Patent Grant
10254436
This application is a National Stage Application of PCT/CA2013/050744, filed 1 Oct. 2013, and which application is incorporated herein by reference. To the extent appropriate, a claim of priority is made to the above disclosed application.
The present invention relates to scanning. More particularly, the present invention relates to a scanning system for scanning an object, as well as to a corresponding method and bracket.
Scanning machines are often used to scan objects. These machines emit a source radiation in the direction of the object being scanned. The reaction of the object with the source radiation produces a signature, which can be read by detectors so as to identify or analyze the object.
The Applicant has filed the following patent applications related to scanning systems and methods: CA 2,574,402 and US 2008/0063140 A1.
The Applicant is also aware of the following prior art: U.S. Pat. No. 6,018,562 A, and U.S. Pat. No. 6,218,943 B1.
Hence, in light of the aforementioned, there is a need for a device which, by virtue of its design and components, would be able to overcome or at least minimize some of the drawbacks of the prior art.
One object of the present invention is to provide a solution to at least one of the above-mentioned prior art drawbacks.
In accordance with an aspect of the present invention, there is provided a scanning system for scanning an object comprising:
a frame having a scanning chamber for receiving the object, the scanning chamber having opposed side surfaces and a third surface extending between the side surfaces;
a displacement assembly engageable with the scanning chamber, the displacement assembly configured for receiving the object and displacing the object into the scanning chamber;
a source mountable to the frame about the scanning chamber, the source configured for emitting electromagnetic radiation against the object in the scanning chamber so that the electromagnetic radiation impacts and passes through the object; and
a plurality of detectors mounted to the frame at least partially about the scanning chamber, each detector being inclined at a detector angle, the detector angle of at least one of the detectors having a different value than the detector angle of an adjacent detector, each detector configured for detecting the electromagnetic radiation passed through the object, thereby scanning the object.
In some embodiments, the source is inclined relative to a horizontal, such as about 20° relative to the horizontal. The source can be mounted to the frame below the displacement assembly, or above the displacement assembly. The source may be configured for emitting electromagnetic radiation from a focal point as a beam having beam boundaries, the beam boundaries being separated by an angular interval of about 80°.
In some embodiments, each detector has a detector card having a centre point and edges. Each detector may be inclined at a corresponding detector angle such that the centre point of each detector card is substantially perpendicular to the focal point. Further optionally, each detector card is inclined at a corresponding detector angle such that the edges of each detector card engage at least one of the third surface and the side surfaces of the scanning chamber.
In some embodiments, the plurality of detectors can include two rows of detectors mounted to the frame, the first row of detectors being disposed adjacent to one of the side surfaces of the scanning chamber, and the second row of detectors being disposed adjacent to the third surface of the scanning chamber. The first and second rows of detectors may form an angle with respect to a horizontal between about 89° and about 45°, or between about 80° and about 70°.
In accordance with another general aspect of the invention, there is provided a bracket for a scanning system for scanning an object, comprising:
a bracket frame mountable to the scanning system, the bracket frame being inclined relative to a horizontal;
a source for emitting electromagnetic radiation through the object, the source mountable to the bracket frame; and
a plurality of detectors mountable to the bracket frame, each detector being inclined at a detector angle, the detector angle of at least one of the detectors having a different value than the detector angle of an adjacent detector, each detector configured for detecting the electromagnetic radiation passed through the object, thereby scanning the object.
In accordance with yet another general aspect of the invention, there is provided a method of generating a three-dimensional image of a scanned object, comprising the steps of:
receiving, at an input port, image data of an object, having been captured via a plurality of detectors disposed at least partially about the object, at least two adjacent ones of the detectors being angled one with respect to the other;
by means of a processor, generating from the image data, an image representing a perspective view of the object; and
storing said image into a storage for presenting on a display, a three-dimensional representation of the object.
In some embodiments, the generating comprises juxtaposing into a row, the image data received from adjacent detectors. In some embodiments, the image data received comprises image captures of segments of the object, and the juxtaposing step is repeated for each one of the segments, the generating step further comprising concatenating the rows.
