Pattern overlay for X-ray microscope sample camera

Abstract

A user interface presented on a display of a microscope system includes a sample motion control for moving an object stage subsystem and an image area in which image data from a camera is displayed together with a graphical overlay provided by the sample motion control indicating different directions of motion. The superimposition preferably provides a dynamic coordinate system graph that highlights the coordinate axes of the 3-axis stage of the object stage subsystem. When the user hovers on a different motion controller, the graphics may provide additional information, such as direction of motion, to help the user know the direction of motion prior to clicking the application.

Description

[0001] Related applications

[0002] This application claims the benefit under 35 USC 119(e) of U.S. Provisional Application No. 63 / 487,067, filed February 27, 2023, the entire contents of which are incorporated herein by reference. Background Art

[0003] X-ray microscopy (XRM) is a powerful imaging technique used to analyze internal structures at the micrometer to nanometer scale. XRM systems provide high-resolution images or projections of a sample, allowing its properties to be studied in detail. XRM systems illuminate the sample with a beam of X-rays and then use a detector to image the sample.

[0004] X-ray computed tomography (CT) is a non-destructive technique used to examine and analyze the internal structure of a sample. When a sample is scanned at different angles, a tomographic volume dataset is reconstructed from a series of these projections via standard CT reconstruction algorithms.

[0005] X-ray CT systems come in many different configurations. In X-ray microscopy systems, because the X-ray source and detector are large and the sample or object being scanned is typically small, the X-ray source or detector is largely stationary while the sample rotates in the X-ray beam.

[0006] In many cases, the sample scanned in an X-ray microscopy system has a shape that is unknown a priori. For example, even in cases where a CAD model is available or the object comes from a rock core sample of known dimensions, the precise alignment of the sample is often unknown. Furthermore, the alignment may change when different regions of interest are selected and the object is realigned in the beam path. It is also often necessary to move the sample completely out of the beam path, for example to obtain baseline performance information about the X-ray source and detector subsystem, or to take reference images. This leads to the problem that the sample may collide with the scanning device (the part of the X-ray source or detector closest to the sample) when the sample is moved (primarily rotated) for scanning or out of the beam path, loaded or unloaded. The challenge of avoiding collisions is often made more difficult by the fact that the X-ray source and / or detector need to be moved close to the sample to obtain optimal system performance.

[0007] Similar setups exist for other microscope / tomography systems operating in other regions of the electromagnetic spectrum, such as optical coherence tomography and confocal microscopy (optical projection tomography). Still other examples include scanning electron microscopes (SEMs) and focused ion beam (FIB) systems (i.e., charged particle imaging systems). Summary of the Invention

[0008] In a typical setup, an object stage subsystem is provided that can position and rotate the sample in the system's beam path. Typically, the object stage subsystem has a 3-axis stage consisting of an x-axis stage, a y-axis stage, and a z-axis stage. This allows the sample's region of interest to be located within the beam path. The 3-axis stage is in turn mounted on a theta stage, which rotates the sample in the beam path. This setup allows the sample to be rotated in the system's reference frame so that it can be scanned at different angles for tomographic reconstruction.

[0009] Manual control of a 3-axis stage is challenging because it is rotated by the theta stage. The orientations of the x- and z-axis stages are functions of the angle of the theta stage. In other words, the coordinate axes, or reference frame, of the 3-axis stage change relative to the system's reference frame as a function of the angular position of the theta stage. Consequently, it is often difficult for users to intuitively understand the relationship between the system's and the user's reference frames and the 3-axis stage's coordinate axes.

[0010] This invention involves the ability to overlay a dynamic coordinate system graphic onto a live image of a sample. This graphic highlights the coordinate axes of the 3-axis stage. Furthermore, when the user hovers over different motion controllers, the graphic can provide additional information, such as the direction of motion, to help the user understand the direction of motion before clicking on an application.

