Machine vision system and method using a hybrid zoom optical assembly

Abstract

An optical assembly for a machine vision system having an image sensor has a lens assembly and a motor system coupled to the lens assembly. The lens assembly has a plurality of solid lens elements and one liquid lens, and the liquid lens may have an adjustable membrane. The motor system may be configured to move the lens assembly to adjust the distance between the lens assembly and the image sensor of the vision system.

Description

Technical Field

[0001] (Cross - Reference to Related Applications) This application claims priority based on and incorporates by reference in its entirety U.S. Provisional Application No. 63 / 336,077, filed on April 28, 2022, entitled "Machine Vision System and Method with Hybrid Zoom Optical Assembly".

[0002] The present disclosure generally relates to machine vision systems, and more specifically to an optical assembly configured to control the focal length and aperture value for image acquisition using a combination of mechanical lens elements and a liquid lens.

Background Art

[0003] A machine vision system (also simply referred to as a "vision system") uses an image acquisition device including an image sensor to deliver information about an observed subject. The system can then interpret this information according to various algorithms for performing programmed decision - making or identification functions. For example, an image of an object containing features of interest to the system can be acquired under appropriate illumination by an on - board image sensor (also simply referred to as an "imager" or "sensor") in the visible light range or a range close to visible light, which can be based on ambient light or light provided by internal or external illuminators.

[0004] Vision systems may be used for a variety of tasks in manufacturing, logistics, and industry. A common task of vision systems is the reading and decoding of symbols (e.g., one-dimensional and two-dimensional codes, also often referred to as "identifiers (ID)"), which are used in a wide variety of applications and industries and can take the form of ID barcodes, two-dimensional data matrix codes, QR codes (registered trademark), and dot codes. An image sensor acquires an image of a subject or object (generally in grayscale or color, and in one, two, or three dimensions) and processes these acquired images using an on-board or interconnected vision system processor. The processor often includes both processing hardware and non-volatile computer-readable program instructions (software) that execute one or more vision system processes to generate a desired output based on the processed information in the image. This image information is typically provided within an array of image pixels, each having various colors or intensities. In the example of an ID reader (also referred to herein as a "reader"), a user or an automated process acquires an image of an object that appears to contain one or more barcodes, two-dimensional codes, or other ID types. The image is processed to identify the encoded features and then decoded by one decoding process or a plurality of decoding processes to obtain the unique alphanumeric data represented by the code.

[0005] In addition, the vision system may be used for other tasks such as, for example, inspection of surfaces and parts, alignment of objects during assembly, measurement, and any other operation in which visual data is acquired and interpreted for use in further processes. For example, the vision system may be used to inspect an object (e.g., a component or part) on a manufacturing line (e.g., during a manufacturing process) to confirm that the object meets a pre-defined standard. For example, each object may be expected to include certain features or characteristics. In the inspection process, the image sensor of the vision system can acquire an image of the object, and the image can be processed (e.g., using a vision system processor) to identify the features or characteristics of the object. The results of the inspection process can be provided to a display for the operator to observe. If the object passes the inspection, the object in question may be stored on the manufacturing line for further processing and / or handling. If the object fails the inspection, the object can be marked and / or removed from the manufacturing line.

Summary of the Invention

[0006] Embodiments of the disclosed technology can provide controllable / controlled movement of a lens assembly that includes a liquid lens and a mechanical lens to provide collective movement of the liquid lens and the mechanical lens relative to an image sensor (e.g., a camera that includes a lens assembly). In combination with corresponding control of the liquid lens, some embodiments can thus provide an improved zoom magnification range (i.e., the ratio of the maximum focal length to the minimum focal length) compared to conventional systems. Thus, for example, a camera for a machine vision system can be operated to acquire images with multiple aperture values and multiple focal lengths without exchanging hardware.

[0007] According to one embodiment, a machine vision system includes an image sensor, an optical assembly, an illumination assembly configured to project light rays onto an object, and a processor device. The optical assembly can include a lens assembly and a motor system coupled to the lens assembly and configured to move the lens assembly. The lens assembly can include a plurality of solid lens elements and a liquid lens, where the liquid lens includes an adjustable membrane. The processor device can communicate with the lens assembly and the motor system. The processor device can determine a working distance between the object to be processed and the lens assembly, adjust the curvature of the adjustable membrane of the liquid lens based on the working distance, and use the motor system to adjust the distance between the lens assembly and the image sensor based on the working distance.

[0008] In some embodiments, the processor device can communicate with the image sensor and can be configured to control the collection of an image of an object. In some embodiments, the lens assembly can further include a diaphragm having a fixed size. In some embodiments, the optical assembly can further include a mechanical iris. In some embodiments, it is possible to set a focal plane based on a combination of the curvature of the adjustable membrane of the liquid lens and the distance between the lens assembly and the image sensor. In some embodiments, the machine vision system can further include a distance sensor to obtain distance data corresponding to the distance to an object. In some embodiments, the processor device can be configured to determine an operating distance based on the distance data. In some embodiments, at least one of the focal length or the aperture value is controlled by adjusting the curvature of the adjustable membrane of the liquid lens and adjusting the distance between the lens assembly and the image sensor. In some embodiments, the processor device can be configured to control the adjustment of the distance between the liquid lens and the image sensor. In some embodiments, the processor device can be configured to control the adjustment of the distance between a plurality of solid lens elements and the image sensor. In some embodiments, the processor device can be configured to control the adjustment of the distance between a plurality of solid lens elements and the liquid lens.

[0009] According to another embodiment, an optical assembly for a machine vision system having an image sensor includes a lens assembly and a motor system coupled to the lens assembly. The lens assembly can include a plurality of solid lens elements and a liquid lens, where the liquid lens includes an adjustable membrane. The motor system can be configured to move the lens assembly to adjust the distance between the lens assembly and the image sensor of the vision system.

[0010] In some embodiments, the motor system can be configured to move the liquid lens to adjust the distance between the liquid lens and the image sensor and to adjust the distance between the liquid lens and the plurality of solid lens elements. In some embodiments, the lens assembly can further include a diaphragm having a fixed size. In some embodiments, the motor system includes a micromotor. In some embodiments, the micromotor is a microstep motor. In some embodiments, the motor system can be configured to move the lens assembly towards or away from the image sensor. In some embodiments, the motor system can be further configured to move the plurality of solid lens elements to adjust the distance between the plurality of solid lens elements and the image sensor and to adjust the distance between the plurality of solid lens elements and the liquid lens. In some embodiments, the motor system can be further configured to move the plurality of solid lens elements in a first direction and to move the liquid lens in a second direction different from the first direction.