In some embodiments, the method further comprises normalizing the image of the object, by means of a normalizing module integrated in the processor. The normalizing may comprises at least one of: correcting an offset for a given pixel of the image data in relation to an offset reference, and correcting a gain for a given pixel of the image data in relation to a gain reference.
In some embodiments, the image data received comprises low energy absorption data and high energy absorption data for each of one or more pixel of the image data. The method may further comprise fusing the low energy absorption data and high energy absorption data for one or more pixel of the image of the object, by means of a fusion module integrated in the processor.
In some embodiments, the method further comprises calculating, by means of a calculator integrated in the processor, an atomic number for one or more pixel of the image data. The calculating may comprise:
receiving said low energy absorption data and high energy absorption data;
receiving a signal level of a source emission detected by the detectors; and
referencing, via reference data stored in the storage, an atomic number to the combination of the low energy absorption data, the high energy absorption data and the signal level of the source emission.
In some embodiments, the method further comprises sharpening the image of the object. The sharpening may include convoluting the image data to enhance portions of the image representing edges of the object.
In accordance with yet another general aspect of the invention, there is provided a data storage (preferably non-transitional) comprising data and instructions for execution by a processor to generate a three-dimensional image of a scanned object, said data and instructions comprising:
code means for receiving image data of an object, having been captured via a plurality of detectors disposed at least partially about the object, at least two adjacent ones of the detectors being angled one with respect to the other;
code means for generating from the image data, an image representing a perspective view of the object; and
code means for storing said image into a storage for presenting on a display, a three-dimensional representation of the object.
In accordance with yet another general aspect of the invention, there is provided a system for generating a three-dimensional image of a scanned object, comprising:
an input port for receiving image data of an object, having been captured via a plurality of detectors disposed at least partially about the object and in an angled configuration, wherein at least two adjacent ones of the detectors are angled one with respect to the other;
a processor for generating from the image data, an image representing a perspective view of the object; and
a storage for presenting the image on a display as a three-dimensional representation of the object.
In accordance with still another general aspect of the invention, there is provided a scanning system for scanning an object, comprising:
a radiation source for emitting electromagnetic radiation toward an object to be scanned; and
a plurality of detectors disposed at least partially about a scanning area, each detector being mounted substantially perpendicularly in relation to the radiation source for capturing the radiation traversing the object from different angles and thereby scanning the object according to a perspective view.
The components, advantages and other features of the system and corresponding method and bracket will become more apparent upon reading of the following non-restrictive description of some optional configurations, given for the purpose of exemplification only, with reference to the accompanying drawings.
In the following description, the same numerical references refer to similar elements. Furthermore, for the sake of simplicity and clarity, namely so as to not unduly burden the figures with several references numbers, not all figures contain references to all the components and features, and references to some components and features may be found in only one figure, and components and features of the present invention illustrated in other figures can be easily inferred therefrom. The embodiments, geometrical configurations, materials mentioned and/or dimensions shown in the figures are optional, and are given for exemplification purposes only.
Furthermore, although the present invention may be used for scanning objects, such as for threat detection or imaging, and as a result, is sometimes described in the context of a possible use for detecting dangerous objects and/or producing 3D images, it is understood that it may be used for other purposes, and in other fields and/or activities. For this reason, expressions such as “scan”, “threat detection”, “dangerous object”, “chemical”, “imaging”, “3D”, etc. as used herein should not be taken as to limit the scope of the present invention to the detection of threats or the production of 3D images in particular. These expressions encompass all other kinds of materials, objects and/or purposes with which the present invention could be used and may be useful, as can be easily understood.
Broadly described, the present invention provides a system, method, and bracket which can improve the process for scanning and detecting an object so as to generate a 3D image of said object, as but one possible example of a use of the invention.
