Imaging device based on a polarization sensitive interferometer, circuitry, electronic device and method

Abstract

An imaging device for capturing an image of a scene comprises a polarization sensitive interferometer whose input light spans a wavelength range, and which is configured to output polarization specific interfered light, and which comprises an image sensor configured to capture the image based on the output polarization specific interfered light for reconstructing the color spectrum of the scene.

Description

[0001] Sony Semiconductor Solutions Corporation et al.

[0002] IMAGING DEVICE, CIRCUITRY, ELECTRONIC DEVICE AND METHOD

[0003] TECHNICAL FIELD

[0004] The present disclosure generally pertains to an imaging device, a circuitry, an electronic device, a method for imaging and a method for image processing.

[0005] TECHNICAL BACKGROUND

[0006] A multi-spectral image sensor captures image data at specific (e.g., predefined) wavelengths across the electromagnetic spectrum. This typically includes wavelengths beyond the visible light range, such as infrared and ultraviolet. Unlike standard cameras that capture images in three primary colors (red, green, and blue), multi-spectral cameras can capture images in multiple spectral bands, allowing for the analysis of materials and objects based on their spectral properties.

[0007] For that purpose, incoming light may be passed through a series of optical filters that selectively transmit specific wavelengths while blocking others. The filtered light is then captured by the sensor's photodetectors (pixels). Each photodetector records the intensity of light at its specific wavelength, creating a separate image for each spectral band.

[0008] During data integration the individual spectral images can be combined into a single multispectral image.

[0009] By combining these spectral layers, multi-spectral imaging can generate detailed color images that offer enhanced information beyond what is possible with standard RGB cameras.

[0010] Although there exist techniques for generating color images, it is generally desirable to improve on existing techniques.

[0011] SUMMARY

[0012] According to a first aspect the present disclosure provides an imaging device for capturing an image of a scene comprising a polarization sensitive interferometer whose input light spans a wavelength range, and which is configured to output polarization specific interfered light, and an image sensor configured to capture the image based on the output polarization specific interfered light for reconstructing the color spectrum of the scene.Sony Semiconductor Solutions Corporation et al.

[0013] According to a second aspect the present disclosure provides a circuitry configured to acquire image data of an image captured by the imaging device as explained above and reconstruct the color spectrum of the scene for different polarizations based on the acquired image data.

[0014] According to a third aspect the present disclosure provides an electronic device comprising an imaging device for capturing an image of a scene, wherein the imaging device comprises a polarization sensitive interferometer whose input light spans a wavelength range, and which is configured to output polarization specific interfered light, and comprises an image sensor configured to capture the image based on the output polarization specific interfered light for reconstructing the color spectrum of the scene, wherein the electronic device further comprises a circuitry configured to acquire image data of the image captured by the imaging device, and reconstruct the color spectrum of the scene for different polarizations based on the acquired image data.

[0015] According to a fourth aspect the present disclosure provides a method for capturing an image of a scene with the imaging device comprising the steps of outputting, with the polarization sensitive interferometer, polarization specific interfered light based on input light which spans a wavelength range and capturing the image based on the output polarization specific interfered light for reconstructing the color spectrum of the scene.

[0016] According to a fifth aspect the present disclosure provides a method comprising the steps of acquiring image data of an image captured by the imaging device and reconstructing the color spectrum of the scene for different polarizations.

[0017] Further aspects are set forth in the dependent claims, the drawings and the following description.

[0018] BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Embodiments are explained by way of example with respect to the accompanying drawings, in which:

[0020] Fig. la illustrates an embodiment of an imaging device including a polarization sensitive interferometer with two cavities;

[0021] Fig. lb illustrates an embodiment of an imaging device including a polarization sensitive interferometer with two cavities and a bandpass filter;

[0022] Fig. 2a illustrates an embodiment of an imaging device including a polarization sensitive interferometer with a beamsplitter;Sony Semiconductor Solutions Corporation et al.

[0023] Fig. 2b illustrates the light portions reflected back along the two arms of the interferometer of Fig- 2a;

[0024] Fig. 2c illustrates an embodiment of an imaging device including a polarization sensitive interferometer with a beamsplitter and a bandpass filter;

[0025] Fig. 3a illustrates an embodiment of an imaging device with a polarization-sensitive interferometer including a liquid crystal polarizer;

[0026] Fig. 3b illustrates an embodiment of an imaging device with a polarization-sensitive interferometer including a liquid crystal polarizer and a bandpass filter;

[0027] Fig. 3c illustrates the orientation of the nematic liquid crystal molecules within the first polarizing element of the embodiments of Figs. 3a and 3b;

[0028] Fig. 3d illustrates the orientation of the nematic liquid crystal molecules within the second polarizing element of the embodiments of Figs. 3a and 3b;

[0029] Fig. 4a illustrates an embodiment of a reconstruction of the color spectrum of an imaged scene from image data;

[0030] Fig. 4b illustrates an embodiment of a generation of a polarization filtered color image;

[0031] Fig. 4c illustrates an embodiment of a reconstruction of the color spectrum of an imaged scene from image data;

[0032] Fig. 5a illustrates an embodiment of reconstruction of the color spectrum of an imaged scene from image data based on a Fourier transform;

[0033] Fig. 5b illustrates an embodiment of reconstruction of the color spectrum of an imaged scene from image data based on an inverse cosine transform;

[0034] Fig. 6 illustrates an embodiment of reconstruction of the color spectrum of an imaged scene from denoised image data;

[0035] Fig. 7 illustrates an embodiment of refocusing of an imaged out-of-focus object based on postprocessing image data;

[0036] Fig. 8 illustrates an embodiment of reconstruction of a color spectrum from image data including denoising.

[0037] Fig. 9a illustrates an embodiment of a method for capturing an image of a scene with an imaging device;Sony Semiconductor Solutions Corporation et al.

[0038] Fig. 9b illustrates an embodiment of a calibration method of an imaging device for capturing an image of a scene with an imaging device; and

[0039] Fig. 10 illustrates a block diagram of an embodiment of an electronic device.

[0040] DETAILED DESCRIPTION OF EMBODIMENTS

[0041] Before a detailed description of the embodiments under reference of Fig. la is given, general explanations are made.

[0042] As explained in the outset during multispectral imaging light passes through a filter, such that only the wavelengths that match the filter's transmission range are allowed to pass through. All other wavelengths are blocked or absorbed by the filter. This means that a significant portion of the incoming light is discarded, reducing the overall light intensity (light throughput) that reaches the sensor.

[0043] Fourier transform spectroscopy

[0044] Using a conventional spectrometer light can be dispersed into individual wavelengths, and each wavelength is measured separately by scanning across the spectrum. As mentioned above with regard to multispectral imaging, this process can be time-consuming and results in lower signal throughput.

[0045] In Fourier transform spectroscopy, on the other hand, an interferometer is used.

[0046] Felgett / Multiplex advantage:

[0047] In an interferometer a broader spectrum of light, often the entire light spectrum, interacts with the detector at the same time. The interferometer can modulate the light to produce an interferogram (a pattern related to the spectral components), and the spectrum may be extracted using Fourier Transform mathematics. Because multiple, e.g., all, wavelengths can be measured simultaneously, the detector is exposed to a more complete, e.g., the entire, light signal throughout the measurement. This increases the overall intensity of the detected signal reducing random noise relative to the signal.

[0048] The increased signal intensity also improves sensitivity, allowing for the detection of weak signals or low-concentration components.

[0049] The advantage is especially pronounced for systems with many spectral components (e.g., gases, complex organic molecules) since all these components can be captured at once.Sony Semiconductor Solutions Corporation et al.

[0050] Jaquinot / Throughput advantage:

[0051] Interferometers can use larger slits or apertures to collect light, allowing more photons to enter the instrument compared to dispersive spectrometers, which rely on narrow slits for spectral resolution.

[0052] The wider aperture results in higher light throughput, which significantly increases the intensity of the detected signal.

[0053] Interferometer

[0054] An interferometer is a device that uses the principle of interference to measure or analyze physical properties of waves, such as light, sound, or radio waves. It can operate by combining two or more waves, for example split from a single source, to create an interference pattern. This pattern arises due to the constructive and destructive interference between the waves and includes information about differences in their paths or other properties.

[0055] There exist different types of interferometers, for example, the Michelson interferometer or the Fabry -Perot interferometer.

[0056] Michelson (two-beam) interferometer:

[0057] A Michelson interferometer includes a beam splitter, and two reflectors arranged orthogonally. The beam splitter divides the incident light into two beams, directing them towards the reflectors. Upon reflection, the beams recombine at the beam splitter, creating an interference pattern. The optical path difference between the two beams can for example be affected by adjusting the position of at least one of the reflectors, allowing for precise control over the interference pattern.

[0058] Fabry -Perot (multi -beam) interferometer:

[0059] A Fabry -Perot interferometer includes two parallel, reflective surfaces (mirrors) separated by a certain distance, forming a cavity. Light entering the cavity undergoes multiple reflections between the mirrors, resulting in multiple beam interference. The interference pattern produced is highly sensitive to changes in the optical path length within the cavity, which can be influenced by variations in wavelength or physical displacement of the mirrors.

[0060] Interferogram

[0061] An interferogram may refer to a graphical representation of the (light) intensity at a specific location (e.g., at a specific pixel of an image sensor or at multiple pixels of an image sensor) within an interference pattern, for example, as a function of the optical path difference (OPD).Sony Semiconductor Solutions Corporation et al.

[0062] As explained above, in an interferometer (e.g., Fabry-Perot or Michelson interferometer), light may be split into multiple beams that travel along different paths before being recombined to produce interference. By carefully adjusting or detuning the interferometer, one may achieve a controlled variation in the OPD, which may result in a linear spacing of these differences. For example, this detuning may be accomplished by moving at least one of the (partially) reflecting elements (e.g., mirrors, reflectors, first and second polarizing element etc.) or other optical components within the interferometer setup.

[0063] As the OPD changes, the intensity of the light at a particular point in the interference pattern can change, creating a series of bright and dark fringes. These intensity variations may be recorded as a function of the OPD, producing the interferogram. The interferogram may include information about the spectral content of the light source, as different wavelengths of light may interfere constructively or destructively at different OPDs. For example, by applying a mathematical transformation, such as the Fourier transform, to the interferogram, one may extract the spectrum of the light source, revealing the intensity distribution of various wavelengths present in the light.

[0064] As will be explained in the following, in addition to spectral information, the structure of the interferometer may be adapted to extract polarization information of the input light from the interferogram.

[0065] Polarization sensitive Fourier transform spectroscopy

[0066] Some embodiments pertain to an imaging device for capturing an image of a scene comprising a polarization sensitive interferometer whose input light spans a wavelength range, and which is configured to output polarization specific interfered light, and an image sensor configured to capture the image based on the output polarization specific interfered light.

[0067] Some embodiments pertain to an imaging device for capturing an image of a scene comprising a polarization sensitive interferometer whose input light spans a wavelength, and which is configured to output polarization specific interfered light, and an image sensor configured to capture the image based on the output polarization specific interfered light for reconstructing the color spectrum of the scene.

[0068] The input light may be the light reflected from the imaged scene or may be light directly from a light source. The input light may be a broad-spectrum light including multiple wavelengths (e.g., white light). The range of wavelengths may therefore span a broad wavelength range, e.g. the visible range, which is visible the human eye, such as 380 to 700 nm.Sony Semiconductor Solutions Corporation et al.

[0069] The input light may be a mixture of red, green and blue light. The mixture of red, green and blue light may be the visible spectrum, but may also include wavelengths outside of the visible spectrum, e.g., above 700nm, such as infrared light, or below 380 nm.

[0070] The output light may therefore be polarization specific interfered mixed light (mixture of red, green and blue). The output light may also span a wavelength range, for example a broad wavelength range, e.g., the visible range.

[0071] The captured image may represent the interference pattern for a fixed optical path difference. From multiple captured images interferograms as defined above (e.g., an interferogram for each or multiple pixels of the image sensor), with a light intensity at a specific location of the interference pattern (e.g., corresponding to the one or multiple pixels) as a function of optical path difference, may be generated.

[0072] As orthogonally polarized light does not interfere with each other, interference may occur only within one polarization state of two orthogonal polarization states of the input light.

[0073] In the case of the imaging device with the polarization-sensitive interferometer, the captured image may represent the interference pattern included in the output light, e.g., the mixed red, green, and blue light, after the input light, e.g., the mixed red, green and blue light, has been processed by the polarization-sensitive interferometer.

