497 results about "Polarization imaging" patented technology

A method, apparatus, and computer program product for identifying features in a sample by analyzing Mueller matrices to calculate an average degree of polarization, a weighted average degree of polarization, a degree of polarization map, a degree of polarization surface. Also, a method, apparatus, and computer program product for identifying features in a sample by analyzing Mueller matrices to calculate depolarization relative to a retardance axis and/or a diattentuation axis, and to calculate a ratio of diattenuation to polarizance or ratios of row and column magnitudes. Also, a method for retinal polarimetry, including a non-depolarizing light tube configured for insertion into the eye.

In addition to having color, light waves have the attribute of polarization. An apparatus and method to convert circular polarized light into linearly polarized light over a wide range of wavelengths is provided by utilizing a first surface-relief grating functioning as a quarter-wave waveplate and a second surface-relief grating functioning as a half-wave waveplate. A plurality of such devices are arranged in a two-dimensional array and combined with an array of linear polarizers and an array of photodetectors to form a polarization imaging sensor. Such a sensor could have applications in automobiles to alert drivers of the presence of other vehicles, especially at night, in fog, or in rain. Military applications include the detection of vehicles placed among trees and shrubs. Another advantage of using circular polarization images is that the sign and magnitude of the circular polarization can potentially be used to reveal the spatial orientation, material, and surface roughness of the object's surface.

A polarization imaging system and method are disclosed for measuring the magnitude and orientation of retardance in a sample. There are no moving parts and the invention is readily constructed as an imaging system that obtains polarization values at all point in a scene simultaneously. The system first takes an image that records the apparent slow axis orientation and the apparent retardance. However, the apparent retardance is indeterminate by mlambda, the wavelength of observation. By recording such images at two wavelengths, and taking note of both the apparent phase and the angular orientation of polarization interference in each of the two cases, the system is able to determine retardance values of 5lambda or more at every point without ambiguity. The actual slow axis orientation is determined as well. The determination of retardance value and axis orientation is independent for each point measured, and does not make use of spatial relationships or distributions within the sample.

A polarization image processing apparatus includes an illumination unit, a splitter, first and second polarization imaging devices, and a processing unit. The illumination unit illuminates a first surface of a transparent or translucent object with first illumination light polarized in a first direction and second illumination light polarized in a second direction, which crosses the first direction, alternately. Illumination axes of the first illumination light and second illumination light substantially coincide with an imaging axis of the polarization image processing apparatus. The splitter divides returning light into at least two light components. The first and second polarization imaging devices receive the light components. The processing unit detects a condition of a second surface of the object on the basis of first and second polarization images obtained by the first polarization imaging device and third and fourth polarization images obtained by the second polarization imaging device.

The invention relates to the technical field of optical instruments, in particular to an underwater video camera system based on polarization identification and a method thereof. The technical scheme is that the underwater video camera system comprises an underwater light source, a polarization modulation part and an image acquisition and processing part, wherein the underwater light source comprises a semiconductor laser, an optical filter, a polarizer, a polarization rotator and a beam expander; the polarization modulation part comprises an analyzer, a stepper motor, a stepper motor controller and an infrared detector; and the image acquisition and processing part comprises a high-frequency CCD (Charge Coupled Device) video camera, an image acquisition system and a computer. The underwater video camera system has the benefits that with the adoption of the underwater camera system and the method, the contrast degree and the definition of target imaging as well as the target detectionand the identification efficiency can be effectively improved; the polarization imaging can utilize the differences of different target back polarizations to eliminate the interference of background light; and as a means for identifying the target from messy background is provided, the method has remarkable advantage as compared with the commoner method for imaging and identifying the target by using light intensity.

