Polarimetric camera for high-fidelity surface characterization measurements

Abstract

Systems and methods for providing a polarimetric camera operable to obtain high-fidelity surface characterization measurements.SOLUTION: The polarimetric camera may include a multi-twist retarder component operable to selectively switch between two or more polarization filtering states, wherein in each polarization filtering state, the multi-twist retarder component passes only light having a particular polarization state or polarization orientation and reflects or absorbs light having other polarization states. When the multi-twist retarder is switched to at least two polarization filtering states, the polarization analysis camera may capture images using the sensor array so that a sequence of polarization-specific images is captured, which may be displayed or used to determine one or more Stokes parameters of the scene in real-time.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE This disclosure relates generally to imaging, and more particularly to systems and methods for providing polarimeters that generate high fidelity surface characterization measurements. [Background technology]

[0002] Measuring light can be useful in a variety of fields, such as science, industry, security, and other fields. In addition to intensity and wavelength, the polarization of light may be measured to characterize various objects or scenes. Generally, polarimetry is the measurement and interpretation of the polarization of electromagnetic waves, such as transverse waves, especially radio waves or light waves. Typically, polarimetry is performed on electromagnetic waves that have traveled through or been reflected, refracted, or diffracted by some material to characterize the object. Polarimetric cameras (or "polarimeters") may be used in remote sensing, aerosol particle characterization, planetary detection, quality control, measuring or detecting biological activity, and many other applications.

[0003] To measure the properties of an object or scene based on the polarization of scattered or reflected light, a polarimeter may be required that is operable to measure the linear and / or circular polarization of light exiting the object. Existing designs utilize beam splitters, polarizing elements, or complex arrangements of moving parts to separate polarization states in space and may require separate imaging components (e.g., lenses, retarders, sensor arrays) to capture the required polarization information. For example, some polarimeters utilize Wollaston prisms to separate light in space based on its polarization, allowing the distinct polarization components to be individually analyzed. However, these types of polarimeters can be relatively large and may require multiple optical paths and associated components, which can introduce spatial alignment errors and further increase complexity, cost, reliability, and space requirements. Summary of the Invention

[0004] A polarization analysis camera may be summarized as including a multi-twist retarder component operable to selectively switch between at least two polarization filtering states, wherein in each polarization filtering state, the multi-twist retarder component passes light having a different one of at least two corresponding polarization states; a sensor array operable to capture two-dimensional images from light passing through the multi-twist retarder component; and a controller operably coupled to the multi-twist retarder component and the sensor array, the controller configured to cause the multi-twist retarder component to continuously cycle through at least two polarization filtering states at a polarization state change rate, cause the sensor array to capture at least one image when the multi-twist retarder component is in each polarization filtering state during the cycling, and store the captured images in at least one non-transitory processor-readable storage medium.

[0005] The at least two polarization filtering states may include four polarization filtering states. The polarization state change rate may be equal to or greater than 30 polarization filtering state changes per second. During the repetitions, when the multi-twist retarder component is in each polarization filtering state, the controller may cause the sensor array to capture exactly one image. The at least two polarization states may include three unique linear polarization states and one circular polarization state. The at least two polarization states may include a horizontal linear polarization state, a vertical linear polarization state, and a 45-degree linear polarization state. The sensor array may include one of a charge-coupled device (CCD) or a complementary metal-oxide semiconductor (CMOS) active pixel sensor.

[0006] The polarization analyzing camera may further include an optical element disposed between the multi-twist retarder component and the sensor array, the optical element operable to focus light onto the sensor array.

[0007] The polarization analyzing camera may further include an optical instrument disposed between the multi-twist retarder component and the sensor array, the optical instrument operable to filter light from the multi-twist retarder component with respect to at least one characteristic. The controller may be operable to process the captured images to generate one or more Stokes parameters. The controller may be operable to process the captured images to generate one or more Stokes parameters for each of at least a subset of pixels of the sensor array. The controller may be operable to process the captured images to generate one or more Stokes parameters in real time during image capture. The controller may be operable to cause a display to display at least one polarization-specific image, the at least one image including a sequence of images captured with respect to one of the polarization filtering states of the multi-twist retarder component.

