GB2600501A

GB2600501A - A robotic system for mapping underground objects

Info

Publication number: GB2600501A
Application number: GB2104310.4A
Authority: GB
Inventors: Arvanitis Michael
Original assignee: Sgndt Symetrics Geophysical And Ndt Ltd
Current assignee: Sgndt Symetrics Geophysical And Ndt Ltd
Priority date: 2021-03-26
Filing date: 2021-03-26
Publication date: 2022-05-04
Also published as: GB202104310D0

Abstract

A robotic-driven imaging system 10 for mapping and imaging underground objects 15 comprises a robot drive unit 12 having a body 17 and an electromagnetic induction data collector 14. The electromagnetic induction data collector is suspended outboard of the body e.g. on a pair of arms made from non-conductive material. A control module (20, Fig.2 ) receives image data indicative of the position of one or more underground objects from the electromagnetic induction data collector. A control computer 28 is connected to the control module. The control module transmits the image data to the control computer which generates a map of the positions of the objects. An odometer may measure the distance travelled by the robot, and an inclinometer may correct for topography in the image data.

Description

A ROBOTIC SYSTEM FOR MAPPING UNDERGROUND OBJECTS

Technical Field

The present disclosure relates to a robotic system for mapping and imaging underground objects, in particular, but not exclusively, the robotic system relates to robotic-driven electromagnetic induction system for detecting and mapping subsurface structures located beneath paved and unpaved roads, bridges and other infrastructure.

Background

Utility firms and infrastructure providers have been burying pipes and cables beneath roads and streets for over 100 years which has led to an intricate and complex network of pipes and cables beneath our roads and streets. The pipes and cables beneath our streets deliver essential services such as electricity, water and internet services to buildings.

However, as the underground piping and cable networks have evolved and become more complex the records mapping where the cables and pipes are located have become outdated and are often inaccurate.

The inaccurate and outdated records of the position of pipes and cables beneath our streets is problematic when it comes to maintaining existing underground cables and pipes and also when laying new cables and pipes or expanding existing networks. The inaccurate records can cause maintenance workers to inadvertently cut through existing cables which can lead to large power outages or burst water pipes. Furthermore, it can be extremely time consuming for maintenance workers to excavate a road to find an existing cable or pipe when performing essential maintenance works on a specific cable or pipe.

Overtime this problem has been alleviated with the development of ground penetrating radar technologies. Ground penetrating radar may be used to map or image underground cables and pipes to generate a 3D map or image of the pipe and cable network extending beneath a road surface. However, existing underground mapping methods are inaccurate and the images generated by existing ground penetrating radar techniques have a lot of noise thereby making it hard to discern what kind of asset is beneath the surface, what material the asset is made from or indeed how deep beneath the surface the asset is. This leads to inaccurate 3D maps being generated which do not give the maintenance workers a clear picture of the subsurface assets. There is therefore a need for a system and method to produce accurate subsurface maps and images.

Summary

According to an aspect of the present invention there is provided a robotic-driven imaging system for mapping and imaging underground objects, the imaging system comprising: a robot drive unit having a body; an electromagnetic induction data collector coupled to the robot drive unit such that the electromagnetic induction data collector is suspended outboard of the body of the robot drive unit; a control module configured to receive image data indicative of the position of one or more underground objects from the electromagnetic induction data collector; and a control computer connected to the control module; wherein the control module is configured to transmit the image data to the control computer and wherein the control computer is configured to generate a map of the positions of the one or more underground objects in dependence on the image data.

The robotic-driven imaging system beneficially allows an area of ground to be mapped or imaged to determine the position of objects located underground. The user of the system may specify an area to be mapped and the robotic drive unit may drive over the area to map the underground objects located in the area. The robot drive unit beneficially covers the area automatically without the requirement of a user to steer or control the path that the robot drive unit follows.

The electromagnetic induction data collector may be configured to generate image data indicative of the location and position of objects underground. Furthermore, the electromagnetic induction data collector may be a ground probing antenna. For example, the ground probing antenna may be configured to emit and receive electromagnetic waves such that ground probing antenna can generate image data indicative of the type and position of underground objects. The ground probing antenna may be, for example, a ground penetrating radar or an electromagnetic locator.