[0011] According to another embodiment, a method of controlling the focal length and aperture value of a machine vision system includes determining a working distance between an object and a lens assembly of the machine vision system. The lens assembly can include a plurality of solid lens elements and a liquid lens, and the liquid lens can include an adjustable membrane. The method further includes adjusting the curvature of the adjustable membrane of the liquid lens based on the working distance and adjusting the distance between the lens assembly and the image sensor based on the working distance using a motor system.

[0012] In some embodiments, the method further includes acquiring an image of an object via a machine vision system. In some embodiments, determining the working distance between the object and the lens assembly includes determining the working distance based on distance data received from a distance sensor. In some embodiments, at least one of the focal length or the aperture value is controlled by adjusting the curvature of the adjustable membrane of the liquid lens and adjusting the distance between the lens assembly and the image sensor. In some embodiments, the focal length controls the field of view (FOV) and the zoom ratio. In some embodiments, the aperture value controls the amount of light received by the image sensor and the depth of field (DOF). In some embodiments, adjusting the distance between the lens assembly and the image sensor includes changing the position of the lens assembly. In some embodiments, adjusting the distance between the lens assembly and the image sensor includes changing the position of the liquid lens. In some embodiments, adjusting the distance between the lens assembly and the image sensor includes changing the positions of a plurality of solid lens elements. In some embodiments, the method further includes using a motor system to adjust the distance between a plurality of solid lens elements and the liquid lens by changing the positions of the solid lens elements along a first direction and changing the position of the liquid lens along a second direction different from the first direction.

[0013] The present disclosure will be described below with reference to the accompanying drawings, in which like reference numerals denote like elements.

Brief Description of the Drawings

[0014]

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DETAILED DESCRIPTION OF THE INVENTION

[0015] The vision system may be used in a variety of applications, including reading and decoding identifiers (IDs, e.g., barcodes), logistics (e.g., presentation mode), inspection of objects and surfaces, alignment of objects during assembly, measurement, factory automation, and any other operation in which visual data is acquired and interpreted for further processing. ID (e.g., barcode) readers are generally configured to track and sort objects, including along a line (e.g., conveyor) in manufacturing and logistics operations. ID readers, or more typically, a plurality of readers (constellation), are placed on the line at an appropriate viewing angle to acquire any expected ID code(s) on the corresponding surface(s) of the object(s) that can pass through the field of view. ID readers may also be provided in a hand-held configuration, allowing the user to move from object to object, e.g., on an inspection floor, and arbitrarily vary the distance or relative angle between the reader and the surface of the object. More generally, the focal length of the ID reader with respect to the object can vary depending on the position of the reader with respect to the line and the size of the object.

[0016] Vision systems for inspection generally capture an image of an object (e.g., a component or part) on a manufacturing or assembly line, process the image to determine whether the object meets a predefined criterion (e.g., one or more expected features are present), and report the inspection results. Such machine vision systems can be useful for the inspection, assembly, and / or handling of various types of articles, parts, and devices, including automotive parts (e.g., fuses, gaskets, and spark plugs), electrical components (e.g., connector pins, keyboards, LEDs, LCD displays), medical and pharmaceutical products (e.g., disposable test kits, syringes, needles, and date lot codes), and consumer products (e.g., razor blades and floppy disks).

[0017] During operation, some vision systems (e.g., ID readers or inspection systems) or associated lighting mounting members function to illuminate a scene that includes one or more objects (e.g., ID components or parts). In the case of an ID reader, this illumination can include a sight that projects colored dots onto the region of interest within the imaged scene, whereby the user can aim the image axis of the reader onto a barcode within the imaged scene. Illumination for a vision system can also include overall illumination to enable the acquisition of an appropriately detailed image. The illuminated scene is then acquired by an image sensor within the imaging system via an optical system. An array of sensor pixels is exposed, and the electronic values generated for each pixel by that exposure are called an “image” of the scene and stored in an array by memory cells. In the context of an ID reading application, the scene can include an object of interest having one or more IDs of an appropriate size and type (e.g., direct part marking (DPM) codes, printed barcodes, etc.). The ID is part of the stored image. In the context of an inspection system, the scene can include a region that encompasses all relevant parts of the object of interest within the field of view and the region around the object of interest.

[0018] Some important considerations for vision system applications include, for example, field of view (or zoom, magnification), the amount of light received from a target (e.g., an object), and depth of field (DOF). For example, the field of view (FOV), amount of light, and depth of field are important design considerations in applications where the working distance to the target is variable. The optimal field of view, amount of light, and depth of field can vary for different vision system applications, including between different images obtained by a particular vision system.

[0019] The field of view of a vision system can be controlled by the focal length of the lens within the system. The focal length is the distance from the center of the lens to the imaging point (focal plane) where light for the image is focused, and is the reciprocal of the refractive power of the vision system. Generally, increasing the focal length may increase the magnification and narrow the field of view, while decreasing the focal length may decrease the magnification and increase (or widen) the field of view. The amount of light and depth of field of a vision system can be controlled by the size of the aperture (e.g., diameter), as well as the aperture value (commonly expressed as an F-number) for the vision system. The aperture value (or F-number) determines the amount of light incident on the image sensor and is proportional to the depth of field. The depth of field determines the range of distances from the vision system within which an object in the acquired image is in focus (e.g., sharpness). Generally, a smaller aperture value (or F-number) produces a brighter system (e.g., more light) and a smaller depth of field, while a larger aperture value (or F-number) produces a darker system (e.g., less light) and a larger depth of field. A larger depth of field enables objects at a wider range of distances from the vision system to be in focus simultaneously.

[0020] In many conventional vision systems, a single fixed aperture is used. The aperture of a vision system is typically selected based on the working distance range expected in a particular application of the vision system. For example, an imaging device may be configured to include a fixed-structure aperture that provides a maximum depth of field at a maximum working distance. Further, the aperture is typically disposed in a lens assembly between various glass elements that make it difficult to access the aperture. In many conventional systems, the aperture (and thus the depth of field) can only be changed by changing the lenses of the system, which can be costly and complex, especially for vision systems that are already deployed in the field. In other conventional devices, the aperture may be mechanically changed, but this is typically slower than is practical for certain applications and raises concerns about reliability due to the complexity of certain moving parts.

[0021] A vision system may include an autofocus function. In the case of a conventional mechanical lens, for example, the mechanical part of the lens can be moved to adjust the focus and refractive power. However, such a mechanical system based on a moving lens generally can only limit the aperture value and cannot control the field of view. For a liquid lens without mechanical moving parts (e.g., to avoid problems such as vibration and speed), the voltage passed through the lens is changed to change the curvature of the liquid lens interface (or membrane). The change in curvature results in a change in the focal length of the lens. However, since the liquid lens is one of the smallest elements in the system and the liquid lens effectively acts as an aperture stop, a system that controls the liquid lens as a focusing element usually has a substantially constant aperture value and cannot change the aperture value. Furthermore, for a liquid lens system, since the liquid lens typically does not transmit strong refractive power to the vision system, the range of change in focal length is limited. Therefore, such a liquid lens system may also not be able to provide useful control of the field of view of the system. Additionally, neither the conventional mechanical system nor the conventional liquid lens system described above can provide control of both the zoom capability (field of view) and the aperture value simultaneously.

