A device for detecting particles in air; said device comprising: a flow channel configured to allow a flow of air comprising particles through the flow channel; a light source configured to illuminate the particles, such that an interference pattern is formed by interference between light being scattered by the particles and non-scattered light from the light source; an image sensor configured to detect incident light, detect the interference pattern, and to acquire a time-sequence of image frames, each image frame comprising a plurality of pixels, each pixel representing a detected intensity of light; and a frame processor configured to filter information in the time-sequence of image frames, wherein said filtering comprises:
identifying pixels of interest in the time-sequence of image frames, said pixels of interest picturing an interference pattern potentially representing a particle in the flow of air, and outputting said identified pixels of interest for performing digital holographic reconstruction.

Apparatuses and methods for improved reconstructions of electron-based holograms are disclosed herein. An example method at least includes forming a hologram of a sample and a known object, forming a reconstruction of the known object using a reconstruction algorithm, comparing the reconstruction of the known object to a reference reconstruction of the known object, and adjusting the reconstruction algorithm based on the comparison of the reconstruction of the known object to the reference reconstruction of the known object. The example method may further include forming a reconstruction of the sample using the adjusted reconstruction algorithm.

Provided is a holographic microscope including an input optical system configured to emit polarized input beam, a first beam splitter configured to emit an object beam by reflecting a portion of the polarized input beam, and emit a reference beam by transmitting a remaining portion of the polarized input beam, a reference optical system configured to separate the reference beam into a first reference beam and a second reference beam, a camera configured to receive the first reference beam and the second reference beam and the object beam that is reflected by an inspection object, the camera including a micro polarizer array, wherein a first polarization axis of the first reference beam is perpendicular to a second polarization axis of the second reference beam.

Examples are disclosed that relate to holographic near-eye display systems. One example provides a near-eye display device, comprising a diverging light source, an image producing dynamic digital hologram panel configured to receive light from the diverging light source and form an image. The near-eye display device also includes and a combiner comprising a holographic optical element positioned to receive light from the dynamic digital hologram panel and to redirect the light toward an eyebox, the holographic optical element being positioned between the eyebox and a view of an external environment to combine a view of the image formed by the dynamic digital hologram panel and the view of the external environment.

A device and method for forming an image of a sample includes illuminating the sample with a light source; acquiring a plurality of images of the sample using an image sensor, the sample being placed between the light source and the image sensor, no magnifying optics being placed between the sample and the image sensor, the image sensor lying in a detection plane, the image sensor being moved with respect to the sample between two respective acquisitions, such that each acquired image is respectively associated with a position of the image sensor in the detection plane, each position being different from the next; and forming an image, called the high-resolution image, from the images thus acquired.

A holographic imaging device is disclosed. In one aspect, the holographic imaging device comprises an imaging unit comprising at least two light sources, wherein the imaging unit is configured to illuminate an object by emitting at least two light beams with the at least two light sources. A first and second light beams have different wave-vectors and wavelengths. The holographic imaging device further comprises a processing unit configured to obtain at least two holograms of the object by controlling the imaging unit to sequentially illuminate the object with respectively the first light beam and the second light beam, construct at least two 2D image slices based on the at least two holograms, wherein each 2D image slice is constructed at a determined depth within the object volume, and generate a three-dimensional image of the object based on a combination of the 2D image slices.

A method for defect inspection of a transparent substrate comprises utilizing a wavefront reconstruction unit to obtain complex defect diffraction wavefront of a transparent substrate; using a complex defect diffraction module to confirm the effective diffraction distance of the complex defect diffraction wavefront; utilizing a defect detection module to detect position of the defect of the transparent substrate; using a defect classification module to perform extraction, analysis and classification of diffraction characteristics and utilizing a machine learning algorithm or a deep learning algorithm to automatically identify the defects.

A digital holographic imaging technique, includes iterative steps of: a) through back-propagation to the object coordinate of a hologram field comprising a spatial distribution of amplitude corresponding to the spatial distribution of intensity of the hologram and a spatial distribution of phase, determining an object field involving a spatial distribution of absorption and of phase shift of the imaged object, b) thresholding the values of the spatial distribution of absorption and of phase shift by decreasing the values to below a respective threshold, the thresholds decreasing in each iteration, c) through repropagation of the object field to the hologram coordinate, determining a modified hologram field comprising a modified spatial distribution of amplitude and a modified spatial distribution of phase, d) replacing the spatial distribution of phase of the hologram field with the modified spatial distribution of phase, the spatial distribution of phase shift and of absorption of the imaged object being those of the object field of the last iteration.

A computer-implemented method for analyzing digital holographic microscopy (DHM) data for hematology applications includes receiving a DHM image acquired using a digital holographic microscopy system. The DHM image comprises depictions of one or more cell objects and background. A reference image is generated based on the DHM image. This reference image may then be used to reconstruct a fringe pattern in the DHM image into an optical depth map.

Digital holographic microscopy and related image processing techniques are described. A hologram captured in an image frame is split into different depths while a new hologram is being captured. Image slices of the hologram are determined and using free space impulse responses that are pre-calculated at a different precision than processing operations using the holographic data. Each computation is calculated in parallel based on the number of available processing cores and threads. The image slices are combined into a 2D array or 3D array to permit further processing of the combined array to count and size particles in the image frame. The reconstructed hologram is displayed at a subsequent image frame than that used to capture the hologram.