FR2628200A1 - DEVICE AND METHOD FOR MEASURING AIR-RUNNING DISTANCES - Google Patents

Abstract

Method and device for determining the distance traveled in the air, in particular in a non-plane and / or inclined landing zone, characterized in that at least one camera 8 and devices which follow the contour of the surface of the landing zone are connected to a processing unit 5 and that this processing unit is coupled to a display unit 10.

Description

FRENCH REPUBLIC Publication no. 2,628,200 (to be used only for

  the NATIONAL INSTITUTE reproduction orders) OF INDUSTRIAL PROPERTY) National registration number 88 02703 PARIS

  Int CI ': G 01 B 21/00; A 63 C 11/00, 19/00.

  @ PATENT INVENTION APPLICATION - A1

  Filing date: March 3, 1988. 9 Applicant (s): Company known as: VEB Carl Zeiss JENA,

Company under German law - DD.

) Priority

  (Inventor (s): Heinrich v. Dehn Rotfelser; Harald Barne-

kow; Stefan Sass.

  Date of public availability of the

  application: BOPI "Patents" n 36 of September 8, 1989.

  ) References to other national documents appearing

rented: (r Holder (s)

() Agent (s): Cabinet Madeuf.

  _ Device and method for measuring distances traveled in the air, Q Method and device for determining the distance traveled in the air, in particular in a non-planar and / or inclined landing zone, characterized in that at least one camera 8 and devices which follow the contour of the surface _ of the landing zone are connected to a processing unit ---- 1 and that this processing unit is coupled to a unit D

display 10.

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2628200-

  The present invention relates to a method and to a device making it possible to measure the distance traveled in the air by bodies which move on flight, jump or jet trajectories, in particular the length of jumps made by skiers.

  It is known to carry out these distance measurements.

  these, for example in the case of ski jumps, by

  visual, direct and subjective processes. The desire to

  r the objectivity of the measures leads to using more

  judges for the distance. This method does not

  Dant hardly improved the accuracy of the measurements because it does not eliminate the shortcomings inherent in the human eye. To remedy this state of affairs, an induction-based distance measurement system has been proposed, in which the anchor is anchored, before the onset of winter, on the

  slope above which jumps must be made

  kill, induction bands formed by parallel metal wires oriented transversely to the direction of the jump and separated by intervals corresponding to the staggering of the jump lengths. A permanent magnet built on the ski produced

  in these bands, when it comes close enough

  sane, an appreciable tension which increases when it gets even closer. These inductive bands are therefore associated with an adjustable threshold comparator which must be adjusted, according to the thickness of the layer of snow and the speed of movement on the aerial path, so that it only reacts when the magnet mounted on the ski is no longer, above the induction strip, at a distance such that it no longer cuts the next induction strip by sliding on it. The disadvantage of this system is that

  the high investment costs it entails for the

  installation in good position of the induction bands, in the difficulties of setting the threshold values of the comparator, in the considerable risks of operational incidents and in the fact that the length of the jump is related to the profile of the jump track located under the snow layer assuming a thickness of

determined layer of snow.

  Similar reasons explain the failure of an analogous process in which, instead of

  induction located under the snow, we use

  tif with photocells mounted above the snow, additional difficulties being caused, in this case, by fogs and

snowfall.

  Another method is based on the use of acoustic receivers distributed in a determined manner along the slope above which the jumps must be made and consists in using the difference in the transmission times to these receivers of the noise produced. during the jump to determine the landing point and, therefore, the distance. In this case also, the investment costs are high, the distance is measured in relation to an assumed profile and the risks of disturbance by noises coming from the environment, produced for example by spectators who trample on the spot to get

warm up, are considerable.

  The costs are lower in the case of disposi-

  transportable assets which do not require fixed-line investments. This is how we know devices

  which are attached to the ski and which, at the landing location-

  rissage, leave in the snow a colored mark.

  Leaving aside the drawbacks that the binding to the ski of a device of this kind presents for the skier, it must be ensured that the mark left on the snow can, before the passage of the skier who will perform the next jump, be erased without leaving a trace and without modifying the sliding properties of the snow surface and, moreover, that a new mark can be made immediately, which has not been possible so far. Another method also consists in using a device which is mounted on the ski which, at the time of landing, actuates a transmitter also mounted on the ski. The differences in transmission times to receivers placed at several determined locations allow the determination of the landing point. The

  system therefore also has the drawback of requiring

  site the mounting of an additional device.

