WO2012097416A1

WO2012097416A1 - Incorporation and use of a position sensor in a metal detector

Info

Publication number: WO2012097416A1
Application number: PCT/AU2012/000048
Authority: WO
Inventors: Oliver Nesper; Pavel Valentine KURSA; Gregory Peter HARMER; Alexander Lewis Jones; Philip David BECK; Laurence STAMATESCU
Original assignee: Minelab Electronics Pty Limited
Priority date: 2011-01-20
Filing date: 2012-01-20
Publication date: 2012-07-26

Abstract

A method for recording information in relation to a use of a metal detector such that the use of the metal detector can be presented visually, including producing positional data indicative of the position of the metal detector relative to a location; and associating, with each of the positional data, information regarding one or more of: a) settings of the metal detector; b) a time; c) characteristics of the ground; d) measurement data indicative of a target, signals from the target fulfilling one or more preselected criteria; and e) one or more functions performed by the metal detector.

Description

INCORPORATION AND USE OF A POSITION SENSOR IN A METAL DETECTOR

TECHNICAL FIELD

This invention relates to functions of a metal detector with a position sensor.

INCORPORATION BY REFERENCE

This patent application claims priority from:

- Australian Provisional Patent Application No. 2011900183 titled "Metal detector with improved applications" filed 20 January 2011.

The entire content of this application is hereby incorporated by reference. BACKGROUND

Metal detectors are used to determine/detect the location of conductive or paramagnetic objects that are buried in the ground. Examples of such objects include coins, relics, gold, mines and minerals.

A typical metal detector operates by transmitting electromagnetic energy into the ground where the energy interacts with a buried object which, in turn, transmits electromagnetic energy. The sensing head of a metal detector, which includes a transmitter and a receiver, is used to receive and measure the electromagnetic energy from the buried object to detect its presence in the ground. A typical method for metal detection using a metal detector is to move the sensing head of the metal detector from side to side, over the ground, while advancing along a path, to sweep an area of interest.

Software functions are developed to improve the performance of a metal detector and to improve the experience of a user when using a metal detector.

BRIEF SUMMARY OF THE INVENTION

According to a first aspect of the present invention, there is provided a method for assisting with an operation of a metal detector by a user, including: defining a detection zone; presenting visually to the user the detection zone; producing a record indicative of a position of the metal detector; checking the record against one or more predefined rules with respect to the detection zone; and indicating to the user when the record fails one or more of the one or more predefined rules.

In one form, the detection zone is an area. In one form, the detection zone is a path.

In one form, the detection zone is defined by at least three coordinate points, the at least three coordinate points defining an area. In one form, the detection zone is defined by at least two coordinate points, the at least two coordinate points defining a path. In one form, one of the one or more predefined rules requires that the metal detector be within a predetermined distance from the detection zone. In one form, the predetermined distance is substantially zero.

In one form, the step of defining the detection zone includes obtaining information from a source external to the metal detector to define the detection zone. In one form, the source is a web application.

In one form, the method further includes the step of: presenting visually to the user a current position of the metal detector with respect to the detection zone. According to a second aspect of the present invention, there is provided a method for storing information in relation to a use of a metal detector such that the use of the metal detector can be presented visually, including: producing positional data indicative of the position of the metal detector relative to a location; and associating, with each of the positional data, information regarding one or more of: a) settings of the metal detector; b) a time; c) characteristics of the ground; d) measurement data indicative of a target, signals from the target fulfilling one or more preselected criteria; and e) one or more functions performed by the metal detector.

In one form, the method further includes storing the positional data with associated information; and displaying a detection history of the metal detector based on a range of selected positional data with associated information.

According to another aspect of the present invention, there is provided a metal detector configurable to perform the first and second aspects, and their various forms. To assist with the understanding of this invention, reference will now be made to the drawings:

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 depicts a block diagram showing a functional block diagram of one embodiment of a metal detector;

Figure 2 depicts a metal detector with a visual display screen;

Figure 3 depicts records created in accordance with the present invention;

Figure 4 shows a flowchart of a function that creates a Trailpoint;

Figure 5 shows a flowchart of a function for the creation of a new, or activation of an extant, GeoHunt; Figure 6 shows a flowchart of a function for the creation of a Findpoint record;

Figure 7 shows a flowchart of a function for the creation and storage of a waypoint as triggered by the user;

Figure 8 shows a flowchart of a function for the erasure of a GeoHunt and its associated GeoTrail; Figure 9 shows detail of the display of part of a detecting session on the screen;

Figure 10 shows the result of increasing the earthly area depicted on the screen;

Figure 1 1 shows a flowchart of a function for creating and maintaining a map on the screen;

Figure 12 depicts one embodiment of how the stored information (which includes positional data, detector settings and any extra information) is shared with other users of compatible detectors;

Figure 13 depicts an example of map presentation using stored information;

Figure 14 depicts another example of map presentation using stored information;

Figure 15 depicts various embodiments of detection zone;

Figure 16 depicts further various embodiments of detection zone;

Figure 17 depicts possible manipulation of a detection zone;

Figure 18 depicts embodiments of detection zone with guiding routes and marked swept areas;

Figure 19 depicts one embodiment of the use of multiple detection zones; and

Figure 20 depicts an example of map presentation based on recording of prospecting activities by a user. Detailed Description of Invention

Figure 1 is a block diagram showing a functional block diagram of one embodiment of a metal detector that can produce data indicative of the position of the metal detector relative to a location.