[0074] The captured image allows (e.g., from multiple captured images) for the extraction of spectral information for each polarization state, e.g., from the interferogram. Consequently, color images can be created by extracting the spectral information of the light coming from the imaged scene from the interferogram which may be based on multiple captured images. As this spectral information can be extracted for the different polarization states of the input light, obstructive scene reflections during imaging can be reduced in the resulting color image. That is, because obstructive reflections (e.g., glare from water, glass, or polished surfaces) tend to be preferentially polarized, meaning that the reflected light has a dominant polarization component (e.g., Transverse Electric (TE) polarization mode or Transverse Magnetic (TM) polarization mode reflect differently when encountering an interface between two media (e.g., air and glass)). Furthermore, this configuration eliminates the need for a polarizing filter, which traditionally must be manually attached and detached, thereby enhancing the convenience and efficiency of the imaging device.

[0075] The polarization sensitive interferometer may include a polarizer. The polarizer may be configured to output a first and second light portion of the input light, wherein the output firstSony Semiconductor Solutions Corporation et al.

[0076] and second light portions are orthogonally polarized and interfered. (Orthogonally polarized and interfered refers to the interference being polarization specific, as orthogonally polarized light cannot interfere with each other). That is, the polarizer may output the first and second light portion as the polarization specific interfered light. For example, the output first and second light portion are orthogonally polarized to each other and interfered within each other.

[0077] For example, the polarizer may be configured to split the input light into the first and second light portion.

[0078] Thus, the polarizer may be configured to split the input light into a first and second light portion and output the first and second light portion, wherein the output first and second light portion are orthogonally polarized and interfered.

[0079] The polarizer may include two polarizing elements. Splitting the input light by the polarizer may, therefore, include that the two polarizing elements may split the input light into the first and second light portion.

[0080] For example, the first polarizing element may only reflect light of the first polarization of the input light in a first Fabry -Perot cavity and the second polarizing element may only reflect light of the second polarization of the input light which is orthogonal to the first polarization in a second Fabry -Perot cavity.

[0081] Alternatively, the first polarizing element may split the first and second light portion of a first beam of the input light, for example in one arm of a Michelson interferometer, and the second polarizing element may split the first and second light portion of a second beam of the input light, for example in a second arm of a Michelson interferometer.

[0082] In both cases, a path difference may be created for, e.g., within, the first light portion and a path difference may be created for, e.g., within, the second light portion leading to an interfered first light portion and an interfered second light portion. Due to the path differences interference within the first light portion and interference within the second light portion can be generated. If the first and second light portions are orthogonally polarized interference occurs within each respective light portion, i.e., for the different light portions (polarizations).

[0083] The first light portion may be horizontally polarized light, and the second light portion may be vertically polarized light. Alternatively, the first light portion may be polarized clockwise, and the second light portion may be polarized anti -clockwise. Also, any other orthogonal polarization may be possible.Sony Semiconductor Solutions Corporation et al.

[0084] The first polarizing element may have a first predefined polarization, the second polarizing element may have a second predefined polarization orthogonal to the first polarizer.

[0085] The first polarizing element of the two polarizing elements may be configured to polarize the first light portion, and the second polarizing element of the two polarizing elements may be configured to polarize the second light portion orthogonally to the first light portion.

[0086] The two polarizing elements may be reflective polarizers. For example, at least one of the two polarizing elements or both may be partially reflective polarizers.

[0087] The two reflective polarizers may be configured to reflect light that is polarized orthogonally to each other. For example, reflected light of the first reflective polarizer of the two polarizers may be polarized orthogonally to reflected light of the second reflective polarizer of the two polarizers.

[0088] The reflective polarizer may be fully reflective for one predefined polarization state. The two reflective polarizers may be fully reflective for orthogonally polarized polarization states. For example, the first polarizing element may be fully reflective for the horizontal polarization and the second polarization element may be fully reflective for the vertical polarization.

[0089] The reflective polarizer may be a wire grid polarizer, a multilayer dielectric polarizer or a polarizing beam splitter (PBS).

[0090] A reflective polarizer may be configured to act on only a single predefined polarization. For, example, incident light may be decomposed in two orthogonal polarizations. For example, the polarization orthogonal to the predefined polarization of the polarizer may be reflected with a certain reflection ratio and the remainder may be transmitted.

[0091] The polarizer may further include a partially transparent reflector. The partially transparent reflector may be disposed between the first and second polarizing elements.

[0092] The two polarizing elements may be aligned parallel to each other.

[0093] For example, the interferometer may be based on a Fabry -Perot interferometer and may include two Fabry-Perot cavities arranged in series. That is the partially transparent reflector may separate the two cavities. The first of the two cavities may therefore be defined by the first polarizing element and one side or surface of the partially transparent reflector. The opposite side or surface of the partially transparent reflector and the second polarizing element may define the second cavity.Sony Semiconductor Solutions Corporation et al.

[0094] The first polarizing element may only reflect one polarization of the input light, creating a fist cavity of one polarization (first light portion) within which reflections, which are reflected between the polarizing element and the partially transparent reflector, interfere with each other according to the Fabry -Perot principle.

[0095] The second polarizing element may only reflect the orthogonal polarization of the input light (e.g., orthogonal to the polarization reflected within the first cavity), creating a second cavity of a different polarization (second light portion) within which reflections, which are reflected between the polarizing element and the partially transparent reflector, interfere with each other according to the Fabry -Perot principle.

[0096] Thus, the output light may include interfered light of one polarization (first light portion) as well as interfered light of the other orthogonal polarization (second light portion), where each interference can be separately tuned.

[0097] Alternatively, the two polarizing elements may be aligned orthogonally to each other.

[0098] The partially transparent reflector may be a beam-splitter splitting the input light into two separate beams: one that is transmitted through the beam splitter and another that is reflected. Thus, the two beams may travel along different paths, a first arm and a second arm, before being recombined at the partially transparent reflector to produce an interference pattern.

[0099] In this way, the interferometer may be based on a Michelson interferometer. Therefore, the polarizer may include two additional reflectors disposed orthogonally to each other.

[0100] The first of the two reflectors may be disposed parallel to the first polarizing element and the second reflector of the two reflectors may be disposed parallel to the second polarizing element. The input light split at the partially transparent reflector (e.g., beam-splitter) into the two beams may therefore travel along their respective arm to their respective polarizing element. The light being transmitted through the respective polarizing elements may be reflected back by the respective reflector. Thus, each reflector may be located behind their respective polarizing element in the direction of the light propagation when the light is transmitted from the polarizing element.

[0101] If the polarizing elements are reflective polarizers and additional reflectors are included in the polarizer, e.g., located behind the polarizing elements, the first polarizing element may transmit the first light portion (e.g., horizontally polarized) of the first beam to the first reflector and reflect the second light portion (e.g., vertically polarized) of the first beam traveling along theSony Semiconductor Solutions Corporation et al.

[0102] first arm back to the beam splitter. Also, the second polarizing element may transmit the second light portion (e.g., vertically polarized) of the second beam traveling along the second arm to the second reflector and reflect the first light portion (e.g., horizontally polarized) back to the beam splitter.

[0103] As the different polarizing elements may transmit and reflect differently polarized light portions, an optical path difference may be created between the first and second arm for the first light portion leading to interference for one polarization state of the input light, and an optical path difference may be created between the first and second arm for the second light portion leading to interference for the other, orthogonal, polarization state of the input light.

[0104] The polarizer may include an adjustment mechanism. The adjustment mechanism of the polarizer may be configured such that the different polarizations are separately tunable.

[0105] The two polarizing elements may be configured such that an optical delay between the two polarizing elements with respect to the partially transparent reflector is adjustable. For example, any one of the first polarizing element, the second polarizing element or the partially transparent reflector may be adjustable. The adjustment may change the length of at least one of the two cavities or it may change the distance to the respective additional reflector, e.g., located behind the polarizing element.

[0106] Additionally or alternatively any one of the two reflectors, e.g., located behind the respective polarizing elements, may be adjustable by the adjustment mechanism. For example, the reflector may be adjustable in the direction of the respective polarizing element. For example, the reflectors may be independently movable parallel to the first and second polarizers respectively. By tuning the displacement of the reflectors independently, it is possible to tune the interference pattern per polarization.

[0107] The optical delay may be adjustable such that an interference pattern for different, e.g., orthogonal, polarizations of the input light is generated.

[0108] The adjustment mechanism may include piezo actuators. The piezo actuator may include a stack of low voltage piezo actuators, to for example achieve an equivalent higher voltage piezo actuator (e.g., over 30 V).

[0109] Alternatively, the adjustment mechanism may be based on applying an external electric field, which may, for example reorient liquid crystal molecules.Sony Semiconductor Solutions Corporation et al.

[0110] Liquid crystals (LCs) are materials that exhibit properties between those of conventional liquids and solid crystals. They can change their optical properties in response to an external electric field. The adjustment mechanism may be configured to switch the LC from fast and slow state and vice versa. The switching speed may define the sampling speed. Switching Speed refers to how quickly liquid crystals can change orientation between fast (on) and slow (off) states. Fast state refers to the liquid crystal molecules being aligned in a particular direction due to the applied electric field. Slow state refers to the liquid crystal molecules being returned to an original orientation after the electric field is removed.

[0111] The optical path difference between fast and slow states may be greater than 1,2 pm for accurate color resolution.

[0112] At least one polarizing element may be a liquid crystal polarizer. For example, the first and second polarizing element may be a liquid crystal polarizer. The liquid crystal of the liquid crystal polarizer may be a nematic liquid crystal. The liquid crystal polarizer may include liquid crystal delay cells configured to introduce a tunable optical delay.

[0113] For example, the interferometer may be based on a Michelson interferometer and the first and second polarizing element disposed orthogonally to each other may be liquid crystal polarizers. The first and second polarizing elements may include a liquid crystal (liquid crystal molecules) oriented such that the first light portion (orthogonally polarized to the second light portion) of the light transmitted through the first polarizing element, e.g., first light beam which travels along the first arm, encounters a refractive index that is different to the refractive index encountered by the first light portion being transmitted through the second polarizing element, e.g., second light beam which travels along the second arm.

[0114] Furthermore, first and second polarizing elements may include a liquid crystal (liquid crystal molecules) oriented such that the second light portion (orthogonally polarized to the first light portion) of the light transmitted through the first polarizing element, e.g., first light beam which travels along the first arm, encounters a refractive index that is different to the refractive index encountered by the second light portion being transmitted through the second polarizing element, e.g., second light beam which travels along the second arm.

[0115] If the respective light transmitted through the liquid crystals is subsequently reflected, e.g., by reflectors. For example, reflected back to the beam splitter where they are recombined, an optical path difference for the respective polarization states can be created.Sony Semiconductor Solutions Corporation et al.

[0116] That is, the optical path difference may be created between the first and second arm for the first light portion leading to interference for one polarization state of the input light, and an optical path difference may be created between the first and second arm for the second light portion leading to interference for the other, orthogonal, polarization state of the input light.

[0117] The imaging device may include a first lens configured to collimate the input light and direct it though the polarization sensitive interferometer.

[0118] Furthermore, the imaging device may include a second lens configured to focus the output polarization specific interfered light from the interferometer to the image sensor.

[0119] The image sensor may be a CMOS, a Single-Photon Avalanche Diode (SPAD) sensor, or a CCD sensor. Due to the polarizer at least two out of four stokes parameters may be measured by the image sensor. That is, from the interferogram which may be based on the captured image at least two of four stokes parameters may be extracted.

[0120] The interferometer may include a two-way beamsplitter. As explained above the partially transparent reflector may be a two-way beamsplitter. The beams splitter may be a plate beam splitter or a cube beam splitter (i.e., without polarization).

[0121] The imaging device may further include a bandpass filter to avoid aliasing. In this way the spectrum of the input light may be reduced to a desired spectrum.

[0122] The imaging device may further include a reference laser for calibration. The reference laser may be disposed within the field of view (FoV) of the interferometer. The reference laser may have a predefined wavelength.

[0123] By adding a reference laser with a known wavelength into the field of view, the imaging device may monitor the interference pattern of this laser. Since the response of the reference laser is well-defined, any deviations in its interference pattern may be detected and used to for the adjustment mechanism. This tuning ensures that the measurements of the input light remain precise, despite any mechanical or thermal variations, thereby improving the overall reliability and accuracy of the spectrometric analysis.

[0124] Some embodiments pertain to a circuitry configured to acquire image data of an image captured by the imaging device as explained above and reconstruct the color spectrum of the scene for different polarizations based on the acquired image data.

[0125] The circuitry may include one or more processors, logical circuits, memory (read only memory, random memory, etc., storage, e.g., hard disk, compact disc, flash drive, etc.), an interface forSony Semiconductor Solutions Corporation et al.

[0126] (wireless, e.g., Bluetooth, infrared) communication via a network (local area network, wireless network, internet). Moreover, it may include input means (mouse, keyboard, microphone, camera etc.), output means (loudspeakers, display (e.g., liquid crystal, (organic) light emitting diode, etc.)), and sensors for sensing audio data (microphone), still image or video image data (image sensor, camera sensor, video sensor, etc.). The image sensor may include any feature regarding the image sensor described in this specification.