[0011] In general, according to one aspect, the present invention features a user interface presented on a display of a microscope system. The system includes a specimen camera for capturing images of a specimen loaded into an object stage subsystem of the microscope system and a computer for processing image data from the camera. The user interface includes specimen motion controls for moving the object stage subsystem and an image area in which the image data from the camera is displayed along with a graphical overlay indicating different motion directions provided by the specimen motion controls.

[0012] In the current example, the sample motion controls include controls for a 3-axis stage of the object stage subsystem, and the graphic overlay includes the orientation of the 3-axis stage.

[0013] Additionally, the sample motion controls include controls for the theta stage of the object stage subsystem, and the graphic overlay includes the orientation of the theta stage.

[0014] Preferably, the graphical overlay is updated as the user hovers over different controls in the sample motion controls.

[0015] In general, according to one aspect, the present invention features an X-ray microscope system. The system includes an X-ray source subsystem for generating X-rays and an object stage subsystem for holding a sample in the X-ray microscope. A detector subsystem detects the X-rays after interacting with the sample, and a sample camera captures images or projections of the sample loaded into the object stage subsystem. A computer receives and processes the projections from the detector subsystem and generates a user interface. The generated interface includes sample motion controls for moving the object stage subsystem and an image area in which image data from the camera is displayed along with a graphical overlay indicating different motion directions provided by the sample motion controls.

[0016] The above and other features of the present invention, including various novel construction details and combinations of parts, as well as other advantages, will now be described in more detail with reference to the accompanying drawings, and pointed out in the claims. It should be understood that the specific methods and devices embodying the present invention are shown by way of illustration and not as limitations of the present invention. The principles and features of the present invention may be employed in various and numerous embodiments without departing from the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In the accompanying drawings, reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale; emphasis is instead placed upon illustrating the principles of the invention. In the drawings:

[0018] Figure 1 is a schematic diagram of an x-ray microscope system employing the present invention in one embodiment;

[0019] Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 6A 、 Figure 6B and Figure 6C The user interface generated by the system is shown. DETAILED DESCRIPTION

[0020] The present invention will be described more fully below with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. However, the present invention may be embodied in many different forms and should not be construed as limited to the embodiments described herein; rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those skilled in the art.

[0021] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. Furthermore, unless expressly stated otherwise, the singular forms and the articles "a," "an," and "the" also include the plural forms. It should be further understood that the terms: includes, comprises, including, and / or comprising, when used in this specification, specify the presence of the features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. Furthermore, it should be understood that when an element comprising a component or subsystem is referred to as and / or shown as being connected or coupled to another element, it may be directly connected or coupled to the other element, or there may be intervening elements.

[0022] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It should also be understood that terms (such as those defined in commonly used dictionaries) should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly defined herein.

[0023] Figure 1 is a schematic diagram of an XRM system 200 to which the present invention is applicable.

[0024] The microscope system 200 shown is an X-ray CT system that typically includes several subsystems. An X-ray source subsystem 102 generates a polychromatic or possibly monochromatic X-ray beam 103. An object stage subsystem 110, having an object holder 112, holds a sample or object 114 in the beam and positions and repositions it so that the sample 114 can be scanned in the stationary beams 103, 105. A detector subsystem 118 detects the beam 105 after it has been modulated by the sample. A base, such as a platform or optical table 107, provides a stable foundation for the microscope system 200 and its subsystems.

[0025] Generally speaking, the object stage subsystem 110 has the ability to position and rotate the sample 114 within the beam 103. Therefore, the object stage subsystem 110 typically includes a linear stage and a rotational stage. The illustrated example features a precision 3-axis stage 150 that very precisely translates and positions the sample along the x, y, and z axes, but within a relatively small range of travel. This allows the region of interest of the object 114 to be located within the beams 103 / 105. The 3-axis stage 150 is mounted on a theta stage 152, which rotates the 3-axis stage 150, thereby rotating the sample 114 within the beam about the y-axis. The theta stage 152 is, in turn, mounted on the base 107.