The metal detector includes a sensing head 1, that includes a magnetic field transmitter and a magnetic field receiver (not shown), to transmit a transmit magnetic field 10 and to receive a receive magnetic field 11. The transmitter and the receiver can be separate coils, or can be the same coil, within the sensing head 1. The transmitter and the receiver can also be other forms and shapes of magnetic field transmitters and receivers known to a person skilled in the art. Receive signal, generated by the receive magnetic field 11 received by the sensing head 1 , may be filtered by filtering module 3 and may be converted to digital form by Analogue-to-Digital Converter (ADC) 5, prior to being processed by the SPU (signal processing unit) 7.

Position sensor 9 produces data indicative of the position of the metal detector relative to a location. The data produced can be stored in a digital data storage medium 12 located within the metal detector or in a storage medium external to, or removable from (not shown), the metal detector. Example of such storage medium is a USB memory device. Position sensor 9 can be a Global Positioning System (GPS) device included within the metal detector, or an external GPS device attached physically or linked wirelessly to the metal detector if for example worn by the user of the metal detector. Alternatively, the position sensor can, with or without a motion sensor (or accelerometer), produce data indicative of the position of the metal detector relative to a reference point, for example a radio beacon, a predetermined location or a location determined by the user.

The data indicative of the position of the metal detector relative to a location can be produced and stored in many forms, as long as the stored data are sufficient to indicate to a person an intended location. For example, the data can be produced and stored under the World Geodetic System (WGS) as used by GPS modules or devices, Universal Transverse Mercator (UTM) or Universal Polar Stereographic (UPS) coordinate systems. Alternatively, the data produced and stored can be in relative form. For example, a datum can indicate a position 100 metres north of a selected start point.

Alternatively, the data produced and stored can be a Cartesian coordinate relative to a location on a selected map. In this specification, data indicative of the position of the metal detector is also referred to as positional data.

Often, the forms of the positional data depend on the types of position sensor 9.

A software function (or a software application) can be executed by SPU 7. One or more functions can be included in SPU 7. The function can be triggered by a user of the metal detector via conventional controls such as buttons, keypad, menus, switches, rotary encoders, knobs, and touch-screen. It can also be triggered automatically by the metal detector once one or more conditions are fulfilled.

The metal detector also includes a timing circuit or clock 15. A time can be extracted in digital form from the clock 15 to SPU 7. The clock 15 can be a real-time clock, incorporated in, or connected to, SPU 7, or it can be included within the sensor 9 if that is a GPS receiver or something similar. The clock 15 can also be connected to a GPS unit such that the clock 15 can be synchronised with the temporal data from the GPS receiver. Synchronisation of the clock could be initiated by the user, or programmed to occur at the occurrence of particular events, for example turning the detector on. With this arrangement of independently running clock, time stamps can continue to be included in data records even if the signals from a GPS receiver are temporarily unavailable. In another embodiment, the time of the clock 15 can be set by the user. In yet another embodiment, the user can set the time-zone of the detector, facilitating the use of local time in the data records, when the temporal data from the sensor 9 is given in time at the meridian. Regardless of whether the clock 15 is included within the sensor 9, or whether it is part of or connected to the SPU 7, the source of temporal data as used by the SPU for storage will be referred to generally as the clock.

Figure 2 depicts an example of a metal detector 20 which includes a visual display screen 29. In this example, the metal detector includes a shaft 27, an interaction panel 25, a processing box 23 and a sensing head 21. The interaction panel 25, the processing box 23 and the sensing head 21 are attached to the shaft 27. A handle 36 and straps 34 are also attached to the shaft 27 to assist the user in equipping and using the metal detector 20. The interaction panel 25 includes a visual display screen 29, control buttons 31 and knobs 33, and data terminal 35. This example merely provides an embodiment of a metal detector which includes a visual display screen. The invention described herein is in relation to functions of a metal detector, and is applicable to any type/model/form of metal detector as long as there is a mechanism to project visual images to a user.

To enable projecting useful images to the user, the SPU of the metal detector (in this case within the processing box 23) processes the data from sensor (in this case located within sensing head 21), clock (in this case within the processing box 23) and sensing head 21, to form various datasets. Figure 3 depicts datatables that define records created in accordance with the present invention. The datatables are used to assist storage of data to be projected as visual images to a user. They are Configuration 41, GeoHunt 43, GeoTrail 45 (which includes Trailpoint 46), Findpoint 49, and

Waypoint 51. The Trailpoint 46 includes 48 positional data, temporal data (time and date), and a GeoHunt identifier that will be a copy of the identifier in a particular GeoHunt record. Configuration 41 includes 42 a unique identifier and settings of the metal detector. GeoHunt 43 includes 44 an identifier, temporal data, and a copy of the identifier in a particular Configuration record. Findpoint 49 includes 50 an identifier, positional data, temporal data, a copy of the identifier in a particular

GeoHunt record, metal detecting data, and a copy of the identifier in a particular Configuration record. Waypoint 51 includes 52 an identifier, positional data, temporal data, a copy of the identifier in a particular GeoHunt record and a copy of the identifier in a particular Configuration record. The creation and usage of instances of each of the different types of records are discussed below.