[0008] A method of operating a polarization analyzing camera, the polarization analyzing camera including a multi-twist retarder component operable to selectively switch into at least two polarization filtering states, wherein in each polarization filtering state, the multi-twist retarder component passes light having a different one of at least two corresponding polarization states, the polarization analyzing camera further including a sensor array operable to capture two-dimensional images from light passing through the multi-twist retarder component, the method may be summarized as including the steps of causing the multi-twist retarder component to continuously cycle through the at least two polarization filtering states at a polarization state change rate, causing the sensor array to capture at least one image when the multi-twist retarder component is in each polarization filtering state during the cycling, and storing the captured images in at least one non-transitory processor-readable storage medium.

[0009] The at least two polarization filtering states may include four polarization filtering states. The polarization state change rate may be equal to or greater than 30 polarization filtering state changes per second. Capturing at least one image with the sensor array may include capturing exactly one image with the multi-twist retarder component in each polarization filtering state during the repetition.

[0010] The method may further include processing the captured image to generate one or more Stokes parameters. Processing the captured images to generate Stokes parameters may include processing the captured images to generate one or more Stokes parameters for each of at least a subset of pixels of the sensor array.

[0011] The method may further include processing the captured images to generate one or more Stokes parameters in real time during capture of the images.

[0012] The method may further include causing a display to display at least one image, the at least one image including a sequence of images captured with respect to one of the polarization filtering states of the multi-twist retarder component. [Brief explanation of the drawings]

[0013] In the drawings, identical reference numbers identify similar elements or acts. The sizes and relative positions of elements within the drawings are not necessarily drawn to scale. For example, the shapes of various elements and angles are not necessarily drawn to scale, and some of these elements may be arbitrarily enlarged and positioned to improve the readability of the drawings. Furthermore, the particular shapes of the depicted elements are not necessarily intended to convey any information regarding the actual shape of the particular elements, but may be selected solely for ease of recognition within the drawings.

[0014] [Figure 1] 1 is a schematic block diagram of an exemplary polarization analysis camera, according to one non-limiting illustrated implementation.

[0015] [Figure 2] 2 is a perspective view of the components of the polarization analysis camera of FIG. 1 illustrating an example of its operation according to one non-limiting implementation.

[0016] [Figure 3] FIG. 10 shows an exemplary sequence for successively capturing images while a multi-twist retarder cycles through polarization filtering states to obtain time-multiplexed polarization-specific image data that can be used to determine Stokes parameters, according to one non-limiting illustrated implementation. DETAILED DESCRIPTION OF THE INVENTION

[0017] In the following description, certain specific details are set forth to provide a thorough understanding of the various disclosed implementations. However, those skilled in the art will recognize that implementations can be practiced without one or more of these specific details, or with other methods, components, materials, etc. In other instances, well-known structures related to computer systems, server computers, and / or communication networks have not been shown or described in detail to avoid unnecessarily obscuring the description of implementations.

[0018] Unless the context otherwise requires, throughout this specification and the claims that follow, the word "comprising" is synonymous with "including" and is inclusive or open-ended (i.e., does not exclude additional, unrecited elements or method acts).

[0019] References throughout this specification to "one implementation" or "an implementation" mean that a particular feature, structure, or characteristic described with respect to that implementation is included in at least one implementation. Thus, the appearances of the phrase "in one implementation" or "in an implementation" in various places throughout this specification are not necessarily all referring to the same implementation. Furthermore, particular features, structures, or characteristics may be combined in any suitable manner in one or more implementations.

[0020] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. It should be noted that the term "or" is generally used in its sense including "and / or" unless the context clearly dictates otherwise.

[0021] The headings and abstracts provided herein are for convenience only and do not interpret the scope or meaning of the implementations.

[0022] One or more implementations of the present disclosure relate to systems and methods for providing a polarization analyzing camera operable to obtain high-fidelity surface characterization measurements. The polarization analyzing camera may include a multi-twist retarder component operable to selectively switch between two or more polarization filtering states, where in each polarization filtering state, the multi-twist retarder component passes only light having a specific polarization state or polarization orientation (e.g., horizontal linear polarization, vertical linear polarization, 45-degree linear polarization, circular polarization) and reflects or absorbs light having other polarization states. When the multi-twist retarder is switched between at least two polarization filtering states, the polarization analyzing camera may capture images using a sensor array, thereby capturing a sequence of polarization-specific images or videos that may be displayed or used to determine Stokes parameters of a scene in real time. Advantageously, the polarization analyzing camera may not require spatial separation of the received light and may have no moving parts, which reduces the required size, complexity, and cost of the camera and improves reliability. Improved reliability and performance can be particularly beneficial in a variety of applications where the polarization analyzing camera is subjected to harsh conditions (e.g., temperature, vibration) and / or where maintenance and component replacement are particularly cumbersome.