In one embodiment the robot drive unit may comprise a pair of arms extending from the body and the electromagnetic induction data collector may be suspended by the pair of arms. The pair of arms may comprise a holder for receiving the electromagnetic induction data collector. This is beneficial as the holder may be configured such that the electromagnetic induction data collector may be easily fitted to or removed from the holder. For example, the holder may be a modular system where different types of electromagnetic induction data collectors may be plugged into or removed from the holder. As such, a user may select and fit the robot drive unit with a data collector that is best suited to the terrain and conditions of terrain that is to be mapped. The pair of arms may extend from the body in a generally forward direction such that the holder is suspended outboard of the body of the robot drive unit.

In an embodiment the holder may be configured to support the electromagnetic induction data collector in a first position in which the electromagnetic induction data collector radar scans in-line and a second position in which the electromagnetic induction data collector is orientated orthogonally compared to the first position such that the electromagnetic induction data collector scans cross-polarised. The user may switch the electromagnetic induction data collector between the first position and the second position by removing the electromagnetic induction data collector from the holder, turning it through 90° and replacing it in the holder.

In one embodiment the pair of arms may be made from a non-conductive material. For example, the pair of arms may be made from a plastics material. Alternatively, the pair of arms may be made from a fibrous plastics material, carbon fibre, fibre glass, wood or any other non-conductive material with sufficient strength and durability to support the electromagnetic induction data collector. Power and data cables may extend along the arms to connect the electromagnetic induction data collector to the robot drive unit.

Alternatively, the electromagnetic induction data collector may be battery powered and the generated image data may be transmitted wirelessly.

In a further embodiment the robot drive unit may comprise a second pair of arms extending from the body in a rearward direction. The second pair of arms may support a second electromagnetic induction data collector outboard of the body. The second pair of arms may be made from a similarly non-conductive material to that of the forward extending pair of arms.

In one embodiment the control module may be configured to operate the electromagnetic induction data collector at a First frequency and the second electromagnetic induction data collector at a second frequency. This is beneficial as the two electromagnetic induction data collectors may be operated simultaneously at different frequencies such that the depth of penetration of the emitted electromagnetic waves and thus depth of investigation is different for each electromagnetic induction data collector is different. This is particularly advantageous as it allows two different depths of investigation to be carried out simultaneously.

Alternatively, the robot drive unit may comprise a single electromagnetic induction data collector and the control module may operate the electromagnetic induction data collector at two frequencies. For example, the electromagnetic induction data collector may be configured to emit electromagnetic waves at a first frequency for relatively low ground penetration and further electromagnetic waves at a second frequency for deeper ground penetration and investigation. As such, two depths of investigation may be carried out simultaneously using a single electromagnetic induction data collector.

In another embodiment the robot drive unit may comprise an odometer for measuring the distance the robot drive unit has travelled. The control module may be configured to activate the electromagnetic induction data collector upon receipt of a signal from the odometer indicative of a movement of the robot drive unit. In a further embodiment the robot drive unit may comprise an inclinometer. The inclination data generated by the inclinometer may be used to correct topography in the image data generated by the electromagnetic induction data collector.

In a further embodiment the robot drive unit may further comprise a GPS positioning module for determining the position of the robot drive unit. This is beneficial as the position of objects detected under the ground may be mapped digitally such that the global position of such objects can be determined using the GPS positioning module.

S

In one embodiment the electromagnetic induction data collector may be a ground probing antenna. For example, the electromagnetic induction data collector may be a ground penetrating radar or an electromagnetic locator.

In an embodiment the robotic-driven imaging system may comprise a pre-processing filter module configured to perform stacking and/or time zero correction on the image data. The pre-processing filter module may form part of the control module and/or the control computer. The robotic-driven imaging system may further comprise a data processing filter module configured perform at least one of: background removal, migration and deconvolution on the generated image data. The control computer or control module may comprise the data processing filter module.

According to a further aspect of the present invention there is provided a robot drive unit for use with the robotic-driven imaging system in accordance with any one of the aforementioned aspects or embodiments.

The invention may also be expressed as a method of mapping or imaging underground objects using a robotic imaging system according to any one of the aforementioned aspects or embodiments, the method comprising: generating image data indicative of the position of one or more underground objects; processing the generated image data to remove unwanted noise from the generated image data; and determining the position of an underground object in dependence on the processed image data.

