Field of the invention

The invention relates to the field of dredging. More particularly, the present invention relates to methods and systems for analyzing a sediment structure and composition, e.g. for determining the density of a sediment layer or the density of a dense sediment flow in order to evaluate a dredging process to be performed.

Background of the invention

In preparation of dredging works the physical parameters of the underwater soil structures and sediment layer need to be characterized, e.g. for estimating the transport requirements and/or time and financial requirements. Sediment layers can be several meters thick, can be loose or consolidated. Furthermore sediment typically is a mixture and the density therefore may vary a lot. One of the important parameters to be measured for characterizing a sediment therefore is the density of the sediment layer.

Also once the sediment layers are dredged and collected in the hopper, a density profile of the hopper mud over the depth of the hopper may need to be measured. The latter may be relevant for evaluating the load of the hopper and/or for evaluating the progress of the dredging process. In view of the difficulty to accurately determine the in situ volume for a dredging process, e.g. when silt layers are to be evaluated or if the dredged volume is strongly dependent on the type of mixture and/or the dewatering behavior of the dredged material, it often is preferred to express the transport, time and/or financial requirements as function of the mass of dry matter content. The amount of dry matter can be determined based on the following formula

™ass _diymatter = (im _dredgedmlume IV)- pw)l psolid)* psolid * V * (1 /1000)

with massdrymatter the mass of the dry matter, rridredgedvoiume the mass of the dredged matter saturated with water, V the volume of the dredged matter saturated with water, p _w the density of the water, p _SO iid the density of the solid matter. The density thereby again plays an important role.

Furthermore, during dredging or before dredging the density of suspended sediment layers present at the bottom can be monitored in order to evaluate the total transported sediment mass, e.g. to better understand or map the sediment process that occurs. Summary of the invention

It is an object of embodiments of the present invention to provide good methods and systems for evaluating a dredging process, e.g. methods and systems for evaluating the transportation, time and/or economical budget for a dredging process.

It is an advantage of embodiments of the present invention to provide a good vertical mud or sediment analyser, e.g. a good vertical mud or sediment profiler or scanner. It is an advantage of embodiments according to the present invention that a profiler system can be provided that is easier, e.g. through its light weight, to handle or install compared to scanners based on radioactive detectors.

It is an advantage of embodiments according to the present invention that a profiler system can be provided that is more user friendly in installation, transport and use.

It is an advantage of embodiments according to the present invention that a profiler system can be provided that is based on a detection principle that is less harmful and/or less legislated than radioactive detection techniques.

It is an advantage of embodiments according to the present invention that a profiler system or scanner, e.g. a vertical profiler or scanner, for e.g. mud or sedimentation is provided that is based on stationary or moving X-ray transmission hardware in a tube in combination with a stack of X-ray detectors or receivers of any kind, such as a scintillation crystal and photo multiplier tube or any kind of semiconductor based photo detector. The complete profiler may comprise two tubes which are transparent for X-ray. The profiler may comprise X-ray blocking tubes, such as metal, with X-ray transparent windows at discrete distances in which the X-ray source and receiver are stationary positioned or move up and down. In the first tube the source can operate in the second tube the X-ray detector or receiver can operate. By moving both sender and receiver synchronous, the sediment in between can be characterized.

Embodiments of the present invention may allow performing static measurements of the density, e.g. determining density of a substantially static mud, soil, sediment, etc.

According to some embodiments of the present invention, the system may allow dynamic characterization of a mud, soil, sediment, etc. e.g. determine a mass transport.

It is an advantage of embodiments according to the present invention that systems and methods are provided for determining physical parameters like density and composition images of underwater soil structures. It is an advantage of embodiments according to the present invention that soil structure, soil type and composition can be derived from such parameters.

It is an advantage of embodiments of the present invention that methods and systems are provided for analyzing one or more physical parameters in parallel with the presence of pollution. It is an advantage of embodiments according to the present invention that the systems are adapted in mechanical design so as to allow characterization of the mud or sand layers substantially without disturbing the measured layer. It is an advantage of embodiments according to the present invention that systems with a specific electronics design and sensor integration can be provided for analysing the sediment or sand layer.