A Trailpoint is a record of positional, temporal and other data, stored in the memory of the SPU, with the positional data being provided by the sensor 9 and the temporal data being provided by the clock 15. The SPU can be set to a mode such that, as the user progresses along a path with the detector, the SPU extracts positional data from sensor 9 and temporal data from the clock 1 S at regular intervals. Along with other types of records, as indicated in Figure 3, a Trailpoint is formed and stored in memory of the SPU. The period between the formation of each Trailpoint can be, for example, 2 seconds. The storage of the Trailpoints is done such that the previous records are preserved, producing a collection of sequential records that can be used to reconstruct a map of the path taken.

For each Trailpoint, the sensor 9 is tested to determine whether it is capable of supplying positional data for the record. If not, no record of the Trailpoint is stored in memory.

In one embodiment, there are two modes of recording Trailpoints. In the first mode, the Trailpoints are stored in volatile memory. In the second mode, the Trailpoints are stored in non-volatile memory so as to retain their data when the detector is turned off. As the data in, and associated with, a GeoHunt are stored in non-volatile memory, the user is able to transfer the data to a computer at a later time. Each GeoHunt has a unique identifier, a copy of which is included in each Trailpoint, indicating the association of each Trailpoint with the GeoHunt that was active at the time of its creation. On the other hand, Trailpoints collected without a GeoHunt are lost whenever the detector is turned off; they are not intended for transfer to any other medium.

As stated previously, a GeoHunt has a collection of associated Trailpoints, in that each of the associated Trailpoints has a copy of the same GeoHunt identifier. Such a collection of Trailpoints, associated with a particular GeoHunt, will be referred to as a GeoTrail. A GeoTrail is a collection, or dataset, of all Trailpoints that have the same GeoHunt identifier. In the field, the user can activate a GeoHunt, either by activating an extant GeoHunt, or by creating a new GeoHunt. Activating an extant GeoHunt causes ensuing Trailpoints to be appended to the GeoTrail.

Initiating the creation of a new GeoHunt triggers a process that can be described as two main steps. The first step is the creation in the memory of SPU 7 of a snapshot of the configuration of the detector, a record of the settings of one or more of the parameters that influence the operation of the detector. Along with that snapshot is created a unique identifier, the Configuration identifier; the snapshot and identifier combined constitute a Configuration record.

The parameters that influence the operation of the detector might include such settings as detection sensitivity, volume of the output indicator signal, base pitch of the output indicator signal and sets of target identities that will not elicit emission of an audio output indicator signal. One or more of these can be included in a Configuration record. The second step causes a new record of data, a GeoHunt record, to be stored in the memory of the SPU 7, in which are stored a unique GeoHunt identifier, the time of creation of the GeoHunt using the temporal data supplied by the clock IS, and a copy of the Configuration identifier that was created in the first step.

Once these two steps are completed, the detector extracts, from the sensor 9 and the clock 15, positional and temporal data at regular intervals and uses these data to create a Trailpoint. One Trailpoint is created at the end of each such interval. Each Trailpoint also has a copy of the identifier of the active GeoHunt included. This associates each Trailpoint with the active GeoHunt. As the user and detector progress along a path, either planned or unplanned, the position of the detector, as determined by the sensor 9, is recorded with the other data in non-volatile memory of the SPU 7.

When a mapping facility of the detector is turned on, regardless of whether a map is being currently drawn on the screen, the sensor 9 is queried for new positional data at regular intervals, say every 2 seconds.

Figure 4 shows a flowchart of a function 50 that creates a Trailpoint every time a periodic "create Trailpoint" signal is received 51. The first active step of the function is to test whether positional data are available 53. If no positional data are available, the program immediately goes to the End 63 of the function. If positional data are available, the program will store positional and temporal data in a new Trailpoint in volatile memory 55. The next step for the program is to determine whether it needs to associate the Trailpoint with the active GeoHunt 57. If there is no GeoHunt active, the program immediately goes to the End 63 of the function. If there is an active GeoHunt, it will copy or store the identifier of the active Geohunt as the GeoHunt identifier of the Trailpoint 59. Because the Trailpoint is now associated with an active GeoHunt, it will transfer the Trailpoint record to non-volatile memory 61.

Figure 5 shows a flowchart of a function for the creation of a new, or activation of an extant, GeoHunt and its subsequent accumulation of data. When initiated by the user, the 'GeoHunt open' flag is set and the signal to start GeoHunt processing is given. This signal is also given when it is time to create a new Trailpoint and the 'GeoHunt open' flag is set.

After GeoHunt processing is started 71, a test 73 is performed to confirm whether there is an active GeoHunt.

If there is no active GeoHunt when the GeoHunt processing is started, a test 75 determines whether the user has initiated the creation of a new GeoHunt or the activation of one that already resides in memory. If re-activation of an extant GeoHunt is required, the Configuration record with which that GeoHunt is associated is loaded into the signal processing of the unit 83 so as to effect the settings stored in that Configuration record. That GeoHunt is then marked as being active 81. The Geohunt processing then goes to the End 97 and is idle until the GeoHunt Processing is started 71 again.

If it is required that a new GeoHunt be created, the relevant data are gathered for it. Temporal data of the moment are collected and stored in the Temporal data field of the new GeoHunt record 77, then a snapshot of the current configuration of the detector is added to a new Configuration record 79. The new GeoHunt is then marked as being active 81. The GeoHunt processing then goes to the End 97 and is idle until the GeoHunt processing 71 is started again.

The situation in which a GeoHunt is already active 73 when the GeoHunt processing is started 71, implies that positional data are available. The current positional and temporal data are stored 85 in an associated Trailpoint. Next, the program searches for any pending user points, that is Findpoints, waypoints etc. that are waiting to be stored 87. If there are, they will be stored 89 and associated with the active GeoHunt and other data records to which they are related.