According to a general aspect, there is provided a system 10 for scanning an object 12, an example of which is shown in
The system 10 has a frame 50, an example of which is also shown in
The frame 50 has a scanning chamber 54, an example of which is shown in
In one possible embodiment, the scanning chamber 54 can be a drawer into which the object 12 can be placed so as to be scanned. The drawer scanning chamber 54 can have two vertical side surfaces 56 supported and connected together by a bottom horizontal third surface 58 upon which the object 12 can rest. In another possible embodiment, the scanning chamber 54 can consist of a relatively large framework into which vehicles and other large devices can be placed. This framework scanning chamber 54 can have two vertical side surfaces 56 connected together by a top horizontal third surface 58, thus defining a passage through which the object 12 can be displaced. Such a framework scanning chamber 54 can advantageously be used to scan cargo containers and other similar large objects.
In yet another possible embodiment, an example of which is shown in the figures, the scanning chamber 54 is a tunnel 55. The tunnel 55 can have an opening at each of its ends, thus defining a passage or channel which extends through some, or all, of the frame 50. The dimensions of the tunnel 55 can vary depending upon a number of factors, such as the following non-limitative list: the nature and shape of objects 12 to be scanned, the cost of implementation of the system 10, and the space available for the system 10. Although shown as substantially box-like, the tunnel 55 can be non-linear, winding, or take other configurations which permit it to receive the object 12 to be scanned.
The system 10 also has a displacement assembly 20, an example of which is shown in
Indeed, in the optional embodiment where the scanning chamber 54 is a drawer, the displacement assembly 20 can be a mechanism which engages the drawer scanning chamber 54 from the exterior of the drawer scanning chamber 54 so as to open and close the drawer scanning chamber 54. In the optional embodiment where the scanning chamber 54 is a framework, the displacement assembly 20 can be a vehicle or other similar mover of the object 12 so as to engage the framework scanning chamber 54 by moving the object 12 into the passage defined by the framework scanning chamber 54. In the optional embodiment where the scanning chamber 54 is a tunnel 55, the displacement assembly 20 can be a conveyor 22 or conveyor belt. The conveyor 22 engages the scanning chamber 54, which can be a tunnel 55, by extending through the scanning chamber 54 so as to convey the object 12 through the scanning chamber 54.
In any of its configurations, the displacement assembly 20 can stop, accelerate, decelerate, or otherwise control the displacement of the object 12, and its direction, within or through the scanning chamber 54. Such functionality advantageously allows for the object 12 to be rescanned or further analysed, if desired. Furthermore, and in light of the preceding description of some of its optional embodiments, it can be appreciated that the displacement assembly 20 can take many different configurations, and engage the scanning chamber 54 in many different ways.
The system 10 also has a source 30, an example of which is also shown in
The source 30 is “mountable to the frame about the scanning chamber”, which means that it can fixedly or removably attached to the frame 50 in proximity to the scanning chamber 54. The source 30 can also mounted to the frame 30 so that it can rotate, pivot, or be displaced around the object 12, which can remain in a fixed position. The actual location and position of the source 30 can depend on the configuration of the scanning chamber 54 and the displacement assembly 20, among other possible factors. In some embodiments, the source 30 can be mounted to the frame 50 at a location below the displacement assembly 20, as shown in
The source 30 can have many different configurations. In one possible embodiment, an example of which is shown in
In some embodiments, an example of which is shown in
In some embodiments, the source 30 can emit EM radiation or X-rays from a focal point 38 as a beam 39. The beam 39 can be any fan or cone beam having an angular width as it is emitted from the focal point 38. The angular width of the beam 39 observed from one direction may be different from the angular width of the same beam 39 observed from another direction. This can be better appreciated by comparing the example of the beam 39 as shown in
The system 10 also has a plurality of detectors 40, examples of which are shown in
In some embodiments, each detector 40 includes a detector card 42 which has a centre point 44 and edges 46. The detector card 42 can be any suitable detector card 42 such as those manufactured by Detection Technologies Ltd., United Kingdom. Each of these detector cards 42 can have a centre point 44, which corresponds to the geographical centre of the detector cards 42. The edges 46 of each detector card 42 define its boundaries. The detectors 40 and/or the system 10 can be linked to a central processing Unit (CPU) 100 (see