[0026] Thus, the reference frame or coordinate system of the 3-axis stage 150 is related to the reference frame or coordinate system 10 of the microscope system 200 through the angular position of the θ stage 152 .

[0027] In some embodiments, source subsystem 102 is typically a synchrotron x-ray radiation source, or a "laboratory x-ray source."

[0028] As used herein, "laboratory x-ray source" refers to any suitable x-ray source that is not a synchrotron x-ray radiation source. Laboratory x-ray source 102 may be an x-ray tube in which electrons are accelerated by an electric field in a vacuum and injected into a metal target, emitting x-rays as the electrons decelerate in the metal. Typically, depending on the type of metal target used, such a source produces a continuous background x-ray spectrum with intensity spikes at specific energies that originate from the characteristic lines of the selected target.

[0029] In one example, source subsystem 102 is a rotating anode or microfocus source with a tungsten target. Target materials including molybdenum, gold, platinum, silver, or copper may also be used. Preferably, a transmission target configuration is used, in which the electron beam strikes a thin target from the back side. X-rays emitted from the other side of the target are used as beam 103.

[0030] The x-ray beam generated by the source subsystem 102 is typically conditioned to suppress unwanted wavelengths or energies of radiation. For example, energy filters, such as those in the filter wheel 160, designed to select a desired x-ray energy range (bandwidth), are used to eliminate or attenuate the presence of undesirable wavelengths in the beam. These energy filters typically include an "air" filter, which corresponds to no filter, and a set of low-energy filters for filtering low-energy x-rays and high-energy filters for filtering high-energy x-rays.

[0031] When object 114 is exposed to X-ray beam 103, X-ray photons or particles propagating through sample 114 form modulated beam 105, which is received by detector subsystem 118. In some other examples, an objective lens is used to form an image on detector subsystem 118 of microscope system 200.

[0032] Typically, a magnified projected image of the object 114 is formed on the detector subsystem 118. The magnification of the x-ray stage is equal to the inverse of the source-to-object distance 202 and the source-to-detector distance 204.

[0033] To achieve high resolution, embodiments of the x-ray CT system 200 also utilize a very high resolution detector 124-1 of the detector subsystem 118 and position the sample 114 close to the x-ray source system 102. In one embodiment of the high resolution detector 124-1, a scintillator is used in conjunction with a microscope objective to provide additional optical magnification in the range of 2x to 100x or greater. The scintillator converts x-rays into an optical image that can be detected by a camera.

[0034] Other detectors are typically included as part of the detector subsystem 118. For example, the detector subsystem 118 may include a lower resolution detector 124-2. In some examples, this may be a flat panel detector and camera, or a detector with a lower magnification microscope objective. Configurations of the detector subsystem 118 with one, two, or even more detectors 124 are possible.

[0035] Preferably, two or more detectors 124 - 1 , 124 - 2 are mounted on a turntable 122 of the detector subsystem 118 so that they can be alternately rotated into the path of the modulated light beam 105 from the sample 114 .

[0036] Typically, the source subsystem 102 and the detector subsystem 118 are mounted on respective z-axis stages. For example, in the illustrated example, the source subsystem 102 is mounted to the base 107 via a source stage 154, and the detector subsystem 118 is mounted to the base 107 via a detector stage 156. In practice, the source stage 154 and the detector stage 156 are low-precision, high-travel-range stages that allow the source subsystem 102 and the detector subsystem 118 to be moved to a position generally very close to the object during scanning, and then retracted to allow the object to be removed from the object holder 112 of the object stage subsystem 110, to load a new object on the object holder 112 of the object stage subsystem 110, and / or to reposition the object on the object holder 112 of the object stage subsystem 110.

