Real-time controller switching

Abstract

The present disclosure relates to real-time controller switching. An imaging system can include: a sample stage having a surface that supports a sample to be scanned by the imaging system; an optical stage having an objective lens, the optical stage being positionable relative to the sample stage; an actuator physically coupled to at least one of the sample stage and the optical stage to move the sample stage relative to the optical stage; a servo circuit that controls the actuator; a first set of control parameters that control the servo circuit; a second set of control parameters that control the servo circuit; and a servo control circuit that applies the first set of control parameters to the servo circuit when the imaging system is operating in a first operating mode and applies the second set of control parameters to the servo circuit when the imaging system is operating in a second operating mode.

Description

[0001] Cross - reference to related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 62 / 617,062, filed on January 12, 2018, and titled "Real Time Controller Switching", and Netherlands Patent Application No. N2020618, filed on March 20, 2018, and titled "Real Time Controller Switching". The entire content of each of the above - mentioned applications is incorporated herein by reference. Background

[0003] Many advancements in the biological field have benefited from improved imaging systems and techniques, such as those used in optical microscopes and image scanning systems. Achieving accurate focusing during imaging with these imaging systems is important for successful imaging operations. The ability to perform high - speed scanning to achieve high imaging quality at high throughput is also important.

[0004] Focusing operations for focus model generation and image scanning often rely on the movement of a sample stage relative to an optical stage such that the sample lies in the focal plane of an objective lens or other optical device in the optical stage. Typically, actuators such as motors, coils, or other drive systems are used to move the optical stage or the sample stage or both to achieve proper focusing. A servo system can be implemented to allow precise control of the actuator.

[0005] Figure 1 An example of a servo system that can be used for actuator control is shown. In this example, a drive signal 3 is provided to the servo system, indicating the desired position of the actuator. Feedback 5 from the controlled process 20 is subtracted from the drive signal 3 to produce an error signal 9 that indicates the error in the actual position deviating from the desired position. The server controller 10 adjusts the signal 7 provided to control the actuator based on the detected amount of error. In this example, the servo system is a proportional - integral - derivative (PID) controller system that includes proportional control 12, integral control 13, and derivative control 14.

[0006] Summary

[0007] The systems and methods disclosed herein can be implemented as an optimized servo control system that is implemented to control an actuator for a focusing operation in an imaging system. Optimization techniques can be implemented so that the current operating mode of the imaging system can be determined during operation of the imaging system. For example, the operating modes can include a focusing model generation mode and an imaging or sequencing mode. In some applications, different sets of operating parameters of the servo control system can be used to optimize the servo control system for different operating modes. Thus, an example implementation can be configured to determine a set of operating parameters that will optimize the servo control system for the determined operating mode and apply the set of operating parameters to the servo system. In various applications, this can be done in real-time while the imaging system is operating and switching between modes. In the case of a change in the operating mode, a new set of operating parameters can be selected and applied to optimize the servo control system for the new operating mode. Additionally, these changes can be made in real-time while the imaging system is operating.

[0008] Some applications of the techniques described herein can include an imaging system that includes: a sample stage that includes a surface for supporting a sample to be scanned by the imaging system; an optical stage having an objective lens that can be positioned relative to the sample stage; an actuator physically coupled to at least one of the sample stage and the optical stage to move the sample stage relative to the optical stage; a servo circuit that controls the actuator; a first set of control parameters for controlling the servo circuit; a second set of control parameters for controlling the servo circuit; and a servo control circuit that applies the first set of control parameters to the servo circuit when the imaging system can operate in a first operating mode and applies the second set of control parameters to the servo circuit when the imaging system can operate in a second operating mode. In some applications, the imaging system can be a sequencer, and the first operating mode can be a focusing model generation mode, and the second operating mode can be a sequencing mode. The control parameters can include servo loop gain and filter value.

[0009] The servo control circuit can also include a mode detection circuit that detects the operating mode of the imaging system and a parameter selection circuit that applies a set of control parameters corresponding to the detected operating mode.

[0010] The servo control circuit can also be implemented to detect the operating mode of the imaging system and select a set of control parameters to apply to the detected operating mode. The servo control circuit can apply the first or second set of control parameters that are identified as the set of control parameters for the detected operating mode.

[0011] At least one of the first and second sets of control parameters can be optimized to account for the structural characteristics of the imaging system. Optimizing at least one of the first and second sets of control parameters can include operating the imaging system, scanning with a range of values of one of the control parameters of one of the first and second sets of control parameters, measuring the stability of the servo circuit during the scan, and selecting a value of the control parameter. Optimizing at least one of the first and second sets of control parameters can include operating the imaging system, scanning with a range of values of a plurality of control parameters of one of the first and second sets of control parameters, measuring the stability of the servo circuit during the scan, and determining an optimal setting of the plurality of control parameters.

[0012] The imaging system can further include a focus tracking circuit electrically coupled to the optical stage; and the servo control circuit can be configured to enable feedback from the focus tracking circuit to the servo circuit when the imaging system is operating in a scan operation mode and to disable feedback from the focus tracking circuit to the servo circuit when the imaging system is operating in a focus model generation operation mode.

[0013] The actuator can be physically coupled to the sample stage to move the sample stage to adjust the distance between the sample stage and the optical stage. Alternatively, the actuator can be physically coupled to the optical stage to move the optical stage to adjust the distance between the sample stage and the optical stage. In another example, the actuator can be coupled to both the sample stage and the optical stage to adjust the distance between the sample stage and the optical stage.

[0014] As another example, a method of servo control of an imaging system can include: during operation of the imaging system, a mode detection circuit determines that the imaging system may be operating in a first operation mode; a servo control circuit determines a first set of control parameters selected for the first operation mode; the servo control circuit applies the determined first set of control parameters to the servo circuit of the imaging system, where the servo circuit controls the operation of an actuator that is physically coupled to at least one of the sample stage and the optical stage of the imaging system to move the sample stage relative to the optical stage; and when the mode detection circuit determines during operation of the imaging system that the imaging system has switched to operating in a second operation mode, the servo control circuit determines a second set of control parameters selected for the second operation mode and applies the determined second set of control parameters to the servo circuit. The method can further include the servo control circuit detecting the operation mode of the imaging system and selecting a set of control parameters to apply to the detected operation mode.

[0015] The example method can further include the servo control circuit detecting the operation mode of the imaging system and selecting a set of control parameters to apply to the detected operation mode. The servo control circuit can apply the first or second set of control parameters of the set of control parameters identified as the detected operation mode.

[0016] Some methods may also include optimizing at least one of the first and second sets of control parameters to account for structural characteristics of the imaging system. Optimizing at least one of the first and second sets of control parameters may include operating the imaging system, scanning with a range of values of one of the control parameters of one of the first and second sets of control parameters, measuring the stability of the servo circuit during the scan, and selecting a value of the control parameter. Optimizing at least one of the first and second sets of control parameters may include operating the imaging system, scanning with a range of values of a plurality of control parameters of one of the first and second sets of control parameters, measuring the stability of the servo circuit during the scan, and determining an optimal setting of the plurality of control parameters.

[0017] In some applications, the imaging system may be a sequencer, and the first operating mode may be a focus model generation mode, and the second operating mode may be a sequencing mode. The servo control circuit may also enable feedback from the focus tracking circuit to the servo circuit when the imaging system is operating in the scan operation mode, and disable feedback from the focus tracking circuit to the servo circuit when the imaging system is operating in the focus model generation operation mode.