According to an embodiment described and illustrated herein, each detector 40 comprises a first scintillator 80, a filter 82, and a second scintillator 84, all of which are sandwiched together, as is schematically represented in
Each detector 40 is inclined at a detector angle D. In most embodiments, but not necessarily all, the detector angle D is defined with respect to a horizontal plane. The detector angle D of one or more of the detectors 40 is different than the detector angle D of an adjacent detector 40. For example, this can mean that the detector angle D of at least one detector 40 is different than the detector angle D of all the other detectors 40. This can also mean that each detector 40 has a detector angle D that is different from the detector angles D of its neighbouring detectors 40. The term “adjacent” in this context refers to neighbouring detectors 40, whether they are located directly next to, or nearby, the at least one detector 40 having a different detector angle D. The determination of the detector angle D for each detector 40 can depend upon numerous factors such as, but not limited to: the angle of the source 30 relative to the horizontal, the position of the source 30 relative to the scanning chamber 54, the position of the centre point 44 of each detector card 42 relative to the source 30, etc.
In some embodiments, the detector angle D of each detector card 42 may optionally be determined by satisfying the following two requirements: 1) the centre point 44 of each detector card 42 is substantially perpendicular to the focal point 38 of the beam 39, and 2) each detector card 43 is positioned as close as possible to the focal point 38 of the beam 39.
Reference is made to
Returning to
According to another general aspect, there is a provided a bracket 60 for a scanning system, such as the one described above. Referring now to
The image processing of the above-described scanning system will now be better explained, with reference to
In the context of the present description, the term “processor” refers to an electronic circuitry that can execute computer instructions, such as a central processing unit (CPU), a microprocessor, a controller, and/or the like. A plurality of such processors may be provided, according to embodiments of the present invention, as can be understood by a person skilled in the art. The processor may be provided within one or more general purpose computer, for example, and/or any other suitable computing device.
Still in the context of the present description, the term “storage” refers to any computer data storage device or assembly of such devices including, for example: a temporary storage unit such as a random-access memory (RAM) or dynamic RAM; a permanent storage such as a hard disk; an optical storage device, such as a CD or DVD (rewritable or write once/read only); a flash memory; and/or the like. A plurality of such storage devices may be provided, as can be understood by a person skilled in the art.
According to the present embodiment, the X-Ray source 30 emits a continuous spectrum of X-Rays, ranging from a lower energy range such as 10 to 70 kV (+/−) up to higher energy ranges such as 60 to 250 kV (+/−).
It is to be understood that depending on particular embodiments of the present invention, the lower energy range may be as low as 1 kV and the higher energy ranges may be greater that the values given above in relation to the described embodiment.
As the object 12 is subjected to the X-Rays, the detectors 40 capture the X-Ray energy that traverses the object 12. As previously mentioned, the first scintillator 80 detects a lower portion of an X-Ray signal, while the second scintillator 84 detects a higher portion of the X-Ray signal. The high energy range penetrates more easily through denser materials, while the low energy range provides better contrast for image portions corresponding to lighter materials.
Broadly, each of the scintillators 80, 82 converts the X-Ray energy to light. A photo-diode 86 then captures the light and generates a corresponding electric signal. The electric signal is further digitized by a converter 88. The digitized value is associated to a pixel of the image which represents the object.
In the present embodiment, the detectors' physical arrangement in the scanner system determines the arrangement of the raw data extracted therefrom. More particularly, according to the embodiment illustrated herein, detectors 40 are aligned in a row, positioned as previously mentioned, along an “L”-shaped configuration, as schematically represented in
As the object 12 moves through the scanning chamber 54, the detectors perform scan captures sequentially at a given rate, which may depend on their integration time, i.e. exposure time. Thus several of said “rows” of data are acquired in a given scanning process. The rows are juxtaposed as schematically represented in
In
As previously mentioned, the X-Ray energy is translated into a digitized value, for each pixel, via the scintillators 80, 82, the photo-diodes 86 and the converter 88. In the conversion by the photo-diodes 86 of the light into an electric signal, some error may occur, in that a given light source may result in different electrical signals due to the fact that every detector card behave slightly differently to the presence or absence of X-Ray signal.