The next step is to check that the user, or some other process, has not terminated the active

GeoHunt 91. If the GeoHunt has been turned off, the current temporal data are stored in the Temporal data field of the GeoHunt record 93. Then the 'GeoHunt open' flag is cleared 95, preventing the start of the GeoHunt processing 71. The GeoHunt processing then goes to the End 97 and will not return until re-activation of an existing GeoHunt, or creation of a new GeoHunt, is initiated by the user. If the GeoHunt has not been turned off, the program goes directly to the End 97. As the session of detecting proceeds, a target might be detected by the detector. There is a facility in the detector for the user to trigger the creation of a Findpoint in order to record information about the target.

Figure 6 shows a flowchart 110 of a function for the creation of a Findpoint record as triggered by the user. The program reacts to a signal to store Findpoint 111. Its response is to store a snapshot of the current device configuration 113 in a Configuration record, then copy the Configuration identifier into a new Findpoint record 114, store the current metal detection data in the new Findpoint record 1 15, then store the current temporal data in the new Findpoint record 117. Next, a test as to whether there is available positional data is conducted 119; if there are available positional data, the next step is to store the positional data in the new Findpoint record 121, after which a test of whether there is a

GeoHunt active 123 is conducted. If there are no positional data available 119, the test as to whether there is a GeoHunt active 123 is conducted immediately after the test for available positional data 1 19. If there is a GeoHunt active 123, the program will store a copy of its identifier in the GeoHunt identifier field of the Findpoint record 125, effectively associating the Findpoint with the active GeoHunt, then go to the end of the function 127. If there is no GeoHunt active 123, the program will go straight to the end of the function 127.

The Findpoint record is stored in non-volatile memory, as is the Configuration record made 113. Note that this means that, even if there is no GeoHunt active at the time, a Findpoint can be downloaded, along with the Configuration record with which it is associated, to a personal computer.

Metal detection data indicating the identity and other attributes of the target can be numbers (digital representations) that represent the determination, by the SPU, of numbers indicating the conductivity of the target, the ferrous nature of the target and the depth at which the target was detected. The test for the availability of positional data 119 is conducted because the primary function of a

Findpoint record is to store the attributes of the detected target. While it is desirable that the position at which the target is detected is stored, a lack of positional data must not prevent the retention of the detection data. If the sensor 9 is a GPS receiver, or some other device that has an appreciable probability of not being able to gather enough data to determine its position, this is a necessary test.

The step to store the GeoHunt identifier in the Findpoint record 127 is the means by which the Findpoint record is associated with the active GeoHunt. The identifier in question is a copy of the identifier of the active GeoHunt. In one embodiment, extra information can be transferred to the SPU 7 to be associated with a stored Findpoint record. For example, the user may enter a description of the object detected. The user may also enter one or more comments via buttons and/or knobs on the interaction panel 25. Furthermore, information such as photographic, video, audio etc may be associated automatically or manually with the respective positional data. For example, a photograph of the ground at a position may be taken by a camera attached to (or integrated with) the metal detector and transferred to the signal processing unit 7 to be associated with the positional data and detector settings at that position in a Findpoint record. Alternatively, the photograph can be stored in a medium separate from the metal detector, for example, in the camera itself, and an identifier of the photograph is sent to the signal processing unit 7 to associate the photograph with the Findpoint record.

A user may use a metal detector may to perform a ground measurement. During ground measurement, the characteristics of a ground near sensing head 1 are measured so that the measured characteristics may be used in further processing to minimise the adverse effect of the ground upon operations of the metal detector (for example, to compensate for the electromagnetic energy returned by the ground interfering with the electromagnetic energy returned by a target). Such minimization of the adverse effect is sometimes be known as "ground balancing". In one embodiment, a user can initiate the storage of a Groundpoint record. A Groundpoint record is similar to a Findpoint record, but containing information about the ground beneath the coil rather than the metal detecting data in a Findpoint record. In the same manner as a Findpoint record, a Groundpoint record will be associated with a GeoHunt, if one is active, and with a Configuration record. Groundpoint records are stored in non-volatile memory and can be uploaded to a personal computer.

Figure 7 shows a flowchart of a function for the creation and storage of a waypoint 130. A user can press a virtual or real button momentarily to start the first step 131. A test as to whether there are positional data available 133 is conducted. If there are no positional data available, the program goes to the End 141 of the function without further ado. If there are positional data available, the positional and temporal data in the waypoint record are recorded 135. The next step is to conduct a test as to whether there is a GeoHunt active 137. If there is no GeoHunt active, the program goes straight to the End 141 of the function. If there is a GeoHunt active, the next step is to store a copy of the GeoHunt identifier in waypoint record 139, after which the program goes to the end 141 of the function.

Principally, a waypoint record stores the positional data of the location at the moment of its creation. In this invention, it can also contain the time of its creation and be associated with an active GeoHunt. In another embodiment, a waypoint record can also be associated with a new Configuration record. With these facilities, a user can initiate storage of waypoints of pivotal points in the progression of the detecting session, and easily record the time and position of any changes in settings of the detector. Again, this is similar to the form and action of storing a Findpoint, except that the data stored are different.

Waypoint records are stored in non-volatile memory and can be uploaded to a personal computer.