[0018] In yet another example, the imaging system may include: a sample stage including a surface that supports a sample to be scanned by the imaging system; an optical stage having an objective lens, the optical stage being positionable relative to the sample stage; a focus tracking circuit coupled to the optical stage; an actuator physically coupled to at least one of the sample stage and the optical stage to move the sample stage relative to the optical stage based on information from the focus tracking circuit; a servo circuit that controls the actuator; and a servo control circuit that enables feedback from the focus tracking circuit to the servo circuit when the imaging system is operating in the scan operation mode, and disables feedback from the focus tracking circuit to the servo circuit when the imaging system is operating in the focus model generation operation mode.

[0019] In an imaging system, a method of servo control may include: during operation of the imaging system, a mode detection circuit determines whether the imaging system is operating in a scan operation mode or a focus model generation operation mode; a servo circuit controls movement of the optical stage relative to the sample stage in the imaging system; and a servo control circuit enables feedback from the focus tracking circuit to the servo circuit when the imaging system is operating in the scan operation mode, and disables feedback from the focus tracking circuit to the servo circuit when the imaging system is operating in the focus model generation operation mode.

[0020] In conjunction with the accompanying drawings, other features and aspects of the disclosed technology will become apparent from the following detailed description, which illustrates, by way of example, features of implementations in accordance with the disclosed technology. This summary is not intended to limit the scope of any invention described herein as defined by the claims and equivalents.

[0021] It should be recognized that all combinations of the foregoing concepts (assuming these concepts are not mutually contradictory) are considered to be part of the inventive subject matter disclosed herein. In particular, all combinations of the claimed subject matter that appear at the end of this disclosure are considered to be part of the inventive subject matter disclosed herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The techniques disclosed herein according to one or more examples are described in detail with reference to the following drawings. These figures are provided to facilitate the reader's understanding of the disclosed techniques and are not specified to be exhaustive or to limit the disclosure to the precise forms disclosed. In fact, the figures in the drawings are provided for illustrative purposes only and depict only general or exemplary examples of the disclosed techniques. Additionally, it should be noted that for simplicity and clarity of illustration, the elements in the figures are not necessarily drawn to scale.

[0023] Figure 1 An example of a servo system that can be used for actuator control is shown.

[0024] Figure 2 A simplified block diagram of an example of an image scanning system is shown, and the systems and methods disclosed herein can be implemented using this image scanning system.

[0025] Figure 3 A block diagram of an exemplary focusing control system for a focusing operation according to an example of the systems and methods described herein is shown.

[0026] Figure 4 A diagram showing an exemplary architecture of a z-stage controller according to an example of the systems and methods described herein is shown.

[0027] Figure 5 A diagram showing another exemplary architecture of a z-stage controller according to an example of the systems and methods described herein is shown.

[0028] Figure 6 A diagram showing another exemplary controller that utilizes a focus tracking input and uses feedback and feedforward control according to an example of the systems and methods described herein is shown.

[0029] Figure 7 A diagram showing a speed controller according to an example of the systems and methods described herein is shown.

[0030] Figure 8 A diagram showing an exemplary implementation of controller switching for an application according to an example of the systems and methods described herein is shown.

[0031] Figure 9 A process of servo controller design switching for an application according to an example of the systems and methods described herein is shown.

[0032] Figure 10FIG. is an example implementation of a servo control circuit showing one application of the systems and methods described herein.

[0033] Figure 11 FIG. shows an example circuit of various components that can be used to implement the disclosed technology.

[0034] It should be understood that the disclosed technology may be practiced with modifications and alterations, and the disclosed technology is limited only by the claims and their equivalents. DETAILED DESCRIPTION

[0035] Various examples of the technology disclosed herein provide systems and methods for real-time setting of operating parameters of a servo control system used in an optical imaging system (such as a sequencing system). Many imaging systems include a sample stage that holds a sample or other object to be imaged and an optical stage that includes optics for imaging operations. A focusing operation involves moving the optical stage relative to the sample stage using an actuator to complete the movement. These imaging systems may be capable of operating in different operating modes, and these different operating modes may require different actuation modes to be implemented by the actuator. For example, an operating mode involving focus model generation may require holding the sample stage at a fixed position relative to the optical stage for a period of time to obtain focus information, while a sequencing operation may require rapid focus adjustment to maintain sufficient throughput. In some applications, the systems and methods disclosed herein can be configured to detect the operating mode of the imaging system during system operation and adjust the operation of the servo system that controls the actuator to optimize the servo control for the operating mode. This can include, for example, adjusting operating parameters of the servo system, such as the gain amount and filter values. As another example, this can include changing the feedback loop in the servo system.

[0036] Accordingly, a set of servo system parameters optimized for various operating modes can be predetermined and stored for recall during system operation. During operation, the system can determine the operating mode, the servo system parameters optimized for the determined operating mode, and apply these servo system parameters to the servo system such that the actuator control is optimized for that mode. This can be done in real time during the imaging operation such that the imaging system does not need to be stopped and parameters can be loaded for a mode change. Similarly, different feedback mechanisms can be determined for different operating modes, and these feedback mechanisms can also be selected to optimize the feedback method of the servo controller. This can also be done in real time such that the imaging system does not need to be stopped due to changes to the servo system.

[0037] Before describing various example systems and methods in detail, it is useful to describe an example environment in which the systems and methods can be implemented. One such example environment is an image scanning system (such as Figure 2the environment of the image scanning system shown in). Example imaging scanning systems can include devices for acquiring or generating images of regions. In Figure 2 The example outlined in shows an example imaging configuration of a backlight design.

[0038] As can be seen in the example of Figure 2 the test sample is positioned on the sample container 110, which is located on the sample stage 170 below the objective lens 142. The light source 160 and associated optics direct a light beam, such as a laser, to a selected sample location on the sample container 110. The sample fluoresces and the resulting light is collected by the objective lens 142 and directed to the light detector 140 to detect the fluorescence. The sample stage 170 is moved relative to the objective lens 142 to position the next sample location on the sample container 110 at the focal point of the objective lens 142. The movement of the sample stage 170 relative to the objective lens 142 can be achieved by moving the sample stage itself, the objective lens, the entire optical table, or any combination of the foregoing. Additional examples can also include moving the entire imaging system over a stationary sample.

[0039] The fluid delivery module or device 100 directs (and through) a reagent stream (e.g., fluorescent nucleotides, buffers, enzymes, lysis reagents, etc.) to the sample container 110 and the waste valve 120. In some applications, the sample container 110 can be implemented as a flow cell including clusters of nucleic acid sequences at multiple sample locations on the sample container 110. The sample to be sequenced can be attached to the substrate of the flow cell along with other optional components.

[0040] The system also includes a temperature station actuator 130 and a heater / cooler 135, which can optionally adjust the temperature state of the fluid within the sample container 110. A camera system 140 can be included to monitor and track the sequencing of the sample container 110. The camera system 140 can be implemented, for example, as a CCD camera, which can interact with various filters within the filter switching assembly 145, the objective lens 142, and the focusing laser / focusing laser assembly 150. The camera system 140 is not limited to a CCD camera and can use other camera and image sensor technologies.

[0041] It may include a light source 160 (e.g., an excitation laser within an assembly that may optionally include multiple lasers) or other light sources to illuminate a fluorescence sequencing reaction within a sample via illumination through a fiber optic interface 161, which may optionally include one or more reimaging lenses, fiber optic mounts, etc. A low wattage lamp 165, a focusing laser 150, and a dichroic mirror 185 are also present in the example shown. In some applications, the focusing laser 150 may be turned off during imaging. In other applications, an alternative focusing configuration may include a second focusing camera (not shown), which may be a quadrant detector, a position sensitive detector (PSD), or a similar detector to measure the positioning of scattered light beams reflected from the surface in parallel with data collection.

