PHOTOGRAMMETRIC SYSTEM FOR POSITIONING GEORADAR DATA ON THE MEASUREMENT SCENARIO

Abstract

A method for ground penetrating radar analysis of a scenario, having a surface, with respect to a cartesian reference system S(x, y) having origin O(0, 0) and axes x and y. The method comprises a step of prearranging a gpr apparatus that comprises at least one gpr sensor, a control unit, a centre of reference C(x.sub.c, y.sub.c) having coordinates x.sub.c and y.sub.c with respect to the cartesian reference system S(x, y), at least one image acquisition devices, each image acquisition devices (110,120) having a pointing direction γ.sub.j known with respect to the centre of reference C(x.sub.c, y.sub.c). The method comprises then the steps of handling the gpr apparatus on the surface and detecting possible underground objects by means of gpr technique.

Claims

1. A method for ground penetrating radar analysis of a scenario, having a surface, with respect to a Cartesian reference system S(x, y) having origin O(0,0) and axes x and y, said method comprising the steps of: prearranging a GPR apparatus, said GPR apparatus comprising: at least one GPR sensor; a control unit; a centre of reference C(x.sub.c, y.sub.c) having coordinates x.sub.c and y.sub.c with respect to said Cartesian reference system S(x, y); at least two image acquisition devices having respective pointing directions γ.sub.1 and γ.sub.2 known with respect to said centre of reference C(x.sub.c, y.sub.c); handling said GPR apparatus on said surface; detecting possible underground objects by means of GPR technique; said method characterized in that said step of handling comprises the steps of: acquiring at least two front images I.sub.F of said scenario by means of respective image acquisition devices, each front image comprising a plurality of pixels; comparing said front images I.sub.F for identifying pixel P.sub.i corresponding to a same point of said scenario; localizing each pixel P.sub.i of each front image I.sub.F with respect to both said pointing directions γ.sub.1 and γ.sub.2, said step of localization comprising a step of defining at least one couple of angles ϑ.sub.xi and ϑ.sub.yi for each pixel P.sub.i; processing, for each pixel P.sub.i, coordinates x.sub.i and y.sub.i with respect to said Cartesian reference system S(x, y); reconstructing a plan image I.sub.p of said scenario, said plan image I.sub.p comprising said plurality of pixels P.sub.i in said coordinates x.sub.i and y.sub.i.

2. The method for ground penetrating radar analysis, according to claim 1, wherein said GPR apparatus comprises a visual interface and where a step is also provided of displaying said plan image I.sub.p of said scenario on said visual interface.

3. The method for ground penetrating radar analysis, according to claim 1, wherein, at time ranges t during said step of handling, it is provided an iteration of said steps of: acquiring at least one front image I.sub.F; localizing each pixel P.sub.i; processing, for each pixel P.sub.i, coordinates x.sub.i and y.sub.i; reconstructing a plan image I.sub.p of said scenario.

4. The method for ground penetrating radar analysis, according to claim 2, wherein also said front image I.sub.F is displayed on said visual interface.

5. The method for ground penetrating radar analysis, according to claim 4, wherein, on said visual interface, in superimposition to said front image I.sub.F and to said plan image I.sub.P, graphic references are displayed for allowing defining a same point of said scenario on said front image I.sub.F and on said plan image I.sub.P.

6. The method for ground penetrating radar analysis, according to claim 1, wherein said GPR apparatus comprises a localization device which is adapted to provide in real time to said control unit said coordinates x.sub.c and y.sub.c.

7. A method for ground penetrating radar analysis of a scenario, having a surface, with respect to a Cartesian reference system S(x, y) having origin O(0,0) and axes x and y, said method comprising the steps of: prearranging a GPR apparatus, said GPR apparatus comprising: at least one GPR sensor; a control unit; a centre of reference C(x.sub.c, y.sub.c) having coordinates x.sub.c and y.sub.c with respect to said Cartesian reference system S(x, y); at least one image acquisition device, each image acquisition device having a pointing direction y.sub.i known with respect to said centre of reference C(x.sub.c, y.sub.c); handling said GPR apparatus on said surface; detecting possible underground objects by means of GPR technique; said method characterized in that said step of handling comprises the steps of: acquiring at least one front image I.sub.F of said scenario, each image comprising a plurality of pixels P.sub.i; localizing each pixel P.sub.i of said or each front image I.sub.F with respect to said or each pointing direction γ.sub.j, said step of localization comprising a step of defining at least one couple of angles ϑ.sub.xi and ϑ.sub.yi for each pixel P.sub.i; processing, for each pixel P.sub.i, coordinates x.sub.i and y.sub.i with respect to said Cartesian reference system S(x, y); reconstructing a plan image I.sub.p of said scenario, said plan image I.sub.p comprising said plurality of pixels P.sub.i in said coordinates x.sub.i and y.sub.i.

8. The method for ground penetrating radar analysis, according to claim 7, wherein steps are provided of: arrangement within said scenario of a marker of known size; acquisition by said or each image acquisition device of at least one front image I.sub.F comprising said marker; calculating by means of said control unit the distance between said marker and said or each image acquisition device.