[0022] In other aspects, the present disclosure describes a vision system (and related methods, etc.) that includes an optical assembly configured to enable control of the focal length and aperture value using a combination of mechanical and liquid lens technologies to provide various imaging configurations. In some cases, the disclosed optical assembly can thus advantageously adapt to different focal lengths and aperture values without the need for hardware changes. The various imaging configurations can usefully provide, for example, a desired field of view (FOV) or zoom, the amount of light reflected by an object received for an image, and a depth of field (DOF) by controlling the focal length and aperture value based on, for example, the working distance.

[0023] In some embodiments, the optical assembly can include a lens assembly having both a solid lens element and a liquid lens element - for example, a plurality of solid (e.g., glass) lens elements and at least one liquid lens element. A motor system can be coupled to the lens assembly and configured to move the lens assembly toward and away from an image sensor within a vision system. Thus, a combination of a plurality of solid lens elements and one or more liquid lenses can be moved together by a motor system (e.g., via an electric movement of a chassis that commonly supports both types of lenses). In some embodiments, the motor system can be used to adjust the distance between the lens assembly and the image sensor to selectively provide a particular imaging configuration. In some embodiments, the motor system can be used to move a liquid lens to adjust the distance between the liquid lens and the image sensor or to adjust the distance between the liquid lens and the plurality of solid lens elements. The liquid lens(es) can include an interface (or membrane), and the curvature of the interface (or membrane) can also be adjusted based on the needs in the system (e.g., for a particular working distance). In some embodiments, the motor system can be used to move a plurality of solid lens elements to adjust the distance between the plurality of solid lens elements and the liquid lens or to adjust the distance between the plurality of solid lens elements and the image sensor. In some embodiments, the motor system may be used to move a plurality of solid lens elements in a first direction and a liquid lens in a second direction that is different from the first direction. For example, the motor system can be used to move the plurality of solid lens elements and the liquid lens away from each other or toward each other to adjust the distance between the plurality of solid lens elements and the liquid lens. Further, in this case, by separating or separating the plurality of solid lens elements and the liquid lens from each other, the distance between the plurality of solid lens elements and the image sensor and the distance between the liquid lens and the image sensor can be changed.

[0024] Advantageously, the position of the lens assembly (e.g., to collectively define a desired spacing between the glass and the liquid lens element) and the curvature of one or more liquid lenses are controlled to provide a desired focal length and aperture value for image acquisition, and to control one or more desired imaging parameters for a vision system, such as, for example, field of view, light quantity, and depth of field. In some embodiments, depending on how the curvature of the membrane of one or more liquid lenses and the adjustable distance between the lens assembly and the image sensor are combined, the vision system can be made such that the focal value becomes shorter or longer (i.e., the field of view becomes larger or smaller), and brighter or darker (i.e., a lower or higher aperture value). For example, for a certain working distance, both the curvature of the liquid lens (or lenses) and the distance between the lens assembly and the image sensor can be set to generate an image having a certain field of view (i.e., zoom or magnification) and light quantity (i.e., brightness).

[0025] In some embodiments, the motor system can include a micromotor, such as a microstep motor. In some embodiments, the motor system can also include, for example, one or more gears and a screw portion assembly that can be used to move the lens assembly towards or away from the image sensor.

[0026] In some embodiments, the vision system may also include one or more processors (or processor devices) and a distance sensor. The processor may communicate with various other elements of the vision system, including, for example, an image sensor, a lens assembly, a motor system, and a distance sensor. The distance sensor (e.g., a time-of-flight (TOF) system) may be configured to obtain distance data regarding an object imaged by the vision system. In some embodiments, the processor may be configured to determine a working distance to the object based on the distance data from the distance sensor. In some embodiments, the processor may be configured to determine the working distance to the object using other techniques, such as image analysis, for example. Based on the determined working distance, the processor may then be used to adjust the curvature of the interface (or membrane) of the liquid lens in the lens assembly to generate a focal length and to control the motor system to adjust the position of the lens assembly to generate an aperture value. In some embodiments, the processor may determine a desired focal length and aperture value based on the determined working distance, for example, by a look-up table of focal length and aperture value based on arithmetic or working distance, and then adjust the liquid lens membrane and the position of the lens assembly to generate the focal length and aperture value. In some embodiments, the processor may perform a predetermined adjustment of the liquid lens membrane and the position of the lens assembly based on the determined working distance. For example, the processor may access and use a look-up table of adjustments to the position of the lens assembly based on the liquid lens membrane or the working distance. Depending on the embodiment, the look-up table can be associated with a particular use of the vision system.

[0027] In some embodiments, the processor and motor system can be used to adjust the distance between the lens assembly (i.e., including all of the plurality of solid lens elements and the liquid lens) and the image sensor. In some embodiments, the processor and motor system can be used to move the liquid lens of the lens assembly to adjust the distance between the liquid lens and the image sensor and to adjust the distance between the liquid lens and the plurality of solid lens elements. In either case, the vision system can be used to obtain an image of an object at the measured working distance using the appropriate position of the lens assembly or the appropriate position of the liquid lens of the lens assembly. In some embodiments, the focal length and aperture value can also be used to control the field of view (or zoom or magnification), the amount of light, and the depth of field used to obtain an image of an object at the measured working distance.

[0028] As described above, in some embodiments, the disclosed optical assembly can appropriately accommodate different focal lengths and different aperture values using the same lens or lens assembly without requiring hardware changes. Thus, the disclosed vision system and optical assembly have the flexibility to be used for a variety of different scenarios. For example, the disclosed vision system can be used to provide a larger aperture value for a larger working distance when it is desirable to collect as much light as possible. In another example, the disclosed vision system may vary the focal length for a shorter working distance when the camera needs to operate at a close distance and the field of view is not large enough. As described above, in some embodiments, the optical assembly can advantageously combine both the focal length and the aperture value because it allows for the simultaneous control of both the focal length and the aperture value. Therefore, the disclosed optical assembly expands the possible uses for existing lenses and thus converts existing lenses into more valuable optical systems.

[0029] In some embodiments, the disclosed vision system can be used in various vision system applications such as for logistics (e.g., for presentation mode scanning) or for fixed-mounted readers for factory automation. Advantageously, by being able to have different aperture values and focal lengths, it is possible to avoid a multi-camera configuration, for example when working with different apertures and / or different working distances.