[0127] The image data may be acquired from the imaging device and / or from a database. The imaging device may include any feature regarding the imaging device described in this specification. The color spectrum of the input light may be reconstructed for each pixel of the image. Also, the polarization may be resolved for each pixel.

[0128] An image pixel may correspond to one or more image sensor pixels. Reconstructing the color spectrum (per pixel) of the scene light may be based on a predefined number (e.g., 6 to 12) of acquisitions by the image sensor. For example, 6 acquisitions with different interference patterns may be conducted for both of the orthogonal polarizations.

[0129] The color may be extracted based on a predefined color space, such as RGB, RGB-IR, grayscale or the like from the reconstructed color spectrum.

[0130] The circuitry may be configured to generate a color image based on the reconstructed color spectrum.

[0131] A color image may be generated, e.g., via the circuitry, based on the reconstructed color spectrum for the different polarizations. Thus, glare or obstructive scene reflections may be reduced in the generated color image based on the polarization information. For example, either or both polarizations may be visualized.

[0132] Therefore, a more faithful color image may be generated under varying lighting conditions, including narrowband lighting. By more accurately representing true colors based on the spectral information, it ensures that images are consistent and reliable regardless of the lighting environment. Also, food quality analyses or imaging in healthcare may be facilitated.

[0133] Furthermore, an anti -reflective filter may be included in the generated color image during postprocessing, e.g., based on the determined color spectrum for the different polarization states of the input light. This reduces unwanted reflections in the final color image, enhancing clarity and visual quality. The circuitry may, therefore, be configured to perform such post-processing. Reconstructing the color spectrum of the scene may be based on a Fourier transform.Sony Semiconductor Solutions Corporation et al.

[0134] For example, reconstructing the color spectrum of the scene may be based on an inverse cosine transform. For example, the inverse cosine transform may be applied to the image data.

[0135] Applying the Fourier transform to the image data, e.g., interferogram, may allow reconstructing the spectrum per polarization.

[0136] Also, further processing may be applied to reconstruct the spectrum per polarization. For example, regarding a Fabry -Perot style interferometer dealiasing, because of the multiple reflections within the cavitie(s), may be applied. The circuitry may therefore be configured to perform such processing.

[0137] Also, boundary conditions may be applied, for example because of underdefined equations, to be able to solve the equations, e.g., assuming the spectrum is zero at the edge of a bandpass filter. The circuitry may, therefore, be configured to apply such boundary conditions.

[0138] The circuitry may be further configured to denoise the acquired image data. Denoising may include estimating noise, for example noise from the image sensor.

[0139] The circuitry may be further configured to determine a focus distance of the imaging device based on acquired image data. That is, based on the measured interference the focus distance may be determined. Thus, it may be determined whether a phase shift of input light has occurred, for example due to an imaged object in the scene being out of focus of the imaging device. In this way a displacement of an out of focus object in the scene may be determined. That is, the phase shift affects the Fourier coefficients extracted from the image data. Thus, the circuitry may be configured to analyze the extracted Fourier coefficients and calculate the displacement needed to focus an out-of-focus object of the imaged scene.

[0140] The circuitry may be further configured to focus the imaging device on the out-of-focus object based on the determined displacement. For example, the circuitry may be configured to displace the imaging device.

[0141] Based on the imaging technique of the imaging device and the image processing of the circuitry accurate color representation even under varying light sources, for example, by directly measuring the emitted spectrum, becomes possible. The above-mentioned technique can resolve primary colors at each pixel, eliminating the need for a demosaicing algorithm.

[0142] Additionally, the ability to separately record polarizations reduces light reflections in the scene, similar to the effect of using a polarizer in photography. The use of a Michelson interferometer as explained above allows for a light throughput of up to 50%, which is higher than the averageSony Semiconductor Solutions Corporation et al.

[0143] (e.g., 33% achieved with a color filter array). Furthermore, the range of the imaging device may be extended to include the near-infrared (NIR) spectrum.

[0144] The circuitry may perform any method or process included in this specification.

[0145] Some embodiments pertain to an electronic device comprising an imaging device for capturing an image of a scene, wherein the imaging device comprises a polarization sensitive interferometer whose input light spans a wavelength range, and which is configured to output polarization specific interfered light, and comprises an image sensor configured to capture the image based on the output polarization specific interfered light, wherein the electronic device further comprises a circuitry configured to acquire image data of the image captured by the imaging device, and reconstruct the color spectrum of the scene for different polarizations based on the acquired image data.

[0146] Some embodiments pertain to an electronic device comprising an imaging device for capturing an image of a scene, wherein the imaging device comprises a polarization sensitive interferometer whose input light spans a wavelength range, and which is configured to output polarization specific interfered light, and comprises an image sensor configured to capture the image based on the output polarization specific interfered light for reconstructing the color spectrum of the scene, wherein the electronic device further comprises a circuitry configured to acquire image data of the image captured by the imaging device, and reconstruct the color spectrum of the scene for different polarizations based on the acquired image data.

[0147] The imaging device of the electronic device may include any feature as described for the imaging device in this specification. The circuitry of the electronic device may include any feature as described for the circuitry in this specification.

[0148] The electronic device may be a smartphone, a laptop computer, a tablet computer, a personal computer, a wearable electronic device, electronic glasses, head-up displays, or the like.

[0149] Some embodiments pertain to a method for capturing an image of a scene with the imaging device comprising the steps of outputting, with the polarization sensitive interferometer, polarization specific interfered light based on input light which spans a wavelength range, and capturing the image based on the output polarization specific interfered light.

[0150] Some embodiments pertain to a method for capturing an image of a scene with the imaging device comprising the steps of outputting, with the polarization sensitive interferometer, polarization specific interfered light based on input light which spans a wavelength range, andSony Semiconductor Solutions Corporation et al.

[0151] capturing the image based on the output polarization specific interfered light for reconstructing the color spectrum of the scene.

[0152] The method may include any feature of the corresponding imaging device described in this specification.

[0153] The method may include taking multiple samples, i.e., capturing multiple images, of the scene while detuning the interferometer for each acquisition. During capture of the multiple images the scene may remain static, thereby preventing blur.

[0154] The method may further include the step of calibrating the imaging device. Calibration may therefore refer to calibrating the optical path difference. For example calibrating the optical path difference for each light portion, i.e., for each polarization.

[0155] Calibration may be performed with a reference laser. In this way accuracy of the polarization sensitive Fourier transform spectrometry can be increased, for example by compensating for mechanical tolerances and temperature fluctuations.

[0156] Calibration may include detecting deviations in the predefined interference pattern for the reference laser. Further it may include adjusting the adjustment mechanism according to the deviation. This tuning ensures that the measurements of the input light remain precise, despite any mechanical or thermal variations, thereby improving the overall reliability and accuracy of the spectrometric analysis.

[0157] Alternatively, when using conductive reflectors, such as wire grid reflectors, calibration may include capacitance measurements between the reflectors and correlating this to the distance between them. For example, in a Fabry-Perot style interferometer with two cavities including two polarizing reflectors and a partially transparent reflector in the middle, distance may refer to the distance from the respective polarizing reflectors to the half-transparent reflector in the middle. Alternatively, in a Michelson style interferometer including a beam splitter, two polarizing reflectors and two mirrors (e.g., non-polarizing reflector) located behind each of the polarizing reflectors, distance may refer to the distance between a mirror and their respective polarizing reflector.

[0158] Some embodiments pertain to a method comprising the steps of acquiring image data of an image captured by the imaging device and reconstructing the color spectrum of the scene for different polarizations.Sony Semiconductor Solutions Corporation et al.

[0159] The method may include any feature of the corresponding imaging device and / or circuitry and / or any method or process regarding reconstruction of the color spectrum for different polarizations and / or any method or process regarding generating a color image from the reconstructed spectrum and / or any method or process regarding image processing or image post-processing described in this specification.

[0160] The methods as described herein are also implemented in some embodiments as a computer program causing a computer and / or a processor to perform the method, when being carried out on the computer and / or processor. In some embodiments, also a non-transitory computer-readable recording medium is provided that stores therein a computer program product, which, when executed by a processor, such as the processor described above, causes the methods described herein to be performed.

[0161] Returning to Fig. la, an imaging device including a polarization sensitive interferometer is illustrated.

[0162] Imaging device 1 includes collimating lens 6, interferometer 2, focusing lens 7 and image sensor 8. Light 15 coming from a scene (not visible) is used as input to the interferometer 2 and includes a broad wavelength range, e.g. the visible range, containing a mixture of red, green and blue light. Light 15 passes through the collimating lens 6 before reaching the interferometer 2. Collimating lens 6 collimates light 15, thereby converting the light 15 into collimated light 15a, e.g., a parallel beam, and directing collimated light 15a to interferometer 2, e.g., the first polarizing element 3a of interferometer 2.

[0163] Interferometer 2 of imaging device 1 of Fig. la is based on the principle of a Fabry-Perot interferometer. Additionally, interferometer 2 is polarization sensitive and therefore includes a polarizer 3. Polarizer 3 includes a first polarizing element 3a, a half-transparent reflector 4 and a second polarizing element 3b. The two polarizing elements 3a, 3b are reflective polarizers that are disposed parallel to each other. Halt-transparent reflector 4 is disposed between the two polarizing elements 3.

[0164] At the half-transparent reflector 4 a portion of the collimated input light 15a is reflected back towards the first polarizing element 3a and a portion of the collimated input light 15a passes through towards the second polarizing element 3b.

[0165] Between the first polarizing element 3a and the half-transparent reflector 4 is a first cavity 2a, which is a Fabry-Perot cavity, as a first portion of the light undergoes multiple reflections between the half-transparent reflector 4 and the first polarizing element 3a. First polarizingSony Semiconductor Solutions Corporation et al.

[0166] element 3a is a reflective polarizer configured to let collimated input light 15a through and reflect polarized light of a predefined polarization state that is reflected from the half-transparent reflector 4 back to the reflective surface 3c facing the half-transparent reflector 4.

[0167] The first polarizing element 3a is a horizontal polarizer, thereby reflecting a first portion (horizontally polarized) of the light Ila, which is reflected towards the reflective surface 3c of the first polarizing element 3a from the half-transparent reflector 4 back. Thus, first cavity 2a is a horizontal cavity.

[0168] In the horizontal cavity, the horizontally polarized first portion of the light Ila undergoes multiple reflections between the half-transparent reflector 4 and the first polarizing element 3a indicated by the arrow Ila, leading to interference of the horizontally polarized first light portion Ila. First cavity 2a, then selects interfered horizontally polarized light portion 11c as output, which also passes cavity 2b during output of the polarizer 3.

[0169] The portion of the collimating light 15a passing through the half-transparent reflector 4 enters second cavity 2b and is vertically polarized and reflected at the surface 3d of the second polarizing element 3b facing the half-transparent reflector 4. The vertically polarized light portion 1 lb is then reflected back from the half-transparent reflector 4 towards the reflective polarizing element 3b.

[0170] Thus, between the second polarizing element 3b and the half-transparent reflector 4 is a second cavity 2b, which is a Fabry-Perot cavity as a vertically polarized second light portion 1 lb undergoes multiple reflections between the half-transparent reflector 4 and the second polarizing element 3b.

[0171] That is, the second polarizing element 3b reflects the second portion of the light 1 lb which is polarized vertically, and the vertically polarized light 1 lb undergoes multiple reflection between the half-transparent reflector 4 and the second polarizing element 3b, indicated by the arrow 1 lb, leading to interference of the vertically polarized first light portion 1 lb. The second cavity 2b then selects interfered vertically polarized light portion 1 Id as output. Thus, second cavity 2b is a vertical cavity.

[0172] In essence, in first cavity 2a polarization predefined reflections are generated and interfered and in second cavity 2b polarization predefined reflections are generated and interfered, wherein the reflections in the first cavity 2a are orthogonally polarized to the reflections in the second cavity 2b. In the example described above the orthogonally polarized light portions Ila and 1 lb (and 11c and lid) are horizontally and vertically polarized respectively.Sony Semiconductor Solutions Corporation et al.