  The object of the invention is the implementation of a

  method and device for measuring, object

  tively and with the possibility of a subsequent check, the distance traveled in the air by bodies moving on flight, jump or jet trajectories, even in the case of non-planar landing surfaces, without it

  it is necessary to mount on the flying object devices

  additional devices, using only transportable devices and at the same time considerably reducing the risk of operating disruption. The object of the invention is the implementation of a method and a device which make it possible to determine the distances traveled in the air during flights, jumps or jets, by means of mobile devices, without additional devices mounted on the bodies in

  movement, and perform a subsequent check.

  This object is achieved, according to the invention, on the one hand by a method of placing, consisting of one or more points having a well-determined position, measurement cameras for the images of which the data of the interior and exterior orientation are known, and which capture at least the scene of the landing of the moving body, To record in memory the images and the orientation data and to report them then or in parallel when the shots are taken to the profile of the surface effective landing, also saved in memory,

and deduce the distance.

  The operation is carried out either by superimposing on the images of the camera (s) a network restoring the

  perspective and positions, formed of longitudi- lines

  nal and transverse, which exactly reproduces the surface of the landing path and which is deduced from the landing profile using the data relating to the interior and exterior orientation, by reading directly or by deducting the distance which, according to the algorithm given for determining the distances, is in the form of a field of lines in the mixed image, when we then examine in slow motion the captured landing scene associated with the network profile frame or else we calculate at from the image coordinates of the observed body and from the data relating to the orientation of the images, the real or virtual trajectory curves of the bodies moving, the point of intersection of the real trajectory curve crossing the landing surface determines the landing point and, therefore, the distance or this is fixed by the discontinuity of the trajectory

  virtual on a regular landing path.

  The object of the invention is achieved on the other hand by the use of a device in which at least one camera and devices which follow the contour of the surface of the landing zone are connected to a

  processing unit and in which this processing unit

  ment is coupled to a display unit. In this system, the camera has a frequency of succession of images which corresponds to the speed of the moving object and to the desired measurement precision. The processing unit can be constituted, on the one hand, by an image memory for slow-motion viewing and by a grid network generator or, on the other hand, by an image memory and by image processing. Various other features of the invention

  moreover emerge from the detailed description which

follows.

  Embodiments of the object of the invention

  tion are shown, by way of non-limiting examples

tifs, to the accompanying drawings.

  FIG. 1 represents an exemplary embodiment of the invention comprising the use of a camera, a tachometer, a processing unit comprising an image memory and a network generator and a display unit. FIG. 2 represents an exemplary embodiment of the invention comprising the use of a camera, a tachometer, a processing unit comprising an image memory and an image processing system

as well as a display unit.

  Figure 1 shows schematically by way of example, a ski jump facility. The reference point for the jump length measurements is the springboard 1. At the measurement point determined in a geodesic way, the installation includes a tachometer 3 which allows to control in a geodesic way a sufficient number of points 4 located on the surface of the jump path. From these points, a processing unit 5, constituted by a network generator with

  grid preferably associated with an electronic computer

  that having an adequate interface and an image memory for slow motion visualizations, calculates the

  profile of the jump trajectory which then is subdi-

  aimed in equal longitudinal bands and in distance lines corresponding to the distance algorithm and perpendicular to the previous ones. At a photographic control point 6, the position of which is geodesically known with respect to the springboard 1, the measurement points 2 and the control point 6 being moreover identifiable, the installation includes a camera 8, preferably electronic, for the images from which the orientation data are known and are also transmitted to the grid network generator 5, whether constant or variable. In view of these values, the grid network generator of the processing unit 5 determines a model, formed of longitudinal lines in the direction of the jump trajectory and of distance lines, which, by means of a video generator , is superimposed on the image of camera 8 and is

  produced at the same time as it, preferably through

  medium of a monitor or is, in a parallel circuit, stored in memory. The camera 8 then makes it possible to follow the landing of the skier by means of

  network of longitudinal and distance lines superimposed.

  Then the landing scene is depicted from

  again in slow motion. It was not until the landing-

  it is wise that the skis become parallel for the first time to the lines oriented in the direction of the length of the jump trajectory. Therefore, it is obviously possible to determine with sufficient accuracy the landing point and to read it directly or to deduce it from the distance lines shown. However, it is also possible not to project the network of profile lines on the image until the

slow motion rehearsal.

  Another possible embodiment of the

  vention is shown schematically in Figure 2.