It is an advantage of embodiments according to the present invention that a physical picture of the mud/sediment can be taken and good image processing can be done. It is an advantage that shear-strength, rigidity and viscosity also can be determined via association methods, resulting in a full characterization of the mud/sediment.

It is an advantage of embodiments according to the present invention that component analysis of the scanned mud/sediment can be done based on spectrometry.

The above object is obtained by a system and/or method according to the present invention. The present invention relates to a profiling system for obtaining information regarding a mud, sediment, sand or soil, the system comprising

a first elongated element comprising an x-ray radiation source system for emitting x-rays, a second elongated element comprising an x-ray detector system for detecting x-rays, the first elongated element and the second elongated element being transparent for x- rays along at least a part of their length and

the x-ray radiation source system and the x-ray detector system being configured in the first elongated element respectively second elongated element so that at a plurality of positions or continuously along the length of the first and the second elongated elements x-ray radiation emitted from the x-ray radiation source system can be detected by the x-ray detector system. The profiling system may be a closed system, whereby no moving component is in contact with the mud, sediment, sand or soil.

The first elongated element may be a closed element. The second elongated element may be a closed element.

It is an advantage of embodiments of the present invention that the mud or sediment is not disturbed by movement of the source system or detector element. At least one of the x-ray radiation source system and/or the x-ray radiation detector system may be arranged on a guiding element for moving the x-ray radiation source system and/or the x-ray radiation detector system along a length of the first elongated element respectively the second elongated element.

The x-ray radiation source system may comprise a plurality of radiation sources along the length of the first elongated element and the x-ray detector system may comprise a plurality of x-ray radiation detector elements along the length of the second elongated element, the radiation sources and detector elements being aligned with respect to each other for emitting and receiving x-ray radiation.

The system furthermore may comprise a controller for controlling a movement of the x-ray radiation source system and/or the x-ray detector source system along the guiding element. The controller may be adapted for synchronously moving the x-ray radiation source system and/or the x-ray detector source system.

The first and/or the second elongated element may comprise position recognition means for recognizing a position of the source system or detector system along the length of the first respectively the second elongated element. Such position recognition means may be optical features.

The first elongated element and the second elongated element may be elements of a single, concave system shaped so as to create a hollow space, the first elongated element and the second elongated element being positioned at opposite sides of said hollow space.

The x-ray source system and the x-ray detector system may be mechanically linked - e.g. connected - to each other and are simultaneously moveable.

The first elongated element and the second elongated element may be two closed separate independent elements. The elements may only be linked through their housing, e.g. to keep them at a fixed distance with respect to each other.

The x-ray radiation source system and the x-ray detector system may be independently moveable.

The system furthermore may comprise a processing means being programmed for deriving, based on said data X-ray receiver data at least one of a density, composition or structure picture of a soil.

The processing means may be programmed for deriving at least the density based on said data. The system may be adapted for performing an X-ray scan and the processing means may be programmed for determining density, viscosity, yield strength or a material component out of the scan by assigning components to sudden intensity changes.

The processing means furthermore may be adapted for deriving soil type or soil structure based on said density, shear strength and scan profile.

It is an advantage of at least some embodiments of the present invention that a profiling system based on x-ray analysis for profiling mud, sediment, sand or soil is provided that is easy to use.

It is an advantage of embodiments of the present invention that a handheld profiling system based on X-ray measurements is provided.

In a particular embodiment, the present invention therefore also relates to a profiling system for obtaining information regarding a mud, sediment, sand or soil, the profiling system being a handheld profiling system comprising an X-ray source and detector, in the present embodiment being a semiconductor based photo detector, wherein the x-ray source and the semiconductor based photo detector being configured for performing X-ray measurements of the mud, sediment, sand or soil for determining a density based on said profiling.

The semiconductor based photo detector may be a silicon based photo detector.

The mass of the profiling system may be less than 10 kg.