[0042] Although illustrated as a backlight device, other examples may include light from a laser or other light source that is directed onto a sample on a sample container 110 through an objective lens 142. The sample container 110 may ultimately be mounted on a sample stage 170 to enable movement and alignment of the sample container 110 relative to the objective lens 142. The sample stage may have one or more actuators to allow it to move in any of three directions. For example, in terms of a Cartesian coordinate system, actuators may be provided to allow the stage to move relative to the objective lens in the X, Y, and Z directions. This may allow one or more sample positions on the sample container 110 to be positioned in optical alignment with the objective lens 142.

[0043] In this example, a focusing (z-axis) component 175 is shown as being included to control the positioning of the optical components relative to the sample container 110 in the focusing direction (commonly referred to as the z-axis or z-direction). The focusing component 175 may include one or more actuators physically coupled to the optical stage or the sample stage or both to move the sample container 110 on the sample stage 170 relative to the optical components (e.g., the objective lens 142) to provide proper focus for the imaging operation. For example, the actuators may be physically coupled to the respective stage by directly or indirectly mechanically, magnetically, fluidically, or otherwise attaching to or contacting the stage. One or more actuators may be configured to move the stage in the z-direction while keeping the sample stage in the same plane (e.g., maintaining a horizontal or level attitude perpendicular to the optical axis). One or more actuators may also be configured to tilt the stage. For example, this may be done so that the sample container 110 can be dynamically leveled to account for any slope of its surface.

[0044] Focusing of the system generally refers to aligning the focal plane of the objective lens with the sample to be imaged at a selected sample location. However, focusing can also involve adjusting the system to obtain desired characteristics of the representation of the sample, such as, for example, a desired level of sharpness or contrast for an image of a test sample. Since the available depth of field of the focal plane of the objective lens can be very small (sometimes about 1 μm or less), the focusing component 175 closely follows the surface being imaged. Since the sample container is not perfectly flat as if fixed in the instrument, the focusing component 175 can be set to follow such a profile when moving in the scanning direction (commonly referred to as the y-axis).

[0045] Light emitted from a test sample at the sample location to be imaged can be directed to one or more detectors 140. For example, the detector can include a CCD camera. An aperture can be included and positioned to allow only light emitted from the focused area to pass to the detector. The aperture can be included to improve the image quality by filtering out components of light emitted from areas other than the focused area. An emission filter can be included in the filter switching component 145, which can be selected to record a determined emission wavelength and remove any stray laser light.

[0046] In various examples, the sample container 110 can include one or more substrates on which the sample is provided. For example, in the case where the system analyzes a large number of different nucleic acid sequences, the sample container 110 can include one or more substrates to which the nucleic acid to be sequenced is bonded, attached, or bound. In various examples, the substrate can include any inert substrate or matrix to which the nucleic acid can attach, such as, for example, a glass surface, a plastic surface, latex, dextran, a polystyrene surface, a polypropylene surface, a polyacrylamide gel, a gold surface, and a silicon wafer. In some applications, the substrate is within a channel or in other areas at multiple locations in a matrix or array formed on the sample container 110.

[0047] One or more controllers (not shown) can be provided to control the scanning system (e.g., as referred to above with reference to Figure 2Operation of the described example scanning system). The controller can be implemented to control various aspects of the system operation, such as, for example, focusing, stage movement, and imaging operations. In various applications, the controller can be implemented using hardware, software, or a combination of the foregoing. For example, in some implementations, the controller can include one or more CPUs or processors with associated memory. As another example, the controller can include hardware or other circuitry to control the operation. For example, the circuitry can include one or more of the following: field programmable gate array (FPGA), application specific integrated circuit (ASIC), programmable logic device (PLD), complex programmable logic device (CPLD), programmable logic array (PLA), programmable array logic (PAL), or other similar processing devices or circuitry. As yet another example, the controller can include a combination of the circuitry and one or more processors.

[0048] Although the systems and methods may be described herein from time to time in the context of this example system, this is merely one example in which these systems and methods can be implemented. After reading this description, one of ordinary skill in the art will understand how the systems and methods described herein can be implemented using this and other scanners, microscopes, and other imaging systems.

[0049] As shown in the example described above with reference to Figure 2 the focusing operation can be an important part of the imaging process. In some applications, a focusing model can be prepared for the imaging operation, and then the focusing model can be used to position the objective lens relative to the sample appropriately during the imaging operation. Typically, in operation, the focusing beam generated by the focusing laser is reflected from the sample position to measure the desired focus, and the sample stage is moved relative to the optical stage to focus the optical stage on the current sample position.

[0050] The movement of the sample stage relative to the optical stage for focusing model generation and for an appropriate in-focus position during imaging is typically described as movement along the z-axis or in the z-direction. The terms "z-axis" and "z-direction" are defined to be used in accordance with their normal use in the technical field of microscopes and imaging systems, where the z-axis refers to the focal axis. Thus, z-axis translation results in increasing or decreasing the length of the focal axis. For example, z-axis translation can be performed by moving the sample stage relative to the optical stage (e.g., by moving the sample stage or the optical element or both). Thus, z-axis translation can be performed by driving the objective lens, the optical stage, or the sample stage, or a combination of the foregoing, any of which components can be driven by actuating one or more servos or motors or other actuators that are in functional communication with the objective lens or the sample stage or both. In various examples, the actuator can be configured to tilt the sample stage relative to the optical stage to effectively level the sample container in a plane perpendicular to the optical imaging axis. In cases where such dynamic tilting is performed to effectively position the sample on the sample container horizontally, this can allow the sample container to move in the x-direction and the y-direction for scanning with little or no movement along the z-axis as needed. Although the present disclosure uses the terms "z-axis" and "direction", it should be understood that this is done for clarity of description and consistency with conventional terms. The principles disclosed herein do not depend on these mnemonics, and other terms can be used to describe movement in the x, y, and z directions.

[0051] In various examples, an actuator can be used to position the sample stage relative to the optical stage by repositioning the sample stage or the optical stage (or portions thereof) or both to achieve a desired focus setting. In some examples, a piezoelectric actuator can be used to move the desired stage. In other examples, a voice coil actuator can be used to move the desired stage. In some applications, using a voice coil actuator can provide reduced focus latency compared to its piezoelectric counterpart. In cases where a voice coil actuator is used, the coil size can be selected to provide the minimum coil size necessary for the desired movement such that the inductance in the coil can also be minimized. Limiting the coil size and thus its inductance provides a faster response time and requires a smaller voltage to drive the actuator.

[0052] For focus model generation, it is often desirable to maintain the optical system with as little movement as possible over a period of time while determining an appropriate focus for sample positioning. For example, in some applications, it may be necessary to hold the position of the objective lens within a few nanometers of a target position relative to a sample container. In contrast, imaging operations require relatively rapid scanning of DNA clusters in the surface of the sample container. The image acquisition scan speed is driven by instrument runtime requirements and results in bandwidth requirements for the focusing system and the z-stage. This typically involves a control system with high bandwidth to achieve high-quality imaging at high throughput rates, which requires the objective lens to be rapidly moved to precise focus positions relative to the sample container. However, this is inconsistent with the control system requirements for focus model generation, which may aim to hold the optical system as stationary as possible at a target position. Thus, the techniques disclosed herein can be implemented to provide real-time switching of the z-stage controller according to the current operating mode. The techniques can be implemented to effectively break this trade-off constraint between holding during focus model generation and high-speed movement during imaging by enabling the application of a first control system optimized for holding and a second control system optimized for rapid imaging and providing a mechanism for switching between these control systems according to the current mode.

[0053] Figure 3 is a block diagram of an example focus control system for a focusing operation showing an application according to the systems and methods described herein. The example focus control system includes a focus tracking circuit 332 configured to determine a current focus setting that is used to generate a drive signal that drives a focus tracking feedback loop in the z-stage 334. As shown in the example of Figure 3 based on the focus setting difference, a command 352 is fed to the z-stage 334 to control the movement of the z-stage 334.