Figure 8 shows a flowchart of a function for the erasure of a GeoHunt and its associated GeoTrail 150. The first step in erasing a GeoHunt record from memory is for the user to select the particular GeoHunt to be deleted 151. Once the GeoHunt for deletion is nominated by the user 151 , a test is performed as to whether the selected GeoHunt record has an associated GeoTrail present 153. If there is an associated GeoTrail, the program will delete the associated GeoTrail 157, then test whether there is any associated Findpointl55. If the test 153 shows that there is no associated GeoTrail, the program immediately tests whether there are any associated Findpoint records 1 5. If there are Findpoint records associated 135 with the selected GeoHunt, the next step is to remove the GeoHunt association from those Findpoints 139, after which the program tests whether there are any associated waypoints 161. If there are no Findpoint records associated with the selected GeoHunt, the program immediately tests whether there are any associated waypoints 161.

If there are any waypoint records associated with the selected GeoHunt, the next step is to remove GeoHunt identifier from all associated waypoints 163, after which the program tests whether there are any associated Configuration records 1 5 associated with the selected GeoHunt record. If the test 161 shows that there are no waypoint records associated 161 with the selected GeoHunt, the program immediately tests whether there are any associated Configuration records 165.

If there are any Configuration records associated 165 with the selected GeoHunt, the next step is to remove associated Configuration records 167, after which the program deletes the selected GeoHunt 169, thence the End 171 of the function. If the test 165 shows that there are no Configuration records associated with the selected GeoHunt, the program immediately deletes the selected GeoHunt 169, thence the End 171 of the function.

Removing an association of a GeoHunt from the record of a user point, say a Findpoint record, is achieved through the erasure of the copy of the copy of the GeoHunt identifier from the Findpoint record.

In another embodiment, the deletion of a selected GeoHunt does not produce the erasure of any associated Configuration records, but removes their associations with the selected GeoHunt, instead.

In another embodiment, the deletion of a selected GeoHunt does not produce the erasure of any associated Trailpoints, but removes their associations with the selected GeoHunt, then transfers them to volatile memory. While Trailpoints, waypoints, Findpoints etcetera are being recorded, they can also be depicted on the visual display screen 29. As the detector is moved along a path, its position with respect to the surface of the earth is depicted on the visual display screen. Depending upon the physical distances represented by the axes of the screen, at least one screen pixel is turned on, or caused to change its emission, to represent a position of the detector. In order that the user can differentiate between Trailpoints collected during GeoHunts and those collected during without an active GeoHunt, the pixels of one mode are displayed differently from those of the other; for example, the pixels representative of a GeoTrail could be green while the others are red. Figure 9 shows detail of the display of part of a detecting session on the visual display screen 29. The solid line 181 is the display of Trailpoints collected during a GeoHunt. The dashed line 183 is the display of Trailpoints collected without a GeoHunt being active. The top and bottom boundaries, 178 and 179 respectively are, by default, in the directions North and South respectively. The left and right boundaries, 176 and 177 respectively, indicate the directions West and East respectively. There are two waypoints 191 and 192 and three Findpoints 185, 186 and 187 shown on Figure 9.

In one embodiment, the scaling of the axes of the screen with respect to earthly distances can be adjusted by the user. This could produce a situation where, upon adjustment of the scale so as to reduce the distance represented by the axes of the screen, some depicted Trailpoints are no longer able to be depicted on the visual display screen; in other words, those Trailpoints are beyond the map range. An example of this is shown in Figure 9. Regardless of that eventuality, the Trailpoints that are beyond the map range will be retained in memory, lest they are required to be displayed because of further adjustment of the screen scale, or because the path of detection requires that they are again shown.

As the user progresses along the path, it might be that the most recently collected Trailpoints are no longer within the map range. In this case, the area depicted on the screen must be changed so as to allow inclusion of the new Trailpoints. A result of this adjustment might be that some of the

Trailpoints that were previously beyond a map range are again within it, requiring that they again be represented on the map; hence a reason to retain Trailpoints that fall beyond a map range.

Figure 10 shows the result of increasing the earthly area depicted on the screen. There are now more Findpoints, with the inclusion of 203 and 204, appearing on the screen. The area depicted in Figure 9 is shown as the area enclosed by the dotted rectangle 201.

In one embodiment, the display of a map can be caused to be rotated 180 degrees. This would be of advantage to the user in that, were the direction of travel in a predominantly southerly direction, rotation of the map in this way would make the relationship between the travel of the user and its depiction on the screen seem more natural.

Figure 11 shows a flowchart of a function for creating and maintaining a map on the screen 210. A signal from the user or the program directs the program to start map screen processing 211. The first active step of this function is to get current positional data 213. Once that is done, the current positional data and the current zoom level are used to determine latitude and longitude ranges, the map range, for the display 215. The prior description deals with the initial scaling of the map on the screen. The next step is to filter Findpoints and waypoints for those within the map range 217, after which the next step is to display filtered Findpoints and waypoints 21 . Once it has been determined which Findpoints and waypoints fit onto the map, a test is performed as to whether there is an active GeoHunt 221. If there is an active GeoHunt, the program will filter the Trailpoints associated with the active GeoHunt that are within the map range 223, then display those filtered Trailpoints of the active GeoHunt 225. After that, the program will filter other Trailpoints for those within map range 227. If the test 221 determines that there is no active GeoHunt, the program will proceed directly to filter unassociated Trailpoints within map range 227.