[0173] Alternatively, also other polarizations may be possible as long as the polarizations are orthogonal to each other. Instead of horizontally and vertically polarized light, the light may therefore be polarized clockwise and anticlockwise respectfully as long as the polarizations are orthogonal to each other. For example, the first light portion Ila may be polarized clockwise and the second light portion 1 lb may be polarized anticlockwise. In this way, the first polarizing element 3a may be a clockwise polarizer and the second polarizing element may be an anti -clockwise polarizer or vice versa, instead of a horizontal polarizer and a vertical polarizer or vice versa. Therefore, interferometer 2 includes two cavities 2a, 2b that are coupled in series, wherein the first light portion Ila reflected multiple times within the first cavity 2a is orthogonally polarized to the second light portion 1 lb reflected multiple times within the second cavity 2b. Due to the multiple reflections within each respective cavity 2a, 2b interference occurs within each respective cavity and for each respective polarized light portion Ila, 1 lb. The interference occurs according to the Fabry -Perot principle, wherein a Fabry -Perot cavity selects light (11c, lid) based on the interference of reflections. Thus, each cavity selects a portion (11c) of the interfered and polarized first light portion Ila and a portion (1 Id) of the polarized and interfered second light portion 1 lb as output.

[0174] In this way, the polarizer 3 of interferometer 2 splits the collimated input light 15a into two orthogonally polarization specific interfered light portions 11c, lid. The interfered and polarized light is selectively output (including light portions 11c, lid) according to the interference pattern produced for each light portion Ila and 1 lb as polarization specific interfered light 15b from the interferometer 2, i.e., the polarizer 3, and focused through focusing lens 7 onto the image sensor 8. Image sensor 8, therefore, captures the focused polarization specific interfered light 15b in an image (e.g., from which an interferogram may be generated). That is, the output light 15b includes interfered horizontally polarized first light portion 11c selected from the first cavity 3a and includes interfered vertically polarized light portion lid selected from the second cavity 2b.

[0175] Thus, a color spectrum can be generated for each polarization, i.e., for the horizontal polarization and for the vertical polarization, via Fourier transform from the output light 15b captured by the image sensor 8 in an image. To generate the color spectrum per polarization also further processing may be applied. For example, dealiasing is applied, because of the multiple reflections within each cavity 2a, 2b.

[0176] The first polarizing element 3a and the second polarizing element 3b are movable via piezo actuator 5 (illustrated schematically as arrows) relative to the half-transparent reflector 4, whichSony Semiconductor Solutions Corporation et al.

[0177] remains static. The movement occurs along the main axis of the interferometer 2 perpendicular to the surfaces 3c, 3d of the polarizing elements 3a, 3b, which is illustrated as vertical movement by the arrows of piezo actuators 5 in the figure. In this way the respective cavity lengths are changeable, thereby changing the optical path as well as the optical path difference (OPD) for each cavity 2a, 2b. Thus, multiple images with different OPDs may be captured by image sensor 8.

[0178] Alternatively, the half-transparent reflector 4 is movable instead of the polarizing elements 3a, 3b. Alternatively, the half-transparent reflector 4 and / or one or both of the polarizing elements 3a, 3b are movable.

[0179] The output intensity / outof the signal 15b output from the interferometer 2 for the different polarizations may follow the following formula (Eq.l):

[0180] >

[0181]

[0182] where

[0183] / outis the output intensity,

[0184] Sa(cr) and Sb(<j) is the spectral power distribution of collimated input light 15a, where the input light 15a has been decomposed in two orthogonal polarizations denoted by the subscript a and b, Tlaand Rlais the respective plate transmittance and reflectance of the first polarizing element 3a,

[0185] T2a= Tlband R2a= Rib is the respective plate transmittance and reflectance of the half-transparent reflector 4,

[0186] T2band R2bis the respective plate transmittance and reflectance of the second polarizing element 3b,

[0187] and d2is the distance between the first polarizing element 3a to the half-transparent reflector 4 and the half-transparent reflector 4 to the second polarizing element 3b respectively, and

[0188] a is the wavenumber, i.e. reciprocal of the wavelength.

[0189] Fig. lb illustrates the imaging device 1 of Fig. la additionally including a bandpass filter 14.Sony Semiconductor Solutions Corporation et al.

[0190] Thus, the imaging device 1 of Fig. lb corresponds to the imaging device of Fig. la, but also includes bandpass filter 14. Bandpass filter 14 isolates a range of wavelengths by blocking unwanted wavelengths of light 15, thereby avoiding aliasing, from entry into interferometer 2. Fig. 2a illustrates an imaging device including a polarization sensitive interferometer.

[0191] Imaging device 1 includes collimating lens 6, interferometer 2, focusing lens 7 and image sensor 8. Light 15 coming from a scene (not visible) is used as input to the interferometer 2 and includes a broad wavelength range, e.g. the visible range containing a mixture of red, green and blue light. Light 15 passes through the collimating lens 6 before reaching the interferometer 2. Collimating lens 6 collimates light 15, thereby converting light 15 into collimated light 15a, e.g., a parallel beam, and directing collimated light 15a to interferometer 2.

[0192] Interferometer 2 of imaging device 1 of Fig. 2a is based on the principle of a Michelson interferometer. Interferometer 2 is configured to split and recombine light creating interference patterns. Additionally, interferometer 2 is polarization sensitive and therefore includes a polarizer 3. Thus interferometer 2 is configured to split the collimated input light 15a into orthogonally polarized (horizontal and vertical) first and second light portions Ila, 11b that are recombined respectively creating an interference pattern for the horizontal first light portion Ila and an interference pattern for the vertical second light portion 1 lb.

[0193] Polarizer 3 includes a beam-splitter 12, a first polarizing element 3a, a second polarizing element 3b, a movable reflector 16 disposed behind the first polarizing element 3a and a movable reflector 16 disposed behind the second polarizing element 3b.

[0194] The two polarizing elements 3a, 3b are reflective polarizers that are disposed orthogonally to each other. Also, the two reflectors 16 are disposed orthogonally to each other. Each reflector 16 can be moved by a respective piezo actuator 5, thereby allowing for adjustment of the optical path length, the movement direction is indicated by the respective double arrow. Alternatively, only one of the two reflectors 16 may be movable, e.g., via a piezo actuator 5. Alternatively or additionally, one or both of the polarizing elements 3a, 3b may be movable, e.g., via a piezo actuator 5.

[0195] The beam-splitter 12 (e.g., non-polarizing beam splitter cube, partially reflective mirror), splits the incoming collimated input light 15a into two perpendicular arms. One part of the beam, along the first arm, is reflected, while the other, along the second arm, is transmitted. The reflected part is reflected towards the first polarizing element 3a and the transmitted part is transmitted to the second polarizing element 3b.Sony Semiconductor Solutions Corporation et al.

[0196] For illustrations purposes two orthogonal polarizations of light (e.g., horizontal Ila, vertical 1 lb) are illustrated as dashed and dotted lines respectively.

[0197] At the first polarizing element 3a the light is polarized such that a first light portion Ila, polarized horizontally (dashed line), is reflected from the first polarizing element 3a and a second light portion 1 lb, polarized vertically (dotted line), is transmitted through the first polarizing element 3a to the reflector 16 behind it and reflected back off the reflector 16.

[0198] At the second polarizing element 3b the light is polarized such that a first light portion Ila, polarized horizontally (dashed light), is transmitted through the second polarizing element 3b to the reflector 16 behind it and reflected back off the reflector 16 and a second light portion 1 lb, polarized vertically (dotted line), is reflected from the polarizing element 3b.

[0199] Thus, along the first arm, a first light portion Ila and a second light portion 1 lb, polarized orthogonally to each other, are reflected back and along the second arm, a first light portion Ila and a second light portion 1 lb, polarized orthogonally to each other, are reflected back. This is illustrated in detail in Fig. 2b.

[0200] After reflecting off their respective reflectors 16 and polarizing elements 3 a, 3b the light portions Ila, 1 lb recombine at the beam splitter 12. Depending on the path difference, they interfere creating an interference pattern, wherein the respective first light portions Ila, polarized horizontally, interfere with each other and the respective second light portions 1 lb, polarized vertically, interfere with each. The interfered light is then output as interfered polarized light 15b from the interferometer 2, i.e., from the polarizer 3, and focused via focusing lens 7 on the image sensor 8. Thus, the output polarization specific interfered light 15b includes the interfered first light portion 11c (horizontally polarized) as well as the interfered second light portion lid (vertically polarized).

[0201] In this way, polarizer 3 of interferometer 2 splits the collimated input light 15a into orthogonally polarization specific light portions Ila, 11b that are interfered and output as polarization specific interfered light portions 11c, lid. Therefore, polarizer 3 of interferometer 2 splits the collimated input light 15a into two orthogonally polarization specific interfered light portions 11c, lid. The interfered and polarized light is output (including light portions 11c, lid) according to the interference pattern produced for each light portion Ila and 1 lb as polarization specific interfered light 15b from the interferometer 2, i.e., the polarizer 3, and focused through focusing lens 7 onto the image sensor 8.Sony Semiconductor Solutions Corporation et al.

[0202] The image sensor 8 captures the polarized and interfered light, i.e., the polarization specific interfered light 15b, as an image. Capturing multiple of these images for various displacements (e.g., various OPD accomplished by detuning the interferometer 2 as described below) allows to create an interferogram, which can be used for extracting a color spectrum from the image for each polarization, the horizontal and the vertical polarization. That is, from multiple images, for which an interferogram could be generated, the color spectrum can be extracted for each polarization.

[0203] Thus, a color spectrum can be generated for each polarization, i.e., for the horizontal polarization and for the vertical polarization, e.g., via Fourier transform, from the output light 15b captured by the image sensor 8 in an image. To generate the color spectrum per polarization also further processing may be applied (see for example Figs. 6 to 8).

[0204] Image sensor 8, therefore, captures the focused polarization specific interfered light 15b in an image. That is, output light 15b includes interfered horizontally polarized first light portion 11c and includes interfered vertically polarized light portion lid.

[0205] Also, other polarizations may be possible as long as the polarizations are orthogonal to each other. Instead of horizontally and vertically polarized light, the light may therefore be polarized clockwise and anticlockwise respectfully as long as the polarizations are orthogonal to each other. For example, the first light portions Ila, 11c may be polarized clockwise and the second light portions 11b, lid may be polarized anticlockwise. In this way, the first polarizing element 3a may be a clockwise polarizer and the second polarizing element 3b may be an anticlockwise polarizer or vice versa, instead of a horizontal polarizer and a vertical polarizer or vice versa.

[0206] The reflectors 16, parallelly disposed to their respective polarizing elements, are movable via piezo actuator 5 relative to their respective polarizing elements 3a, 3b which remains static. The movement occurs along the optical axis (perpendicular to the respective reflectors 16 surface), which is illustrated as vertical movement for the reflector 16 disposed behind the first polarizing element 3a and as horizontal movement for the reflector 16 disposed behind the second polarizing element 3b by the arrows in the figure.

[0207] Thus, the reflectors 16 are movable toward or away from the beam splitter 12 (along the same direction as the light path in its arm). This movement changes the optical path length, altering the interference pattern. For example, one reflector 16 may be fixed while the other reflector 16 is modulated. The one kept fixed will show up as a DC offset in the interference pattern.Sony Semiconductor Solutions Corporation et al.

[0208] In this way the multiple images with different interference patterns according to the varied OPD may be captured. That is, by adjusting, e.g., detuning, interferometer 2, variation in the OPD may be achieved, e.g., for the first and second light portions Ila, 11b respectively, changing the interference pattern, such that an interferogram could be generated from the captured multiple images of different interference patterns.

[0209] Fig. 2b illustrates the light portions reflected back along the two arms of the interferometer of Fig. 2a that recombine creating an interference pattern.

[0210] Fig. 2b shows the reflected light portions 1 la, 1 lb arriving along the first arm 20a from the first polarization element 3a and its respective reflector 16 located behind it (illustrated vertically in the figure). Fig. 2b also shows the reflected light portionsl la, 1 lb arriving along the second arm 20b from the second polarization element 3a and its respective reflector 16 located behind it (illustrated vertically in the figure). The first arm 20a and the second arm 20b are perpendicular to each other. Thus, the light portions Ila, 1 lb of the first arm 20a, i.e., arriving along the path of the first arm 20a, arrive perpendicularly to the light portions Ila, 1 lb of the second arm 20b. As discussed above regarding Fig. 2a the first light portion 1 la of the first arm 20a is horizontally polarized and the second light portion 1 lb of the first arm 20a is vertically polarized. Also, the first light portion 1 la of the second arm 20a is horizontally polarized and the second light portion 1 lb of the first arm 20a is vertically polarized. The dashed line indicates the horizontal polarization and the dotted line indicates the vertical polarization of the respective light portions Ila, 1 lb of the arms 20a, 20b.

[0211] The respective light portions Ila, 1 lb of the first arm 20a recombine with the respective light portions Ila, 1 lb of the second arm 20b at the beam splitter (12, Fig. 2a). There, the horizontally polarized light portion 1 la of the first arm 20a interferes with the horizontally polarized light portion Ila of the second arm 20b creating an interference pattern, i.e., an interfered horizontally polarized first light portion 11c.