A multi-energy polarization imaging method consisting of a multi-fusion, dual-rotating retarder/multiple-energy complete Mueller matrix-based polarimeter and dual-energy capabilities, has been invented. The term multifusion describes the use of several imaging functions altogether such as polarimetric imaging, dual-energy subtraction, multifocal imaging and other. By substracting polarimetric parameters such as degree of polarization, degree of linear polarization, degree of circular polarization, respectively, obtained with interrogation light beams of wavelengths λ₁ and λ₂, he system, enhanced imaging is obtained. The system includes a light source for illuminating a target with a first quantity of light having a first wavelength and a second quantity of light having a second wavelength, the first and second wavelengths being different. A polarization-state generator generates a polarization state for each of the first and second quantities of light, and includes a first polarizer through which the first and second quantities of light are transmitted before entering a first waveplate. A polarization-state receiver evaluates a resulting polarization state of the first and second quantities of light following illumination of the target, the polarization-state receiver including a second waveplate through which the first and second quantittes of light are transmitted before entering a second polarizer. An optical image-capture device captures a first image of the target illuminated by the first quantity of light and a second image of the target illuminated by the second quantity of light. A processing unit assigns a weighting factor to at least one of the first and second images and evaluates a weighted difference between the first and second images to generate a multi-energy image of the target.

The invention discloses a spectrum polarization detection device and a method for synchronous polarization modulation interference imaging. The spectrum polarization detection device comprises a preposed polarization imaging system, an image plane interference imaging spectrometer and a signal processing system which are arranged on the same optical axis in sequence. Incident light forms four groups of light beams with different polarization state information through a polarization element and the light beams are separated on a space of a back focal plane of a microlens array. The separated light beams shoot into a lateral cutting beam splitter after passing through a collimator objective lens and are divided into two crosswise, and optical path difference information is brought in. Two branches of emergent light passes through a postpositional imaging objective lens, a target image with interference information and polarization state information is obtained on a target face of a detector, and the target image is transformed into an electrical signal and enters a signal processing system. Fourier transform is carried out, and light intensity information, spectral information and complete Stokes polarization information of a two-dimensional space of each target point are obtained. The spectrum polarization detection device for synchronous polarization modulation interference imaging has the advantages of being high spectral resolution, high in signal to noise ratio and simultaneous in complete Stokes polarization information and can be used for spectrum detection of a narrow band or a wide band.

The invention relates to a polarimetric imaging device comprising a multiple-quantum-well structure operating on inter-sub-band transitions by absorbing radiation at a wavelength λ, said structure comprising a matrix of individual detection pixels, characterized in that the matrix is organized in subsets of four individual pixels, a first pixel comprising a first diffraction grating (R_P1) sensitive to a first polarization, a second polarimetric pixel comprising a second diffraction grating (R_P2) sensitive to a second polarization orthogonal to the first polarization, a third polarimetric pixel comprising a third diffraction grating (R_P3) sensitive to a third polarization oriented at an angle between the first and second polarizations and a fourth pixel not comprising a polarization-selective diffraction rating (R_2D).

The invention discloses a spiral-like metal chiral metamaterial circular polarizer, which comprises a substrate, a transparent dielectric space layer firmly combined with the substrate and a spiral-like metal chiral micro structure array embedded in the transparent dielectric space layer, wherein the micro structure array comprises N periodically-arranged micro structure units, and N is more than 1 but no more than 106; the micro structure unit comprises m vertically-stacked metal arcs with the same size and with an angle of theta, the metal arcs are arranged rotarily around the same center, upper-layer metal arcs rotate for an angle of theta in relative to lower-layer metal arcs, theta is no less than 10 DEG but no more than 180 DEG, m is no less than 360/theta+1 but no more than 10, and tail ends of the upper-layer metal arcs and the lower-layer metal arcs are connected via metal cylinders to form a spiral-like shape. Compared with the traditional circular polarizer, the size is small, the waveband is wide, the extinction ratio is high, manufacturing of a micro circular polarization array can be realized, integration with a linear polarization structure uniwafer is even realized, a core polarization device is provided for full-Stokes vector real-time polarization imaging, and the spiral-like metal chiral metamaterial circular polarizer can be applied to fields such as polarization imaging detection, display and laser.