[0030] The disclosed vision system and optical assembly can also offer other advantages. For example, the disclosed vision system and optical assembly enable the camera to have different fields of view and different aperture values for optimizing 1) the amount of light (e.g., aperture value control), 2) the field of view size (zoom or focal length control), and 3) the reading range (depth of field control). In another example, the disclosed vision system can be used with existing lenses or lens assemblies to extend the imaging techniques conceivable in the field. In yet another example, in some embodiments, the disclosed vision system and optical assembly can be implemented with only one additional hardware assembly that is required, i.e., a motor system including, for example, a micromotor.

[0031] In some embodiments, the disclosed system and method can be used to convert a fixed-focus lens or lens assembly into multiple sets of imaging options or configurations that are given the ability to set both the curvature of the liquid lens interface (or membrane) and the adjustable distance between the lens (or lens assembly) itself and the image sensor. Thus, using the lens assembly, the vision system can be converted into a more versatile imaging system, providing more flexibility for the vision system to handle various use cases depending on, for example, how much light and field of view size are required.

[0032] In some embodiments, the disclosed optical assembly can be combined with a steerable (tilting) mirror configured to further control the field of view for a vision system. For example, in some embodiments, the disclosed vision system can further include a steerable two-axis mirror as described in U.S. Patent Application Publication No. 2021 / 0185233, entitled "Machine Vision System and Method with a Steerable Mirror", which is hereby incorporated by reference in its entirety. In some embodiments, the steerable mirror can be placed in front of the lens assembly and used to provide an additional magnification factor for each dedicated field of view of the vision system. By combining the disclosed optical assembly with a steerable field-of-view element, such as a steerable mirror, it is advantageously possible to cover a large area with the camera and, for example, due to a zoom effect that can be important at a greater working distance, enable more details in the image.

[0033] FIG. 1 is a schematic configuration diagram of a vision system including a hybrid optical assembly according to an embodiment of the present technology. FIG. 1 shows one embodiment of the vision system configuration, but it should be understood that the various embodiments described herein can be implemented on different types of vision systems, including but not limited to mobile (e.g., handheld) or stationary mount ID readers, inspection systems, etc. Note that the illustrated arrangement of components is exemplary of a wide range of layouts and types of components. This explanatory diagram is therefore provided to teach a possible arrangement of components that provide the functions of an exemplary embodiment, but other embodiments can also show other configurations.

[0034] The vision system 100 includes a processor 102, a vision camera assembly 114, an illumination system 116, and a distance sensor (ranging sensor) 122 and can be used to acquire an image of an object 110 or an exemplary identifier (ID, e.g., barcode) 112 on the object 110. In the illustrated example, at least the vision camera assembly 114 and the motor system 118 can form part of an integrated assembly (e.g., within a single housing or module of a single camera or operably attached). In the illustrated embodiment, the vision camera assembly 114 includes an image sensor 104 and an optical assembly 120. The optical assembly 120 shown in FIG. 1 includes an optical system 106 having a lens assembly 108. The image can be acquired by projecting illumination light onto the object 110 (e.g., via active or passive illumination) and receiving the reflected illumination light from the object 110. Thus, the optics 106 of the optical assembly 120 are disposed in front of the image sensor 104. The lens assembly 108 of the optical assembly 120 includes a series of lens elements that project image light onto an area of the image sensor 104 and, correspondingly, define a focus for imaging by the image sensor 104. The vision system 100 also includes processing components (e.g., the processor 102) that perform various vision system tasks such as ID code discovery and decoding, inspection, etc.

[0035] In some embodiments, the lens assembly 108 includes a plurality of solid (e.g., glass) lens elements and at least one liquid lens (e.g., collectively supported on a common chassis). The motor system 118 is coupled to the lens assembly 108 and is thus configured to move the lens assembly 108 (e.g., the plurality of solid lens elements and the liquid lens) toward or away from the image sensor 104. Advantageously, in some embodiments, the motor system 118 can be used to change the position of the lens assembly 108, adjust the distance 124 between the lens assembly 108 and the imaging device 104, and selectively provide any of a variety of desired imaging configurations. In some embodiments, the motor system can be used by itself to change the position of the liquid lens in order to adjust the distance 132 (shown in FIG. 2) between the liquid lens and the plurality of solid lens elements, as well as the distance between the liquid lens and the image sensor 104. In some embodiments, the motor system 118 is used to change the position of the plurality of solid lens elements by itself to adjust the distance 132 (shown in FIG. 2) between the plurality of solid lens elements and the liquid lens, as well as the distance between the plurality of solid lens elements and the image sensor 104. In some embodiments, the motor system 118 can be used to change the position of the plurality of solid lens elements along a first direction and to change the position of the liquid lens along a second direction different from the first direction. For example, the motor system 118 can be used to move the plurality of solid lens elements and the liquid lens away from each other or closer to each other to adjust the distance 132 (shown in FIG. 2) between the plurality of solid lens elements and the liquid lens. Further, in this case, by separating or separating the plurality of solid lens elements and the liquid lens from each other, the distance between the plurality of solid lens elements and the image sensor 104 and the distance between the liquid lens and the image sensor 104 can be changed. Also, the focal length and refractive power of the liquid lens can be adjusted, for example, by changing the voltage applied to the liquid lens to change the curvature of the interface (or membrane) of the liquid lens.In some embodiments, the motor system 118 can include a micromotor (not shown), such as a microstep motor for example. In one embodiment, the motor system 118 can also include, for example, one or more gears and a screw assembly (not shown) that can be used in combination with the micromotor to move the lens assembly 108 towards or away from the image sensor 104. However, as another embodiment, it can include various transmission elements for the controllable linear movement of the lens assembly 108 with respect to the image sensor 104.

[0036] Processor 102 may be in communication with lens assembly 108 (e.g., a liquid lens), motor system 118, and distance sensor 122. In some embodiments, processor 102 may be configured to receive distance data regarding an object from distance sensor 122. The distance sensor may be, for example, a time-of-flight (TOF) sensor or system. In some embodiments, processor 102 may use various methods to determine the working distance between object 110 and lens assembly 108 based on the acquired distance data. In some embodiments, processor 102 may be configured to determine the working distance between object 110 and lens assembly 108 using other techniques such as, for example, image analysis. In some embodiments, various constraints of a particular vision system application, such as, for example, the speed of an object on a conveyor, the curvature of the object, the size of ID 112 (e.g., a code) on object 110, etc., may be considered when determining the working distance to the object. In some embodiments, once the working distance to object 110 is determined, processor 102 may be used to set and control the focal length (and related refractive power and field of view) and aperture value (and related light amount and depth of field) of vision system 100 based on the determined working distance. For example, the focal length and aperture value may be controlled based on the working distance to obtain a sharp image. Further, the focal length may be used, for example, to control the field of view, and the aperture value may be used, for example, to control the amount of light reflected from object 110 and the depth of field.