[0054] In this example, the z-stage 334 is configured to move the objective lens 346 (e.g., objective lens 142). The actuator 344 moves the optical stage, and in particular the objective lens 346, in response to a drive signal provided by the z-stage amplifier 338. As mentioned above, the actuator 344 can include a piezoelectric actuator, a voice coil actuator, a motor, or other similar actuators. The position encoder 342 provides information about the actuator position and its movement. This encoder information 354 can be fed back to the focus tracking circuit 332 by the z-stage controller 336 and can be used in determining the error signal.

[0055] A controller for controlling the movement can be implemented using a PID controller with feedforward - including position and velocity controllers. They can include proportional, integral, and derivative control of the error signal and the feedforward control branch. Some examples can also include additional filters and trajectory generation, which can be used to improve the stability of the system according to the usage.

[0056] Figure 4 FIG. is an example architecture of a z-stage controller showing an example according to the systems and methods described herein. The example controller incorporates feedforward and feedback control to generate a drive signal to control the stage actuator. In some examples, this can be implemented as proportional, integral, and derivative (PID) control of one or both of the error signal of the control system and a feedforward control branch. As shown in this example, the difference between the target focus setting (target z-position 470) and the actual focus setting (actual z-position 472) is calculated and fed to control block 488. Position information is also sent via feedforward path 476 and added to the output signal of control block 488. This output signal from the drive circuit within control block 488 provides a control output signal for driving actuator 490. As shown, the magnitude of the difference between the target focus position and the actual position is provided via feedforward path 476 to adjust the control output signal.

[0057] Figure 5 FIG. is a diagram showing another example architecture of a z-stage controller showing an example according to the systems and methods described herein. This example also incorporates feedback and feedforward control. In operation, the target focus setting (e.g., target z-position 570) is used to command the position of the stage. The target z-position 570 is provided to servo controller 588, which determines the drive signal required to command actuator 590 to position the stage. Servo controller 588 may also include a drive circuit to generate the drive signal. The drive signal determination is made using the magnitude of the difference between the target focus setting (target z-position 570) and the current focus setting (actual z-position 572) that can be provided by, for example, actuator 590. In this example as well as in the previous example, the drive signal for driving the actuator is adjusted by a signal from feedforward control path 576.

[0058] However, in Figure 5 the example, the measured focus correction signal 578 is also generated by focus tracking circuit 592, which can be active, for example, during a scan mode. In this case, the correction information can be determined, for example, using the measured focus correction information. The correction information in this example is added to the commanded stage position to adjust the drive signal according to the slope of the change in the focus setting of the scan operation. For example, when the imaging system is in scan mode, this feedback path can be turned on or enabled to provide this correction information to the servo controller. In some applications, the system can be controlled such that when the system is in scan mode, the position loop of the servo controller can be disconnected or partially disconnected because the focus tracking circuit 592 provides real-time feedback on the moving target.

[0059] Figure 6FIG. is a diagram of another example servo controller that uses feedback and feedforward control with a focus tracking input, showing an example according to the systems and methods described herein. A target imaging distance 623 is provided as an input to the control system to generate a stage position signal 624 that controls a stage (e.g., stage 334). In addition to position control 628, the system also includes feedforward control 626. The feedforward path can provide a faster response by bypassing the usually slower position loop and going directly to the velocity loop (described below). When the position change is more drastic, to achieve a faster system response than can be achieved otherwise relying solely on position PID 628, the forward path of the feedforward control 626 forwards the change to the velocity PID 630. The velocity control 630, which can also be implemented as a PID controller, is implemented in the position loop in this example. The feedback 634 of the velocity loop takes the form of the derivative of the determined position. In some cases, the constant position error can be small enough that the position PID 628 alone does not generate enough torque to overcome the static friction of the system. In such cases, the velocity PID 630 provides additional gain to overcome this friction. The force has a 90-degree phase shift with respect to the velocity, which allows for higher gain for better contour tracking and holding.

[0060] Similar to Figure 5 the example, this example includes measured focus correction feedback from a focus tracking circuit 692. As in Figure 5 the example, the measured focus correction signal 678 can be generated by the focus tracking circuit 692. In this example, this correction information is added to the commanded stage position to adjust the drive signal according to the slope of the change in the focus setting of the scan operation. Just as in Figure 5 the example, in some applications, the system can be controlled such that when the system is in the scan mode, the position loop of the servo controller can be disconnected or partially disconnected because the focus tracking circuit 592 provides real-time feedback about the moving target.

[0061] Figure 7 FIG. is a diagram of a velocity controller showing an example according to the systems and methods described herein. This shows an example implementation of a velocity PID controller 630 that can be used to provide the velocity loop within a servo controller. This example includes gain stages for a proportional term 712, an integral term 714, and a derivative term 716. The gains are summed by a summing circuit 720 to provide a control output for the velocity PID controller 630.

[0062] As mentioned, various applications of the systems and methods described herein can be used to provide real-time mode detection and control parameter switching to optimize servo control or operating parameters based on the currently detected mode of an operating instrument. For example, in the case of a sequencing instrument, the systems and methods described herein can be implemented to detect whether the sequencing instrument is in a focusing model mode or a sequencing mode, determine the correct set of operating parameters defined for that operating mode for the z-stage servo controller, and update the servo controller parameters with the specific parameters defined for that operating mode. Any one of a number of servo controller parameters can be defined and selected to optimize servo operation for the detected mode. For example, different sets of parameters such as, for example, integral gain, derivative gain, feedforward, and filter cutoff frequency, and other similar parameters can be defined for various operating modes and implemented for the desired operating mode. For example, a high loop gain can be implemented to achieve response performance and help suppress interference. However, a high loop gain can also lead to instability.

[0063] Table 1 shows an example set of parameters that can be defined for a hold mode and a scan mode in a sequencing instrument.

[0064] Table 1: Example Parameters

[0065] Mode Relative Movement Trajectory Generator PP Gain VP Gain Control Version MemID 0x06010800 0x06010300 0x07000300 0x07000307 Hold 0 1 800 4.00E-04 5.0 Scan 1 0 200 9.00E-04 5.8

[0066] In this example, predefined values for the position loop gain and the velocity loop gain are provided for the hold mode and the scan mode. The relative movement implementation is designed to reduce or minimize the error in the current position, since the local controller has the latest measurement of the position of the stage actuator, and reducing or minimizing latency is important for scan operations. Additionally, many scan operations rely only on relative movement. On the other hand, the trajectory generator implementation is useful for focus model generation. Focus model generation typically relies on knowledge of the absolute position of the z-position to calibrate the focusing system. However, latency is generally less important for focus calibration, and absolute positioning can be used. Thus, in the example provided in Table 1, the gains of the position loop are higher for hold operations than they are for scan operations, while the gains of the velocity loop are lower than those that can be set for scan operations. This example in Table 1 does not show every parameter that can be adjusted, and the systems and methods disclosed herein can be extended to additional predefined parameters in the focus servo system.

[0067] Figure 8FIG. is a diagram showing an example implementation of controller switching for an application of the systems and methods described herein. The example shown includes a mode selection circuit 814 and a servo control circuit 816 that can be implemented to control or adjust the operating parameters or feedback mechanisms, or a combination thereof, of one or more servo controllers 810 that control the movement of the console 812. The mode selection circuit 814 can be implemented in a sequencing instrument (or other instrument to which these systems and methods can be applied) to select an operating mode, including the selection of operating parameters and feedback mechanisms for the servo controllers. For example, in the case of an example scenario using a scanning mode and a focus model generation mode, the mode selection circuit 814 can be implemented to place the sequencing instrument in either of these modes based on the current operation of the imaging system. The mode selection circuit 814 can include a separate circuit, or it can be part of a controller (such as the controller described above with reference to Figure 1 described controller) for controlling the operation of the scanning system.