[0212] Also, the vertically polarized light portion 1 lb of the first arm 20a interferes with the vertically polarized light portion 1 lb of the second arm 20b creating an interference pattern, i.e., an interfered vertically polarized first light portion lid.

[0213] The reflections arriving from the first and second polarizing elements 3a, 3b are located closer to the beam splitter 12 than the reflections arriving from the reflectors 16.

[0214] Therefore, a path difference occurs between the first light portion 1 la of the first arm 20a, which takes a shorter path, and the first light portion 1 la of the second arm 20b, which takes a longerSony Semiconductor Solutions Corporation et al.

[0215] path. In this way interference due to the optical path difference (OPD) between horizontally polarized light portions 1 la of the two arms 20a, 20b is generated at the recombination location (beam splitter 12, Fig. 2a).

[0216] Similarly, a path difference occurs between the second light portion 1 lb of the first arm 20a, which takes a longer path, and the second light portion 1 lb of the second arm 20b, which takes a shorter path. In this way an interference due to the optical path difference (OPD) between vertically polarized light portions 1 lb of the two arms 20a, 20b is generated at the recombination location (beam splitter 12, Fig. 2a).

[0217] After recombination of the light portions, output light 15b therefore includes interfered polarized first and second light portions Ila, 1 lb. In other words, interferometer 2, i.e., polarizer 3, outputs polarization specific interfered light 15b including an interfered polarized first light portion 11c and an interfered orthogonally, relative to the first light portion Ila, polarized light portion lid. Instead, of the horizontal and vertical polarizations, also any other polarization, such as a clockwise and anti-clockwise polarization may be possible.

[0218] The output intensity / outof the signal 15b output from the interferometer 2 for the different polarizations may follow the following formula (Eq.2):

[0219]

[0220] / outis the output intensity,

[0221] Ixis the maximum light intensity for the first polarization state, i.e., the first light portion Ila, He,

[0222] Iyis the maximum intensity for the second, orthogonal polarization state, i.e., the second light portion 11b, lid,

[0223] m is the angular frequency of the light,

[0224] Adxis the optical path difference within the first light portion,

[0225] Ad2is the optical path difference within the second light portion, and

[0226] c is the speed of light.

[0227] Fig. 2c, illustrates the imaging device 1 of Fig. 2a additionally including a bandpass filter 14. Thus, the imaging device 1 of Fig. 2c corresponds to the imaging device of Fig. 2a, but also includes bandpass filter 14. Bandpass filter 14 isolates a range of wavelengths by blockingSony Semiconductor Solutions Corporation et al.

[0228] unwanted wavelengths of light 15, thereby avoiding aliasing, which are excluded from entry into the interferometer 2.

[0229] Fig. 3a illustrates an imaging device with a polarization-sensitive interferometer including a liquid crystal polarizer.

[0230] Imaging device 1 includes collimating lens 6, interferometer 2, focusing lens 7 and image sensor 8.

[0231] Light 15 coming from a scene (not visible) is used as input to the interferometer 2 and spans a broad wavelength range, e.g. the visible range containing a mixture of red, green and blue light. Light 15 passes through the collimating lens 6 before reaching the interferometer 2. Collimating lens 6 collimates light 15, thereby converting light 15 into collimated light 15a, e.g., a parallel beam, and directing collimated light 15a to interferometer 2.

[0232] Interferometer 2 is configured to split and recombine light creating interference patterns.

[0233] Additionally, interferometer 2 is polarization sensitive and therefore includes a polarizer 3. Thus interferometer 2 is configured to generate interference for orthogonally polarized (e.g. horizontal and vertical) first and second light of the collimated input light 15a, such that interference for the horizontal first light portion and interference for the vertical second light portion is created. Polarizer 3 includes a beam-splitter 12, a first polarizing element 3a, a second polarizing element 3b, a reflector 16 disposed behind the first polarizing element 3a and a reflector 16 disposed behind the second polarizing element 3b.

[0234] The two polarizing elements 3a, 3b are nematic liquid crystal planes that are disposed orthogonally to each other. Also, the two reflectors 16 are disposed orthogonally to each other and parallel to their corresponding polarizing element 3a, 3b.

[0235] The beam-splitter 12 (e.g., non-polarizing beam splitter cube or partially reflective mirror), splits the incoming collimated input light 15a into two perpendicular arms. One part of the beam, along the first arm, is reflected, while the other, along the second arm, is transmitted. The reflected part is reflected towards the first polarizing element 3a and the transmitted part is transmitted to the second polarizing element 3b.

[0236] The nematic liquid crystal of the first polarizing element 3a is oriented in the x-z-plane (i.e., (pi = 0, wherein (pi is the azimuth angle within the plane of the first polarizing element 3a (x-y-plane), measured from the reference axis x).Sony Semiconductor Solutions Corporation et al.

[0237] The surface of the first polarizing element 3 a lies within the x-y plane of the global coordinate system. The normal of the first polarizing element 3a corresponds to the z-axis of the global coordinate system.

[0238] In other words, the director of the nematic liquid crystal has no y component, in terms of the global coordinate system.

[0239] The global coordinate system is used in the following.

[0240] Furthermore, within the x-z-plane the nematic liquid crystal is tilted at a tilt angle 0i relative to the normal of the first polarizing element 3a, i.e., relative to the z-axis. For example, 9i = 90°, then the director of the nematic liquid crystal of first polarizing element 3a is aligned along the x-axis.

[0241] The light arriving at the first polarizing element 3a along the first arm propagates along the z-axis. Since the light arriving along the first arm propagates along the z-axis, it includes a horizontally (x-oriented) and a vertically (y-oriented) polarized light portion.

[0242] The vertically polarized light portion (second light portion) is oriented perpendicular to the director of the nematic liquid crystal of the first polarizing element 3 a, since the director lies in the x-z plane. Therefore, the vertically polarized light portion (second light portion) experiences the ordinary refractive index noi(see Fig. 3c).

[0243] The horizontally polarized light portion (first light portion) is oriented such that it includes a component along the director depending on the angle 0i within the x-z-plane. Therefore, it experiences a combination of the ordinary (noi) and extraordinary (nei) refractive indices depending on 0i. For example, if 0i = 90°, the director is aligned along the x-axis, and the horizontally polarized light portion (first light portion), being aligned parallel to the director, experiences the extraordinary refractive index nei(see Fig. 3c).

[0244] The subsequent path of the individual components of the light (first and second light portions, which are orthogonally polarized) thus depend on the respective refractive indices noi, neithey experience.

[0245] Upon exiting first polarizing element 3a the light is subsequently reflected off the reflector 16 located behind the first polarizing element 3a back to the beam splitter 12.

[0246] The second polarizing element 3b, oriented orthogonally to the first polarizing element 3a has an opposite response to the horizontally and vertically polarized light portions arriving along the second arm, which is explained in the following.Sony Semiconductor Solutions Corporation et al.

[0247] That is, the surface of the second polarizing element 3b lies in the y-z plane in the global coordinate system, i.e., it is orthogonally oriented to the first polarizing element 3a. The normal of the second polarizing element 3b corresponds to the x-axis of the global coordinate system. The nematic liquid crystal of the second polarizing element 3b is oriented in the x-y plane in the global coordinate system. In other words, the director of the nematic liquid crystal has no z component in terms the global coordinate system, i.e., cp2 = 90°, wherein q>2 is the azimuth angle within the plane of the second polarizing element 3b (y-z plane), measured from the reference axis z of the global coordinate system.

[0248] The global coordinate system is used in the following.

[0249] Furthermore, within the x-y plane the nematic liquid crystal is tilted at a tilt angle 02 relative to the normal of the second polarizing element 3b, i.e., relative to the x-axis in global coordinates. For example, 02 = 90°, so that the director of the nematic liquid crystal is aligned along the y-axis.

[0250] The light arriving at the second polarizing element 3b along the second arm propagates along the x-axis. Since the light arriving along the second arm propagates along the x-axis, it includes a horizontally (z-oriented) and a vertically (y-oriented) polarized light portion.

[0251] The horizontally polarized light portion (first light portion) is oriented perpendicular to the director of the nematic liquid crystal of the first polarizing element 3 a, since the director lies in the x-y plane. Therefore, the horizontally polarized light portion experiences the ordinary refractive index n02.

[0252] The vertically polarized light portion (second light portion) is oriented such that it includes a component along the director depending on the angle 02 within the x-y plane. Therefore, it experiences a combination of the ordinary (n02) and extraordinary (ne2) refractive indices depending on 02. For example, if 02 = 90°, the director is aligned along the y-axis, and the vertically polarized light portion (second light portion), being aligned parallel to the director, experiences the extraordinary refractive index ne2.

[0253] The subsequent path of the individual components of the light (first and second light portions) thusly depends on the respective refractive indices n02, ne2 they experience.

[0254] Upon exiting the second polarizing element 3b the light is subsequently reflected off the reflector 16 located behind the second polarizing element 3b to the beam splitter 12.Sony Semiconductor Solutions Corporation et al.

[0255] After reflecting off their respective reflectors 16 the light arriving along the first and second arms recombine at the beam splitter 12.

[0256] Polarizer 3 is configured such that the first light portion (horizontally polarized) of the first arm experiences a different refractive index at the first polarizing element 3a than the refractive index the first light portion (horizontally polarized) of the second arm experiences at the second polarizing element 3b.

[0257] In the same way polarizer 3 is configured such that the second light portion (vertically polarized) of the first arm experiences a different refractive index at the second polarizing element 3 a than the refractive index the second light portion (vertically polarized) experiences at the second polarizing element 3b.

[0258] In this example, noi= n02 and nei= ne2, and the light travelling back along the first arm from the reflector 16 located behind the first polarizing element 3a includes a vertically polarized second light portion, which had experienced noi. On the other hand, the light travelling back along the second arm from the reflector 16 located behind the second polarizing element 3b includes a vertically polarized second light portion, which had experienced a refractive index different from noi, for example ne2 if 02 = 90°.

[0259] In this way, an optical path difference is introduced for the vertically polarized second light portions of the respective first and second arm recombined at the beam splitter 12, affecting the interference of the respective vertically polarized second light portions.

[0260] Similarly, the light travelling back along the second arm from the reflector 16 located behind the first polarizing element 3b includes a horizontally polarized first light portion, which had experienced n02. On the other hand, the light travelling back along the second arm from the reflector 16 located behind the first polarizing element 3a includes a horizontally polarized first light portion, which had experienced a refractive index different from n02, for example neiif 0i = 90°.

[0261] In this way, an optical path difference is introduced for the horizontally polarized first light portions of the respective first and second arm recombined at the beam splitter 12, affecting the interference of the respective horizontally polarized first light portions.

[0262] The liquid crystals of the first and second polarizing elements 3a, 3b are tunable, such that the director can be reoriented. As the director tilts (affecting at least one of 0i, 02, (pi, (p2) the effective index experienced by a particular polarization changes, thereby affecting the interference pattern at recombination.Sony Semiconductor Solutions Corporation et al.

[0263] The director may, for example, be reoriented such that the noiaxis of the first polarizing element 3a remains oriented orthogonally to the noiaxis of the second polarizing element 3b and that the neiaxis of the first polarizing element 3a remains oriented orthogonally to the neiaxis of the second polarizing element 3b.

[0264] Alternatively, the polarizer 3 may be configured such that the first polarizing element 3a includes an extraordinary refractive index neithat is different to the extraordinary refractive index ne2 of the second polarizing element 3b. Furthermore, the polarizer 3 may be configured such that the first polarizing element 3a includes an ordinary refractive index noithat is different to the ordinary refractive index n02 of the second polarizing element 3b.

[0265] If the respective first and second polarizing elements 3a, 3b have nematic liquid crystals with directors oriented the same relative to the incoming light beam, a path difference may be introduced between the first light portion of the first arm (horizontally polarized) and the first light portion of the second arm (horizontally polarized) due to the difference in extraordinary refractive indices noiand noiand / or neiand ne2 depending on which orientation the first light portions experience. This would then affect the interference between the respective horizontally polarized light portions recombined at the beam splitter 12.

[0266] In the same way, there may be a path difference introduced between the second light portion of the first arm (vertically polarized) and the second light portion of the second arm (vertically polarized) due to the difference in refractive indices noiand n02 and / or neiand ne2 depending on which orientation the second light portions experience. This would then affect the interference between the respective vertically polarized light portions recombined at the beam splitter 12. Alternatively, it may be considered that the refractive index experienced by the light of the first arm at the first polarizing element 3a is nefn, which is the refractive index seen by the light as a function of 0i, (pi. In the same way, the refractive index experienced by the light of the second arm at the second polarizing element 3b is neft2, which is the refractive index seen by the light as a function of 02, (p2. Therefore, the optical path difference may be defined based on a difference between nefn and neft2.