Once all Trailpoints have been filtered, the program will display filtered Trailpoints 229, after which a test is performed as to whether the map screen is being displayed 231. If the map screen is not active, the program immediately goes to the End 245 of the function. If the map screen is active, the program performs a test as to whether there is a new user point 233 that might need to be displayed. If there is a new user point, the program will filter Findpoints and waypoints for those within the map rage 217, then follow the same sequence of tests and actions from that point as have already been described. If there is no new user point, another test is performed to determine whether the zoom level is changed 235. If the zoom level is changed, the program will return to determine the new map range for the display 215, then follow the same sequence of tests and actions from that point as have already been described.

If the zoom level has not changed, the function will wait for new positional data 237. Once there are new positional data, the program will get the positional data 239, then the program will add the new positional data to Trailpoints 241. After that, the program will determine whether the new location is within the map range 243. If it is not, the program will return to determine map range for the display 215, then follow the same sequence of tests and actions from that point as have already been described. If the new location does lie within the map range, the program will immediately test whether there is a GeoHunt active 221, then follow the same sequence of tests and actions from that point as have already been described.

In one embodiment, in order to determine latitude and longitude ranges for the map range 215, the program performs a calculation using both the zoom level and the current positional data as inputs. In one embodiment, during the step in which the program will filter Findpoints and waypoints for those within the map range 223, 227, it also filters Groundpoints or any other user points that the program are able to create, for those within the map range. The user points that are filtered thus are displayed on the map during steps 225 and 229, respectively. In a further embodiment, the program will filter Trailpoints associated with the active GeoHunt when it filters Trailpoints of GeoHunt within the map range 217, and will filter Trailpoints not associated with the active GeoHunt when it filters other Trailpoints for those within map range.

In another embodiment, when the program displays filtered Trailpoints of the active GeoHunt 225, it marks the Trailpoints on the map using an icon that is distinguishable from that it uses when it displays other Trailpoints 229. In one embodiment, a new user point 233 is any of Findpoint, waypoint, Groundpoint or any other user point that the program can create at the command of the user.

In one embodiment, the zoom level is changed 235 by the user with the detector interface panel. With the creation and storage of one or more of the aforementioned records and datasets, a user can retrieve and review information contained by one or more of the stored records and datasets. For example, it is possible to retrieve all the locations where coins were found by commanding the processing unit 7 of the metal detector to present all the positional data with an ID representing coins. The user can also retrieve stored detector settings and set the current detector settings to one of the retrieved settings.

The stored records and datasets and information can be transferred to another storage medium, for example, an external database, or a personal computer. The transferred data and information can be shared with other users and/or devices.

Figure 12 depicts one embodiment of how the stored information, including positional data, detector settings and any extra information, using one or more of the datasets according to the present invention, is shared with others.

The data and information stored in the storage medium are uploaded 250 by user 251 to a web application 253. For example, in the case where the storage medium 12 is within a metal detector, the metal detector can be connected to a personal computer through a physical connection or through wireless connection. The user 251 can then access the stored information in the storage medium 12 through the web application 253, or through local client software embedded within the metal detector, to upload/transfer 250 selected stored information to web application 253. The transferred information can be presented in many ways, one way being on a map selectable by the user 251. As the data and information are with respect to a positional datum, they can be presented on a map, for example, as shown in Figure 13. The map in Figure 13 shows the recorded positions where targets have been found. For example, locations marked by markers 263 may indicate locations where coins were found, and locations marked by markers 261 may indicate locations where gold nuggets were found. The map may be presented differently. In this example shown in Figure 13, a map 265 (for example a map provided by Google) is superimposed with the markers. A user may also choose to view the elevation of the ground by choosing to view the map with elevation contour lines 266.

Alternatively, a user may prefer to view the markers without markers being superimposed with a map or contours.

Any of the transferred information can be retrieved 256 by other users 255. For example, a user 256 found that a gold nugget was found by user 251 at position X using settings Y based on the information provided by web application 253. This user 256 may then download settings Y for gold nugget prospecting around position X.

The web application 253 may combine data and information uploaded by more than one user to present all data and information having positional data within a selected range. For example, one may request the web application to show all the data and information within a 1km x 1km area selected using a map. The web application can also, based on all the uploaded data and information provide a suggestion to a user regarding the settings of a metal detector for prospecting a selected type of target (for example, gold nugget) in an area selected by the user.

The web application can also be set to reuse only portions of the uploaded data such that, for example, the exact locations of detected targets are not made available, but that regions and successful settings for those regions are.

Alternatively, a user can send the stored information to another user directly. For example, as illustrated in Figure 12, user 251 sends stored information through a wired or wireless connection 258 to user 255. In another embodiment, the stored information is sent using email.

Web application 253, with sufficient uploaded information, can recommend the type of detector, or settings for a chosen type of detector, when a user selects a positional coordinate.

The description with reference to Figure 13 is in relation to datasets of Findpoints and waypoints. Nonetheless, any stored characteristics in accordance with any of the records and datasets described herein can be transferred, uploaded to be shared, downloaded by other users etc using the same concept described with reference to Figure 12.

Figure 14 shows an example of use of the detector being enhanced through interaction with the web application 253 of Figure 12. Before venturing out for a session of detecting, the user can plan and plot a path using the web application. This can be done by choosing successive waypoints on a map displayed by the personal computer. Such waypoints are normally not associated with GeoHunt or Configuration records. The planned waypoints can be uploaded to the detector before the user begins the search for targets.