According to a yet further aspect of the present invention there is provided a method of mapping or imaging underground objects, the method comprising: generating image data indicative of the position of one or more underground objects; pre-processing the generated image data to improve a signal:noise ratio of the generated image data by stacking the image data; processing the pre-processed generated image data to remove unwanted noise from the generated image data by background removal and further processing the generated image data to remove hyperbolas in the image data by migration; and determining the position of an underground object in dependence on the processed image data.

The method may be performed using a robotic imaging system comprising a robot drive unit configured to automatically drive over an area of ground to be imaged or mapped. The robot drive unit may comprise an electromagnetic induction data collector for generating the image data. Determining the position of underground objects may comprise generating a map of the underground images.

In one embodiment processing the pre-processed image data further comprises deconvolution to remove ringing from the pre-processed image data. This is particularly beneficial when mapping or imaging terrain having a high moisture content, for example a moisture content of 60% or greater. Deconvolution may be performed after background removal has been performed but prior to migration to remove ringing from the data prior to performing migration.

In a further embodiment pre-processing the generated image data may further comprise performing time zero correction on the generated image data. This is beneficial as time zero correction accounts for electromagnetic energy being emitted from an emitter that is detected by a receiver prior to passing through the ground.

In another embodiment the method may comprise generating an image or map of the position of underground objects in dependence on the determined position of the underground objects. The method may further comprise displaying the generated image or map on a control computer. Furthermore, the method may comprise marking the ground at the determined position of the underground object.

In an embodiment generating image data may comprise driving a robotic drive unit over an area of ground to be mapped or imaged. The robot drive unit may be driven over the area automatically. The method may also comprise determining a path that the robot should travel along to cover the area of ground to be mapped or imaged. Furthermore, the method may comprise determining a depth of investigation and selecting a frequency to be emitted from the electromagnetic induction data collector to generate image data indicative of objects at the determined depth of investigation.

In a further embodiment the method may comprise generating inclination data and correcting topography in the generated image data in dependence on the generated inclination data. Generating inclination data may comprise generating inclination data from an inclinometer.

According to a yet further aspect of the present invention there is provided a method of mapping or imaging underground objects using a robot drive unit comprising an electromagnetic induction data collector for generating image data indicative of objects located beneath the ground, the method comprising: determining a path that the robot drive unit should travel along to cover an area to be imaged or mapped; determining a desired depth of investigation and selecting a frequency to be emitted from the electromagnetic induction data collector in dependence on the desired depth of investigation; driving the robot drive unit along the determined path and activating the electromagnetic induction data collector to emit electromagnetic waves at the selected frequency to generate image data indicative of underground objects; and transmitting the generated image data to a control computer.

Further features and advantages of the aforementioned aspects and embodiments of the present disclosure will become apparent from the claims and the following description.

Brief Description of Drawings

Embodiments of the present disclosure will now be described by way of example only, with reference to the following diagrams, in which:-Figure 1 is a schematic side view of a robotic imaging system for mapping and imaging underground objects according to an embodiment of the invention; Figure 2 is a schematic block diagram of components within the robotic imaging system of Figure 1; Figure 3 is a flow chart outlining a method of generating a map of underground objects using the robotic imaging system of Figure 1; and Figure 4 is a flow chart outlining a method of filtering raw image data generated by the robot imaging system of Figure 1.

Detailed Description

In general terms embodiments of the invention relate to a robotic imaging system for mapping and imaging underground objects, such as cables and pipes in real-time. The robotic imaging system comprises a robot drive unit with an electromagnetic induction data collector, such as a ground penetrating radar, for gathering image data indicative of the position and type of subsurface objects. The robot drive unit may be driven over an area such that the electromagnetic induction data collector may scan the ground to generate image data. The image data gathered by the ground penetrating radar is filtered in real-time using a series of filters to remove noise from the gathered image data such that the image data may be used to generate an accurate map of the position and type of objects located beneath the ground surface.

