Systems and methods are provided for counting particles in a fluid flow. In an aspect, coordinates of particles are obtained from video data of particles in a fluid, the video data made up of a sequence of image frames. The particle positions are linked in each pair of consecutive image frames of the video data. The linked particle positions are used to calculate particle trajectories through sequential image frames of the video data, and the particles are counted based on the particle trajectory. In another aspect, the particle positions within each image frame are transformed to estimated positions within a common coordinate frame. The estimated particle positions of a particle are grouped into a cluster center, and the particle count is calculated based on the cluster centers.

The layered generation of at least one volume grating in a recording medium by way of exposure, the recording medium having at least one photosensitive layer which is sensitized for a presettable wavelength of the exposure light. Each volume grating is generated in the recording medium by at least two wave fronts of coherent light capable of generating interference, the wave fronts being superposed in the recording medium at a presettable depth, at a presettable angle and with a presettable interference contrast. The depth and the thickness of the refractive index modulation and/or transparency modulation of a volume grating in the recording medium is controlled by depth-specific control of the spatial and/or temporal degree of coherence of the interfering wave fronts in the direction of light propagation.

The invention relates to a digital holography method for detecting the vibration amplitude of an object (15) having a vibration frequency ω, comprising: generating object illumination waves (W.sub.t) and reference waves (W.sub.LO); acquiring interferograms between the reference wave (W.sub.LO) and a signal wave (W.sub.s) by means of a bandwidth ω s detector (19), the reference wave comprising two components E.sub.LO1, E.sub.LO1 of frequencies ω.sub.1, ω.sub.2 that are respectively staggered in relation to the laser frequency ω.sub.L by a quantity δ.sub.1=γ.sub.1ω.sub.s and δ2=qω+γ2ω.sub.s, where q is an integer and −0.5≦γ1, γ.sub.2≦0.5; and calculating the vibration amplitude of the object from the optical beats spectrum deduced from the complex amplitude of an interferogram.

A method of extracting particles from a two-dimensional (2D) hologram recorded as part of a digital inline holography system includes reconstructing a three-dimensional (3D) optical field from the recorded 2D hologram. In addition, particles are extracted/segmented from the 3D optical field, wherein segmented particles are identified by particle location in three-dimensional space and a cross-sectional area of the segmented particle. Based on the identified particle location and cross-sectional area, extracted particles are removed from the 2D hologram to generate an updated 2D hologram. These steps are repeated iteratively until a threshold is met.

The present disclosure relates to systems and methods for cell recognition. At least one embodiment relates to a method for recognizing cell. The method includes receiving an image of the cell. The method also includes performing edge detection on the image of the cell. Further, the method includes detecting ridges within the image of the cell. In addition, the method includes quantifying an internal complexity of the cell by gauging a contrast of the ridges with an average of a Laplacian on the detected ridges.

A device for determining a 3D structure of an object having first and second laser emitters which generate laser radiation with first and second different wavelengths, respectively. A first beam splitter splits the laser radiation of each laser emitter into reference and illuminating radiation. The illuminating radiation is adapted to impinge on the object to be measured, be reflected by the object as object radiation, and interfere with the reference radiation to form interference patterns. A detector receives the interference patterns. A selection hologram deflects object radiation which impinges on it within a predefined incidence angle range and passes object radiation which impinges on it outside of the incidence angle range undiffracted. The undiffracted radiation either passes by the determination area of the detector or impinges on the determination area at an angle outside the determination angle range.

In-line holography to create images of a specimen, such as one or more particles dispersed in a transparent medium. Analyzing these images with results from light scattering theory yields the particles' sizes with nanometer resolution, their refractive indexes to within one part in a thousand, and their three dimensional positions with nanometer resolution. This procedure can rapidly and directly characterize mechanical, optical and chemical properties of the specimen and its medium.

A method of analyzing a sample receiving a particle of interest, including: defining a reference point located on a first interface of the sample, or at a known distance from the sample, along the optical axis of the optical system; acquiring a reference image transmission of the sample, the object plane of the optical system being located at a known distance from the reference point along an axis parallel to the optical axis of the optical system, and the particle of interest being located outside of the object plane; using the reference image, digitally constructing a series of reconstructed images, each associated with a predetermined offset of the object plane along the optical axis of the optical system; and using the series of reconstructed images, determining the distance along an axis parallel to the optical axis of the optical system, between the particle of interest and the reference point.

There is disclosed herein a method of light detection and ranging. The method comprises a first step of illuminating a scene with a first light pattern and monitoring for first light return from the scene with an array of detection elements. The method comprises a second step of obtaining first point cloud data from first parts of the scene where the first light return exceeds a first threshold value. The method comprises a third step of determining a second light pattern by reducing, such as substantially zeroing, the intensity of the first light pattern in the areas wherein first point cloud data was obtained. The method comprises a fourth step of illuminating the scene with the second light pattern and monitoring for second light return from the scene with the array of detection elements.

Methods of identifying a subterranean tunnel using digital imaging that may include: obtaining data of a propagating wavefield through a propagating volume that includes a portion of the earth's subsurface; obtaining a reference digital image of the propagating volume; selecting a holographic computational method of wavefield imaging; selecting a wavefield based on one or more parameters; calculating a sampling ratio by dividing a number of data samples in the data subset by a number of image samples in the data subset; decimating the data subset; generating a new digital image based on the selected holographic computational method of imaging, the decimated data subset, and parameters corresponding to the data subset; determining a quantitative difference measure between the reference digital image and the new digital image, and image quality; and identifying the subterranean tunnel.