A zoom full-polarization spectral imaging detection system consists of a zoom optical lens, a spectral filter, two liquid crystal variable retarders (an LCVR1 and an LCVR2), a polarizer, a microspur optical lens, a charge-coupled device, an electronic driver, an image acquisition card and a computer. The imaging system of the system adopts a zoom optical system; the corresponding spectral imaging is achieved through the selection of suitable spectral filers; as the phase delay is changed by controlling the value of voltage applied to the two LCVRs, the full-polarization imaging of the system is realized; and the image signal of the target to be detected is collected by the computer and is subjected to image processing. The invention has the ability of subjecting a target to be detected to full-polarization spectrum detection within the range of visible wavelength or near infrared wavelength, and can achieve varying spatial resolutions in the same detection distance.

The present invention is directed to a novel multi-spectral exogenous fluorescence polarization imaging technique that enables rapid imaging of large tissue fields. The imaging device includes a tunable monochromatic light source and a CCD camera. Linear polarizers are placed into both the incident and collected light pathways in order to obtain fluorescence polarization or/and anisotropy image. To acquire exogenous fluorescence image, fluorescent contrast agents are delivered to a target tissue.

The invention discloses a three dimensional polarization image laser radar remote sensor. The invention comprises a light path system, a device for the generation of polarization light and the reception of dispersion light, the generation of three dimensional data and a processing method for three dimensional data. The invention is characterized in that the light path system is the same optical system which is composed by a range finder and a device for the generation, emission and detection of the polarization light. The device for the generation, emission and detection of the polarization light comprises a laser instrument, a beam splitter, a double frequency crystal, a plurality of lenses, a code disc, a scan motor, a scanning mirror, a telescope, a polarizer, a wave plate, an echo ranging reception device, a color separation filter, a CCD and a computer. The generation device and the method for target three dimensional surface data comprises a distance measurement device and the method for distance measurement data generation, location data generation and remote sensor attitude data generation. The processing method for polarization image data and three dimensional surface data comprises the processing method for laser distance measurement data, location data and attitude data. The invention can obtain the three dimensional image of the detected target with polarization information.

The invention discloses a salient visual method based on polarization imaging and applicable to underwater target detection, comprising the following steps: (A) acquiring auto-registration polarization images of the same underwater position at multiple angles; (B) performing underwater image restoration based on polarization information; (C) extracting global texture features; (D) extracting color features based on global contrast; (E) fusing visual saliency features; (F) performing saliency map optimization and target extraction based on the target center and the gray gravity center; and (G) performing threshold segmentation on a final saliency map to realize underwater target detection. Salience optimization is realized by use of the target center probability, image gray gravity center and space smoothness. The background is further restrained, and the foreground is highlighted. High detection rate and high identification rate are achieved for target detection in a complicated water environment, and the real-time requirement is satisfied. The method has a good application prospect.

The invention provides a snapping type high-flux polarization imaging method and a polarization imager. The polarization imager comprises a front optical imaging system, a microlens array and an array type polarization imaging detector. The microlens array is arranged on the imaging face of the front optical imaging system. The array type polarization imaging detector is arranged on the focal plane of the front optical imaging system. The array type polarization imaging detector is composed of a CCD detector array and a linear polarizing film array in a coupled mode. Each linear polarizing film corresponds to a CCD detector pixel. Light emitted or reflected by a target in different directions passes through the front optical imaging system and is imaged on a certain microlens. The received light in the different directions of the target is distributed to the pixels of the array type polarization imaging detector through the microlenses so that sub images can be formed and finally an image, at each polarizing angle, of the target is obtained. The polarization imager has the advantages that the images at the multiple polarizing angles of the target can be obtained through exposure conducted at a time and can be used for monitoring and tracking the rapidly-changing or moving target.