If sensor 9 is capable of determining absolute global position, upon nearing the area in which the coordinates of the selected waypoints lie, the planned waypoints 282 will appear on the map rendered on the screen of the detector. The user can search for targets, going from one planned waypoint 282 to the next. The user may use an active GeoHunt during the session; either way, the path he takes will be plotted 273 on the screen as usual. Along the way, any Findpoints 276, waypoints 280 etcetera initiated by the user will be shown on the map and stored in memory in the usual manner.

In one embodiment, the trail between successively selected waypoints is marked with a straight line 271, with some manner so as to distinguish it from associated and un-associated Trailpoints. T is will help the user to better gauge the deviation from the planned path. In order for these lines 271 to be connected between the pairs of planned waypoints 282 intended, the unique identifier in each could be replaced by number that indicates the order in which it was chosen using the web application 253.

A metal detector which can produce data indicative of the position of the metal detector relative to a location can be used by a user to first identify the location, where the user is interested in prospecting, prior to any actual prospecting using one or more datasets in accordance with the present invention. The identified location, or the detection zone, can be an area, or a path.

In one embodiment, a user selects at least three points (for example using waypoints) to define an area on a map. The zone enclosed is a 'detection zone'. Figure 1 shows one example of a detection zone defined by three points 291, 292 and 293.

In another embodiment, a user can move around with a metal detector to define detection zone 290. A user need not physically complete a closed loop to define a detection zone, as long as at least three points along the route moved are entered into the detector as positional data. In one embodiment, if the movement of the user does not form a closed loop, it is possible for the metal detector to link the start and end points of the user to form a closed loop. In another embodiment, a user selects at least two points to identify a path as a detection zone. The at least two points then define a line (path) as the detection zone. Figure IS shows one example of a path defined by points 295, 296 and 297. Of course, two points are sufficient to define a path, for example, with just points 295 and 296.

Three points may be used to define a path rather than an area. For example, a user may be required to input to the processing unit whether the user wants to an area type or a path type of detection zone. In another embodiment, as illustrated in Figure 16, a user may identify a start point 308 and walk towards an end point 309. The user can also specify a distance 31 1 to the left of the path and a distance 312 to the right of the path. The area 310 covered by the path and distances 311 and 312 then defines a detection zone. The distances 31 1 and 312 may be the same and the user may only be required to specify one value for both distances 311 and 312.

In another embodiment, also illustrated in Figure 16, a user may identify a start point 313, and specify distances 314, 315, 16 and 317 to define an area 318 as a detection zone.

The user can select the points using stored waypoints, or based on a map shown in the display of the metal detector or associated position determination device. Such a device may be a commercial off-the-shelf device. There exist agreed communication protocols for external devices to extract data from such position-determination devices. Alternatively, the user can input coordinates into the metal detector as the points. The metal detector itself can be used by transporting it to each point, then registering those points using the position sensors and the processor.

Alternatively, a user can use shape templates (for example, square shape, rectangular shape templates etc) to define a detection zone. For example, as shown in Figure 17, a user can choose a square template 319, resize the template according to the scale of the map if desired (not shown), and move to position the square template on the map as displayed at a desired location (for example, locations 320 or 321 to define the detection zone to be used).

It is also possible to combine one or more of the techniques described above to define a detection zone. For example, it is possible to identify point 313, specify distance 314, and specify the distances to the left and to the right of the path defined by distance 314 to define an area as a detection zone (without the need to specify distances 315, 316 and 317). In one embodiment, the detection zone is defined by external software before transferred to the signal processing unit of the metal detector.

After a detection zone has been defined, the user may begin prospecting, or sweeping. The processing unit, using the position data provided by the position sensor, monitors the movement of the user.

When the user moves outside of the defined detection zone, the metal detector may alert the user. The alert may be in various forms, for example, an audio alert, a video alert, a vibration alert, or the combination of two or more thereof. Alternatively, the user can define one or more rules with reference to the detection zone to initiate the alert when the user fails at least one of the rules. For example, rules may be defined such that the user will be alerted only when the user is more than 1 metre outside the defined detection zone. In another example, the alert will be initiated only when the user is outside the detection zone for more than a predefined period of time. In another example, the alert will be initiated immediately the user is outside of the defined detection zone.

The rules can be uploaded or downloaded from the web application described above. The rules can also be created and stored, and be selected by a user. The processing unit can also keep track of progress of the detector within the detection zone. For example, with reference to Figure 18, locations which have been visited or prospected may be marked or coloured differently 326 from locations which have not been visited. The processing unit can also suggest a guiding route 324, and 329 for the user to follow in order for the user to complete sweeping within detection zone efficiently. The guiding route may be shown, on a map, together with the detection zone, the locations visited, and the present location of the detector. The processing unit can alert the user when all locations of the detection zone have been swept.

The processing unit may take into consideration impassable terrain, for example a river 323 in Figure 18 through the superimposed map 265. The processing unit may suggest a route 325 to allow the user to finish sweeping the detection zone.

The detection zone can be stored, with swept locations, so that the sweeping activities by a user can be paused, and resumed later. In one embodiment, it is possible to merge detection zones into one detection zone. In another embodiment, it is possible to split one detection zone into multiple detection zones. For example as illustrated in Figure 19, a detection zone is first specified and then split into detection zones 337, 338 and 339.