The robotic imaging system beneficially allows an area to be quickly assessed and mapped to determine the type of and position of objects located beneath the ground surface in the specified area. Furthermore, the robot drive unit may transmit the gathered image data to a control computer in real-time such that the image data may be used to generate a map of the position of underground objects in real-time. This is advantageous as a user of the system may quickly determine the position and nature of objects located underground such that, for example, groundwork can be safely carried out in an area.

To place embodiments of the invention in a suitable context reference will firstly be made to Figure 1 which shows a schematic side view of a robotic drive unit 12 within a robotic ground imaging system 10. The robot drive unit 12 is shown travelling over an object 15, such as a pipe or cable located under the ground 11. The robotic imaging system 10 comprises a robot drive unit 12 coupled to an electromagnetic induction data collector 14, for example a ground penetrating radar. The robot drive unit 12 comprises a body 17 and wheels 18 to propel the robot drive unit 12 over the ground 11.

The robot drive unit 12 is wirelessly coupled to the control computer 28. Raw image data gathered by the electromagnetic induction data collector 14 may be transmitted to the control computer 28. The control computer 28 receives the raw image data before filtering the raw image data to remove noise from the data such that an image or map of objects 15 located beneath the ground 11 can be generated.

The electromagnetic induction data collector 14 is suspended distally of the front of the robot drive unit 12 by a pair of supporting arms 16 such that the electromagnetic induction data collector 14 is positioned outboard of the body 17 of the robot drive unit 12. The supporting arms 16 suspend the electromagnetic induction data collector 14 in front of the robot drive unit 12 such that as the robot drive unit 12 is driven over the ground 11 the electromagnetic induction data collector 14 may scan the ground 11 ahead of the robot drive unit 12 and detect objects 15 beneath the ground 11.

Suspending the electromagnetic induction data collector 14 outboard of the body 17 of the robot drive unit 12 is beneficial as it reduces the background noise in image data generated by the electromagnetic induction data collector 14 which may be caused by the body 17 of the robot drive unit 12. The supporting arms 16 may be a pair of arms made from a nonconductive material, for example a plastics material, which further reduces the background noise in image data generated by the electromagnetic induction data collector 14.

The electromagnetic induction data collector 14 is located within a holder at a distal end of the arms 16 which facilitates easy attachment and removal of the electromagnetic induction data collector 14 from the arms 16 of the robot drive unit 12. The holder and thus electromagnetic induction data collector 14 may be positioned between the pair of arms 16. This is beneficial as it allows a user of the robot imaging system 10 to quickly change the type of data collector 14 that is fitted to the robot drive unit 12. For example, the user may quickly select and fit the relevant data collector to the robot drive unit 12 in dependence on the terrain type, moisture levels, the depth of investigation or the type of objects 15 to be mapped.

Furthermore, the holder is configured such that the orientation of the electromagnetic induction data collector 14 may be varied when it is fitted to the holder. For example, the electromagnetic induction data collector 14 may be placed within the holder such that the electromagnetic induction data collector 14 scans in-line with the path that the robot drive unit 12 travels along. Alternatively, the electromagnetic induction data collector 14 may be turned through 900 such that the electromagnetic induction data collector is cross- polarised. Varying the electromagnetic induction data collector between inline and cross-polarised beneficially allows the user to prioritise different subsurface information when using the robot imaging system 10 to scan for underground objects 15.

In another embodiment the robot drive unit 12 may have a second pair of supporting arms 16 extending outboard of the body 17 of the robot drive unit 12 in a rearward direction.

The second pair of arms may also comprise a second holder for holding a second electromagnetic induction data collector 14 at a distal end of the second pair of arms. This is beneficial as the robot drive unit 12 may be fitted with two electromagnetic induction data collectors 14 that can be operated simultaneously to generate image data indicative of objects 15 located beneath the ground 11.

For example, the robot drive unit 12 may be fitted with two ground penetrating radars where one radar is suspended in a holder by the arms 16 outboard of the front of the body 17 and a second radar is suspended by a second holder and a rearwardly extending pair of arms such that the second radar is suspended outboard of the body 17 in a rearward direction of the body 17. The two ground penetrating radars may then be operated at two different frequencies such that, for example, the first radar generates image data indicative of objects 15 located close to the surface of the ground 11 and the second radar generates image data indicative of objects 15 located at a greater depth.