The processing means may be configured for determining, based on the X-ray measurements, a density of the mud, sediment, sand or soil.

The processing means may be configured for determining a depth, thickness, cone resistance or shear strength of underwater sediment layers.

The system can be integrated in the housing. To miniaturize an accurate density profiler that can be used in situ, the X-ray source and the X-ray detector needs to fit in a small housing. For the detector in such embodiments, a silicon based photomultiplier could be used in order to fit in the small housing.

The present invention also relates to a processing means for determining mud, sediment, sand or soil characteristics, the processing means being adapted for receiving X-ray data recorded of a mud, sediment, sand or soil, and

the processing means being programmed for deriving, based on the X-ray data, at least the density of the mud, sediment, sand or soil.

The processing means may be adapted for receiving X-ray data of a profiling system as described above. The processing means furthermore may be programmed for determining density, viscosity, yield strength or material components and/or chemical composition out of the scan by assigning components to sudden intensity changes for a certain spectrum.

The processing means furthermore may be adapted for deriving soil type or soil structure based on said density, a shear strength and scan profile.

The present invention also relates to a computer program product for determining mud, sediment, sand or soil characteristics, the computer program product providing, when run on a computer, the functionality of the processing means as described above.

The computer program product may be a web application.

The present invention also relates to a data carrier comprising a computer program product as described above or to the transmission of a computer program product as described above over a network, e.g. a local or wide area network.

The present invention also relates to a dredging hopper comprising a profiling system as described above.

The present invention also relates to the use of a profiling system as described above for determining the mass of dry matter in dredged materials based on X-ray density measurements.

The present invention also relates to the use of a profiling system as described above for determining the liquefaction point of a consolidated sediment based on density measurement in order to prepare water injection dredging works. In other words, based on the density measurements of the sediment, the amount of water is determined that needs to be added to render the sediment sufficiently liquid in order to dredge it.

The present invention also relates to the use of a profiling system as described above for determining the nautical bottom level in sediment based on X-ray density measurements using a profiling system as described above. The nautical bottom thereby is the level where the density of the sediment has a value of 1.2 ton/m ³ .

The present invention also relates to the use of a profiling system as described above for the evaluation of consolidation at dredge storage places and underwater cells.

The present invention furthermore relates to the use of a profiling system as described above for determining a dynamic characteristic of a mud, sediment, sand or soil. The dynamic characteristic may be a mass transport thereof or therein. The present invention also relates to the use of a profiling system as described above for determining a static characteristic of a mud, sediment, sand or soil. The static characteristic may be a density thereof.

The present invention furthermore relates in one aspect to a system for determining density profile information regarding a sediment or dredged material, the system comprises an x-ray radiation source system for emitting x-rays, an x-ray detector system for detecting x-rays, whereby the x-ray radiation source system and the x-ray detector system are configured for allowing an elongated volume of sediment or dredged material to pass in between the x-ray radiation source system and the x-ray detector system so as to obtain density profile information. The system may comprise a movement means for shifting the elongated volume of sediment or dredged material in between source and detector system.

The present invention also relates to a method for determining density profile information regarding a sediment or dredged material, the method comprising obtaining an elongated volume of sediment or dredged material, translating the elongated volume of sediment or dredged material in between an x-ray source system and the x-ray detector system for determining x-ray profile data for the length of the elongated volume, and determining from said x-ray profile data density related information. The method may comprise the step of correlating the x-ray data with the position information where the x-ray data is recorded. The method may comprise detecting positional information, e.g. using an optical strip.

Particular and preferred aspects of the invention are set out in the accompanying independent and dependent claims. Features from the dependent claims may be combined with features of the independent claims and with features of other dependent claims as appropriate and not merely as explicitly set out in the claims.

These and other aspects of the invention will be apparent from and elucidated with reference to the embodiment(s) described hereinafter.

Brief description of the drawings

Figure 1 to Figure 4 display different schematic representations of systems according to an embodiment of the present invention.

Figure 5 displays a vertical X-ray density scan of a sediment sample as can be obtained using an embodiment of the present invention.