A full automatic atmospheric polarization mode image acquisition system and a system control method are characterized in that the system comprises a polarization imaging module, a mechanical movement module, a brightness acquisition module and a system control and processing center; and the system control and processing center respectively controls the rotation angle of a base and the lift height of a worm in the mechanical movement module through a controller and records and processes the light intensity information acquired by a light intensity detector and the polarization image of sky area acquired by the polarization imaging module in a CCD camera. The invention has simple operation, accurate measurement result which is easy to calibrate, and does not need to mechanically rotate a polaroid sheet in the measurement process.

The invention discloses a binocular three-dimensional imaging method combining a laser dot matrix and polarization vision. The binocular three-dimensional imaging method comprises the steps of: enabling laser dot matrix projection formed by means of a random dot matrix laser module to act on a target object; filtering to reduce interference of ambient light and suppress part of flare by means of alens group module; and finally, using a binocular polarization camera for capturing an effective target image pair, carrying out point matching on the two images, and then calculating parallax and three-dimensional coordinates to form a target surface three-dimensional point cloud image. According to the binocular three-dimensional imaging method, the polarization camera is used for replacing a common visible light camera, background light is suppressed by means of the filter, surface flare is suppressed by using polarization imaging, and the number of saturation points in all pixel points covered by light spots in an image is reduced, so that the calculation precision of the centers of the light spots is improved, the defects of a traditional binocular vision system are overcome, and thebinocular three-dimensional imaging method can be applied to a metal-like target with a smooth surface, low texture and high reflection.

A multimode fundus camera enables three-dimensional and/or spectral/polarization imaging of the interior of the eye to assist in improved diagnosis. In one aspect, the multimode fundus camera includes a first imaging subsystem, a filter module, and a second imaging subsystem. The first imaging subsystem is positionable in front of an eye to form an optical image of an interior of the eye. The filter module is positioned at a pupil plane of the first imaging subsystem or at a conjugate thereof. The second imaging subsystem include a microimaging array and a sensor array. The microimaging array is positioned at the image plane or a conjugate thereof, and the sensor array is positioned at the pupil plane or a conjugate thereof.

The invention discloses an underwater detection separate aperture double CCD real-time polarization imaging device and method. The device comprises a detected target, a front co-aperture imaging lens set, a non-polarization splitting prism, a polarization component set, a back separate aperture imaging lens set, a CCD detector, an LED light source and a transparent resin sealing compartment. The CCD separate-aperture design device is employed, a polarization imaging system integrated with separate apertures and separate amplitudes is realized, and circular polarization and linear polarization original images and luminous intensity images are simultaneously acquired. A multi-optical information fusion polarization imaging method based on machine learning is employed, for the underwater environments with different water depths and water qualities, modeling is carried out based on optical parameters including image colors, light intensity and a polarization degree, the waters environment and the detection distance under the artificial light source condition, the learning mechanism is established, underwater target detection images having relatively high contrast and sharpness are acquired, and underwater polarization imaging adaptability is improved.

The invention relates to the field of hyperspectral imager technology, in particular to a hyperspectral full polarization imager based on acousto-optic filtering and electro-optical phase modulation. The hyperspectral full polarization imager is an imaging device combining hyperspectral imaging and full polarization imaging, and relates to a method for simultaneous detection and acquisition of the space, spectral and polarization information of an observed object. The hyperspectral full polarization imager is based on an acousto-optic tunable filter for splitting and a DKDP longitudinal electro-optical phase modulator for polarization detection; and comprises a front imaging lens used for collection, collimation and contraction of radiation, reflection, scattering and transmission light of the object under test and primary imaging to an AOTF; DKDP longitudinal electro-optical phase modulators for phase modulation; the AOTF for filtering and polarization detection; a light shielding plate for shielding 0-level and +1-level diffracted light through the AOTF; a secondary imaging conduction lens for secondary imaging of -1-level diffracted light to a planar array imaging CCD; and a control computer. The invention is mainly used in the field of a hyperspectral imager.