[0037] Based on the determined working distance, the processor may be used to adjust the curvature of the interface (or membrane) of the liquid lens within the lens assembly to generate a focal length and to control a motor system to adjust the position of the lens assembly to generate an aperture value. In some embodiments, the processor determines a desired focal length and aperture value based on the determined working distance, for example, by a look-up table of focal length and aperture value by calculation or working distance, and then adjusts the position of the liquid lens membrane and the lens assembly to generate the specified focal length and aperture value. In some embodiments, the processor may perform a predetermined adjustment of the liquid lens membrane and the position of the lens assembly based on the determined working distance. For example, the processor can access and use a look-up table of adjustments to the position of the lens assembly based on the liquid lens membrane or the working distance. Depending on the embodiment, the look-up table can be associated with a particular application of the vision system.

[0038] In some embodiments, both the focal length (or focus value) and the aperture value (or F-number) may vary for different working distances. In one example application, as the working distance increases, the features or objects being imaged appear smaller. In this example application, it is assumed that there is sufficient light for all possible working distances of the application. Based on the working distance, the focal length can be controlled (e.g., to a larger focal length) to generate an optimal magnification, and the aperture value can be controlled (e.g., to a larger aperture value) to generate an optimal depth of field. In this example application, the focal length and the aperture value can be controlled such that as the working distance increases, the aperture value (or F-number) increases and the focal length (or focus value) increases. Thus, the vision system may be configured for a large field of view at a close working distance with a larger depth of field. In another example application, it is necessary to create an image of a larger object at a larger working distance. In this example application, the amount of light may be limited for larger working distances. However, the disclosed apparatus can expand the field of view (i.e., use a shorter focal length (or focus value)). Based on the working distance, the focal length can be controlled (e.g., to a shorter focal length) to generate a larger field of view. In this example application, the focal length and the aperture value can be controlled such that as the working distance increases, the aperture value (or F-number) decreases and the focal length (or focus value) decreases. Thus, the vision system may be configured for a large field of view at a larger working distance with a larger light reception amount or light amount.

[0039] In some embodiments, one of the focal length or the aperture value may be the same for all working distances, and the other of the focal length or the aperture value may be different for different working distances. In one example application, the focal length may be the same for all working distances (i.e., the magnification is sufficient), but at larger working distances, it is necessary to increase the amount of light (i.e., it is necessary to collect more light). In this exemplary application, the amount of light can be controlled by controlling the combination of the luminous intensity of the liquid lens and the distance of the lens from the image sensor. Accordingly, the vision system may be configured to provide the brightness required at large working distances. In this example application, the focal length and the aperture value can be controlled such that as the working distance increases, the aperture value (or F-number) decreases and the focal length (or focus value) decreases.

[0040] The processor 102 may be configured to adjust the curvature of the interface of the liquid lens in the lens assembly 108 and generate and set the focal length, for example, by applying a voltage to the liquid lens. Further, the processor 102 can be used to control the motor system 118 to adjust, for example, the distance between the lens assembly 108 and the image sensor 104 to generate an aperture value. In some embodiments, the processor 102 is used to control the motor system 118 to adjust the distance 132 (shown in FIG. 2) between the liquid lens of the lens assembly 108 and the image capturing element 104, as well as the distance between the liquid lens and the image capturing element 104.

[0041] In some embodiments, the lens assembly 108 can have a fixed aperture size (i.e., diameter). In certain embodiments, the lens assembly 108 can further include a mechanical iris (not shown), which can provide an additional parameter to be controlled in addition to the curvature of the liquid lens interface and the distance between the lens assembly 108 and the image sensor 104. In particular, by using a mechanical iris and changing the size of the mechanical iris, the range of possible aperture values (or F-numbers) for the vision system 100 can be expanded.

[0042] In some embodiments, a combination of adjusting the distance between the lens assembly 108 and the image sensor 104 and adjusting the curvature of the liquid lens within the lens assembly 108 can advantageously be used to enable, for example, automatic adjustment and control of the focal length and aperture value for images at different working distances. Further, the focal plane of the lens assembly can be set based on a combination of adjusting the curvature of the membrane of at least one adjustable liquid lens and the distance between the lens assembly and the image sensor. By controlling the focal length and aperture value, various characteristics and parameters of the vision system, such as the field of view, the amount of light, and the depth of field of the subject, can be controlled. In some embodiments, the focal length and aperture value can be controlled for a single image of an object, for multiple images of an object, or for each image within a series of images of an object. Generally, while some specific examples are provided above, the processor 102 can generally be configured to determine a specific imaging configuration (e.g., focal length and aperture value) for a particular image collection based on any of a variety of considerations for machine vision operations implemented via a control system and process according to embodiments of the disclosed technology.

[0043] In addition, the processor 102 can communicate with the image sensor 104 and the illumination assembly 116. The illumination assembly 116 can be configured to provide illumination such as light in a specific wavelength band centered around the visible spectrum, light of a specific polarization, etc. In some embodiments, the illumination assembly can include one or more LEDs or laser diodes to provide the illumination light (or light beam). The light projected from the illumination assembly 116, reflected from the object 110, and returned to the vision system 100 passes through the lens assembly 108 and is directed towards the image sensor 104 along the reader optical axis (OA). The image sensor 104 can be configured to detect light of different wavelengths or can also be configured to detect different polarizations of light. In certain embodiments, the image sensor 104 can be a monochromatic sensor (e.g., black and white) or a color sensor. The reflected light is received by the image sensor 104 for processing (e.g., by the processor 102), for example, to generate an image of the subject (e.g., the object 110). Various methods can be used to generate an image of the scene and decode the data therein.

[0044] In some embodiments, the processor 102 can be provided on one or more circuit boards and can include one or more processor devices operably interconnected by a suitable ribbon cable or other communication channel (not shown). The processor 102 can be configured to control vision system analysis processing (e.g., ID reading and decoding), as well as illumination for image acquisition (e.g., timing or intensity of illumination, selection of light sources for illumination, etc.), autofocus adjustment, and other functions. The system 100 can also be configured to wirelessly transmit the decoded data (via a wireless link not shown) to a data processing device such as an inventory tracking computer or for logistics applications. Alternatively, the system 100 can be wired to a data processing network or can store and then transfer information collected when connected to a base unit. Also, the processor 102 can communicate with various other components (not shown) such as a motor for adjusting the orientation of the system, or various other actuators.

[0045] In some embodiments, the disclosed optical assembly 120 can be combined with an optional steerable (tiltable) mirror 140 configured to further control the field of view for the vision system. In some embodiments, the steerable mirror 140 can be a steerable two-axis mirror. The steerable mirror 140 can be placed in front of the lens assembly 108 and can be used to provide an additional magnification factor for each dedicated field of view of the vision system 100. By combining the disclosed optical assembly 120 with a steerable field of view element such as, for example, the steerable mirror 140, it is advantageously possible to cover a larger area with the camera 114 and also to enable more detail in the image, for example, by a zoom effect that can be valued at greater working distances.