[0267] Instead of horizontally and vertically polarized first and second light portions, the respective light portions may be considered to have other orientations, for example they may be considered to be polarized clockwise and anticlockwise, as long as the polarizations are orthogonal to each other.Sony Semiconductor Solutions Corporation et al.

[0268] The interfered light is output as polarization specific interfered light 15b from the interferometer 2, i.e., from the polarizer 3, and focused via focusing lens 7 on the image sensor 8.

[0269] Image sensor 8, therefore, captures the focused polarization specific interfered light 15b in an image (e.g., interference pattern). That is, output light 15b includes a interfered horizontally polarized first light portion and includes an interfered vertically polarized light portion.

[0270] In this way, a color spectrum can be generated for each polarization, i.e., for the horizontal polarization and for the vertical polarization, via Fourier transform from the output light 15b captured by the image sensor 8 in an image.

[0271] The output intensity / outof the signal 15b output from the interferometer 2 for the different polarizations may follow the following formula (Eq.3):

[0272]

[0273] / outis the output intensity,

[0274] Ixis the maximum light intensity for the first polarization state, i.e., the first light portion, Iyis the maximum intensity for the second, orthogonal polarization state, i.e., the second light portion,

[0275] m is the angular frequency of the light,

[0276] d is the thickness of the liquid crystal layer,

[0277] n01is the ordinary refractive index of the first polarizing element 3a, encountered in the example above by the second light portion (vertically polarized),

[0278] no2is the ordinary refractive index of the second polarizing element 3b, encountered in the example above by the first light portion (horizontally polarized),

[0279] 71(0-]) is the refractive index encountered by the first light portion (horizontally polarized) in the first polarizing element 3a,

[0280] n(02) is the refractive index encountered by the second light portion (vertically polarized) in the second polarizing element 3b, which lies between the ordinary and the extraordinary refractive index depending on the respective director angle 0i and 02, (as explained in the example above), and

[0281] c is the speed of light.

[0282] Fig. 3b illustrates the imaging device 1 of Fig. 3a additionally including a bandpass filter 14.Sony Semiconductor Solutions Corporation et al.

[0283] Thus, the imaging device 1 of Fig. 3b corresponds to the imaging device of Fig. 3a, but also includes bandpass filter 14. Bandpass filter 14 isolates a range of wavelengths by blocking unwanted wavelengths of light 15, thereby avoiding aliasing, are excluded from entry into the interferometer 2.

[0284] Fig. 3c illustrates the orientation of the nematic liquid crystal molecules within the first polarizing element 3a of Figs. 3a and 3b.

[0285] Fig. 3c illustrates the global coordinate system of Figs. 3a and 3b, with the horizontal axis being the x-axis of Figs. 3a, 3b and the vertical axis being the z-axis of Figs. 3a and 3b. The y-axis is out-of-plane as indicated by the “x” in the circle.

[0286] The first polarizing element 3a of Figs. 3a and 3b (not illustrated in Fig. 3c) lies in the x-y plane of the global coordinate system. The director 71a of liquid crystal 72a of the first polarizing element aligns with the x-axis of the global coordinate system. Therefore, the azimuth angle (pi within the x-y-plane (starting from the x-axis) of the first polarizing element is 0°and not visible in Fig. 3c, and the tilt angle 0i relative to the z-axis, which is the normal of the first polarizing element (Fig. 3a, 3b), is 90°.

[0287] The light (not illustrated) arriving at the first polarizing element along the first arm propagates along the z-axis of Fig. 3c and includes a horizontally (x-oriented) and a vertically (y-oriented) polarized light portion.

[0288] Therefore, the vertically polarized light portion (second light portion), which is y-oriented experiences the ordinary refractive index noiof the nematic liquid crystal 72a. The horizontally polarized light portion (first light portion), which is x-oriented experiences the extraordinary refractive index neiof the nematic liquid crystal 72a.

[0289] Fig. 3d illustrates the orientation of the nematic liquid crystal molecules within the first polarizing element 3a of Figs. 3a and 3b.

[0290] Fig. 3d illustrates the global coordinate system of Figs. 3a and 3b, with the horizontal axis being the y-axis of Figs. 3a, 3b and the vertical axis being the z-axis of Figs. 3a and 3b. The x-axis is out-of-plane as indicated by the dot in the circle.

[0291] The second polarizing element 3b of Figs. 3a and 3b (not illustrated in Fig. 3c) lies in the y-z plane of the global coordinate system. Fig. 3d shows that the director 71b of liquid crystal 72b of the second polarizing element aligns with the y-axis of the global coordinate system. Therefore, the azimuth angle (p2 within the y-z-plane (starting from the z-axis) of the first polarizing elementSony Semiconductor Solutions Corporation et al.

[0292] is 90°, and the tilt angle 02 relative to the x-axis, which is the normal of the second polarizing element, is 90°.

[0293] The light (not illustrated) arriving at the second polarizing element along the second arm propagates along the x-axis of Fig. 3c and includes a horizontally (z-oriented) and a vertically (y-oriented) polarized light portion.

[0294] Therefore, the horizontally polarized light portion (first light portion), which is z-oriented experiences the ordinary refractive index n02 of the nematic liquid crystal 72b. The vertically polarized light portion (second light portion), which is y-oriented experiences the extraordinary refractive index ne2 of the nematic liquid crystal 72a.

[0295] Fig. 4a illustrates reconstruction of the color spectrum of an imaged scene from image data. At 30 image data of an image, e.g., multiple images, captured by an imaging device 1 of Figs, la to 3b is acquired, for example by a circuitry. As the image data includes interference patterns of the wavelengths included in the light reflected from the imaged scene (e.g., light 15, Figs. la-3b) a color spectrum can be reconstructed from the acquired image data. Furthermore, the image data includes interference patterns for the orthogonally polarized light portions (e.g., 11c, lid, Figs. la-2b) of the light reflected from the imaged scene, as described in detail in Figs, la to 3b. Thus, a color spectrum can be reconstructed for the different polarizations.

[0296] At 31 the color spectrum of the scene for different polarizations is reconstructed, for example by the circuitry.

[0297] Fig. 4b illustrates generation of a polarization filtered color image.

[0298] Steps 30 and 31 correspond to steps 30 and 31 of Fig. 4a.

[0299] Thus at 30 image data of an image, e.g., multiple images (see Fig. 4c), captured by an imaging devices 1 of Figs, la to 3b is acquired, e.g., by a circuitry. The image data is acquired from the imaging device 1. Alternatively, the image data may be acquired, e.g., by the circuitry, from a database.

[0300] After reconstruction of the color spectrum of the imaged scene for different polarizations, a color image 50 is generated. Color image 50 includes the accurate color information determined based on the image data, i.e., based on the color spectrum reconstructed at 31 from the image data. The color spectrum may be reconstructed based on image data of multiple interference patterns (see Fig. 4c), e.g., 6 to 12 samples, wherein the images captured by the imaging device 1 are ofSony Semiconductor Solutions Corporation et al.

[0301] the same (static) scene. In this way interference patterns across the image sensor for multiple optical path differences can be acquired.

[0302] Furthermore, color image 50 is a polarization filtered image with reduced glare as the image output from imaging device 1, on which the generation of the color image 50, is based includes polarization information for the scene light. Thus, color image 50 is generated based on the reconstructed color spectrum for the orthogonal polarizations of the scene light extracted at 31 from the image data.

[0303] Step 31 of Fig. 4b may also correspond to step 31a or 31b of Fig. 5a or 5b respectively. Further processing as described in Figs. 6 to 8 may also occur.

[0304] Fig. 4c illustrates an embodiment of reconstruction of the color spectrum of an imaged scene from image data.

[0305] At 30 image data of multiple images, e.g., captured by an imaging device 1 of Figs, la to 3b, is acquired, for example by a circuitry. Step 30 may correspond to step 30 of Figs. 4a and 4b. The image data of multiple captured images includes interference patterns for multiple optical path differences (OPDs). For example, the image data is such that an interferogram as explained above may be generated. Alternatively, also an interferogram based on the multiple images captured by the imaging device 1 of Figs, la to 3b may be acquired.

[0306] At 3 la the reconstruction of the color spectrum of the scene for different polarizations is extracted based on the image data. Step 31 corresponds to step 31 of Figs. 4a and 4b.

[0307] Next a color image 50 as described in Fig. 4b may be generated. Further image processing as for example described in Figs. 6 to 8 may occur, for example, beforehand.

[0308] Fig. 5a illustrates reconstruction of the color spectrum of an imaged scene from image data. Steps 30 and 31a correspond to steps 30 and 31 of Figs. 4a and 4c.

[0309] Thus, at 30 image data of an image, e.g., multiple images, captured by an imaging device 1 of Figs, la to 3b is acquired, for example by a circuitry. The image data is such that it includes interference information for multiple optical path differences (OPDs). For example, each pixel of the image (which may correspond to one or more pixels of the image sensor) may correspond to a specific location of the interference patterns, wherein multiple interference patterns, each corresponding to a different optical path difference may be included. Alternatively, also an interferogram based on the multiple images captured by the imaging device 1 of Figs, la to 3b may be acquired.Sony Semiconductor Solutions Corporation et al.

[0310] At 3 la the reconstruction of the color spectrum of the scene for different polarizations is based on the Fourier transform. The color spectrum for the different polarizations is extracted by removing the static term and applying the inverse Fourier transform on the acquired image data. Next a color image 50 as described in Fig. 4b may be generated. Further image processing as for example described in Figs. 6 to 8 may occur, for example, beforehand.

[0311] Fig. 5b illustrates reconstruction of the color spectrum of an imaged scene from image data. Steps 30 and 31a correspond to steps 30 and 31 of Figs. 4a and 4c and steps 30 and 3 la of Fig. 5a.

[0312] Thus, at 30 image data of an image, e.g., multiple images, captured by the imaging device 1 of Figs, la to 3b is acquired, for example by a circuitry.

[0313] At 3 lb the reconstruction of the color spectrum of the scene for different polarizations is based on the removal of the static term and application of the inverse cosine transform on the acquired image data.

[0314] Next a color image 50 as described in Fig. 4b may be generated. Further image processing as for example described in Figs. 6 to 8 may occur, for example, beforehand.

[0315] Fig. 6 illustrates reconstruction of the color spectrum of an imaged scene including denoising of image data.

[0316] Step 30 of Fig. 6 corresponds to step 30 of Figs. 4a to 5b.

[0317] Thus, at 30 image data of an image, e.g., multiple images, captured by the imaging device 1 of Figs, la to 3b is acquired, for example, by a circuitry.

[0318] At 32 the image data is denoised and at 31 the color spectrum of the scene for different polarization is reconstructed based on the denoised image data. Steps 31 and 32 may be conducted conjointly, for example as described in Fig. 8 in more detail.

[0319] Fig. 7 illustrates refocusing of an imaged out-of-focus object based on postprocessing image data.

[0320] Step 30 of Fig. 6 corresponds to step 30 of Figs. 4a to 6.

[0321] Thus, at 30 image data of an image, e.g., multiple images, captured by the imaging device 1 of Figs, la to 3b is acquired, for example, by a circuitry.

[0322] At 33 a phase shift of input light 15 is determined based on the acquired image data. That is, an out-of-focus object of the imaged scene of the image of the acquired image data introduced aSony Semiconductor Solutions Corporation et al.

[0323] phase shift to the input light 15, which is reflected in the image data and subsequently extracted from the image data at 33.

[0324] At 34 displacement of the object in the image is determined based on the determined phase shift. For example, displacement of the out-of focus object relative to the focus.

[0325] At 35 the object is focused in the image based on the determined phase shift. That is, at 35 the image sensor (e.g., 8 of Figs, la to 3b) is shifted to get an imaged object in focus according to the determined displacement.

[0326] Next a new image may be captured according to step 30 of Fig. 4b. On that basis a color image 50 as described in Fig. 4b may be generated, wherein the imaged object is focused.

[0327] Further image processing as for example described in Figs. 6 and 8 may occur, for example, beforehand or afterwards.

[0328] Fig. 8 illustrates extracting of a color spectrum from image data including denoising.

[0329] The input spectrum 41 represents the incoming light spectrum that is to be analyzed (e.g., light 15, Figs. la-3b).

[0330] The input spectrum 41 is first passed through bandpass filter 14 (e.g., 14, Figs, lb, 2c, 3b).

[0331] Bandpass filter sets the incoming spectrum to zero at the band edges considered by the inverse Fourier transform used in post-processing, ensuring that the spectrum is confined within a specific frequency range.