[0037] The microscope system 200 includes an optical camera 210 (e.g., a video camera) that collects image data of a sample 114 held in an object holder 112. The camera is typically mounted directly or indirectly to the system base 107 via a mounting system 215 (e.g., a bracket). Typically, the optical camera 210 collects images in the visible portion of the spectrum and / or in adjacent spectral regions (e.g., the infrared spectrum). Typically, the optical camera 210 includes a CCD or CMOS image sensor. Also included is a light source 212 that illuminates the object in the spectral region used by the optical camera.

[0038] The operation of the microscope system 200 and the scanning of the object 114 are controlled by a computer subsystem 224 which generally includes an image processor 220 and a controller 222 .

[0039] The computer system 224 includes one or more processors 260 and its data storage resources (such as disks or solid-state drives, and memory MEM). The processor 260 executes an operating system 262 and runs various applications on the operating system 262 to allow the user to control and operate the microscope system 200. In particular, a user interface application 250 executes on the operating system 262 and generates a user interface that is presented on a display device 236 connected to the computer subsystem 224. The user interface enables the operator to control the system and observe projections, images, and tomographic reconstructions. A user input device 235 (such as a touch screen, computer mouse, and / or keyboard) enables interaction between the operator and the computer subsystem 124. A graphics overlay application 252 adds graphical information to the image data from the camera 210 for display on the display device 236.

[0040] The controller 222 allows the computer subsystem 224 to control and manage the components in the X-ray CT microscope 200 under software control. The controller can be a separate computer system suitable for handling real-time operations or an application executed on the processor 260. The source subsystem 102 includes a control interface 130 that allows the controller 222 to control and monitor it. Similarly, the object stage subsystem 110 and the detector subsystem 118 have respective control interfaces 132, 134 that allow the computer subsystem 224 to control and monitor them via the controller 222.

[0041] To configure the microscope system 200 to scan a sample and adjust other parameters (e.g., geometric magnification), the operator utilizes the user interface presented on the display device 236 and the user interface generated by the user interface application 250 to operate the source stage 154 and the detector stage 156, respectively, to adjust the source-to-object distance 202 and the source-to-detector distance 204 to achieve the desired scanning settings.

[0042] Specifically, the source stage 154 and the detector stage 156 include respective motor-encoder systems or other actuator systems that allow the computer system 224, via the controller 222, to position the respective x-ray source subsystem 102 and detector subsystem 118 to specified positions via the control interfaces 130, 134. In addition, the source stage 154 and the detector stage 156 signal their actual positions to the controller 222.

[0043] An operator of the system under automatic control operates the object stage subsystem 110 to perform a CT scan via the computer subsystem, controller 222, and control interfaces 130, 132, 134. Typically, the object stage subsystem 110 positions an object by rotating the object about an axis orthogonal to the optical axis of the x-ray beams 103, 105 by controlling the theta stage 152 and / or positions a sample in the x, y, and z directions using the stage 150.

[0044] Using a user interface presented by user interface application 250 on display device 236, the operator defines / selects scan settings, including acquisition parameters, via UI device 235. These acquisition parameters include x-ray source voltage settings, which help determine the x-ray energy spectrum and exposure time, as well as the number of frames on the x-ray source subsystem 102. The operator also typically selects other settings, such as the field of view of the x-ray beam 103 incident on the sample 114, the number of x-ray projection images created for the sample 114, and the selected detectors 124-1 and 124-2. Typically, acquisition parameters include x-ray source voltage, x-ray source filtering, camera exposure time, number of frames, and total number of projections, and scan settings include the angle by which the object stage subsystem 110 rotates the sample. Additionally, the source-to-object distance 202 and the source-to-detector distance 204 are typically specified, and these distances are converted to the necessary positions or settings for the source stage 154 and detector stage 156 as part of the scan settings.

[0045] operate:

[0046] Figure 2 A user interface 500 is shown generated by a user interface application 250 executing on an operating system 262 of a computer system 224 and presented on a display device 236 .

[0047] In the illustrated mode, the user interface 500 includes an optical camera pane 318. This shows the current image data received from the optical camera 210 and any graphics overlays generated by the graphics overlay application 252.