Figure 6 displays a density interpretation based on Figure 5. Figure 7 displays a yield strength map as can be obtained using embodiments according to the present invention.

Figure 8 and 9 display the analysis of a horizontal slice through a CT-scanned sediment volume as can be used according to embodiments of the present invention.

Figure 10 displays a handheld density profiler according to an embodiment of the present invention.

Figure 11 displays a density profile for a muddy access channel wherein ships can navigate, according to an embodiment of the present invention.

Figure 12 illustrates a density profile for a waterway wherein the nautical bottom can be determined, according to an embodiment of the present invention.

Figure 13 illustrates water injection liquefaction of mud, as an application that can make use of a system or method according to the present invention.

Figure 14 illustrates a method for sampling of a mud or sediment and for removing it to measure it at a different location, according to an embodiment of an aspect of the present invention.

Figure 15 illustrates a process of scanning a column of mud or sediment on shore according to an embodiment of an aspect of the present invention.

Figure 16 illustrates a density profile obtainable through a system according to Figure 15. The drawings are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes.

Any reference signs in the claims shall not be construed as limiting the scope.

Detailed description of illustrative embodiments

The present invention will be described with respect to particular embodiments and with reference to certain drawings but the invention is not limited thereto but only by the claims. The drawings described are only schematic and are non-limiting. In the drawings, the size of some of the elements may be exaggerated and not drawn on scale for illustrative purposes. The dimensions and the relative dimensions do not always correspond to actual reductions to practice of the invention.

Furthermore, the terms first, second and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequence, either temporally, spatially, in ranking or in any other manner. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

Moreover, the terms top, under and the like in the description and the claims are used for descriptive purposes and not necessarily for describing relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other orientations than described or illustrated herein.

It is to be noticed that the term "comprising", used in the claims, should not be interpreted as being restricted to the means listed thereafter; it does not exclude other elements or steps. It is thus to be interpreted as specifying the presence of the stated features, integers, steps or components as referred to, but does not preclude the presence or addition of one or more other features, integers, steps or components, or groups thereof. Thus, the scope of the expression "a device comprising means A and B" should not be limited to devices consisting only of components A and B. It means that with respect to the present invention, the only relevant components of the device are A and B.

Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments.

Similarly it should be appreciated that in the description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this invention. Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those skilled in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

In one aspect, the present invention relates to a profiling system for obtaining information regarding a mud, sediment, sand or soil, the system comprising a first elongated element comprising an x-ray radiation source system for emitting x-rays and a second elongated element comprising an x-ray detector system for detecting x-rays. X-rays may for example refer to electromagnetic radiation with an energy in the range 1 keV to 200 keV, e.g. in the range 10 keV to 200 keV, e.g. in the range 15 keV to 150 keV, e.g. in the range 30 keV to 150 keV. The first elongated element and the second elongated element may be transparent for x-rays along at least a part of their length. According to embodiments of the present invention, the x-ray radiation source system and the x-ray detector system being configured in the first elongated element respectively second elongated element so that at a plurality of positions along the length of the first and the second elongated elements x-ray radiation emitted from the x-ray radiation source system can be detected by the x-ray detector system. The materials used may be any suitable material, such as but not limited to composite material.

By way of illustration, embodiments of the present invention not being limited thereto, examples of optional features have been described above and will be described below, with reference to the drawings. Figure 1 displays a set of X-ray sources and receivers positioned in an array, as can be used in an embodiment according to the present invention. The proposed set-up allows the measurement of a vertical density profile of the sediment at a predefined discrete distance interval. The X-ray sources and receivers are mounted in a metal housing with X-ray transparent windows.

Figure 2 displays an extruded composite or other X-ray transparent material in which all rail and positioning infrastructure is available for the movement of an X-ray source and receiver configuration mounted on a sled. It is an advantage of the proposed set-up that source and receiver do not move independently. It is an advantage of the extrusion of the tube that all necessary infrastructure to guide and position the X-ray source and receiver configuration is entirely available and factory calibrated.