[0046] FIG. 2 is a schematic configuration diagram of a hybrid optical assembly according to an embodiment implemented for the hybrid optical assembly 120 of FIG. 1. In the illustrated embodiment, the hybrid optical assembly 120 can include a lens assembly 108 and a motor system 118 coupled to the lens assembly 108. Light projected from an illumination assembly (e.g., illumination assembly 116 shown in FIG. 1) that is reflected back from an object (e.g., object 110) to the vision system passes through the lens assembly 108 and is directed toward the image sensor 104 along the reader optical axis (OA). Thus, the lens assembly 108 can project light rays reflected from the object onto the image sensor 104.

[0047] In particular, as shown in the example of FIG. 2, the lens assembly 108 can include a plurality of solid (e.g., glass) lens elements 126 with at least one liquid lens 128. In some embodiments, the plurality of solid lens elements 126 and the liquid lens 128 can be located within the housing 134, and the motor system 118 can be coupled to the housing 134. As also described above, in some embodiments, the motor system 118 can include a micromotor, such as a microstep motor. Similarly, in certain embodiments, the motor system 118 can include, for example, one or more gears and a screw assembly (not shown) that can be used in combination with the micromotor to move the lens assembly 108 towards or away from the image sensor 104. The motor system 118 is controlled, for example, using the processor 102 of the vision system 100 (shown in FIG. 1) to move the position of the lens assembly 108 (i.e., the entirety of the plurality of solid lenses 126 and the liquid lens 128). For example, the motor system 118 can be controlled to adjust the distance 124 between the lens assembly 108 and the image sensor 104 of the vision system based on a determined working distance or other relevant parameters. In some embodiments, the motor system 118 is controlled (e.g., using the processor 102 of the vision system 100) to change only the position of the liquid lens 128 (i.e., adjust the distance between the liquid lens 128 and the lens element 126). For example, the motor system 118 can be controlled to adjust the distance 124 between the liquid lens 128 and the image sensor 104, as well as the distance 132 between the liquid lens 128 and the plurality of solid lens elements 126. In some embodiments, the motor system 118 is controlled (e.g., using the processor 102 of the vision system 100) to change only the position of the plurality of solid lens elements 126, and for example, can adjust the distance 132 between the plurality of solid lens elements 126 and the liquid lens 128, as well as the distance between the plurality of solid lens elements 126 and the image sensor 104.In some embodiments, the motor system 118 can be controlled to vary the positions of the plurality of solid lens elements 126 along a first direction (e.g., using the processor 102 of the vision system 100) and to vary the position of the liquid lens 128 along a second direction different from the first direction. For example, the motor system 118 can be controlled to move the plurality of solid lens elements 126 and the liquid lens 128 away from or closer to each other to adjust the distance 132 between the plurality of solid lens elements 126 and the liquid lens 128. Further, in this example, by moving the plurality of solid lens elements 126 and the liquid lens 127 away from or closer to each other, the distance between the plurality of solid lens elements 126 and the image sensor 104 and the distance between the liquid lens 128 and the image sensor 104 can be varied. As described above, the distance 124 between the lens assembly 108 (or, in some embodiments, the liquid lens 128) and the image sensor 104 and / or the distance 132 between the liquid lens 128 and the plurality of solid lens elements 126 may be adjusted based on the measured working distance to an object (e.g., object 110 shown in FIG. 1) imaged by the vision system.

[0048] In some embodiments, the lens assembly 108 can have a fixed aperture dimension (i.e., diameter). In some embodiments, the lens assembly 108 can further include a mechanical iris (not shown), which can be used to expand the range of aperture values (or F-numbers) possible for the vision system by changing the size of the mechanical iris (e.g., in combination with the control of the motor system 118 and the liquid lens 128 to adjust the overall aperture value).

[0049] The liquid lens 128 can include an interface (or membrane) 136 having an adjustable curvature 130. In some embodiments, the curvature 130 of the liquid lens interface 136 can be adjusted by applying a voltage to the liquid lens interface 136 using a processor, such as processor 102 of vision system 100 shown in FIG. 1. As described above, the curvature of the liquid lens interface 136 can be adjusted based on the working distance measured with respect to an object (e.g., object 110 shown in FIG. 1) imaged by the vision system.

[0050] As described above, by using the optical assembly 120 to control the focal length and aperture value, various characteristics and parameters of the vision system, such as, for example, the field of view, the amount of light, and the depth of field of the subject, can be controlled. In some embodiments, the focal length and aperture value can be controlled for a single image of an object, for multiple images of an object, or for each image within a series of images of an object.

[0051] FIG. 3A is a diagram showing exemplary ray tracing for the lens assembly of the hybrid optical assembly of FIGS. 1 and 2, according to an embodiment of the present technology. As described above, the lens assembly 108 can include a plurality of lens elements including a plurality of solid lens elements 126 and at least one liquid lens 128. The lens assembly 108 can be used to project light reflected from an object being imaged onto the image sensor 104. Further, as described above, the focal length and aperture value defined by the lens assembly 108 can be controlled based on the requirements of the vision system to obtain, for example, an image of an object at a specific working distance.

[0052] Figure 3B is a diagram simplifying the complex system of the lens assembly in Figure 3A according to an embodiment of the present technology, thereby further showing the principles and advantages of the disclosed optical assembly and method for controlling the focal length and aperture value by providing different imaging configurations using a combination of mechanical lens and liquid lens technologies. As described above, the disclosed optical assembly including the lens assembly 108 can advantageously adapt to different focal lengths and aperture values without requiring hardware changes. Various imaging configurations can provide, for example, a desired field of view (FOV) or zoom, the amount of light reflected by an object, and the depth of field (DOF) by controlling the focal length and aperture value based on, for example, the working distance. In Figure 3B, the complex system of the lens assembly 108 is simplified into two single components, namely, a plurality of solid (e.g., glass) lens elements 126 represented by the arrow 142 and a liquid lens 128 represented by the arrow 144. Further, the following distances of interest are also shown in the figure: 1) a g = object distance with respect to the solid lens element 142 (with respect to the object O) (i.e., the working distance with respect to the object O); b) f’ g = focal length of the solid lens element 142; c) a’ g = image distance with respect to the solid lens element 142 (with respect to the image I); d) a LL = object distance with respect to the liquid lens 144; e) f’ LL = focal length of the liquid lens 144; f) a’ LL = image distance with respect to the liquid lens 144 (i.e., the image sensor plane); g) = coupling optical distance between the solid element 142 and the liquid lens 144. The image distance a’ with respect to the solid lens element 142 g is given as follows:

Equation

[0053] In the field of optics, any pair of lenses can function effectively as just one lens element, and thus any number of lenses can also be described as just one element via the combined optical system equation (or abbreviated as the combined equation). The main elements within the lens assembly 108 are the fixed solid lens elements 126, 142 and the liquid lenses 128, 144 which are movable elements, and thus can affect other parts of the system. The combined equation for the assembly 108 is thus represented by the following equation: [Number]

[0054] where f’ total is the overall focal length of the system 108. Considering that for only the liquid lens element, f’ LL can vary in Equation 2, the overall focal length f’ total of the system is generally considered to be restricted to a usually limiting and very narrow set of focal values, corresponding to the drawbacks in conventional systems (such as those described above). However, another potential depth of field for the assembly 108 is to make the distance a’ LL a variable by moving the entire system 108.

