily have an opportunity to obtain following effective computational data: 1) the length and width size of nacelle top; 2) the outermost freeboard coordinate of heavily loaded ship.Thereby obtain to be blocked ship relative profile size.

For navigating by water in the same way:

1) the maximum probability calculation of blocking in full force and effect

Because maximum of blocking in full force and effect blocks near the far-end (the navigation channel the most close outside) of nidus in observation station, and two ships are positioned at the situation that the relative position of lower heavily loaded ship inboard navigates by water in the same way with higher lightship.In order to obtain the probability that above situation takes place, we observe the ship that navigates by water in the inland river, we count down to through in 1050 ships below the laser instrument, navigating by water in the same way and the quantity that partly (comprises all) ship that blocks is arranged is 95, can calculate from the condition of setting, in half side wide 40 meters navigation channel, the situation that two ships can take place effectively to block is for working as the navigation channel section of ship's navigation 32 meters to 4.7 meters of distance middles of fairway, and two ships are during at interval less than 5.25 meters

Like this, suppose that being even shape at the boats and ships that navigate by water on the inland river is distributed on the inland river at the uniform velocity by under the condition of measurement zone, we can calculate, unloaded and fully loaded ship by above-mentioned condition side by side the maximum probability of navigation be=distance overlaps fully less than the probability X two ship cabins of combination low inside and high outside in four kinds of combinations of probability X of 5.25 meters between the probability X of the boats and ships that may take place to navigate by water in the blocked area two ships probability X observed data=(40 meters-4.7 meters)/40 meters X5.25/35.3X25%X10%X9%)=0.000295.

Obviously, this probability is little of having ignored from the statistical significance.

In the formula,

Probability=(40 meters-4.7 meters) of the boats and ships that may take place to navigate by water in the blocked area/40 meters

Distance is less than 5.25 meters probability=5.25/ (40-4.7) between two ships;

Block in four kinds of relative position combinations of boats and ships when taking place probability=25% that low inside and high outside combination is complete

Probability=10% that two ship cabins overlap fully

Observed data=95/1050=9%

2) largest portion effectively blocks probability calculation

Under the situation that part is effectively covered,

Unloaded and fully loaded ship navigates by water side by side by above-mentioned condition, and the maximum probability that partial occlusion (do not contain fully and block) takes place is=distance overlaps fully less than the full probability X(1-two ship cabins of group low inside and high outside in four kinds of combinations of probability X of 2 meters between the probability X of the boats and ships that may take place to navigate by water in the blocked area two ships probability) X observed data=(40 meters-6 meters)/40 meters X2/34X25%X90%X9%)=0.001072.It still is a small probability event.

In the formula

Probability=(40 meters-6 meters) of the boats and ships that may take place to navigate by water in the blocked area/40 meters

Distance is less than 2 meters probability=2/34 between two ships

Low inside and high outside full probability=25% of group in four kinds of combinations

(probability that 1-two ship cabins overlap fully)=1-0.1

Observed data=9%

By top calculating, we obtain conclusion, on equidirectional, walk abreast by two ships of laser scans ripple, part or in full force and effect blocking so that can not to obtain the probability of effective computational data (cabin width and freeboard) be 0.000295+0.001072=0.001367 are taken place, this be one less than 0.2% small probability everything part.Simultaneously, because the accuracy requirement of this project only is greater than 90%, we determine and will in project the occlusion issue of both of these case ship and the situation of blocking of towboat team not handled especially.

For the ship that navigates by water in opposite directions, we always can obtain relevant data by the method for mirror image.

The fact that other is useful and condition:

1) we can reasonably be provided with the height of laser sensor, so just can further reduce the situation (15 meters height has been selected in this case) that generation is blocked fully;

2) two ships that travel also are very little numerals with isometric fully (or outside heavy duty ship is less than inboard lightship and just within its projection) and with the probability by full measurement zone of constant speed almost;

3) in accordance with regulations less than the ship of certain tonnage not within the scope of monitoring.

In sum, the appearance profile size of our the appearance profile size by the ship that adopts laser data and directly obtain or the ship of calculating by mirror image has accounted for and has passed through more than 99.8% of navigation channel ship.

1.6 measured by the overall size of partial occlusion boats and ships

The measurement of so-called partial occlusion boats and ships is meant navigation in the same way and when being positioned at the laser measuring equipment of top, the part hull is arranged because of blocked the situation that can not directly be scanned by laser beam by another ship between two ships.Zero load of navigating by water in the navigation channel and heavily loaded ship are parallel or during to row, if (1) also/oceangoing ship would be zero load to navigating, or (2) also/oceangoing ship is heavy duty to navigating, prove easily, be positioned at laser instrument under the situation of suitable height, the laser beam that laser range sensor sends can directly obtain also/to all whole appearance profile lines of the oceangoing ship of navigating, thus calculate the tonnage of boats and ships.In like manner, also/to the oceangoing ship of navigating in, if lightship is positioned at away from middle of fairway heavily loaded accommodation (high outside and low outside) under the situation of inboard, the acquisition of appearance profile line also is to realize easily.

And/in the oceangoing ship of navigating, heavily loaded accommodation is in lightship is positioned at inboard (low inside and high outside) and the measuring method of physical dimension of heavily loaded boats and ships of the situation of partial occlusion has taken place away from middle of fairway:

Got rid of take place in full force and effect block and the part situation of effectively blocking after, we just can guarantee at boats and ships during by the laser beam measuring zone, obtain the cabin physical dimension of the heavily loaded boats and ships in the outside and can obtain somewhere outside the freeboard of heavily loaded boats and ships.After whole boats and ships pass through measurement zone, just can extrapolate whole overall sizes of boats and ships by the cabin size is carried out mirror image processing.Thereby accurately obtain these two kinds also/to the appearance profile line of the oceangoing ship of navigating.In like manner, we can obtain relatively and whole overall sizes of the boats and ships of row more easily.

1. 7 testing processes

After the distance of having determined the water surface, adopt laser sensor uninterruptedly under the navigation channel carry out laser scanning.After collecting image, at first carry out data processing work such as filtering, judged whether boats and ships and several boats and ships are arranged,, then continue images acquired if do not have.Judged it is the image of boats and ships for system, continue to have gathered and the cross section of real time record boats and ships, judged according to the shape in cross section whether boats and ships leave measured zone, if, to the boats and ships flow statistics that adds up.The testing process of system, as shown in Figure 1.

In addition to the implementation, the present invention can also have other embodiments.All employings are equal to the technical scheme of replacement or equivalent transformation formation, all drop on the protection domain of requirement of the present invention.

Claims (1)

1. based on the vessel traffic quantity monitoring method of laser sensor, it is characterized in that, may further comprise the steps:

1) step of images acquired and Flame Image Process if having detected boats and ships passes through, enters step 2), if there is not repeating step 1);

2) carry out section record, Flame Image Process and filtering, when boats and ships leave, add up, if do not leave, then repeating step 2).

Images