[0023] 1-3 illustrate an exemplary embodiment of a polarization-analyzing camera 100 of the present disclosure, which may be used to determine the polarization profile of multiple points of a scene 102 from an image or video frame using Stokes parameters or other measurements. Advantageously, the systems and methods described herein can generate Stokes parameters more quickly, reliably, and accurately than conventional methods, while, at least in some embodiments, requiring a smaller form factor by providing a single optical path and utilizing thin-film optical components. The polarization-analyzing camera 100 may generally include a multi-twist retarder component 104, optics 105, a sensor array 106, and a controller 108 operably coupled to the multi-twist retarder component and the sensor array. The multi-twist retarder component 104, which may include one or more multi-twist retarders, may be operable to selectively switch between at least two polarization filtering states. In each polarization filtering state, the multi-twist retarder element 104 passes light having a different one of at least two corresponding polarization states and absorbs or reflects light of the other polarization state or polarization orientation.

[0024] The sensor array 106 may be operable to capture two-dimensional images from light passing through the multi-twist retarder component 104 and focused by the optics 105. Generally, the controller 108 may be configured to cause the multi-twist retarder component 104 to continuously cycle through at least two polarization filtering states at a polarization state change rate (e.g., greater than 10 times per second, greater than 30 times per second, greater than 50 times per second). When the multi-twist retarder component is in each polarization filtering state during the cycle, the controller 108 may cause the sensor array 106 to capture at least one image (e.g., one image, two images, multiple images). The controller 108 may store the captured images as image data 112 in at least one non-transitory processor-readable storage medium, such as data storage 110. As discussed further below, the polarization analysis camera 100 may include a Stokes determinator module 114 operable to process the image data 112 to determine some or all of the Stokes parameters for the scene 102.

[0025] The multi-twist retarder element 104 may be formed from a birefringent material. Birefringence is the property of a material to have a refractive index that depends on the polarization and propagation direction of light. The multi-twist retarder changes the polarization state or phase of light traveling through it. The multi-twist retarder may have a slow axis (or extraordinary axis) and a fast axis (or ordinary axis). When polarized light travels through the multi-twist retarder, light along the fast axis travels faster than light along the slow axis. Generally, the multi-twist retarder element 104 is a waveplate-like retardation film that may be configured to provide precise, customized levels of broadband, narrowband, or multiband retardation in a single thin film. More specifically, the multi-twist retarder element 104 includes two or more twisted liquid crystal (LC) layers on a single substrate, along with a single alignment layer. Subsequent LC layers are directly aligned with the previous layer, enabling simplified fabrication, automatic layer alignment, and a monolithic film with a continuously varying optical axis. As discussed elsewhere herein, the multi-twist retarder 104 is switchable between multiple polarization filtering states and, in at least some implementations, may also include static or switchable diffraction patterns that focus light onto the sensor array. The multi-twist retarder component 104 may include a single multi-twist retarder or multiple multi-twist retarders positioned adjacent to one another (e.g., in a stacked arrangement). Depending on the particular application, the multi-twist retarder component 104 may be configured to operate over one or more specific regions of wavelength (e.g., the visible region, a specific color region, or the infrared region).

[0026] In at least some implementations, the polarization analyzing camera 100 may include data storage 110 that stores image data 112, a Stokes determiner module 114, and / or other programs and data 116. The polarization analyzing camera 100 may also include various I / O components 118, which may include one or more user interfaces (e.g., buttons, touchpad, speaker), a display, one or more wired or wireless communication interfaces, etc. By way of example, the I / O components 118 may include a communication interface that enables the polarization analyzing camera 100 to communicate with an external device 120 via a wired or wireless communication link 122. By way of non-limiting example, the external device 120 may include a host computer, a server, a mobile device (e.g., a smartphone, a wearable computer), etc. The various components of the polarization analyzing camera 100 may be housed in a single housing, in one or more separate housings (e.g., a host computer), or any combination thereof.