[0068] Information about the operating mode of the system is provided to the servo control circuit 816. The servo control circuit 816 detects the operating mode of the instrument and selects appropriate servo controller parameters or feedback modes (or both) based on the operating mode of the system. The servo control circuit 816 can further be implemented to set the affected parameters of one or more servo loops that make up the servo circuit 810. In the case of selecting appropriate servo controller parameters, these parameters can be stored in registers or other memory and the appropriate parameters or parameter sets are retrieved based on the operating mode of the system. In the case of adjusting the feedback mechanism, the servo control circuit 816 can provide switching or control to enable feedback from an appropriate source (such as, for example, from a focus tracking circuit).

[0069] Figure 9 FIG. shows a process for servo controller design switching for an application of the systems and methods described herein. In this example, at operation 912, a servo mode control circuit (e.g., servo control circuit 816) determines the operating mode of the sequencing instrument. In some applications, this determination can be made by receiving a signal from the controller of the sequencing instrument or other device that indicates to the servo motor control circuit the current state of the machine. For example, the signal path can provide different signal levels to indicate the state of the sequencing instrument. As another example, the signal path can provide a series of bits or bytes indicating the current operating mode.

[0070] At operation 914, the servo motor control circuit determines the operating mode of the sequencing instrument. According to the above example, at this step, the servo motor control circuit can determine whether the instrument is operating in the focus model generation mode or in the sequencing mode. If the servo motor control circuit determines that the instrument is operating in the sequencing mode, then at operation 918, the servo motor control circuit selects parameters optimized for imaging operations of the control z-stage. In applications where a feedback mechanism is also selected (or alternatively selected), when the instrument is operating in the sequencing mode, the servo motor control circuit can also enable the feedback path from the focus tracking circuit. On the other hand, if the servo motor control circuit determines that the instrument is operating in the focus model generation mode, then at operation 920, the servo motor control circuit selects servo control parameters optimized for controlling the z-stage in this mode. In additional applications, additional operating modes can be detected and parameters for these modes can be selected.

[0071] At operation 926, the selected servo control parameters are loaded into the appropriate loop or loops of the servo controller. At operation 928, the servo system uses the loaded parameters and the appropriate feedback mechanism to control the z-stage.

[0072] Figure 10 FIG. is an example implementation of a servo control circuit showing an application of the systems and methods described herein. In this example, the servo control circuit 1010 controls the application of operating parameters to the servo controller 1020. The servo controller 1020 includes a feedforward control 1022, a position control loop 1024, and a speed control loop 1028. Depending on the servo system, the servo controller can include additional or other control loops. These control loops can be implemented to operate at different performance levels based on operating parameters such as gain amounts, filter values, etc.

[0073] The example servo control circuit 1010 includes a mode detection circuit 1014, a parameter selection circuit 1012, and a parameter file 1016. The mode detection circuit 1014 receives information from the instrument controller, and the mode detection circuit 1014 can use this information to determine the operating mode of the instrument. In some applications, the instrument can output a digital or analog signal indicating the current operating mode of the instrument. For example, in the case of a sequencing instrument, the operating modes can include modes such as a focus model generation mode and a sequencing mode. As another example, one bit or a group of bits or a flag indicating the mode can be set, and this bit or bits are read by the mode detection circuit 1014 to determine the operating mode.

[0074] Once the operating mode is determined, the parameter selection circuit 1012 selects a parameter set corresponding to the detected operating mode. In the example shown, the parameter set may be stored in a memory or other similar storage device, such as stored in parameter file 1016 and retrieved by the parameter selection circuit 1012. The parameter selection circuit 1012 loads the parameters into one or more controllers of the appropriate loops of the servo controller 1020. When the mode of the instrument changes, this change can be detected by the mode detection circuit 1014, and new parameters are selected and loaded into the appropriate control loops of the servo controller 1020. In some applications, the parameter set loading can occur in real time (but may still depend on system latency or other delays), such that the servo parameters can be changed on the fly.

[0075] One or more sets of parameters identified for servo operation can be further optimized for a given instrument with which the servo system is implemented. For example, different instruments can have different structures or other characteristics that can respond to and interact with the control system. Such interactions can cause vibrations, harmonic motion, or other instabilities that can adversely affect system performance or even cause failures. Thus, the parameters can be optimized for the instrument by a manual refinement process or by using automated tools to create a customized implementation of the parameters for operating modes (such as hold and scan) for the given instrument.

[0076] In some applications, the process of optimizing the parameters of a parameter set for a given instrument can be accomplished by operating the instrument and scanning through a predetermined range of values of one or more control parameters while measuring the stability of the control system during each operation. In some cases, each control parameter can be measured and optimized individually, while in other cases, multiple control parameters can be adjusted systematically to determine the optimal setting of the control parameter combination. During the calibration process, a rest time can be inserted between operations at various control parameter settings such that instabilities caused by one parameter setting do not compromise the measurements at subsequent parameter settings. For a given system, an optimal operating point can be selected, such as a set of parameters that introduce a minimum of instability. The optimal operating point can manifest itself as a minimum of performance variability, typically having a quadratic relationship for which the operating minimum can be determined by calculation and saved as a customized implementation file for the given instrument.

[0077] Although the examples disclosed herein relate to parameter sets that can be used to optimize a servo system for a particular operating mode, the optimization may not achieve a fully ideal operation. Given the constraints on operating parameters, system constraints, and the real-world conditions under which the system operates, a set of parameters designed to optimize operation in a given mode can achieve the highest possible level of operation. The optimization may also be subject to design trade-offs, and the amount of optimization achieved can be based on an appropriate level of operation as determined by a system designer who weighs these trade-offs.

[0078] As used herein, a circuit can be implemented using any form of hardware, software, or a combination thereof. For example, one or more processors, controllers, ASICs, PLAs, PALs, CPLDs, FPGAs, logic components, software routines, or other mechanisms can be implemented to form a circuit. In an implementation, the various circuits described herein can be implemented as discrete circuits, or the described functions and features can be partially or fully shared among one or more circuits. In other words, the various features and functions described herein can be implemented in any given application and can be implemented in one or more individual or shared circuits in various combinations and permutations. Even though the various features or elements of a function may be described or claimed separately as individual circuits, one of ordinary skill in the art will understand that these features and functions can be shared among one or more general-purpose circuits, and such a description should not require or imply the need for separate circuits to implement such features or functions.

[0079] As described herein, the system controller, servo controller, and other components of the systems and methods described herein can be implemented as circuits. In cases where the circuits are implemented, in whole or in part, using software, in one implementation, these software elements can be implemented to operate with a computing or processing system capable of performing the functions described thereof. Figure 11 One such example computing system is shown. Various examples are described in terms of this example computing system 1100. After reading this description, it will become apparent to those skilled in the relevant art how to implement the technology using other computing systems or architectures.

[0080] Now refer to Figure 11, the computing system 1100 can represent computing or processing capabilities found, for example, in desktop computers, laptop computers, and notebook computers; handheld computing devices (smartphones, cellular phones, personal digital assistants, tablet computers, etc.); mainframes, supercomputers, workstations, or servers; or any other type of special-purpose or general-purpose computing device that may be desirable or suitable for a given application or environment. The computing system 1100 can also represent computing capabilities embedded within a given device or otherwise available to the given device. For example, computing systems can be found in other electronic devices such as, for example, digital cameras, navigation systems, cellular phones, portable computing devices, modems, routers, WAPs, terminals, and other electronic devices that may include some form of processing capability.