[0332] The output 42 of the bandpass filter 14 is then subjected to a Fourier transform 43. This transform 43 converts the filtered spectrum 42 into its frequency domain representation (e.g., 15b, Fig. 1 a-3b). For example, by detuning the cavities 2a, 2b of Figs, la, lb, a transform of the incoming spectrum 41, 42 is carried out (e.g., a cosine transform for the Michelson-style interferometer, such as interferometer 2 of Figs. 2a, 2c, 3a, 3b).

[0333] The output 15b of the Fourier transform (e.g., 15b, Figs. 1 a-3b) is combined with noise 48 at the addition node 44. The noise 48 represents the readout noise introduced by the imaging sensor (e.g., 8, Figs. 1 a-3b), such as a Single-Photon Avalanche Diode (SPAD) or a CMOS sensor. The combined signal, which includes the transformed spectrum (e.g., 15b, Figs. 1 a-3b) and the added noise 48, is then detected by the image sensor 8. The image sensor captures the intensity variations of the interference pattern, producing a set of pixel values that represent the noisy signal.Sony Semiconductor Solutions Corporation et al.

[0334] The output 45 of the image sensor 8 is processed using an inverse cosine transform 46 (This applies for example to the output 45 based on output 15b of Figs. 2a to 3c of interferometer 2, which correspond to a Michel son- style interferometer. Concerning output 15b of Figs, la, lb from interferometer 2 which corresponds to a Fabry-Perot style interferometer, the Eq. 1 may be undone as outlined for example in “Fourier transform spectrometer based on Fabry -Perot interferometer”, Saeed & Khalil, 2026, Applied Optics, Vol. 55, No. 20).

[0335] The inverse cosine transform 46 converts the detected pixel values back into the frequency domain representation, effectively recovering the original spectrum 41 from the noisy signal 48. The output of the inverse cosine transform 46 generates the recovered spectrum 47. This recovered spectrum 47 includes both the original spectral 41 information and the noise 48 introduced during detection.

[0336] It is also possible to estimate the noise introduced by the detection process. The signal is then detected by the SPAD or any other imaging sensor, which adds noise to the detection. The data is then inversely transformed to recover the original spectrum, transforming the measured pixel values to Fourier coefficients.

[0337] Assuming the bandpass filter (BPF) 14 (see also 14, Fig. lb, 2c, 3b) sets the incoming spectrum 41 to zero at the band edges of the Fourier band, the following formula (Eq. 4) applies for the Michelson (style) interferometer and similarly for the Fabry-Perot (style) interferometer:

[0338] <

[0339]

[0340] In the above c0is the zero Fourier coefficient (DC term), representing the average value of the signal over the frequency range,

[0341] ckare the higher-order Fourier coefficients, which represent the amplitude of the cosine components at different frequencies k,

[0342] f is the bandwidth of the bandpass filter 14,

[0343] fo is the lower bound of the frequency range,Sony Semiconductor Solutions Corporation et al.

[0344] / ( ) represents the intensity of the signal as a function of frequency f representing the spectral content of the incoming light 41,

[0345] n( ) represents the noise 48 at each frequency ,

[0346] This simplification is possible because / ( ) is multiplied with a Dirac train that peaks at the band edges, where I f)= 0.

[0347] Noise Estimation for Non-Zero Optical Path Difference:

[0348] As k = 0 might be difficult to obtain in practice (implying a zero optical path difference), it is also possible to estimate the noise using the following equation (Eq. 5):

[0349]

[0350] This simplification occurs because / ( ) is multiplied with an alternating Dirac train.

[0351] Thus, Fig. 8 provides a detailed representation of the system and method for spectral analysis and noise estimation using the interferometric setup as described in Figs, la to 3d. The described components and processes enable accurate recovery of the original spectrum while accounting for detection noise, thereby enhancing the reliability and precision of spectral measurements. Fig. 9a illustrates a method for capturing an image of a scene with the imaging device of Figs. la-3b.

[0352] At 61 polarization specific interfered light is output, e.g., with polarization sensitive interferometer 2 of imaging device 1 of Figs, la to 3b, based on input light (e.g., 15, Figs, la to 3b) which spans a wavelength range, e.g., is a mixture of red, green and blue light.

[0353] At 62 the image of the scene is captured, e.g., by the image sensor 8 of Fig. la-3b, 8, based on the output polarization specific interfered light for reconstructing the color spectrum of the scene.

[0354] Fig. 9b illustrates a calibration method of an imaging device for capturing an image of a scene with the imaging device of Figs. la-3b.

[0355] At 60 imaging device 1 of Figs. la-3b is calibrated, e.g., by using a reference laser, or by capacitance measurement between the reflective elements and correlating this to the distance between them. Within the context of the capacitance measurement between reflective elements may refer to between the first polarizing element 3a and the half-transparent reflector 4 (see e.g., d-L of Eq. 1) of Figs, la, lb and / or between the second polarizing element 3b and the half-Sony Semiconductor Solutions Corporation et al.

[0356] transparent reflector 4 (see e.g., d2of Eq.l) of Figs, la, lb and / or between first polarizing element 3a and the second polarizing element 3b (see e.g., d + d2) of Figs, la, lb. Alternatively, it may refer to between the first polarizing element 3a to the reflector 16 located behind it of Figs. 2a, 2c or 3a, 3b and / or between the second polarizing element 3b to the reflector 16 located behind it of Figs. 2a, 2c or 3a, 3b. Then the imaging (steps 61 and 62) as described in Fig. 9a proceeds.

[0357] Afterwards image data processing and color image 50 generation as described in Figs. 4a to 8 may proceed.

[0358] Fig. 10 illustrates an electronic device for imaging and color spectrum reconstruction for different polarizations from image data. The embodiments of Fig. 10 can implement any process as described for Figs, la to 9b.

[0359] The electronic device 100 includes a CPU 101 as processor. Additionally, or alternatively, other computation hardware, such as GPU, TPU, DSP etc. may be used. The electronic device 100 further includes camera(s) 206, microphone(s) 107 and loudspeaker(s) 108 that are connected to the processor 101. The CPU 101 may implement the processes as described in Figs, la to 9b. The processor 101 may for example implement: imaging as described in Figs. la-3b, 9a, 9b e.g., generating the polarization specific interfered light (e.g., 15b) and capturing the image based on the polarization specific interfered light. It may also implement calibration of the imaging device (e.g., 1, Figs. la-3b), acquiring the image (e.g., Figs. 4a-8), reconstructing the color spectrum for different polarizations (e.g., Figs. 4a-8), denoising (e.g., Figs. 6, 8, and / or object focusing (e.g., Fig. 7).

[0360] The microphone 107 may be configured to receive any kind of audio signal. The loudspeaker 108 may be configured to emit any kind of audio signal. At least one of the camera(s) 106 may be the imaging device 1 of Figs. la-3b.

[0361] Camera 106 may also be one or more cameras, such as an RGB camera, a ToF camera, for example, an iToF or dTof or the like.

[0362] The electronic device 100 further include a user interface 109 that is connected to the processor 101. This user interface 109 acts as a man-machine interface and enables a dialogue between a user and the electronic device 100.

[0363] The electronic device 100 further includes a Bluetooth interface 104, and a WLAN interface 105. These units 104, 105 act as I / O interfaces for data communication with external devices. ForSony Semiconductor Solutions Corporation et al.

[0364] example, additional loudspeakers, microphones, and cameras, e.g., imaging device 1 of Figs, la-3b, with WLAN or Bluetooth connection may be coupled to the processor 101 via these interfaces 104 and 105.

[0365] The electronic device 100 further includes a data storage 102 and a data memory 103 (here a RAM). The data memory 103 is arranged to temporarily store or cache data or computer instructions for processing by the processor 101, for example the acquired image data or the color spectrum for different polarizations (see e.g., Figs. 4a to 8) may be stored. The data storage 102 is arranged as a long-term storage, e.g., of for example the acquired and generated image data.

[0366] The connection between the processor 101 and the camera 106 may include a camera serial interface (CSI). The CSI is an interface between a camera 106 and a host processor 101. Thus, control signals and data from the processor 101 to the camera 106 as well as from the camera 106 to the processor 101 may be sent.

[0367] The electronic device 100 may be a stationary electronic device, such as a laptop computer, a personal computer, or a mobile device of any other kind of portable or wearable device, for example, a smartphone, a tablet computer, smart glasses, head mounted displays (HMDs), or other type of mobile platform, or other types of smart wearable devices, or the like.

[0368] It should be recognized that the embodiments describe methods and processes with an exemplary ordering of method steps. The specific ordering of method steps is however given for illustrative purposes only and should not be construed as binding. For example, the ordering of 31 and 32 in the embodiment of Fig. 6 may be exchanged. Other changes of the ordering of method steps may be apparent to the skilled person.

[0369] Please note that the division of the processor into CPU 106 is only made for illustration purposes and that the present disclosure is not limited to any specific division of functions in specific units. For instance, the processor 101 could be implemented by a respective programmed processor, field programmable gate array (FPGA) and the like.

[0370] A method for controlling imaging device 1, for controlling a circuitry and / or for controlling an electronic device, such as electronic device 100 discussed above, is described above under reference of Figs. 4a-9b. The method can also be implemented as a computer program causing a computer and / or a processor, such as processor 106 discussed above, to perform the method, when being carried out on the computer and / or processor. In some embodiments, also a non-transitory computer-readable recording medium is provided that stores therein a computerSony Semiconductor Solutions Corporation et al.

[0371] program product, which, when executed by a processor, such as the processor described above, causes the method described to be performed.

[0372] All units and entities described in this specification and claimed in the appended claims can, if not stated otherwise, be implemented as integrated circuit logic, for example on a chip, and functionality provided by such units and entities can, if not stated otherwise, be implemented by software.

[0373] In so far as the embodiments of the disclosure described above are implemented, at least in part, using software-controlled data processing apparatus, it will be appreciated that a computer program providing such software control and a transmission, storage or other medium by which such a computer program is provided are envisaged as aspects of the present disclosure.

[0374] Note that the present technology can also be configured as described below.

[0375] [1] An imaging device (1) for capturing an image of a scene comprising:

[0376] a polarization sensitive interferometer (2) whose input light spans a wavelength range, and which is configured to output polarization specific interfered light (15b); and an image sensor (8) configured to capture the image based on the output polarization specific interfered light (15b) for reconstructing the color spectrum of the scene.

[0377] [2] The imaging device (1) of [1], wherein the polarization sensitive interferometer (2) includes a polarizer (3) configured to output a first and second light portion (1 la-d) of the input light (15, 15a), wherein the output first and second light portions (1 la-d) are orthogonally polarized and interfered.

[0378] [3] The imaging device (1) of [2], wherein the polarizer (3) is configured to split the input light (15, 15a) into the first and second light portion (1 la-d).

[0379] [4] The imaging device (1) of [2] or [3], wherein the polarizer (3) includes two polarizing elements (3a, 3b).

[0380] [5] The imaging device (1) of [4], wherein the first polarizing element (3a) of the two polarizing elements is configured to polarize the first light portion (Ila), and wherein the second polarizing element (3b) of the two polarizers is configured to polarize the second light portion (1 lb) orthogonally to the first light portion (Ila).

[0381] [6] The imaging device (1) of [4] or [5], wherein the two polarizing elements (3a, 3b) are reflective polarizers.Sony Semiconductor Solutions Corporation et al.

[0382] [7] The imaging device (1) of [6], wherein the two reflective polarizers are configured to polarize light orthogonally to each other, such that reflected light of the first reflective polarizer of the two polarizing elements (3a, 3b) is polarized orthogonally to reflected light of the second reflective polarizer of the two polarizing elements (3a, 3b).

[0383] [8] The imaging device (1) of any one of [2] to [7], wherein the polarizer (3) further includes a partially transparent reflector (3, 12).

[0384] [9] The imaging device (1) of [8], wherein the partially transparent reflector (12) is a two-way beamsplitter.

[0385]

[0010] The imaging device (1) of any one of [4] to [8], wherein the two polarizing elements (3a, 3b) are configured such that an optical delay between the two polarizing elements (3a, 3b) with respect to the partially transparent reflector (4) is adjustable.

[0386]

[0011] The imaging device (1) of

[0010] , wherein the optical delay is adjustable such that an interference pattern for different polarizations of the input light (15, 15a) is generated.

[0387]

[0012] The imaging device (1) of any one of [4] to

[0011] , wherein the two polarizing elements (3a, 3b) are aligned parallel to each other.

[0388]

[0013] The imaging device (1) of [4] to

[0012] , wherein the two polarizing elements (3a, 3b) are aligned orthogonally to each other.

[0389]

[0014] The imaging device (1) of any one of [4] to

[0013] , wherein at least one polarizing element (3a, 3b) is a liquid crystal polarizer.

[0390]

[0015] The imaging device (1) of any one of [1] to

[0014] , wherein the imaging device (1) includes a first lens (6) configured to collimate the input light (15, 15a) and direct it though the polarization sensitive interferometer (2).