It is possible to have separate users with separate detectors operating in different detection zones, the users sharing the relevant information in real-time to prevent one user from sweeping an area which has been previously swept by another. With reference to Figure 19, user A is assigned detection zone 337, user B is assigned detection zone 338 and user C is assigned detection zone 339. User A has swept area 330, user B has swept area 331 and user C has swept 332. The information as shown in Figure 19 is available to users A, B and C. Thus user B no longer needs to sweep area 332 within area 338 which has already been swept by user C. It is also possible for the user to share other information, for example objects found by any of the user, detector settings etc.

The detection zone, with swept locations indicated, can be transferred, uploaded to be shared, downloaded by other users using the same concept described with reference to Figure 12.

A metal detector which can produce data indicative of the position of the metal detector relative to a location can be used by a user to record prospecting activities by a user using one of more of the datasets described herein. Types of activities performed by a metal detector and any relevant information may be stored or used by a metal detector.

The types of activities include one or more of, but are not limited to:

1) beginning/pausing/resuming/ending sweeping;

2) performing measurement of magnetic properties of ground;

3) defining a detection zone or path; and

4) changing detector settings.

Relevant information may be recorded are:

1) detector settings;

2) magnetic characteristics of ground;

3) target identification; and

4) position or route. The recording may be paused and resumed by a user. The recorded activities and/or relevant information can also be reviewed at any time during the recording. Figure 20 depicts an example of the recording of prospecting activities by a user. The user switched the detector on, then began the recording at position 351. The user also performed ground measurement at position 3S1. The user then walked, as indicated by route 350, up a small slope, as indicated by elevation contour lines 355. The user performed a ground measurement at position 353 near the top of the slope and began sweeping from 353. The user found a target at 357, which was a coin, and inserted a comment "found a square coin" when recording the discovery of the coin at 357. The user stopped sweeping and walked down the slope toward the bank of river shown by superimposed map 265. The user defined a detection path using points 359 and 360. The user began sweeping from 359 towards 360 but was too far away from the path at one instance. At location 361, the user was alerted that the detector was too far from the defined detection zone. The user walked towards location 360 and defined a detection zone 363. The user began sweeping within the detection zone following a route suggested by the processing unit of the metal detector. The user paused the detection at 365, and walked to 367. The user inserted comment at 367 "stop for lunch". After lunch, the user continued to location 369 following the route 350 and decided to stop recording at point 369. Each event and information is recorded with a time-stamp so that they can be presented in chronological order.

The recorded activities and/or relevant information can be transferred, uploaded to be shared, downloaded by other users etcetera using the same concept described with reference to Figure 12.

As illustrated in 20, the route 350 presents only the general forward movement of the metal detector. With the addition of one or more movement sensors, it is also possible to record side-to-side sweeping movement of the sensor head of a metal detector (not shown). Such records can be used to review the sweeping activities of a user. For example, a user may improve their sweeping movement pattern based on the review.

A detailed description of one or more preferred embodiments of the invention is provided above along with accompanying figures that illustrate by way of example the principles of the invention. While the invention is described in connection with such embodiments, it should be understood that the invention is not limited to any embodiment. On the contrary, the scope of the invention is limited only by the appended claims and the invention encompasses numerous alternatives, modifications, and equivalents. For the purpose of example, numerous specific details are set forth in the description above in order to provide a thorough understanding of the present invention. The present invention may be practised according to the claims without some or all of these specific details. For the purpose of clarity, technical material that is known in the technical fields related to the invention has not been described in detail so that the present invention is not unnecessarily obscured. Throughout this specification and the claims that follow unless the context requires otherwise, the words 'comprise' and 'include' and variations such as 'comprising' and 'including' will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

The reference to any prior art in this specification is not, and should not be taken as, an

acknowledgment or any form of suggestion that such prior art forms part of the common general knowledge of the technical field.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A method for assisting with an operation of a metal detector by a user, including:

defining a detection zone;

S presenting visually to the user the detection zone;

producing a record indicative of a position of the metal detector;

checking the record against one or more predefined rules with respect to the detection zone; and

indicating to the user when the record fails one or more of the one or more predefined rules.0

2. The method of claim 1, wherein the detection zone is an area.

3. The method of claim 1, wherein the detection zone is a path. 5

4. The method of claim 1, wherein the detection zone is defined by at least three coordinate points, the at least three coordinate points defining an area.

5. The method of claim 1, wherein the detection zone is defined by at least two coordinate points, the at least two coordinate points defining a path.

0

6. The method of claim 1, wherein one of the one or more predefined rules requires that the metal detector be within a predetermined distance from the detection zone.

7. The method of claim 6, wherein the predetermined distance is substantially zero.

5

8. The method of claim 1, wherein the step of defining the detection zone includes obtaining information from a source external to the metal detector to define the detection zone.

9. The method of claim 8, wherein the source is a web application.

0

10. The method of claim 1, further including the step of:

presenting visually to the user a current position of the metal detector with respect to the detection zone. 5

11. A method for storing information in relation to a use of a metal detector such that the use of the metal detector can be presented visually, including: producing positional data indicative of the position of the metal detector relative to a location; and

associating, with each of the positional data, information regarding one or more of:

a) settings of the metal detector;

b) a time;

c) characteristics of the ground;

d) measurement data indicative of a target, signals from the target fulfilling one or more preselected criteria; and

e) one or more functions performed by the metal detector.

12. A method according to claim 11, further including:

storing the positional data with associated information; and

displaying a detection history of the metal detector based on a range of selected positional data with associated information.

13. A metal detector configurable to perform the method of claim 1.

14. A metal detector configurable to perform the method of claim 11.