  In this case also, the springboard 1 constitutes the reference point for the distance measurements. At one point

  measure 2 geodesically defined, a tachometer 3 records

  be the coordinates of a sufficient number of points 4 on the surface of the jump trajectory and send them to a processing unit 5 preferably to an electronic computer which determines from them the profile

  effective of the jump trajectory and sends it in met

  moire. At points 6 and 7, preferably two in number which are geodesically on either side of the jump trajectory and one of which may be identical to measurement point 2, the installation includes measurement cameras 8 and 9 for which the orientation data, constant or variable, are known and which follow the skier's landing scene. The images and the data relating to the orientation of the cameras 8 and 9 are also sent to the processing unit 5 and saved in memory. In addition to capturing the

  landing scene, or also then, the coordinates

  born from the image of the moving body or one or more

  several points of these images are determined in the images of

  cameras and, taking into account the data relating to the

  tation of the camera in question, the device determines the direction that the poihts observed of the moving body had at the time of the photograph, by

  report to checkpoint 6 or 7 at the same time.

  As synchronized images are obtained at the two photographic control points and direction vectors are deduced therefrom, the processing unit 5 makes it possible, by determining the point of intersection of the two direction vectors, to define a point of the trajectory on the flight curve of the moving body and from a sufficient number of these points of the trajectory, in particular on the last part of the flight trajectory, it is possible to plot the effective flight curve. The point where it reaches the surface of the profile of the determined jump trajectory is the landing point. The result obtained is indicated by means of the monitor II and / or

display unit 10.

  This embodiment allows a fully automatic determination of the landing point, but is technically more complicated than the first embodiment described. It can also be subject to a modification consisting in the fact that there is a camera on only one side of the jump trajectory, that a direction vector oriented towards the point of the object which is moving is also determined and that the trace of this direction vector is followed on the regularly performed landing surface. As long as the moving body has not yet reached the landing point, it comprises, related to the surface of the landing trajectory, movement components oriented in the direction of landing and transversely by

  relative to this direction which, from the point of landing-

  smoothing, only exist in the direction of the

  terrissage. This system makes it possible to determine the point

  landing with a single camera.

Claims (8)

  1. Method for determining the distance traveled in the air by bodies whose speed is such that it no longer makes it possible to determine on sight in a sufficiently precise manner the landing point, these bodies not leaving, during their landing, the fact that their movement continues, sufficiently measurable marks and the images of the landing not making it possible to detect on sight a spatial subdivision, in particular in the case of a non-planar landing zone and / or tilted,   characterized in that the surface of the landing zone   wise is, for determining the distance, calculated using a suitable number of geodesic points   of the trajectory and that a mathematical profile function   tick is deduced from these values for its description, in   that the landing of moving bodies is monitored, by means of a camera having the necessary frame rate, from a point situated at a determined location in relation to the starting point of the yol, jump or jet, and that the values of the interior and exterior orientation elements of the captured images are calculated and in that the distance traveled is determined by correlation of the mathematical profile function with the trajectory and the data relating to the orientation of the flight. 2. Method according to claim 1, characterized in that preferably a camera is used with the images of which is superimposed, without altering the perspective and   the positions, taking into account the internal orientation   upper and outer of the images, a network which covers the landing trajectory and which is constituted by a projection of the trajectory in the air and by distance lines perpendicular to it and in that the distance traveled in the air is read directly from the distance lines or deducted, the scene of the 1o landing being, for data exploitation, observed in slow motion. 3. Method according to claim 1, characterized in that preferably two cameras are used which follow the movable body in its front section, in that the trajectory of the movable body is calculated from the image coordinates of the body and data relating to   the orientation of the images and that the point where this path   roof crosses the surface of the landing zone and, therefore, the distance flown, are determined in this way.   4. Method according to claim 1, characterized in that there is only a camera on one side of the landing surface to follow the moving body, in that a virtual trajectory on the surface of the area regular landing is calculated from   coordinates of body images and related data   ves to the orientation of the images and that the point of landing-   smoothing and, therefore, the distance traveled are determined by the discontinuity of this virtual trajectory. 5. Device for determining the distance traveled or the air, in particular. in a non-planar and / or inclined landing zone, characterized in that at least one camera (8) and devices which   follow the contour of the surface of the landing zone   sage are connected to a processing unit (5) and that this processing unit is coupled to a unit display (10).   6. Device according to claim 5, character-   laughed at in that the camera has a frame rate that corresponds to the speed of movement   the moving object and at the desired measurement accuracy.   7. Device according to claim 5, character-   laughed at in that the processing unit is constituted, by   a memory for the camera images, by a general   grid network and by a link device between these two components.   8. Device according to claim 5, character-   rised in that the processing unit is constituted by a memory of images of the camera and by a system of   image processing connected to memory. PL 1/2 Co C I.) I TO -.t - g \ aJ I 2a Fig. 2 7 Co o, ru