[0027] As discussed above, the polarization analyzing camera 100 may be used to determine the polarization profile of multiple points in a scene 102 from video or image frames 124 ( FIG. 2 ) using the Stokes parameters (e.g., parameters S0, S1, S2, and S3). The polarization analyzing camera 100 may be operable to generate a sufficient number of unique scene images 124 to determine each Stokes parameter in real time (or near real time). Such parameters may be used to characterize one or more objects in the scene 102.

[0028] In at least some implementations, the multi-twist retarder component 104 may be controlled to selectively switch between multiple (e.g., two, three, four) polarization filtering states or to cycle through these polarization filtering states. The time required to acquire the unique images required to determine the Stokes parameters may be determined, at least in part, by the switching speed of the multi-twist retarder component 104 and the frame rate of the sensor array 106. As an example, in an implementation in which the multi-twist retarder component 104 switches between four polarization filtering states (e.g., three linear polarization states or orientations and one circular polarization state), the time required to capture four unique images may be the time it takes the multi-twist retarder component 104 to switch between the four states, during which the sensor array 106 captures at least one image while the multi-twist retarder is in each polarization filtering state.

[0029] 2, the scene 102 may have a horizontal axis 200, a vertical axis Y perpendicular to the X axis, and a Z axis perpendicular to the X and Y axes. An operator of the polarization-analyzing camera 100 desires to obtain polarization information of the scene 102, which may be one or more objects, a landscape, or any other scene.

[0030] As discussed above, the multi-twist retarder component 104 may be switchable into multiple polarization filtering states. By way of example, the multi-twist retarder may be configurable into four polarization states that respectively pass horizontal linearly polarized light, vertical linearly polarized light, 45 degree (or other angle) linearly polarized light, and circularly polarized light.

[0031] 3, during operation, the controller 108 may repeatedly cycle the multi-twist retarder component 104 through different polarization filtering states P1, P2, P3, and P4, while also controlling the sensor array 106 to capture images or frames during that time. In the illustrated frame sequence 300, four sets of frames (e.g., set 302 including frames 1-4 and set 304 including frames 5-8) correspond to four images each captured when the multi-twist retarder component 104 was in a different one of the four polarization filtering states P1, P2, P3, and P4. In this manner, the polarization-analyzing camera 100 can generate four independent polarization-specific image sequences or videos, each capturing the scene 102 using a different polarization filter provided by the multi-twist retarder component 104.

[0032] The optics 105 may include one or more lenses that focus light received from the multi-twist retarder component 104 onto the sensor array 106. The optics 105 may further include one or more other optics that filter or modify at least one characteristic of the light, such as a color filter or other type of optics. The optics 105 may include multiple optical elements and may be positioned at a different location in the optical path than shown in the exemplary figures. In at least some implementations, the multi-twist retarder component 104 may be configured to provide one or more static or dynamic diffraction patterns that may be operable to focus light onto the sensor array 106. In such implementations, the optics 105 may be modified or even omitted.

[0033] As a non-limiting example, the sensor array 106 may include a two-dimensional sensor array, such as a charge-coupled device (CCD) or a complementary metal-oxide semiconductor (CMOS) sensor array. More generally, the sensor array 106 may be implemented using any suitable photoreceptor that provides functionality suitable for a particular application.

[0034] The scene 102 may provide (e.g., reflect) light rays 126, which may be received by the multi-twist retarder component 104. Although not shown for clarity, the polarization analyzing camera 100 may include one or more optical elements disposed between the scene 102 and the multi-twist retarder component 104. The light rays 126 are generally emitted in the direction of the Z-axis shown in FIG. 2. The multi-twist retarder component 104 may provide the light rays 128 to the optics 105, polarized in a polarization state or orientation (e.g., P1, P2, P3, or P4) depending on the current polarization filtering state of the multi-twist retarder component 104. The optics 105 may provide the polarized light rays 130 to the sensor array 106 as the scene image 124.

[0035] The polarization filtering states of the multi-twist retarder component 104 may have any orientation relative to the sensor array 106. As a non-limiting example, in at least some implementations, the multi-twist retarder component may be configured to implement a first polarization filtering state that provides a linear polarizer with a transmission axis oriented in the horizontal direction, a second polarization filtering state that provides a linear polarizer with a transmission axis oriented in the vertical direction, a third polarization filtering state that provides a linear polarizer with a transmission axis oriented at a 45 degree angle with respect to the horizontal direction, and a fourth polarization filtering state that provides a circular polarizer with a fast axis oriented in the vertical direction.