[0081] The computing system 1100 can include, for example, one or more processors, controllers, control modules, or other processing devices, such as processor 1104. Processor 1104 can be implemented using a general-purpose or special-purpose processing engine such as, for example, a microprocessor (whether single-core, dual-core, or multi-core processor), a signal processor, a graphics processor (e.g., GPU), a controller, or other control logic. In the example shown, processor 1104 is connected to bus 1102, but any communication medium can be used to facilitate interaction with other components of the computing system 1100 or communication with the outside world.

[0082] The computing system 1100 can also include one or more memory modules, herein referred to simply as main memory 1108. For example, in some implementations, random access memory (RAM) or other dynamic memory can be used to store information and instructions to be executed by processor 1104. Main memory 1108 can also be used to store temporary variables or other intermediate information during the execution of instructions to be executed by processor 1104. The computing system 1100 can also include a read-only memory (“ROM”) or other static storage device coupled to bus 1102 for storing static information and instructions for processor 1104.

[0083] The computing system 1100 may also include one or more forms of information storage means 1110, which may include, for example, a media drive 1112 and a storage unit interface 1120. The media drive 1112 may include a drive or other mechanism to support fixed or removable storage media 1114. For example, a hard disk drive, a floppy disk drive, a tape drive, an optical disk drive, a CD or DVD drive (R or RW), a flash drive, or other removable or fixed media drives may be provided. Thus, the storage media 1114 may include, for example, a hard disk, a floppy disk, a tape, a cartridge, an optical disk, a CD or DVD, or other fixed or removable media that can be read, written to, or accessed by the media drive 1112. As these examples illustrate, the storage media 1114 may include computer-usable storage media having computer software or data stored therein.

[0084] In an alternative implementation, the information storage means 1110 may include other similar means for allowing computer programs or other instructions or data to be loaded into the computing system 1100. Such means may include, for example, a fixed or removable storage unit 1122 and an interface 1120. Examples of such storage units 1122 and interfaces 1120 may include a program cartridge and cartridge interface, a removable memory (such as a flash memory or other removable memory module) and memory slot, a flash drive and associated slot (such as a USB drive), a PCMCIA slot and card, and other fixed or removable storage units 1122 and interfaces 1120 that allow software and data to be transferred from the storage unit 1122 to the computing system 1100.

[0085] The computing system 1100 may also include a communication interface 1124. The communication interface 1124 may be used to allow software and data to be transferred between the computing system 1100 and external devices. Examples of the communication interface 1124 may include a modem or soft modem, a network interface (such as Ethernet, a network interface card, WiMedia, IEEE 802.XX, or other interface), a communication port (such as, for example, a USB port, an IR port, an RS232 port, or other port), or other communication interfaces. The software and data transmitted via the communication interface 1124 are typically carried on signals that may be electrical signals, electromagnetic signals (which include optical signals), or other signals capable of being exchanged by a given communication interface 1124. These signals may be provided to the communication interface 1124 via a channel 1128. This channel 1128 may carry signals and may be implemented using a wired or wireless communication medium. Some examples of channels may include telephone lines, cellular links, RF links, optical links, network interfaces, local area networks or wide area networks, and other wired or wireless communication channels.

[0086] In this document, the terms "computer program medium" and "computer usable medium" generally refer to media such as, for example, memory 1108, storage unit 1122, medium 1114, and channel 1128. These and various other forms of computer program medium or computer usable medium can involve carrying one or more sequences of one or more instructions to a processing device for execution. Such instructions embodied on a medium are often referred to as "computer program code" or "computer program product" (which may be grouped in the form of a computer program or other groupings). When executed, such instructions can enable computing system 1100 to perform the features or functions of the disclosed technology as discussed herein.

[0087] It should be recognized that all combinations of the foregoing concepts (assuming these concepts are not mutually inconsistent) are considered to be part of the inventive subject matter disclosed herein. In particular, all combinations of the claimed subject matter appearing at the end of this disclosure are considered to be part of the inventive subject matter disclosed herein.

[0088] Although various examples of the disclosed technology have been described above, it should be understood that they are presented by way of example only and not limitation. Similarly, the various figures may depict example architectures or other configurations of the disclosed technology that are implemented to aid in understanding the features and functions that may be included in the disclosed technology. The disclosed technology is not limited to the example architectures or configurations shown, but rather various alternative architectures and configurations may be used to implement the desired features. Indeed, it will be apparent to those skilled in the art how alternative functional, logical, or physical partitioning and configurations may be implemented to implement the desired features of the technology disclosed herein. Additionally, many different component module names other than those depicted herein may be applied to the various blocks. Further, with respect to flowcharts, operational descriptions, and method claims, the order in which steps are presented herein should not require that various examples be implemented to perform the recited functions in the same order, unless the context dictates otherwise.

[0089] Although the disclosed technology has been described above in terms of various example embodiments and implementations, it should be understood that the various features, aspects, and functions described in one or more of the individual examples are not limited in their applicability to the particular examples in which they are described, but instead may be applied, either individually or in various combinations, to one or more other examples of the disclosed technology, regardless of whether such examples are described and regardless of whether such features are presented as part of the described examples. Accordingly, the breadth and scope of the disclosed technology should not be limited by any of the above-described example embodiments. It should be recognized that all combinations of the foregoing concepts (assuming such concepts are not mutually inconsistent) are considered to be part of the inventive subject matter disclosed herein. In particular, all combinations of the claimed subject matter appearing at the end of this disclosure are considered to be part of the inventive subject matter disclosed herein.

[0090] Unless otherwise expressly stated, the terms and phrases used in this document and their variants shall be construed as open-ended rather than limiting in contrast thereto. As an example of the foregoing: the term "including" should be understood to mean "including but not limited to", etc.; the term "example" is used to provide example instances of the item under discussion, rather than an exhaustive or limiting list thereof; the term "a" or "an" should be understood to mean "at least one", "one or more", etc.; and adjectives such as "conventional", "traditional", "normal", "standard", "known", and terms of similar import should not be construed as limiting the item described to a given time period or to items available as of a given time, but rather should be understood to encompass conventional, traditional, normal, or standard techniques available or known at any time present or future. In this document, the term "comprising" is specified as being open-ended and includes not only the recited elements, but also any additional elements. Similarly, in instances where this document refers to techniques that are apparent or known to a person of ordinary skill in the art, such techniques encompass those that are apparent or known to the person skilled in the art at any time present or future. To the extent applicable, the terms "first", "second", "third", etc. in this document are merely used to denote the corresponding objects described by such terms as separate entities and do not imply a sense of chronological order, unless expressly stated otherwise herein.

[0091] The term "coupled" means directly or indirectly joined, connected, fastened, contacting, or linked, and can refer to various forms of coupling such as, for example, physical, optical, electrical, fluidic, mechanical, chemical, magnetic, electromagnetic, communication, or other couplings, or combinations of the foregoing. Where a particular form of coupling is specified, this does not imply the exclusion of other forms of coupling. For example, a component physically coupled to another component can involve physical attachment or contact (directly or indirectly) between the two components, but does not exclude other forms of coupling between the components, such as, for example, a communication link (e.g., RF or optical link) can also communicatively couple the two components. Similarly, the various terms themselves are not intended to be mutually exclusive. For example, fluidic coupling, magnetic coupling, or mechanical coupling, etc. can be a form of physical coupling.

[0092] In some cases, the presence of expansive words and phrases such as "one or more", "at least", "but not limited to", or other similar phrases should not be construed to imply a narrower case where such expansive phrases might not be present. The use of the term "component" does not imply that the elements or functions described or claimed as part of a component are all configured in a common enclosure. In fact, any one or all of the various elements of a component (including structural elements) can be combined in a single enclosure or maintained separately, and can be further distributed in multiple groupings or enclosures.