[0048] To the left of the optical camera pane 318 is the source Z stage control area 338. This area includes a step size indicator that indicates the step size the source stage 154 will move in response to each user input. It also includes a current position display. It also includes a user data entry line that allows the user to enter the desired absolute position for the source stage 154, as well as a "Go" button.

[0049] To the right of the optical camera pane 318 is a similar detector control area 340 for the detector stage 156, which provides Z-axis control functionality. Here, it again includes a step size indicator that indicates the step size the source stage will move. It also includes a current position display. Finally, the user can enter the desired absolute position.

[0050] The sample motion controls are located at the bottom of the window. The sample x position control area 330 controls the x-axis stage of the 3-axis stage 150 to move the object holder 112 along the x-axis, thereby moving the sample or object 114 along the x-axis. The sample y position control area 332 controls the y-axis stage of the 3-axis stage 150 to achieve movement along the y-axis. The sample z position control area 334 controls the z-axis stage of the 3-axis stage 150 to achieve movement along the z-axis. The sample theta control area 336 controls the theta stage 152 to rotate the object holder 112 and the 3-axis stage 150, thereby rotating the sample or object 114.

[0051] Each of the control areas 330, 332, 334, and 336 includes a separate step size indicator 392. In this context, the user can enter a desired step size using the user interface device. Also included are forward and backward movement controls 394 that allow for the reduction or increase of the associated stage. These also include a pause button for stopping the movement of the corresponding stage. The current position of the corresponding stage is indicated by an absolute position indicator 398. Finally, the user can move to a desired absolute position by entering the desired position in the data entry line 396 using the user interface device 235 and then selecting the associated "Go" button 395.

[0052] In addition, the user interface includes a coordinate overlay 380, which is a set of graphical indicators overlaid on the image data from the camera 210 and presented by the graphic overlay application 252 in the optical camera pane 318. This overlay indicates the relative orientation of the various axes of the 3-axis stage 150 within the reference frames of the system 200 and the user. This is important information because each of the Z and X axes of the 3-axis stage 150 depends on the current angular position of the theta stage 152.

[0053] Coordinate overlay 380 is useful because an operator cannot typically view the specimen 114 in the image data from the optical camera pane 210 and know which direction the X and Z axes of the 3-axis stage 150 are pointing unless they also know the current angle of the theta stage and mentally apply the transformation between the coordinate systems of that system to the coordinate system of the 3-axis stage 150. This information is now provided by coordinate overlay 380.

[0054] More specifically, for the Z-axis of the 3-axis stage 150, coordinate overlay 380 includes a negative Z-axis indicator 382 and a positive Z-axis indicator 383. Similarly, coordinate overlay 380 also includes a negative X-axis indicator 384 and a positive X-axis indicator 385. Finally, coordinate overlay 380 also includes a negative Y-axis indicator 386 and a positive Y-axis indicator 387. However, it should be noted that the direction of the Y-axis does not depend on the angle of the theta stage. Finally, there is a theta indicator 388 that indicates the two rotational directions of the theta stage 152.

[0055] Furthermore, in a preferred embodiment, coordinate overlay 380 is dynamic. In the example shown, the user has manipulated mouse pointer 390 using user interface device 235 so that it is positioned within the region of Y-axis control 332. Consequently, the corresponding axis indicators in coordinate overlay 380 are indicated by graphics overlay application 252, which updates overlay 380 based on the mouse position information generated by user interface application 250. In the current example, mouse pointer 390 is positioned within Y-axis stage region 332. Consequently, negative Y-axis indicator 386 and positive Y-axis indicator 387 change color or are indicated in other ways (such as by changing size, blinking, or other common methods).