9. The method for ground penetrating radar analysis, according to claim 7, wherein said GPR apparatus comprises at least one angular position transducer, or encoder, able to detect changes in angular position of said or each image acquisition device.

10. The method for ground penetrating radar analysis, according to claim 7, wherein a step of acquisition of the angular position of said or each image acquisition device with respect to said scenario is provided.

11. The method for ground penetrating radar analysis, according to claim 7, wherein said GPR apparatus comprises at least two images acquisition devices having respective pointing directions γ.sub.1 and γ.sub.2 known with respect to said centre of reference C(x.sub.c, y.sub.c).

12. The method for ground penetrating radar analysis, according to claim 11, wherein said step of acquisition provides the acquisition of two front images I.sub.F by means of respective images acquisition devices, each front image I.sub.F comprising a plurality of pixels P.sub.i, and wherein said step of localization provides the localization of each pixel P.sub.i of each of said front images I.sub.F and the definition of a couple of angles ϑ.sub.xi and ϑ.sub.yi for each pixel P.

13. The method for ground penetrating radar analysis, according to claim 12, wherein are also provided the steps of: comparing said front images I.sub.F for identifying pixel P.sub.i corresponding to a same point of said scenario; localizing each pixel P.sub.i with respect to both said pointing directions γ.sub.1 and γ.sub.2.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0076] Further characteristic and/or advantages of the present invention are more bright with the following description of an exemplary embodiment thereof, exemplifying but not limitative, with reference to the attached drawings in which:

[0077] FIG. 1 shows a flow chart of the method, according to the present invention, wherein a single image acquisition device is provided;

[0078] FIG. 2 shows a flow chart of implementation variant of the method, according to the present invention, wherein two images acquisition devices are provided;

[0079] FIG. 3A shows a front image of the scenario;

[0080] FIG. 3B shows a plan image of the scenario.

DESCRIPTION OF A PREFERRED EXEMPLARY EMBODIMENT

[0081] The flow chart 300 of FIG. 1 shows the steps of a first variant of the method for ground penetrating radar analysis in a scenario, according to the present invention, wherein a single image acquisition device 110 is provided, in particular a video camera or a camera.

[0082] The method provides a first step of prearranging a GPR apparatus with a camera on board [310], a second step of handling the apparatus on the surface of the scenario to be investigated [320] and a third step of detecting possible underground objects [330].

[0083] With reference even at FIGS. 3A and 3B, the method according to the present invention provides that, during the step of handling the apparatus 100, there are some steps arranged to allow the operator to locate, even in real time, the apparatus 100 and to display objects of the scenario 200 in a plan image of the scenario itself, in order to virtually superimpose such objects of the scenario 200 to the detected underground objects.

[0084] In particular, there is a step of acquiring by the camera 110 a front image I.sub.F [321], of which a schematic example is shown in FIG. 3A.

[0085] Then, by knowing the pointing direction γ.sub.1 of the camera 110 with respect to the centre of reference C(x.sub.cy.sub.c) of the apparatus 100, there is a step of localizing each pixel P.sub.i of the image acquired, in terms of angles ϑ.sub.xi and ϑ.sub.yi with respect to the pointing direction γ.sub.1 [322].

[0086] Once localized the pixel P.sub.i with respect to the position of the apparatus 100, it is possible, by transformation of coordinates, to process the x.sub.i and y.sub.i coordinates of each pixel P.sub.i with respect to a Cartesian reference system S(x,y) of known origin and orientation [323].

[0087] Finally, by combining all the pixel with respect to their coordinates in the reference system S(x,y), it is possible to reconstruct a plan image I.sub.p of the scenario 200, in order to provide an operator with a top plan view of its own position with respect both to possible underground objects detected, both with respect to objects present in the scenario above the surface 200 [324].

[0088] The above described steps are then iterated at predetermined time ranges in such a way that the plan image I.sub.p is updated periodically.

[0089] In a variant of the method, schematically shown by the diagram 300′ of FIG. 2, two cameras 110 and 120 are provided having respective pointing directions γ.sub.1 and γ.sub.2.

[0090] In this case, there are two front images I.sub.F obtained and there is an additional step of comparing the front images in order to identify the pixel P.sub.i corresponding to a same point of the scenario 200 [325′].

[0091] This way, there is a three-dimensional localization of each pixel, by the acquisition of two couples of angles, and so there is a more precise reconstruction of the scenario.

[0092] The foregoing description some exemplary specific embodiments will so fully reveal the invention according to the conceptual point of view, so that others, by applying current knowledge, will be able to modify and/or adapt in various applications the specific exemplary embodiments without further research and without parting from the invention, and, accordingly, it is meant that such adaptations and modifications will have to be considered as equivalent to the specific embodiments. The means and the materials to realise the different functions described herein could have a different nature without, for this reason, departing from the field of the invention. it is to be understood that the phraseology or terminology that is employed herein is for the purpose of description and not of limitation.