[0093] Additionally, the various examples set forth herein are described in terms of example diagrams and other illustrative aspects. As will become apparent to one of ordinary skill in the art upon reading this document, the examples shown and their various alternatives can be implemented without limitation to the examples shown. For example, block diagrams and their accompanying descriptions should not be construed as mandating a particular architecture or configuration.

[0094] It should be recognized that all combinations of the foregoing concepts and additional concepts discussed in more detail below (assuming such concepts are not mutually inconsistent) are contemplated as part of the inventive subject matter disclosed herein. In particular, all combinations of the claimed subject matter appearing at the end of this disclosure are considered part of the inventive subject matter disclosed herein.

[0095] Aspects of the present disclosure may be implemented in one or more of the embodiments described below.

[0096] 1) An imaging system, comprising:

[0097] A sample stage including a surface for supporting a sample to be scanned by the imaging system;

[0098] An optical stage having an objective lens, the optical stage being positionable relative to the sample stage;

[0099] An actuator physically coupled to at least one of the sample stage and the optical stage to move the sample stage relative to the optical stage;

[0100] A servo circuit that controls the actuator;

[0101] A first set of control parameters that controls the servo circuit;

[0102] A second set of control parameters that controls the servo circuit; and

[0103] A servo control circuit that applies the first set of control parameters to the servo circuit when the imaging system is operating in a first operating mode and applies the second set of control parameters to the servo circuit when the imaging system is operating in a second operating mode.

[0104] 2) The imaging system according to 1), wherein the servo control circuit includes a mode detection circuit that detects the operating mode of the imaging system and a parameter selection circuit that applies a set of control parameters corresponding to the detected operating mode.

[0105] 3) The imaging system according to 1), wherein the imaging system is a sequencer, and the first operating mode is a focus model generation mode, and the second operating mode is a sequencing mode.

[0106] 4) The imaging system according to 1), wherein the servo control circuit further detects the operating mode of the imaging system and selects a set of control parameters to apply to the detected operating mode.

[0107] 5) The imaging system according to 4), wherein the servo control circuit applies the first set of control parameters or the second set of control parameters that are identified as a set of control parameters for the detected operating mode.

[0108] 6) The imaging system according to 4), wherein at least one of the first set of control parameters and the second set of control parameters is optimized to consider the structural characteristics of the imaging system.

[0109] 7) The imaging system according to 6), wherein optimizing at least one of the first set of control parameters and the second set of control parameters includes operating the imaging system, scanning with a range of values of a control parameter in one of the first set of control parameters and the second set of control parameters, measuring the stability of the servo circuit during the scanning, and selecting the value of the control parameter.

[0110] 8) The imaging system according to 6), wherein optimizing at least one of the first set of control parameters and the second set of control parameters includes operating the imaging system, scanning with a range of values of a plurality of control parameters in one of the first set of control parameters and the second set of control parameters, measuring the stability of the servo circuit during the scanning, and determining an optimal setting of the plurality of control parameters.

[0111] 9) The imaging system according to 1), wherein the imaging system further includes a focus tracking circuit electrically coupled to the optical stage; and wherein the servo control circuit further enables feedback from the focus tracking circuit to the servo circuit when the imaging system operates in a scanning operation mode, and disables feedback from the focus tracking circuit to the servo circuit when the imaging system operates in a focus model generation operation mode.

[0112] 10) The imaging system according to 1), wherein the control parameters include servo loop gain and filter value.

[0113] 11) The imaging system according to 1), wherein the actuator is physically coupled to the sample stage to move the sample stage to adjust the distance between the sample stage and the optical stage.

[0114] 12) The imaging system according to 1), further including a plurality of actuators physically coupled to the sample stage to adjust the tilt of the sample stage.

[0115] 13) The imaging system according to 1), wherein the actuator is physically coupled to the optical stage to move the optical stage to adjust the distance between the sample stage and the optical stage.

[0116] 14) The imaging system according to 13), wherein the actuator includes at least one of a piezoelectric device, a voice coil, and a drive motor.

[0117] 15) The imaging system according to 1), wherein the sample is contained in a flow cell or on a slide.

[0118] 16) A method for servo control in an imaging system, the method comprising:

[0119] During operation of the imaging system, a mode detection circuit determines that the imaging system operates in a first operation mode;

[0120] A servo control circuit determines a first set of control parameters selected for the first operation mode;

[0121] The servo control circuit applies the determined first set of control parameters to the servo circuit of the imaging system, where the servo circuit controls the operation of an actuator that is physically coupled to at least one of a sample stage and an optical stage of the imaging system to move the sample stage relative to the optical stage; and

[0122] When the mode detection circuit determines during operation of the imaging system that the imaging system has switched to operating in a second operation mode, the servo control circuit determines a second set of control parameters selected for the second operation mode and applies the determined second set of control parameters to the servo circuit.

[0123] 17) The method according to 16), wherein the servo control circuit includes a mode detection circuit that detects an operation mode of the imaging system and a parameter selection circuit that applies a set of control parameters corresponding to the detected operation mode.

[0124] 18) The method according to 16), further comprising the servo control circuit detecting an operation mode of the imaging system and selecting a set of control parameters to apply to the detected operation mode.

[0125] 19) The method according to 18), further comprising the servo control circuit applying the first set of control parameters or the second set of control parameters identified as a set of control parameters for the detected operation mode.

[0126] 20) The method according to 16), further comprising optimizing at least one of the first set of control parameters and the second set of control parameters to account for structural characteristics of the imaging system.

[0127] 21) The method according to 20), wherein optimizing at least one of the first set of control parameters and the second set of control parameters includes operating the imaging system, scanning with a range of values of a control parameter in one of the first set of control parameters and the second set of control parameters, measuring the stability of the servo circuit during the scanning, and selecting a value of the control parameter.

[0128] 22) The method according to 20), wherein optimizing at least one of the first set of control parameters and the second set of control parameters includes operating the imaging system, scanning with a range of values of a plurality of control parameters in one of the first set of control parameters and the second set of control parameters, measuring the stability of the servo circuit during the scanning, and determining an optimal setting of the plurality of control parameters.

[0129] 23) The method according to 16), wherein the servo control circuit further enables feedback from the focus tracking circuit to the servo circuit when the imaging system is operating in a scanning operation mode, and disables the feedback from the focus tracking circuit to the servo circuit when the imaging system is operating in a focus model generation operation mode.

[0130] 24) The method according to 16), wherein the control parameters include servo loop gain and filter values.

[0131] 25) The method according to 16), further comprising the actuator moving the sample stage to adjust the distance between the sample stage and the optical stage.

[0132] 26) The method according to 25), wherein the actuator includes at least one of a piezoelectric device, a voice coil, and a drive motor.

[0133] 27) The method according to 16), wherein the imaging system is a sequencer, and the first operation mode is a focus model generation mode, and the second operation mode is a sequencing mode.

[0134] 28) An imaging system, comprising:

[0135] A sample stage including a surface for supporting a sample to be scanned by the imaging system;

[0136] An optical stage having an objective lens, the optical stage being positionable relative to the sample stage;

[0137] A focus tracking circuit coupled to the optical stage;

[0138] An actuator physically coupled to at least one of the sample stage and the optical stage to move the sample stage relative to the optical stage based on information from the focus tracking circuit;

[0139] A servo circuit for controlling the actuator; and

[0140] A servo control circuit that enables feedback from the focus tracking circuit to the servo circuit when the imaging system is operating in a scanning operation mode, and disables the feedback from the focus tracking circuit to the servo circuit when the imaging system is operating in a focus model generation operation mode.