Thus, in order to correct these variations and for the final image to appear more homogeneously, a normalization module 102, by means of the CPU 100, normalizes (or “calibrates”) each pixel of the low and high energy captures, by correcting an offset and a gain in the light conversion.
The offset is determined based on the signal perceived by the scintillators of the detectors when no source is emitted. When no source is emitted, as represented by the dark band 97 appearing in
After removing the offset, there are still variations in the capture of each detector when fully exposed to the source emission, as represented by the light band 98 appearing in
The high and low energy information is then fused, at an image fusion module 104, by means of the CPU 100. More particularly, each pixel of the image results from a combination of high energy data in some proportion and low energy data in some proportion. Depending on the density of the material detected, it may be desirable to emphasize the low energy information or the high energy information in suitable proportion. Indeed, as previously mentioned, the high energy range penetrates more easily through denser materials, while the low energy range provides better contrast for image portions corresponding to lighter materials. The high and low energy data is thus combined accordingly to better illustrate particular regions of the image. For example, a pixel may be the result of 25% of the high energy data and 75% of the low energy data because it is determined by the X-Ray signal is relatively high, meaning that it is more desirable to see contrast. The proportion of high and low energy is determined based on ranges of low energy data value and/or high energy data value for a particular pixel.
An atomic number is then associated to each pixel of the image, via an atomic number calculation module 106, by means of the CPU 100. More particularly, the atomic number is determined based on the low energy absorption data and high energy absorption data, as well as a signal level of a source emission 30.
In a calibration step, materials having a known atomic number are scanned, in order to correlate each of their particular combination of low and high energy, for a given source signal level, with their atomic number. Based on the correlations made based on the known materials, a set of reference data is generated. The reference data includes combinations of low and high energy (at a given source signal level) and their corresponding atomic number. Thus, for each pixel, the combination of the corresponding low and high energy data, is correlated with a corresponding atomic number.
The image is then sharpened via a filtering module 108, by means of the CPU 100, in order to reduce blurriness when the image is displayed for viewing on a display 110. More particularly, the image data is convoluted to enhance portions of the image representing edges of the object 12.
The resulting image is then store in a database 112, from the basis of which a three-dimensional or perspective representation of the object 12 may be presented on the display 110.
Embodiments of the present invention thus provide the advantage of generating a three-dimensional or perspective representation of the object 12, by virtue of the detectors being positioned at different angles depending on their location in relation to the source emission, and of enhancing detection capabilities, thereby allowing for an operator to better analyze the object 12.
Further advantageously, such a three-dimensional or perspective representation may provide more a revealing image of the object 12 when compared to two-dimensional images generated by traditional scanners. More specifically, such a representation may allow a user to visualize more walls or boundaries of the object 12, and may have fewer “dark spots” corresponding to parts of the object 12 which have planes aligned with the plane of the EM radiation emitted by the source.
It is to be understood that, in accordance with alternate embodiments, the above-described system and method may be adapted to operate with a single energy level of X-Ray signal captured at the detectors, as well as a plurality, i.e. two or more of such energy levels of X-Ray signal (instead of only low energy and high energy, as in the context of the above-described embodiments). Indeed, any suitable ranges of energy levels may be defined and captured by the detectors and further processed, for example to obtain more information on the composition of the object being scanned.
Of course, numerous other modifications could be made to the above-described embodiments without departing from the scope of the invention, as defined in the appended claims.
| Filing Document | Filing Date | Country | Kind |
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| PCT/CA2013/050744 | 10/1/2013 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
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| WO2015/048874 | 4/9/2015 | WO | A |
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