Furthermore, the holders located at the distal ends of the forward extending pair of arms 16 and the rearwardly extending pair of arms beneficially allow the orientation of the first and second electromagnetic induction data collectors 14 to be varied. For example, the first electromagnetic induction data collector 14 may be orientated in-line with the robot drive unit 12 and the second electromagnetic induction data collector may be cross-polarised such that the second electromagnetic induction data collector scans in an orthogonal direction compared to the first electromagnetic induction data collector 14.

The arms 16 may extend in front of and/or behind the body 17 of the robot drive unit 12 by between about 0.3m and 2m. Extending the arms further from the body 17 is beneficial as it helps to eliminate background noise in the generated image data.

Turning now to Figure 2 there is shown a block diagram of the components within the robot drive unit 12. As shown in Figure 2, the robot drive unit 12 comprises at least one electromagnetic induction data collector 14. The electromagnetic induction data collector 14 may be a ground penetrating radar for generating image data of objects 15 located beneath the ground 11. The electromagnetic induction data collector 14 is configured to output an ultra-wide range of frequencies, from 40MHz to 4000MHz. A user of the robot imaging system 10 may select the scanning frequency of the electromagnetic induction data collector 14 in dependence on the depth of investigation required beneath the ground 11.

The electromagnetic data collector 14 comprises at least one pair of transmitter and receiver antennas positioned in line or cross-line. The transmitter antenna is configured to transmit the electromagnetic waves at the ultra-wide frequency range and the receiver antenna is configured to receive the resultant signal comprising image data indicative of objects 15 located beneath the ground 11.

The electromagnetic induction data collector 14 generates image data from the emitted and received electromagnetic waves and the generated image data may be input to a control module 20. The control module 20 receives the raw image data which may be transmitted to the control computer 28 by the communication module 22 as described in further detail below. Furthermore, the control module 20 may control the electromagnetic induction data collector 14 to vary the frequency of the emitted electromagnetic waves thereby controlling the depth of penetration of the waves into the ground 11.

As shown in Figure 2, the robot drive unit 12 further comprises an odometer 26 coupled to the wheels 18 of the robot drive unit 12. The odometer 26 may be coupled to the wheels 18 and the control module 20 such that the odometer 26 may detect when the robot drive unit 12 is moving and input the data into the control module 20. This is beneficial as the odometer 26 may be used to determine how far the robot drive unit 12 has travelled and furthermore may be used to control the operation of the electromagnetic induction data collector 14. For example, the odometer 26 may trigger or activate data collection from the electromagnetic induction data collector 14 when it is determined that the robot drive unit 12 is in motion and stop data collection when it is determined that the robot drive unit 12 is stationary.

The robot drive unit 12 further comprises a GPS positioning module 24 such that an accurate position of the robot drive unit 12 may be determined from the GPS positioned data. The GPS positioning module 24 beneficially allows the robot drive unit 12 to be driven along specific paths or grids selected by a user of the robotic imaging system 10. For example, a user of the robotic imaging system 10 may specify that the robot drive unit 10 should drive over and thus image a specific region or area of ground 11 such that an image or map of objects 15 located beneath the ground 11 can be generated.

As shown in Figure 2 the robot drive unit 12 is connected, typically wirelessly, to a control computer 28 by the communication module 22. The control computer 28 is configured to receive raw image data and location data from the communication module 22 within the robot drive unit 12. The communication module 22 may transmit data to the control computer 28 via Wi-Fi, Bluetooth, GSM or the like in real time. Furthermore, a user of the robot imaging system 10 may control the operation of the robot drive unit 12 from the control computer 28 and view the image data gathered by the electromagnetic induction data collector 14111 real time. This is beneficial as the user of the robotic imaging system 10 may view the image data being gathered by the robot drive unit 12 and vary the position of the robot drive unit 12 in dependence on the gathered image data. For example, the user of the robotic imaging system 10 may control the robot drive unit 12 to follow the path of a pipe or cable being mapped beneath the ground 11.

The robot drive unit 12 may further comprise an inclinometer (not shown in Figure 3) to correct the generated image data topography which improves the accuracy and resolution of the generated image data. This is beneficial as the map or image generated from the 10 image data may be more accurate.