[0141] 29) A method for servo control in an imaging system, the method comprising:

[0142] During operation of the imaging system, a mode detection circuit determines whether the imaging system is operating in a scanning operation mode or a focus model generation operation mode;

[0143] The servo circuit controls the movement of the optical stage relative to the sample stage in the imaging system; and

[0144] The servo control circuit enables feedback from the focus tracking circuit to the servo circuit when the imaging system is operating in the scan operation mode, and disables the feedback from the focus tracking circuit to the servo circuit when the imaging system is operating in the focus model generation operation mode.

Claims

1. An imaging system, comprising: a sample stage including a surface for supporting a sample to be scanned by the imaging system; an optical stage having an objective lens, the optical stage being positionable relative to the sample stage; an actuator physically coupled to at least one of the sample stage and the optical stage to move the sample stage relative to the optical stage; a servo circuit controlling the actuator; a first set of control parameters controlling the servo circuit; a second set of control parameters controlling the servo circuit; and a servo control circuit that applies the first set of control parameters to the servo circuit when the imaging system is operating in a first operation mode and applies the second set of control parameters to the servo circuit when the imaging system is operating in a second operation mode, wherein the imaging system further includes a focus tracking circuit electrically coupled to the optical stage; and wherein the servo control circuit further enables feedback from the focus tracking circuit to the servo circuit when the imaging system is operating in a scan operation mode and disables feedback from the focus tracking circuit to the servo circuit when the imaging system is operating in a focus model generation operation mode.

2. The imaging system according to claim 1, wherein the servo control circuit includes a mode detection circuit for detecting the operation mode of the imaging system and a parameter selection circuit for applying a set of control parameters corresponding to the detected operation mode.

3. The imaging system according to claim 1, wherein the imaging system is a sequencer, the first operation mode is a focus model generation mode, and the second operation mode is a sequencing mode.

4. The imaging system according to claim 1, wherein the servo control circuit further detects the operation mode of the imaging system and selects a set of control parameters to apply to the detected operation mode.

5. The imaging system according to claim 4, wherein the servo control circuit applies the first set of control parameters or the second set of control parameters identified as a set of control parameters for the detected operation mode.

6. The imaging system according to claim 4, wherein at least one of the first set of control parameters and the second set of control parameters is optimized to take into account the structural characteristics of the imaging system.

7. The imaging system according to claim 6, wherein optimizing at least one of the first set of control parameters and the second set of control parameters includes operating the imaging system, scanning with a range of values of a control parameter in one of the first set of control parameters and the second set of control parameters, measuring the stability of the servo circuit during the scan, and selecting the value of the control parameter.

8. The imaging system according to claim 6, wherein optimizing at least one of the first set of control parameters and the second set of control parameters includes operating the imaging system, scanning with a range of values of a plurality of control parameters in one of the first set of control parameters and the second set of control parameters, measuring the stability of the servo circuit during the scanning, and determining an optimal setting of the plurality of control parameters.

9. The imaging system according to claim 1, wherein the first set of control parameters or the second set of control parameters includes servo loop gain and filter values.

10. The imaging system according to claim 1, wherein the actuator is physically coupled to the sample stage to move the sample stage to adjust a distance between the sample stage and the optical stage.

11. The imaging system according to claim 1, further comprising a plurality of actuators physically coupled to the sample stage to adjust the tilt of the sample stage.

12. The imaging system according to claim 1, wherein the actuator is physically coupled to the optical stage to move the optical stage to adjust a distance between the sample stage and the optical stage.

13. The imaging system according to claim 12, wherein the actuator includes at least one of a piezoelectric device, a voice coil, and a drive motor.

14. The imaging system according to claim 1, wherein the sample is contained in a flow cell or on a slide.

15. A method for servo control in an imaging system, the method comprising: During operation of the imaging system, a mode detection circuit determines that the imaging system is operating in a first operation mode; A servo control circuit determines a first set of control parameters selected for the first operation mode; The servo control circuit applies the determined first set of control parameters to a servo circuit of the imaging system, wherein the servo circuit controls the operation of an actuator physically coupled to at least one of a sample stage and an optical stage of the imaging system to move the sample stage relative to the optical stage; and When the mode detection circuit determines during operation of the imaging system that the imaging system has switched to operating in a second operation mode, the servo control circuit determines a second set of control parameters selected for the second operation mode and applies the determined second set of control parameters to the servo circuit, wherein the servo control circuit also enables feedback from a focus tracking circuit to the servo circuit when the imaging system is operating in a scanning operation mode and disables feedback from the focus tracking circuit to the servo circuit when the imaging system is operating in a focus model generation operation mode.

16. The method according to claim 15, wherein the servo control circuit includes a mode detection circuit for detecting an operation mode of the imaging system and a parameter selection circuit for applying a set of control parameters corresponding to the detected operation mode.

17. The method according to claim 15, further comprising the servo control circuit detecting an operation mode of the imaging system and selecting a set of control parameters to apply to the detected operation mode.

18. The method according to claim 17 further comprises the servo control circuit applying the first set of control parameters or the second set of control parameters, which are identified as a set of control parameters for the detected operation mode.

19. The method according to claim 15 further comprises optimizing at least one of the first set of control parameters and the second set of control parameters to account for the structural characteristics of the imaging system.

20. The method according to claim 19, wherein optimizing at least one of the first set of control parameters and the second set of control parameters comprises operating the imaging system, scanning with a range of values of a control parameter in one of the first set of control parameters and the second set of control parameters, measuring the stability of the servo circuit during the scanning, and selecting the value of the control parameter.

21. The method according to claim 19, wherein optimizing at least one of the first set of control parameters and the second set of control parameters comprises operating the imaging system, scanning with a range of values of a plurality of control parameters in one of the first set of control parameters and the second set of control parameters, measuring the stability of the servo circuit during the scanning, and determining the optimal settings of the plurality of control parameters.

22. The method according to claim 15, wherein the first set of control parameters or the second set of control parameters comprises a servo loop gain and a filter value.

23. The method according to claim 15 further comprises the actuator moving the sample stage to adjust the distance between the sample stage and the optical stage.

24. The method according to claim 23, wherein the actuator comprises at least one of a piezoelectric device, a voice coil, and a drive motor.

25. The method according to claim 15, wherein the imaging system is a sequencer, and the first operation mode is a focus model generation mode, and the second operation mode is a sequencing mode.

26. An imaging system comprising: a sample stage comprising a surface for supporting a sample to be scanned by the imaging system; an optical stage having an objective lens, the optical stage being positionable relative to the sample stage; a focus tracking circuit coupled to the optical stage; an actuator physically coupled to at least one of the sample stage and the optical stage to move the sample stage relative to the optical stage based on information from the focus tracking circuit; a servo circuit controlling the actuator; and a servo control circuit that enables feedback from the focus tracking circuit to the servo circuit when the imaging system is operating in a scanning operation mode and disables feedback from the focus tracking circuit to the servo circuit when the imaging system is operating in a focus model generation operation mode.

27. A method for servo control in an imaging system, the method comprising: during operation of the imaging system, a mode detection circuit determines whether the imaging system is operating in a scanning operation mode or a focus model generation operation mode; a servo circuit controls the movement of the optical stage relative to the sample stage in the imaging system; and The servo control circuit enables feedback from the focus tracking circuit to the servo circuit when the imaging system operates in the scanning operation mode, and disables the feedback from the focus tracking circuit to the servo circuit when the imaging system operates in the focus model generation operation mode.

28. A computer program medium having one or more instructions thereon that, when executed by a processing device, cause the processing device to perform the method according to any one of claims 15 - 25 and 27.

Images