Figure 3 displays a source and receiver configuration mounted in a tube equipped with X-ray transparent windows. In such a configuration, positioning of the configuration should be highly accurate. Optical markers or any other type of markers can be used to position both source and receiver unit, allowing independent movement in two separate tubes.

Figure 4 displays metal clamps to guide X-ray transparent tubes in which source and receiver unit move independent. A vertical discrete receiver array allows an automatic positioning of the X-ray receiver.

Based on the attenuation of the x-rays, detected using the x-ray detector, a density of the material measured can be determined. Even more, as the profiling system allows measurements at different locations along a length (in sediment typically along a depth) of a material studied, a density profile can be obtained. The density values can be determined based for example on mathematical calculations, e.g. taking into account the specifications of the setup used, can be based on pre-calibration and look up tables, can be based on earlier performed measurements, etc. In some embodiments, the processing means provided for performing measurements may be configured for directly deriving from the density profile measured a corresponding physical characteristic of the material measured, such as for example a sediment type, an average density, the mass of the amount of dry matter present, etc. The processing means therefor may make use of predetermined algorithms, a neural network, look-up tables, etc.

Figure 5 displays a vertical X-ray density scan of a sediment sample, where black indicates air and white indicates the highest density. It can be seen that the density profile of the sediment can be accurately obtained. Such a density profile can result in relevant information for example for evaluating the transport, time and/or financial requirements of a dredging project. Figure 6 displays a density interpretation of figure 5 and a vertical bulk density profile and related ton dry mass profile.

Figure 7 displays a yield strength map derived from the bulk density map based on equilibrium flow conditions and thyxotropic properties.

Figure 8 displays the analysis of a horizontal slice through a CT-scanned sediment volume. The derived density spectrum is narrow and the resulting strength spectrum is narrow as well, making the mean density value a good strength predictor.

Figure 9 displays the analysis of a horizontal slice through a CT-scanned sediment volume. The derived density spectrum is wide and the resulting strength spectrum is wide as well. The mean density in this case is not a good predictor for sediment strength. Measuring the density spectrum allows to have a strength estimate. In one particular embodiment, the present invention relates to a handheld profiling system for obtaining information regarding a mud, sediment, sand or soil. Similar as the profiling system identified above, the handheld profiling system comprises an X-ray source and a detector. In handheld devices, the detector advantageously may be a semiconductor based photo detector. A system according to such an exemplary embodiment is shown in Figure 10 displaying a handheld density profiler less than 10 kg based on an X-ray source and a silicon photo detector. Standard and optional features of the system described above may, mutates mutandis, also be applied.

In another aspect, the present invention relates to a processing means for determining mud, sediment, sand or soil characteristics. The processing means being adapted for receiving X-ray data recorded of a mud, sediment, sand or soil. The processing means may therefore comprise an input port, or may be coupled to or be part of ; a profiling system as described in the first aspect. The processing means furthermore is programmed for deriving, based on the X-ray data, at least the density of the mud, sediment, sand or soil. The processing means may be separate or may be included in the profiling system of embodiments of the first aspect.

According to some embodiments of the present invention, the processing means may be adapted for deriving an amount of dry matter. The processor used may be configured to make use of a predetermined algorithm, a neural network, look up tables, etc. In one particular embodiment, the processor may make use of the following formula for determining the dry matter mass :

™ass _diymatter = (im _dredgedmlume IV)- pw)l psolid)* psolid * V * (1 /1000)

with massdrymatter the mass of the dry matter, rridredgedvoiume the mass of the dredged matter saturated with water, V the volume of the dredged matter saturated with water, p _w the density of the water, p _SO iid the density of the solid matter. The density thereby again plays an important role. Alternatively, other definitions for determining dry mass also can be used, without diverting from the present invention.

In other embodiments, the processing means may be configured for determining a liquefaction point of a consolidated sediment based on the density measurement in order to prepare water injection dredging works. In other words, based on the density measurements of the sediment, the amount of water is determined that needs to be added to render the sediment sufficiently liquid in order to dredge it. The processing means alternatively or in addition thereto can also be configured for determining the nautical bottom level in sediment based on X-ray density measurements. The nautical bottom thereby typically may be defined as the level where the density of the sediment has a value of 1.2 ton/m ³ . In yet another example, the processing means may be configured for evaluation of consolidation at dredge storage places and underwater cells.