[0055] e, a’ g, a LL Considering the relationship between them, and the fact that the focal length of the solid lens element 142 can be given as follows: [Number] The notation of f’ g in Equation 3 can be substituted into the equation for the overall focal length f’ total given by Equation 1, and the focal length f’ LL of the liquid lens 144 which is a function of the focal refractive power f’ total and the distance a’ LL which can be varied via the overall displacement of the lens assembly 108 with respect to the image sensor 104.can be used to derive the relationship therewith. Therefore, the overall focal length f’ total is expressed by the following equation:

Equation

[0056] Finally, the aperture value (i.e., F-number) is given by the following equation:

Equation

Equation

Equation

[0057] Figure 4 shows a method for controlling the focal length and aperture value of a vision system according to an embodiment of the present technology. In block 402, the working distance between the object to be imaged and the lens assembly of the optical assembly of the vision system is determined. Generally, various methods can be used to determine the working distance to the object. For example, in some embodiments, an integrated or attached distance sensor (e.g., a TOF sensor) may be used to obtain distance data about the object, and a processor may be used to determine the working distance based on the distance data obtained from the distance sensor. In some embodiments, the working distance to the object can be determined using other techniques such as, for example, image analysis. In some embodiments, various constraints of a particular vision system application may be considered when determining the working distance to the object, and may include, for example, the speed of the object on the conveyor, the curvature of the object, the size of the ID (e.g., code) on the object, etc. In some embodiments, the lens assembly includes a plurality of solid lens elements and a liquid lens, and the working distance is measured between the plurality of solid lens elements and the object.

[0058] In block 404, based on the measured working distance, the curvature of the interface (or membrane) of the liquid lens within the lens assembly may be adjusted. For example, in some embodiments, a processor may be used to apply a voltage to the liquid lens interface to change the curvature. In some embodiments, the desired focal length can be determined based on the measured working distance by, for example, a look-up table including at least a predetermined focal length depending on the operation or working distance (e.g., using a processor). In some embodiments, a predetermined adjustment of the liquid lens membrane may be identified using a look-up table including at least a set of predetermined adjustments to the liquid lens membrane based on the working distance (e.g., using a processor). In some embodiments, each look-up table can be associated with a particular application of the vision system.

[0059] In block 406, based on the measured working distance, it is possible to adjust the distance between the lens assembly and the image sensor within the vision system. For example, in some embodiments, the optical assembly can also include a motor system that can be coupled to the lens assembly. In some embodiments, the motor system can be controlled by a processor to move the lens assembly towards or away from the image sensor to adjust the distance between the lens assembly and the image sensor. In some embodiments, the motor system is used to move the entire lens assembly, i.e., a plurality of solid lens elements and optionally a liquid lens, together. In some embodiments, the motor system is used to move the liquid lens of the lens assembly towards the image sensor and away from the plurality of solid lens elements, or to move the liquid lens away from the image sensor and towards the plurality of solid lens elements. In some embodiments, the motor system is used to move the plurality of solid lens elements of the lens assembly towards the liquid lens and the image sensor, and to move the plurality of solid lens elements away from the liquid lens and the image sensor. In some embodiments, the motor system is used to move the plurality of solid lens elements in a first direction and the liquid lens in a second direction different from the first direction. For example, using the motor system 118, it is possible to move the plurality of solid lens elements and the liquid lens away from each other or towards each other. Thus, for example, in FIG. 3B, a third input parameter e corresponding to the distance (e.g., in addition to the optical lens focal length and the optical lens image distance) can be controlled to provide an optimized imaging configuration. In some embodiments, the desired aperture value can be determined (e.g., using a processor) based on the measured working distance, for example, by a look-up table including at least a predetermined aperture value depending on the calculation or the working distance.In some embodiments, a predetermined adjustment of the position of the lens assembly can be identified (e.g., using a processor) using a look-up table that includes at least one set of predetermined adjustments of the position of the lens assembly based on the working distance. In some embodiments, each look-up table can be associated with a particular use of the vision system.

[0060] In some embodiments, the lens assembly has a fixed aperture value. In some embodiments, the lens assembly may also include a mechanical iris that can be used to expand the range of aperture values (or F-numbers) for the vision system by changing the size of the mechanical iris. As described above, by controlling the focal length and the aperture value, various characteristics and parameters of the vision system, such as, for example, the field of view, the amount of light, and the depth of field of the subject, can be controlled. For example, the field of view, the amount of light, and the depth of field of the subject can be controlled based on the needs of the vision system for the measured working distance.

[0061] In block 408, the vision system can be used to acquire an image of an object using a desired focal length and aperture value based on the working distance measured for the object. It is possible to use various methods to generate an image of the corresponding scene and decode the data therein.

[0062] The foregoing is a detailed description of exemplary embodiments of the present technology. Various modifications and additions can be made without departing from the spirit and scope of the present disclosure. Each feature of the various embodiments described above can be combined, as appropriate, with the features of other described embodiments to provide combinations of numerous features in related new embodiments. Further, although numerous individual embodiments of the apparatus and method of the present disclosure have been described above, what has been described herein is merely illustrative of the application of the principles of the present disclosure. Accordingly, the description is to be regarded as illustrative only and not as limiting the scope of the present disclosure.

[0063] In some embodiments, aspects of the technology that include computerized realizations of the method by technology may generate software, firmware, hardware, or any combination thereof to control a processor device (e.g., serial or parallel general-purpose or specialized processor chips, single or multi-core chips, microprocessors, field-programmable gate arrays, control units, arithmetic logic units, and any combination of processor registers, etc.), a computer (e.g., a processor device operably coupled to memory), or another electronically operated controller implemented in detail herein using standard programming or engineering techniques, and can be implemented in various ways as a system, method, apparatus, or variety. Thus, for example, embodiments of the present technology can be implemented as an instruction set tangibly embodied on a non-volatile computer-readable medium, and the processor device can implement the instructions based on reading the instructions from the computer-readable medium. Some embodiments of the present technology include control devices such as automation devices, special-purpose or general-purpose computers including various computer hardware, software, firmware, etc., and are consistent with the following description. As a specific example, the control device can include a processor, a microcontroller, a field-programmable gate array, a programmable logic controller, logic gates, etc., and other typical components understood in the art for the realization of appropriate functionality (e.g., memory, communication system, power supply, user interface and other inputs, etc.).