[0036] As discussed herein, the image or video frame 124 may be stored in the data storage 110 as image data 112 (FIG. 1) and may be processed using the Stokes determinator module 114 or other programs. For example, the Stokes determinator module may utilize pixel values ​​from one or more sets of four polarization-specific images to obtain Stokes parameters for each point in the scene 102 using known equations. The Stokes parameters may be provided to a user via a display or communicated to a user in any other manner. In at least some implementations, the polarization-analyzing camera 100 may display polarization-specific videos or images of the scene 102 to a user via a display.

[0037] It is understood that the illustrated computing systems and devices are merely exemplary and are not intended to limit the scope of the present disclosure. For example, polarization analyzing camera 100 and / or external device 120 may be connected to other devices not shown, including through one or more networks such as the Internet or via the Web. More generally, such computing systems or devices may comprise any combination of hardware capable of interacting with one another and performing the types of functions described, such as when programmed with appropriate software or otherwise configured, including, but not limited to, desktop computers, laptop computers, slate computers, tablet computers, head-mounted display (HMD) systems or other computers, smartphone computing devices and other mobile phones, Internet appliances, PDAs and other electronic organizers, database servers, network storage devices and other network devices, wireless telephones, pagers, television-based systems (e.g., using set-top boxes, personal / digital video recorders, game consoles, and / or media servers), and various other consumer products including appropriate intercommunication capabilities. For example, the illustrated polarization analyzing camera 100 may, in at least some embodiments, include executable software instructions and / or data structures that, when loaded into and / or executed by particular computing systems or devices, may be used to program or otherwise configure those systems or devices, including configuring the processors of those systems or devices. Alternatively, in other embodiments, part or all of the software system may execute in memory on another device and communicate with the illustrated computing system / device via computer-to-computer communications.Additionally, while various items are shown as being stored in memory or storage at various times (e.g., during use), these items, or portions thereof, may be transferred between memory and storage and / or between storage devices (e.g., in different locations) for purposes of memory management and / or data integrity.

[0038] Thus, in at least some embodiments, the illustrated system is a software-based system including software instructions that, when executed by a processor and / or other processor means, program the processor to automatically perform the operations described for the system. Furthermore, in some embodiments, part or all of the system may be implemented or provided in other ways, such as at least partially by firmware and / or hardware means, including, but not limited to, one or more application-specific integrated circuits (ASICs), standard integrated circuits, controllers (e.g., by executing appropriate instructions and including microcontrollers and / or embedded controllers), field programmable gate arrays (FPGAs), complex programmable logic devices (CPLDs), etc. Part or all of the system or data structures may also be stored (e.g., as software instruction content or structured data content) on a non-transitory computer-readable storage medium such as a hard disk or flash drive read by an appropriate drive or via an appropriate connection, or other non-volatile storage device, volatile or non-volatile memory (e.g., RAM), network storage device, or portable media article (e.g., DVD disk, CD disk, optical disk, flash memory device, etc.). The systems, modules, and data structures may, in some embodiments, be transmitted as a generated data signal (e.g., as part of a carrier wave or other analog or digital propagated signal) over a variety of computer-readable transmission media, including wireless-based and wired / cable-based media, and may take a variety of forms (e.g., as part of a single or multiplexed analog signal, or as multiple discrete digital packets or frames). Such computer program products may also take other forms in other embodiments. Accordingly, the present disclosure may be practiced with other computer system configurations.

[0039] Those skilled in the art will recognize that many of the methods or algorithms described herein may utilize additional operations, omit some operations, and / or perform operations in a different order than specified.