[0056] As another example, if the user moves the mouse pointer 390 so that it is within the Z-axis control area 334, the graphics overlay application 252 will update the overlay 380 based on the mouse position information generated by the user interface application 250. Specifically, the negative Z-axis indicator 382 and the positive Z-axis indicator 383 will change color or indicate otherwise. At the same time, the Y-axis indicators 386 and 387 will return to their normal color or state.

[0057] Furthermore, the coordinate overlay 380 is dynamic to indicate the direction of movement that the user is currently commanding. Figure 3As shown. In this example, mouse pointer 390 is hovering over the negative direction arrow in movement control 394 of X-axis control area 330. As a result, coordinate overlay 380 is modified by graphical overlay application 252 so that negative X-axis indicator 384 is now indicated by a different color. Similarly, when the user manipulates UI device 235 to move the mouse pointer over any arrow control in control areas 330, 332, 334, and 336, the corresponding arrow or arrows of coordinate overlay 380 are graphically indicated or highlighted.

[0058] Figure 4 and Figure 5 It further illustrates how the graphics overlay application 252 updates the coordinate overlay 380 based on the state and angle of the θ stage 152. Specifically, Figure 4 As shown, when the θ stage is at a -90 degree angle, the negative X axis extends to the left and the positive X axis extends to the right. In contrast, within the reference frame of system 200 and optical camera 210, the negative Z direction is in the rear direction and the positive Z direction is in the front direction.

[0059] in turn, Figure 5 A coordinate overlay 380 is shown when the theta stage 152 is set to -45 degrees.

[0060] Figure 6A 、 6B 6C shows a more detailed view of a portion of the theta control 336. Specifically, it includes a graphical representation 350 of the sample holder 112. Specifically, the graphical representation 350 rotates as the theta stage rotates. Specifically, Figure 6A 、 Figure 6B 、 Figure 6C Shown respectively with Figure 2 、 Figure 3 、 Figure 5 The graphical representation of the stage angle θ corresponds to 350.

[0061] While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made without departing from the scope of the invention as encompassed by the appended claims.

Claims

1. A user interface presented on a display of a microscope system, the microscope system comprising a specimen camera and a computer, the specimen camera being configured to capture images of a specimen loaded into an object stage subsystem of the microscope system, the computer being configured to process image data from the camera, the user interface comprising: a sample motion control for moving the object stage subsystem; as well as An image area in which image data from a camera is displayed along with a graphical overlay indicating different directions of motion provided by the sample motion control.

2. The user interface according to claim 1, wherein The specimen motion controls include controls for a 3-axis stage of the object stage subsystem, and the graphical overlay includes directions for the 3-axis stage.

3. The user interface according to claim 1 , wherein: The specimen motion controls include controls for a theta stage of the object stage subsystem, and the graphical overlay includes directions for the theta stage.

4. The user interface according to any one of claims 1 to 3, wherein: The graphical overlay is updated as the user hovers over different controls in the sample motion controls.

5. The user interface according to any one of claims 1 to 4, wherein: The graphical overlay includes indicators for the three axes of a 3-axis stage of the object stage subsystem.

6. The user interface according to any one of claims 1 to 5, wherein: The graphical overlay includes an indicator for the theta stage of the object stage subsystem.

7. The user interface according to any one of claims 1 to 6, wherein: The graphical overlay includes a graphical representation of a sample holder.

8. The user interface according to claim 7, wherein: The graphical representation rotates as the θ stage rotates.

9. An X-ray microscope system comprising: An X-ray source subsystem, wherein the X-ray source subsystem is used to generate X-rays; an object stage subsystem for holding a sample in the X-ray; a detector subsystem for detecting the X-rays after interacting with the sample; a sample camera for capturing images of samples loaded into the object stage subsystem; as well as a computer for receiving projections from the detector subsystem and generating a user interface comprising sample motion controls for moving the object stage subsystem and an image area in which image data from the camera is displayed along with a graphical overlay provided by the sample motion controls indicating different directions of motion.

10. The system according to claim 9, wherein: The user interface is as described in any one of claims 2-8.

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