[0391]

[0016] The imaging device (1) of any one of [1] to

[0015] , wherein the imaging device (1) includes a second lens (7) configured to focus the output polarization specific interfered light (15b) from the interferometer (2) to the image sensor (8).

[0392]

[0017] The imaging device (1) of any one of [1] to

[0016] , wherein the imaging device (1) includes a bandpass filter.

[0393]

[0018] Circuitry configured to:

[0394] acquire image data of an image captured by the imaging device (1) of any one of [1] to

[0017] ; andSony Semiconductor Solutions Corporation et al.

[0395] reconstruct the color spectrum of the scene for different polarizations based on the acquired image data.

[0396]

[0019] The circuitry of

[0018] , wherein reconstructing the color spectrum of the scene is based on a Fourier transform.

[0397]

[0020] The circuitry of

[0018] or

[0019] , wherein reconstructing the color spectrum of the scene is based on an inverse cosine transform.

[0398]

[0021] The circuitry of any one of

[0018] to

[0020] , further configured to denoise the acquired image data.

[0399]

[0022] The circuitry of any one of

[0018] to

[0021] , further configured to determine a focus distance of the imaging device (1) based on acquired image data.

[0400]

[0023] An electronic device (100) comprising:

[0401] an imaging device (1) for capturing an image of a scene comprising a polarization sensitive interferometer (2) whose input light (15, 15a) spans a wavelength range, and which is configured to output polarization specific interfered light (15b), and

[0402] an image sensor (8) configured to capture the image based on the output polarization specific interfered light (15b) for reconstructing the color spectrum of the scene; and

[0403] a circuitry configured to

[0404] acquire image data of the image captured by the imaging device (1), and reconstruct the color spectrum of the scene for different polarizations based on the acquired image data.

[0405]

[0024] An electronic device (100) comprising an imaging device (1) according to any one of [1] to

[0017] and a circuitry according to any one of

[0018] to

[0022] ,

[0406]

[0025] A method for capturing an image of a scene with the imaging device of any one of [1] to

[0017] comprising the steps of

[0407] outputting, with the polarization sensitive interferometer (2), polarization specific interfered light based on input light (15, 15a) which spans a range of wavelengths; andSony Semiconductor Solutions Corporation et al.

[0408] capturing the image based on the output polarization specific interfered light (15b) for reconstructing the color spectrum of the scene.

[0409]

[0026] The method of

[0025] , further including the step of calibrating the imaging device (1) of any one of [1] to

[0017] ,

[0410]

[0027] A method comprising the steps of

[0411] acquiring image data of an image captured by the imaging device (1) of any one of [1] to

[0017] ; and

[0412] reconstructing the color spectrum of the scene for different polarizations.

[0413]

[0028] An imaging device (1) for capturing an image of a scene comprising:

[0414] a polarization sensitive interferometer (2) whose input light spans a wavelength range, and which is configured to output polarization specific interfered light (15b); and an image sensor (8) configured to capture the image based on the output polarization specific interfered light (15b).

[0415]

[0029] The imaging device (1) of

[0028] , wherein the polarization sensitive interferometer (2) includes a polarizer (3) configured to output a first and second light portion (1 la-d) of the input light (15, 15a), wherein the output first and second light portions (1 la-d) are orthogonally polarized and interfered.

[0416]

[0030] The imaging device (1) of

[0029] , wherein the polarizer (3) is configured to split the input light (15, 15a) into the first and second light portion (1 la-d).

[0417]

[0031] The imaging device (1) of

[0029] or

[0030] , wherein the polarizer (3) includes two polarizing elements (3a, 3b).

[0418]

[0032] The imaging device (1) of

[0031] , wherein the first polarizing element (3a) of the two polarizing elements is configured to polarize the first light portion (Ila), and wherein the second polarizing element (3b) of the two polarizers is configured to polarize the second light portion (1 lb) orthogonally to the first light portion (Ila).

[0419]

[0033] The imaging device (1) of

[0031] or

[0032] , wherein the two polarizing elements (3a, 3b) are reflective polarizers.

[0420]

[0034] The imaging device (1) of

[0033] , wherein the two reflective polarizers are configured to polarize light orthogonally to each other, such that reflected light of the first reflective polarizerSony Semiconductor Solutions Corporation et al.

[0421] of the two polarizing elements (3 a, 3b) is polarized orthogonally to reflected light of the second reflective polarizer of the two polarizing elements (3a, 3b).

[0422]

[0035] The imaging device (1) of any one of

[0029] to

[0034] , wherein the polarizer (3) further includes a partially transparent reflector (3, 12).

[0423]

[0036] The imaging device (1) of

[0035] , wherein the partially transparent reflector (12) is a two-way beamsplitter.

[0424]

[0037] The imaging device (1) of any one of

[0031] to

[0036] , wherein the two polarizing elements (3a, 3b) are configured such that an optical delay between the two polarizing elements (3a, 3b) with respect to the partially transparent reflector (4) is adjustable.

[0425]

[0038] The imaging device (1) of

[0037] , wherein the optical delay is adjustable such that an interference pattern for different polarizations of the input light (15, 15a) is generated.

[0426]

[0039] The imaging device (1) of any one of

[0031] to

[0038] , wherein the two polarizing elements (3a, 3b) are aligned parallel to each other.

[0427]

[0040] The imaging device (1) of

[0031] to

[0039] , wherein the two polarizing elements (3a, 3b) are aligned orthogonally to each other.

[0428]

[0041] The imaging device (1) of any one of

[0031] to

[0040] , wherein at least one polarizing element (3a, 3b) is a liquid crystal polarizer.

[0429]

[0042] The imaging device (1) of any one of

[0028] to

[0041] , wherein the imaging device (1) includes a first lens (6) configured to collimate the input light (15, 15a) and direct it though the polarization sensitive interferometer (2).

[0430]

[0043] The imaging device (1) of any one of

[0028] to

[0042] , wherein the imaging device (1) includes a second lens (7) configured to focus the output polarization specific interfered light (15b) from the interferometer (2) to the image sensor (8).

[0431]

[0044] The imaging device (1) of any one of

[0028] to

[0043] , wherein the imaging device (1) includes a bandpass filter.

[0432]

[0045] Circuitry configured to:

[0433] acquire image data of an image captured by the imaging device (1) of any one of

[0028] to

[0044] ; and

[0434] reconstruct the color spectrum of the scene for different polarizations based on the acquired image data.Sony Semiconductor Solutions Corporation et al.

[0435]

[0046] The circuitry of

[0045] , wherein reconstructing the color spectrum of the scene is based on a Fourier transform.

[0436]

[0047] The circuitry of

[0045] or

[0046] , wherein reconstructing the color spectrum of the scene is based on an inverse cosine transform.

[0437]

[0048] The circuitry of any one of

[0045] to

[0047] , further configured to denoise the acquired image data.

[0438]

[0049] The circuitry of any one of

[0045] to

[0048] , further configured to determine a focus distance of the imaging device (1) based on acquired image data.

[0439]

[0050] An electronic device (100) comprising:

[0440] an imaging device (1) for capturing an image of a scene comprising a polarization sensitive interferometer (2) whose input light (15, 15a) spans a wavelength range, and which is configured to output polarization specific interfered light (15b), and

[0441] an image sensor (8) configured to capture the image based on the output polarization specific interfered light (15b) for reconstructing the color spectrum of the scene; and

[0442] a circuitry configured to

[0443] acquire image data of the image captured by the imaging device (1), and reconstruct the color spectrum of the scene for different polarizations based on the acquired image data.

[0444]

[0051] An electronic device (100) comprising an imaging device (1) according to any one of

[0028] to

[0044] and a circuitry according to any one of

[0045] to

[0049] ,

[0445]

[0052] A method for capturing an image of a scene with the imaging device of any one of

[0028] to

[0044] comprising the steps of

[0446] outputting, with the polarization sensitive interferometer (2), polarization specific interfered light based on input light (15, 15a) which spans a range of wavelengths; and capturing the image based on the output polarization specific interfered light (15b) for reconstructing the color spectrum of the scene.Sony Semiconductor Solutions Corporation et al.

[0447]

[0053] The method of

[0052] , further including the step of calibrating the imaging device (1) of any one of

[0028] to

[0044] ,

[0448]

[0054] A method comprising the steps of

[0449] acquiring image data of an image captured by the imaging device (1) of any one of

[0028] to

[0044] ; and

[0450] reconstructing the color spectrum of the scene for different polarizations.

[0451]

[0055] A computer program comprising program code causing a computer to perform the method according to anyone of

[0025] to

[0027] and

[0052] to

[0054] , when being carried out on a computer.

[0452]

[0056] A non-transitory computer-readable recording medium that stores therein a computer program product, which, when executed by a processor, causes the method according to anyone of

[0025] to

[0027] and

[0052] to

[0054] to be performed.

Claims

Sony Semiconductor Solutions Corporation et al.CLAIMS1. An imaging device for capturing an image of a scene comprising:a polarization sensitive interferometer whose input light spans a wavelength range, and which is configured to output polarization specific interfered light; andan image sensor configured to capture the image based on the output polarization specific interfered light for reconstructing the color spectrum of the scene.

2. The imaging device of claim 1, wherein the polarization sensitive interferometer includes a polarizer configured to output a first and second light portion of the input light, wherein the output first and second light portions are orthogonally polarized and interfered.

3. The imaging device of claim 2, wherein the polarizer is configured to split the input light into the first and second light portion.

4. The imaging device of claim 2, wherein the polarizer includes two polarizing elements.

5. The imaging device of claim 4, wherein the first polarizing element of the two polarizing elements is configured to polarize the first light portion, and wherein the second polarizing element of the two polarizers is configured to polarize the second light portion orthogonally to the first light portion.

6. The imaging device of claim 4, wherein the two polarizing elements are reflective polarizers.

7. The imaging device of claim 6, wherein the two reflective polarizers are configured to polarize light orthogonally to each other, such that reflected light of the first reflective polarizer of the two polarizing elements is polarized orthogonally to reflected light of the second reflective polarizer of the two polarizing elements.

8. The imaging device of claim 4, wherein the polarizer further includes a partially transparent reflector.

9. The imaging device of claim 8, wherein the partially transparent reflector is a two-way beamsplitter.

10. The imaging device of claim 8, wherein the two polarizing elements are configured such that an optical delay between the two polarizing elements with respect to the partially transparent reflector is adjustable.Sony Semiconductor Solutions Corporation et al.

11. The imaging device of claim 10, wherein the optical delay is adjustable such that an interference pattern for different polarizations of the input light is generated.

12. The imaging device of claim 4, wherein the two polarizing elements are aligned parallel to each other.

13. The imaging device of claim 4, wherein the two polarizing elements are aligned orthogonally to each other.

14. The imaging device of claim 4, wherein at least one polarizing element is a liquid crystal polarizer.

15. The imaging device of claim 1, wherein the imaging device includes a first lens configured to collimate the input light and direct it though the polarization sensitive interferometer.

16. The imaging device of claim 1, wherein the imaging device includes a second lens configured to focus the output polarization specific interfered light from the interferometer to the image sensor.

17. The imaging device of claim 1, wherein the imaging device includes a bandpass filter.

18. Circuitry configured to:acquire image data of an image captured by the imaging device of claim 1; and reconstruct the color spectrum of the scene for different polarizations based on the acquired image data.

19. The circuitry of claim 18, wherein reconstructing the color spectrum of the scene is based on a Fourier transform.

20. The circuitry of claim 18, wherein reconstructing the color spectrum of the scene is based on an inverse cosine transform.

21. The circuitry of claim 18, further configured to denoise the acquired image data.

22. The circuitry of claim 18, further configured to determine a focus distance of the imaging device based on acquired image data.

23. An electronic device comprising:an imaging device for capturing an image of a scene comprisingSony Semiconductor Solutions Corporation et al.a polarization sensitive interferometer whose input light spans a wavelength range, and which is configured to output polarization specific interfered light, andan image sensor configured to capture the image based on the output polarization specific interfered light for reconstructing the color spectrum of the scene; anda circuitry configured toacquire image data of the image captured by the imaging device, and reconstruct the color spectrum of the scene for different polarizations based on the acquired image data.

24. A method for capturing an image of a scene with the imaging device of claim 1 comprising the steps ofoutputting, with the polarization sensitive interferometer, polarization specific interfered light based on input light which spans a range of wavelengths; andcapturing the image based on the output polarization specific interfered light for reconstructing the color spectrum of the scene.

25. The method of claim 24, further including the step of calibrating the imaging device of claim 1.

26. A method comprising the steps ofacquiring image data of an image captured by the imaging device of claim 1; and reconstructing the color spectrum of the scene for different polarizations.

Images