[0040] The various implementations described above can be combined to provide further implementations. These and other changes can be made to the implementations in light of the above description. In general, in the following claims, the terms used should not be construed to limit the scope of the claims to the specific implementations disclosed in the specification and claims, but should be construed to include all possible implementations, along with the full range of equivalents to which such claims are entitled. Accordingly, the scope of the claims is not limited by this disclosure. [Other possible items] [Item 1] A polarization analysis camera, a multi-twist retarder component operable to selectively switch between at least two polarization filtering states, wherein in each polarization filtering state, the multi-twist retarder component passes light having a different one of at least two corresponding polarization states; a sensor array operable to capture a two-dimensional image from light passing through the multi-twist retarder component; a controller operably coupled to the multi-twist retarder component and the sensor array, causing the multi-twist retarder element to continuously cycle through the at least two polarization filtering states at a polarization state change rate; causing the sensor array to capture at least one image when the multi-twist retarder component is in each polarization filtering state during the iterations; storing the captured images in at least one non-transitory processor-readable storage medium; and a controller configured as A polarization analysis camera comprising: [Item 2] Item 1. The polarization analyzing camera of item 1, wherein the at least two polarization filtering states include four polarization filtering states. [Item 3] Item 2. The polarization analysis camera of item 1, wherein the polarization state change rate is equal to or greater than 30 polarization filtering state changes per second. [Item 4] Item 1. The polarization analyzing camera of item 1, wherein the controller causes the sensor array to capture exactly one image when the multi-twist retarder component is in each polarization filtering state during the repetition. [Item 5] Item 1. The polarization analyzing camera of item 1, wherein the at least two polarization states include three unique linear polarization states and one circular polarization state. [Item 6] Item 1. The polarization analyzing camera of item 1, wherein the at least two polarization states include a horizontal linear polarization state, a vertical linear polarization state, and a 45-degree linear polarization state. [Item 7] Item 10. The polarization analysis camera of item 1, wherein the sensor array comprises one of a charge-coupled device (CCD) or a complementary metal-oxide semiconductor (CMOS) active pixel sensor. [Item 8] Item 1. The polarization analyzing camera of item 1, further comprising an optical instrument disposed between the multi-twist retarder component and the sensor array, the optical instrument operable to focus light onto the sensor array. [Item 9] Item 1. The polarization analysis camera of item 1, further comprising an optical instrument disposed between the multi-twist retarder component and the sensor array, the optical instrument operable to filter light from the multi-twist retarder component with respect to at least one characteristic. [Item 10] Item 1. The polarization analyzing camera of item 1, wherein the controller is operable to process the captured image to generate one or more Stokes parameters. [Item 11] Item 1. The polarization analyzing camera of item 1, wherein the controller is operable to process the captured image to generate one or more Stokes parameters for each of at least a subset of pixels of the sensor array. [Item 12] Item 1. The polarization analyzing camera of item 1, wherein the controller is operable to process the captured image to generate one or more Stokes parameters in real time during capture of the image. [Item 13] 13. The polarization analyzing camera of any one of items 1 to 12, wherein the controller is operable to cause a display to display at least one polarization-specific image, the at least one image comprising a sequence of images captured with respect to one of the polarization filtering states of the multi-twist retarder component. [Item 14] 1. A method of operating a polarization analyzing camera, the polarization analyzing camera comprising a multi-twist retarder component operable to selectively switch between at least two polarization filtering states, wherein in each polarization filtering state the multi-twist retarder component passes light having a different one of at least two corresponding polarization states, the polarization analyzing camera further comprising a sensor array operable to capture a two-dimensional image from light passing through the multi-twist retarder component, the method comprising: causing the multi-twist retarder element to continuously cycle through the at least two polarization filtering states at a polarization state change rate; causing the sensor array to capture at least one image when the multi-twist retarder element is in each polarization filtering state during the iterations; storing the captured images in at least one non-transitory processor-readable storage medium; A method comprising: [Item 15] Item 15. The method of item 14, wherein the at least two polarization filtering states include four polarization filtering states. [Item 16] Item 15. The method of item 14, wherein the polarization state change rate is equal to or greater than 30 polarization filtering state changes per second. [Item 17] Item 15. The method of item 14, wherein causing the sensor array to capture at least one image comprises causing the sensor array to capture exactly one image when the multi-twist retarder component is in each polarization filtering state during the repetition. [Item 18] Item 15. The method of item 14, further comprising processing the captured image to generate one or more Stokes parameters. [Item 19] Item 19. The method of item 18, wherein processing the captured image to generate Stokes parameters comprises processing the captured image to generate one or more Stokes parameters for each of at least a subset of pixels of the sensor array. [Item 20] Item 15. The method of item 14, further comprising processing the captured image to generate one or more Stokes parameters in real time during capture of the image. [Item 21] 21. The method of any one of items 14 to 20, further comprising: displaying at least one image on a display, the at least one image comprising a sequence of images captured for one of the polarization filtering states of the multi-twist retarder component.

Claims

[Claim 1] The invention described herein.

Images