The processing means may comprise an input means for receiving user input and for receiving the measurement data from the detector. The processing means typically also may comprise a processor for processing the x-ray data. Such a processor may be a at least one programmable processor coupled to a memory subsystem that includes at least one form of memory, e.g., RAM, ROM, and so forth. It is to be noted that the processor or processors may be a general purpose, or a special purpose processor, and may be for inclusion in a device, e.g., a chip that has other components that perform other functions. Thus, one or more aspects of the present invention can be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or in combinations of them. More elements such as network connections, interfaces to various devices, and so forth, may be included. The various elements of the device 11 may be coupled in various ways, including via a bus subsystem.

In yet another aspect, the present invention relates to a dredging hopper, wherein the dredging hopper comprises a profiling system as described in certain embodiments of the first aspect.

In still another aspect, the present invention relates to the use of a system as described in the first aspect or to the use of a processing means as described in the second aspect for determining a characteristic of a mud, sediment, sand or soil. The use may be for determining a dynamic characteristic, such as for example a mass transport, or may be for determining a static characteristic, such as for determining a density. In some embodiments, such a use may be for determining the mass of dry matter in dredged materials based on X-ray density measurements. In another embodiment, such use may be for determining the liquefaction point of a consolidated sediment based on density measurement in order to prepare water injection dredging works. In other words, based on the density measurements of the sediment, the amount of water is determined that needs to be added to render the sediment sufficiently liquid in order to dredge it. In still another embodiment, such use may be for determining the nautical bottom level in sediment based on X-ray density measurements using a profiling system as described above. The nautical bottom thereby is the level where the density of the sediment has a value of 1.2 ton/m ³ . In yet another embodiment, the use may be for the evaluation of consolidation at dredge storage places and underwater cells. Based on the obtained results, it can be decided to further use the dredge storage place, to switch the functionality of the dredge storage place, etc.

The present invention furthermore relates to the use of a profiling system as described above for determining a dynamic characteristic of a mud, sediment, sand or soil. The dynamic characteristic may be a mass transport thereof or therein.

The present invention also relates to the use of a profiling system as described above for determining a static characteristic of a mud, sediment, sand or soil. The static characteristic may be a density thereof. In still another aspect, the present invention relates to a method for evaluating a dredging process. The method comprises contacting a profiling system and a sediment or dredged material and detecting x-ray radiation emitted through the sediment or dredged material at a plurality of positions or continuously along a length/depth direction of the sediment or dredged material, determining, based on the detected x-ray radiation, a density-related profile of the sediment or dredged material, and deriving, based on the determined density-related profile, a characteristic of the dredging process. Such contacting may be performed by filling a recipient, e.g. a dredging hopper with a profiling system installed therein. Alternatively the profiling system may be inserted in the sediment or dredged material. Such inserting may be inserting by hand, using a handheld device, or may be performed in an automated way. Deriving a characteristic of the dredging process may comprise deriving a parameter expressing the transportation, time and/or financial budget for the dredging process, deriving the mass of dry matter of a load, deriving a nautical bottom level, deriving a liquefaction point and/or the amount of water to be injected for obtaining this point, etc. The method also may comprise evaluating, e.g. monitoring, a consolidation process of a dredge storage place or underwater cell. The method according to embodiments of the present invention also may include steps expressing a functionality of elements of systems as described in the first aspect.

In a further aspect, the present invention relates to a computer program product for, when executing on a computing device, executing the determining and/or deriving of information as described in the method according to the above aspects. The present invention also relates to a computer-readable data carrier storing a computer program product according to this further aspect, and to the transmission of such computer program product over a communication network. The present invention thus also includes a computer program product, e.g. an application program product also referred to as applet, which provides the functionality of any of the data processing steps of the methods according to the present invention when executed on a computing device. The computer program product can also be transmitted via a carrier wave in a network, such as a LAN, a WAN or the Internet. Transmission media can take the form of acoustic or light waves, such as those generated during radio wave and infrared data communications. Transmission media include coaxial cables, copper wire and fibre optics, including the wires that comprise a bus within a computer.