Figure 3 shows a flow chart outlining the steps of generating an image or map of objects 15 located under the surface of the ground 11 using the robotic imaging system 10. In Step 101 a user of the robotic imaging system 10 may determine the area that is required to be surveyed by the robot imaging system 10. The user may determine a path that the robot drive unit 12 should travel along in order to scan or survey the area of ground 11 that is to be investigated. Alternatively, the user may define an area that is required to be mapped and the control module 20 may automatically determine a suitable path that the robot drive unit 12 should follow to survey the entire target area.

In Step 102 the user may determine the depth of investigation. Upon specifying the desired depth of investigation the control module 20 may determine a frequency or range of frequencies that the electromagnetic induction data collector 14 should operate at for the electromagnetic waves to achieve the required depth of penetration. For example, for a relatively low depth of penetration the frequency of electromagnetic waves emitted by the electromagnetic induction data collector 11 may be between about 40MHz and 1000MHz. Alternatively, for a higher depth of penetration the electromagnetic induction data collector 11 may emit electromagnetic waves at a frequency between about 1000MHz and 4000MHz.

In Step 103 the robot drive unit 12 is driven along the path determined by the control module 20 or control computer 28 and the electromagnetic induction data collector 14 is activated to scan the ground 11 thereby generating image data indicative of objects 15 located beneath the ground 11. The electromagnetic induction data collector 14 may be activated by the control module 20 upon receipt of an input signal to the control module 20 from the odometer 26 that the robot drive unit 12 is moving.

In Step 104, after the electromagnetic induction data collector 14 is activated image data indicative of the position of objects 15 underground is generated by the electromagnetic induction data collector 14. Generating the image data may comprise emitting electromagnetic waves from the data collector 14 and detecting a return signal of reflected electromagnetic waves. For example, emitting the electromagnetic waves may comprise radar scanning at least one line by emitting electromagnetic waves from a radar transmitter and detecting received electromagnetic waves using a radar receiver. The received radar waves or scan signal may be radar waves that have passed through an underground object 15 such that the position, shape and type of object 15 may be inferred from the scan signal. The electromagnetic induction data collector 14 may comprise a radar transmitter and a radar receiver configured to transmit radar waves and detect radar waves respectively. The radar scanning may be performed in-line and/or cross-polarised.

In Step 105 the generated image data is transmitted to the control computer 28. The image data may be transmitted to the control computer 28 in real time. In Step 106 the generated image data is filtered to remove unwanted noise from the image data. The image data is typically filtered by the control computer 28 following transmission of the image data from the robot drive unit 12 to the control computer 28. However, the skilled reader will understand that in some embodiments the image data may also be filtered by the control module 20 prior to being transmitted to the control computer 28. The process of filtering the image data is discussed in further detail below with reference to Figure 4.

In Step 107 a map or image of objects 15 is generated and displayed on the control computer 28 such that a user of the robotic imaging system 10 may view images or a map of objects 15 located under the ground 11 in real time. This is beneficial as the user may control the path that the robot drive unit 12 follows in dependence on the real time map or image generated by the robot imaging system 10.

Generating the map of objects 15 located underground may further comprise marking the ground 11 to indicate where an object 15 has been detected. For example, the robot drive unit 12 may comprise a paint marker configured to spray paint on the ground 11 where an object 15 is detected. This is beneficial as it provides a visual marker to the user of the system 10 of the location of an object on the ground 11. For example, the robot drive unit 12 may mark the ground 11 along the path of an underground electrical cable thereby providing a visual indication of the location of the position of the underground cable. This may in turn provide an indication to workers not to dig into the ground at the location of the underground cable as they may risk damaging the electrical cable.

Turning now to Figure 4 a flow chart outlining the steps of filtering the image data generated by the electromagnetic induction data collector 14 on the robot drive unit 12 is shown. The method of filtering the raw or unfiltered image data as outlined in Figure 4 may be performed by the control computer 28 or by the control module 20 on the robot drive unit 12 upon receipt of the raw image data 30.

As a first step stacking 34 is carried out on the received raw image data 30 in order to improve the signal:noise ratio in the received raw data 30. Stacking the received raw image data 30 increases the quality and resolution of the raw image data 30. Averaging multiple traces of the raw image data 30 has the effect of removing unwanted noise caused by variations in parameters of the soil, for example water content, voids or rocks. The number of stacks may be varied by the user on the control computer 28 to achieve the desired signal:noise ratio. For example, the user may select 4, 16, 32 or 64 stacks depending on the signal:noise ratio requirements.