[0064] As used herein, the term "manufactured article" is intended to encompass a computer program accessible from any computer-readable device, carrier (e.g., non-volatile signal), or medium (e.g., non-volatile medium). For example, computer-readable media can include, but are not limited to, magnetic storage devices (e.g., hard disks, floppy disks, magnetic strips, etc.), optical disks (e.g., compact disks (CDs), digital versatile disks (DVDs), etc.), smart cards, and flash memory devices (e.g., cards, sticks, etc.). Further, it should be understood that a carrier wave can be used to carry computer-readable electronic data such as for sending and receiving electronic mail and accessing networks such as the Internet or local area networks. Those skilled in the art will recognize that many modifications can be made to these configurations without departing from the scope or spirit of the claimed subject matter.

[0065] Certain operations of the methods according to this technology, or the systems performing those methods, are schematically represented in the figures or otherwise discussed herein. Unless specifically stated or limited, the representation of a particular operation in a figure in a particular spatial order does not necessarily require that those operations be specified in a particular order corresponding to that particular spatial order. Correspondingly, the particular operations shown in the figures, or otherwise disclosed, can be performed in an order different from that explicitly illustrated or described, as appropriate for a particular implementation of the technology. Further, in some embodiments, certain computations can be performed in parallel, including using dedicated parallel processing devices or separate computing devices configured to interoperate as part of a large-scale system.

[0066] Here, when used in the context of computer implementation, unless otherwise specified or limited, terms such as "component", "system", "module", "block", etc. are intended to include, in execution, hardware, software, a combination of hardware and software, or a part or all of a computer-related system that includes software. For example, a component may be, but is not limited to, a processor device, a process (or executable process) executed by the processor device, an object, an executable, a thread of execution, a computer program, or a computer. For the sake of explanation, both an application running on a computer and the computer can be components. One or more components (or systems, modules, etc.) can exist within a process or thread of execution, can be localized on one computer, can be distributed between two or more computers or other processor devices, or can be included within another component (or system, module, etc.).

Claims

1. An image sensor, a lens assembly including a liquid lens having a plurality of solid lens elements and an adjustable membrane, and a motor system coupled to the lens assembly and configured to move the lens assembly, and an illumination assembly configured to project light rays onto an object, a processor device in communication with the lens assembly and the motor system, determining a working distance between the object and the lens assembly, adjusting the curvature of the adjustable membrane of the liquid lens based on the working distance, configured to adjust the distance between the lens assembly and the image sensor based on the working distance using the motor system, a processor device; A machine vision system comprising:

2. The processor device communicates with the image sensor, The processor device is further configured to control the acquisition of an image of the object, The machine vision system according to claim 1.

3. The lens assembly further includes a fixed-size aperture, the machine vision system according to claim 1.

4. The optical assembly further includes a mechanical iris, the machine vision system according to claim 1.

5. The focal plane is set based on a combination of the curvature of the adjustable membrane of the liquid lens and the distance between the lens assembly and the image sensor, the machine vision system according to claim 1.

6. The machine vision system according to claim 1, further comprising a distance sensor configured to acquire distance data corresponding to the distance of the object.

7. The processor device is configured to determine the working distance based on the distance data, the machine vision system according to claim 6.

8. Adjusting the curvature of the adjustable membrane of the liquid lens and adjusting the distance between the lens assembly and the image sensor control at least one of the focal length or the aperture value, the machine vision system according to claim 1.

9. The processor device is further configured to control an adjustment regarding the distance between the liquid lens and the image sensor, the machine vision system according to claim 1.

10. The machine vision system according to claim 1, wherein the processor device is further configured to control an adjustment regarding a distance between the plurality of solid lenses and the image sensor.

11. The machine vision system according to claim 1, wherein the processor device is further configured to control an adjustment regarding a distance between the plurality of solid lenses and the liquid lens.

12. An optical assembly for a vision system having an image sensor, a lens assembly including a plurality of solid lens elements and a single liquid lens having an adjustable membrane, a motor system coupled to the lens assembly, configured to move the lens assembly, and configured to adjust a distance between the lens assembly and the image sensor of the vision system.

13. The optical assembly according to claim 12, wherein the motor system is further configured to move the liquid lens so as to adjust a distance between the liquid lens and the image sensor and to adjust a distance between the liquid lens and the plurality of solid lenses.

14. The optical assembly according to claim 12, wherein the lens assembly further includes a diaphragm of a fixed size.

15. The optical assembly according to claim 12, wherein the motor system includes a micromotor.

16. The optical assembly according to claim 15, wherein the micromotor is a microstep motor.

17. The optical assembly according to claim 15, wherein the motor system is configured to move the lens assembly towards or away from the image sensor.

18. The optical assembly according to claim 12, wherein the motor system is further configured to move the plurality of solid lens elements so as to adjust a distance between the plurality of solid lens elements and the image sensor and to adjust a distance between the plurality of solid lens elements and the liquid lens.

19. The optical assembly according to claim 12, wherein the motor system is configured to move the plurality of solid lens elements in a first direction and to move the liquid lens in a second direction different from the first direction.

20. A method for controlling a focal length and an aperture value of a machine vision system, Determine the working distance between the object and the lens assembly of the machine vision system, the lens assembly including one liquid lens having a plurality of solid lenses and an adjustable membrane, Adjust the curvature of the adjustable membrane of the liquid lens based on the working distance, A method including using a motor system to adjust the distance between the lens assembly and the image sensor based on the working distance.

21. The method according to claim 20, further comprising obtaining an image of the object via the machine vision system.

22. Determining the working distance between the object and the lens assembly includes determining the working distance based on distance data received from a distance sensor, the method according to claim 20.

23. Adjusting the curvature of the adjustable membrane of the liquid lens and adjusting the distance between the lens assembly and the image sensor control at least one of the focal length or the aperture value, the method according to claim 20.

24. The focal length controls the field of view (FOV) and magnification, the method according to claim 23.

25. The aperture value controls the amount of light received by the image sensor and the depth of field (DOF), the method according to claim 23.

26. Adjusting the distance between the lens assembly and the image sensor includes changing the position of the lens assembly, the method according to claim 20.

27. Adjusting the distance between the lens assembly and the image sensor includes changing the position of the liquid lens, the method according to claim 20.

28. Adjusting the distance between the lens assembly and the image sensor includes changing the positions of the plurality of solid lens elements, the method according to claim 20.

29. The method according to claim 20, further comprising adjusting the distance between the plurality of solid lens elements and the liquid lens by using the motor system to change the position of the solid lens elements along a first direction and changing the position of the liquid lens along a second direction different from the first direction.

Images