By way of illustration, an example of an application making use of a system and method according to the present invention is discussed below. In muddy access channels, ships can navigate close to or through a loose sediment layer. Potentially a ship can enter with 7% of its draught inside the mud. Important is the navigability and controllability of a ship during navigation. Today many ports are using a mud density criterion to determine the depth inside the mud layer to where the navigability and controllability of a ship is guaranteed. This is based on the PIANC 1997 report.

Many waterway authorities are using a 1.200 or 1.250 T/m ³ criterion to identify the level inside the mud layer where the nautical bottom is set as depicted in Figure 11. In Figure 12 a density profile for a waterway as can be obtained with embodiments of the present invention is shown. Another application is the determination of the gel point of the sediment in preparation of WID (water injection dredging). WID is often used to liquefy sediment and remove it under a gravity flow. There are two important aspects that need to be visualized in order to determine what the dredging effort will be to mobilize the sediment layer. First the density of the sediment layer is of importance to understand how much water needs to be added to liquefy the sediment or to make it loose. Typically a water sediment emulsion with a density of 1.100 T/m3 is needed to reach the gel point or the level where the sediment can start to flow. Once this point is reached the sediment can flow under gravity to a lower point or under influence of a tidal flow in a certain direction. A second important parameter to control WID works is the dredging effort of the water jet to erode the sediment layer. The water jet needs to overcome the binding strength of the sediment in order to loosen it up and to break up the binding forces of the sediment. Mud erosion resistance and binding strength are related. This type of parameters can be determined not with a density meter but with a rheology meter. As an in situ rheology meter, a free fall penetrometer can be used. Figure 13 illustrates water injection liquefaction of mud wherein arrow 1302 indicates the liquefied mud, arrow 1304 indicates the consolidated mud and arrow 1306 indicates the top of the mud under water.

In one aspect, the present invention also relates to a method and system for determining density profile information regarding a sediment or dredged material, the system comprises an x-ray radiation source system for emitting x-rays, an x-ray detector system for detecting x- rays, whereby the x-ray radiation source system and the x-ray detector system are configured for allowing an elongated volume of sediment or dredged material to pass in between the x- ray radiation source system and the x-ray detector system so as to obtain density profile information. The elongated volume of sediment or dredged material can be moved manually or in automated manner in between the x-ray radiation source system and the x-ray detector system so that at a plurality of positions or continuously along the length of the elongated volume of sediment or dredged material data can be recorded. Such an automated movement can for example be obtained using a movement system. The x-ray radiation source system may comprise a single radiation source or a plurality of radiation sources and the x-ray detector system may comprise one or more x-ray detectors. In embodiments of the present invention, the x-ray radiation source and the x-ray detector system may be substantially stationary, while the elongated volume of sediment or dredged material is moving.

The corresponding method may comprise in a first step obtaining an elongated volume of sediment or dredged material. By way of illustration, embodiments of the present invention not being limited thereto, an exemplary system for probing an elongated volume of sediment or dredged material is shown in Figure 14. The method further comprises shifting the elongated volume of sediment or dredged material in between an x-ray source system and the x-ray detector system for determining x-ray profile data along the length of the elongated volume. Figure 15 illustrates how such an elongated volume of sediment 1502 can pass (shift) in between the x-ray source and x-ray detector 1504. The x-ray source and x-ray detector may be positioned in a shielded enclosure 1506. The movement of the volume is illustrated in snapshots for three moments in time. In Figure 16 the analysis results are shown. If the elongated volume is not shifted at a fixed shifting rate, a calibration system may be provided for correlating x-ray data with the position information where the x-ray data is recorded. Such a calibration system may be an optical strip provided on the elongated volume. The calibration system can for example be determined with an optical detection or an inspection camera.