After stacking 34 has been performed on the raw image data 30 the control computer 28 may apply a time zero correction 31 on the stacked raw data 30 to shift the traces of raw data 30 to time-zero. The time-zero correction 31 beneficially removes airwaves from the received raw data 30. Typically, approximately 2% of the electromagnetic energy emitted by the electromagnetic induction data collector 14 travels directly from the electromagnetic wave emitter to the receiver without passing through the ground 11. This is undesirable as the measured depth of objects 15 beneath the ground 11 may be affected and as such time-zero correction 31 is required to correct the raw image data 30 prior to generating a map or image of the underground objects 15.

Stacking 34 and time zero correction 31 are pre-processing steps that may be performed on the raw image data 30 prior to filtering and processing the raw image data 30 to remove noise and ringing from the raw image data 30. Pre-processing the raw image data is beneficial as it improves the signal:noise ratio and also removes airwaves prior to processing the raw image data 30. The pre-processing steps of stacking 34 and time zero correction 31 may be performed by the control module 20 or the control computer 28.

Once the pre-processing steps of stacking 34 and time-zero correction 31 have been performed the control computer 28 or control module 20 processes and filters the preprocessed image data. As a first processing step the control computer 28 or control module 20 checks if the received pre-processed raw image data 30 comprises noise 32. If the control computer 28 determines that the received raw image data 30 comprises noise 32 a background removal 33 procedure is performed on the raw image data 30 to remove the background noise from the data signal. Background removal 33 beneficially removes background noise frequencies in the raw image data 30 to remove unwanted frequencies caused by noise in the raw image data 30. A bandpass filter may be used to remove the unwanted frequencies from the raw image data 30 in the background removal filter 33.

Following background removal 33 of noise in the raw image data 30 the control computer 28 performs a check to determine if ringing 35 is still present in the raw image data 30. Low to medium levels of ringing 35 in the raw image data 30 may be removed by background removal 33 and/or by migration 36. However, this may not be sufficient to remove high levels of ringing 35 found in the raw image data 30 the like of which may be found in raw image data 30 gathered from ground with high moisture levels and/or high salinity levels. If ringing 35 is detected in the raw image data 30 following background removal 33 then deconvolution 37 is performed on the raw image data 30 to remove ringing 35 from the raw image data 30.

After deconvolution 37 has been performed on the raw image data 30, or in cases where it is determined that no ringing 35 or noise 32 is present in the raw image data 30, migration 36 is performed on the raw image data 30. Migration 36 beneficially removes hyperbolas from the raw image data 30. Migration 36 is performed as a final step in the processing or filtration process to generate the processed or filtered data 38. Performing migration 36 as a final step is beneficial as the image data input into the migration filter 36 has already had background noise and ringing removed such that migration 36 may be performed to remove any remaining hyperbolas in the image data 30 to generate the Filtered image data 38.

Finally, the filtered image data 38 is output from the robotic imaging system 10. The filtered image data 38 may be used to generate a map or image indicating the position and depth of objects 15 positioned under the ground 11. The map or image may be displayed on a display of the control computer 28 such that a user of the robot imaging system 10 may view the map in real-time.

Furthermore, the filtered data 38 may be used to determine the position and/or type of object 15 located beneath the ground 11. The position of the object may be transmitted back to the robot drive unit 12 by the control computer 28 and the robot drive unit 12 may mark or spray paint on the ground 11 to mark the location of the object 15 on the ground 11.

Although particular embodiments of the disclosure have been disclosed herein in detail, this has been done by way of example and for the purposes of illustration only. The aforementioned embodiments are not intended to be limiting with respect to the scope of the appended claims.

