An object detection system uses a change in a linear polarization statistic between a first image at a first time and a second image at a second time to determine the presence or the likelihood of an object beneath a surface. The presence of the object may be determined by regions of anomalously high changes in the polarization statistic. The system may use a polarization change detection detector which may simultaneously capture images in multiple polarization channels. Further, the polarization change detection detector may be coupled with a laser interferometry system.

An object detection system uses a change in a linear polarization statistic between a first image at a first time and a second image at a second time to determine the presence or the likelihood of an object beneath a surface. The presence of the object may be determined by regions of anomalously high changes in the polarization statistic. The system may use a polarization change detection detector which may simultaneously capture images in multiple polarization channels. Further, the polarization change detection detector may be coupled with a laser interferometry system.

A method of determining machined characteristics of a surface with a camera system, the camera system operable to obtain six camera images. The camera images are formed by illuminating the surface with light at each of two different angles. After reflecting off the surface, the light is passed through a polarizer at each of three different angles.

Reflected light detecting device and method with surface reflected light components collectively be extracted/removed when detecting reflected light arising in casting light onto target-object range having non-planar surface. The device includes: a first illuminating device causing first-measurement light in predetermined polarization direction to enter target-object first region from first direction; polarization optical system position part of first-surface reflected light enters the polarization optical system, the first-surface reflected light being the first-measurement in the first region surface; a second illuminating device causing second-measurement light in the same first-measurement light polarization direction to enter second region from second direction, the second region being on the target-object surface, different from the first region; adjusting direction of the second-measurement light optical axis so part of second-surface reflected light enters the polarization optical system, the second-surface reflected light being the second-measurement in second region surface; and detecting light having passed through the polarization optical system.

A micro object detection apparatus (11) includes an optical system (50). The first optical system (50) includes a first reflection region (101), a second reflection region (102), and a light reception element (6). The first reflection region (101) has an ellipsoidal shape, and reflects scattered light scattered when irradiation light hits a particle to direct the scattered light to the light reception element (6), by utilizing two focal point positions of the ellipsoidal shape. The second reflection region (102) reflects scattered light coming from the particle (R) to direct the scattered light to the first reflection region (101), so that the scattered light is directed to the light reception element (6) by utilizing the ellipsoidal shape of the first reflection region (101). The light flux diameter of the scattered light reflected by the second reflection region (102) is larger than the particle (R), at the position of the particle (R) ate, which the scattered light is generated.

Methods, apparatuses, and systems for detecting and classifying individual airborne biological and non-biological particles, in real time, based on particle size and polarized elastic scatter. Auto-fluorescence content may also be used along with particle size and polarized elastic scatter for further orthogonal classification. With polarized elastic scattering, the degree of linear or circular depolarization produced from particle morphology, refractive index, internal asymmetric structures and molecular optical activity can be used for classifying individual airborne particles. Alternatively, circular intensity differential scattering (CIDS) or linear intensity differential scattering (LIDS) can be used to discriminate individual particles.

A scanning device for laser detection and ranging (LiDAR), the scanning device includes, arranged in optical free space: an optical input for receiving a pulsed broadband laser beam having a linear polarization; a separating unit configured for transmitting the laser beam along a scanning optical path while changing the polarization into a circular one; a wavelength selection unit; and a scanning unit. The separating unit is configured for deviating the reflections (4) on a broadband detector while changing the orthogonal circular polarization into an orthogonal linear polarization compared to the linear polarization of the laser beam. The broadband detector is configured to receive the deviated reflections, and to detect a time-of-flight and an optical power of the light reflection.

A micro object detection apparatus includes an optical system. The first optical system includes a first reflection region, a second reflection region, and a light reception element. The first reflection region has an ellipsoidal shape, and reflects scattered light scattered when irradiation light hits a particle to direct the scattered light to the light reception element, by utilizing two focal point positions of the ellipsoidal shape. The second reflection region reflects scattered light coming from the particle to direct the scattered light to the first reflection region, so that the scattered light is directed to the light reception element by utilizing the ellipsoidal shape of the first reflection region. The light flux diameter of the scattered light reflected by the second reflection region is larger than the particle, at the position of the particle at which the scattered light is generated.

An apparatus for spectroscopic tissue analysis is disclosed. The apparatus comprises: a light delivery system configured to direct an excitation signal on to a tissue sample; a light collection system configured to collect a backscattered signal comprising diffuse reflectance photons backscattered by the tissue sample; an imaging device; a spectrometer; an optical adaptor configured to direct a first portion of the backscattered signal to the imaging device and a second portion of the backscattered signal to the spectrometer; and an analysis system configured to apply polar decomposition to spectral image data of the tissue captured by the imaging device and the spectrometer and thereby derive polarization metrics for the tissue sample.

Methods, devices and systems for estimating polarization characteristics of materials based on partial polarimetry are described. One example method for estimating polarization characteristics of a material includes illuminating the material with incident light, which can be unpolarized or have a particular polarization state. Two polarimetric measurements are conducted based on the interaction of the incident light with the material. The two polarimetric measurements detect light having orthogonal polarization states, and the interaction of the incident light with the material includes a depolarizing interaction. The method additionally includes determining an estimated coherency matrix eigenvalue and an estimated Mueller matrix throughput parameter using the first and the second polarimetric measurements, and determining an estimate of a full depolarizing Mueller matrix by extrapolating a reduced-rank Mueller matrix to obtain all sixteen elements of the depolarizing Mueller matrix that identifies the polarization characteristics of the material.