Claims

CLAIMS1. A robotic-driven imaging system for mapping and imaging underground objects, the imaging system comprising:Sa robot drive unit having a body; an electromagnetic induction data collector coupled to the robot drive unit such that the electromagnetic induction data collector is suspended outboard of the body of the robot drive unit; a control module configured to receive image data indicative of the position of one or more underground objects from the electromagnetic induction data collector; and a control computer connected to the control module; wherein the control module is configured to transmit the image data to the control computer and wherein the control computer is configured to generate a map of the positions of the one or more underground objects in dependence on the image data.
2. A robotic-driven imaging system as claimed in Claim 1, wherein the robot drive unit comprises a pair of arms extending from the body and wherein the electromagnetic induction data collector is suspended by the pair of arms.
3. A robotic-driven imaging system as claimed in Claim 2, wherein the pair of arms comprise a holder for receiving the electromagnetic induction data collector.
4. A robotic-driven imaging system as claimed in Claim 3, wherein the holder is configured to support the electromagnetic induction data collector in a first position in which the electromagnetic induction data collector radar scans in-line and a second position in which the electromagnetic induction data collector is orientated orthogonally compared to the first position such that the electromagnetic induction data collector scans cross-polarised.
5. A robotic-driven imaging system as claimed in any one of Claims 2 to 4, wherein the pair of arms extend from the body in a generally forward direction.
6. A robotic-driven imaging system as claimed in any one of Claims 2 to 5, wherein the pair of arms are made from a non-conductive material.
7. A robotic-driven imaging system as claimed in any one of Claims 2 to 6, wherein the robot drive unit comprises a second pair of arms extending from the body in a rearward direction and wherein the second pair of arms support a second electromagnetic induction data collector outboard of the body.
8. A robotic-driven imaging system as claimed in Claim 7, wherein the control module is configured to operate the electromagnetic induction data collector at a first frequency and the second electromagnetic induction data collector at a second frequency.
9. A robotic-driven imaging system as claimed in any preceding claim, wherein the robot drive unit comprises an odometer for measuring the distance the robot drive unit has travelled.
10. A robotic-driven imaging system as claimed in Claim 9, wherein the control module is configured to activate the electromagnetic induction data collector upon receipt of a signal from the odometer indicative of a movement of the robot drive unit.
11. A robotic-driven imaging system as claimed in any preceding claim, wherein the robot drive unit comprises an inclinometer and wherein inclination data generated by the inclinometer is used to correct topography in the image data.
12. A robotic-driven imaging system as claimed in any preceding claim, wherein the robot drive unit further comprises a GPS positioning module for determining the position of the robot drive unit.
13. A robotic-driven imaging system as claimed in any preceding claim, wherein the electromagnetic induction data collector is a ground penetrating radar.
14. A robotic-driven imaging system as claimed in any preceding claim, comprising a pre-processing filter module configured to perform stacking and/or time zero correction on the image data.
15. A robotic-driven imaging system as claimed in any preceding claim, comprising a data processing filter module configured perform at least one of background removal, migration and deconvolution on the image data.
16. A robotic-driven imaging system as claimed in Claim 15, wherein the control computer comprises the data processing filter module.
17. A robot drive unit for use with the robotic-driven imaging system as claimed in any preceding claim.
18. A method of mapping or imaging underground objects, the method comprising: generating image data indicative of the position of one or more underground objects; pre-processing the generated image data to improve a signal:noise ratio of the generated image data by stacking the image data; processing the pre-processed generated image data to remove unwanted noise from the generated image data by background removal and further processing the generated image data to remove hyperbolas in the image data by migration; and determining the position of an underground object in dependence on the processed image data.
19. A method as claimed in Claim 18, wherein processing the pre-processed image data further comprises deconvolution to remove ringing from the pre-processed image data.
20. A method as claimed in Claim 18 or Claim 19, wherein pre-processing the generated image data further comprises performing time zero correction on the generated image data.
21. A method as claimed in any one of Claims 18 to 20, comprising generating an image or map of the position of underground objects in dependence on the determined position of the underground objects.
22. A method as claimed in Claim 21, comprising displaying the generated image or map on a control computer.
23. A method as claimed in any one of Claims 18 to 22, comprising marking the ground at the determined position of the underground object.
24. A method as claimed in any one of Claims 18 to 23, wherein generating image data comprises driving a robotic drive unit over an area of ground to be mapped or imaged.
25. A method as claimed in any one of Claims 18 to 24, comprising generating inclination data and correcting topography in the generated image data in dependence on the generated inclination data.