The accuracy of estimation of a focal distance in digital holography is enhanced. In an image reproduction method, a two-dimensional power spectrum is generated from an interference fringe image generated from object light and reference light, the two-dimensional power spectrum having an intensity specified by a first frequency in a first direction and a second frequency in a second direction. A one-dimensional power spectrum is generated by, for each frequency component specified by the first frequency and the second frequency in the two-dimensional power spectrum, associating the frequency component with a feature quantity, the feature quantity being calculated by aggregating a plurality of intensities corresponding to the frequency component. A focal distance between an object and a detector is estimated using a trained distance estimation model, the trained distance estimation model receiving, as input, a plurality of feature quantities included in the one-dimensional power spectrum.

The present disclosure provides a method and apparatus for generating a full-color holographic image. The method of generating a full-color holographic image includes forming images for each color channel based on complex hologram data extracted from rays propagating from a target object, and combining the formed images into one color image, wherein the images for each color channel are formed at reconstruction points for each color channel derived based on the complex hologram data.

Systems and methods for uniquely identifying fluid-phase products by endowing them with fingerprints composed of dispersed colloidal particles, and by reading out those fingerprints on demand using Total Holographic Characterization. A library of chemically inert colloidal particles is developed that can be dispersed into soft materials, the stoichiometry of the mixture encoding user-specified information, including information about the host material. Encoded information then can be recovered by high-speed analysis of holographic microscopy images of the dispersed particles. Specifically, holograms of individual colloidal spheres are analyzed with predictions of the theory of light scattering to measure each sphere's radius and refractive index, thereby building up the distribution of particle properties one particle at a time. A complete analysis of a colloidal fingerprint requires several thousand single-particle holograms and can be completed in ten minutes.

A lensless holographic imaging system having a holographic optical element includes: a coherent light source for outputting a first light beam and a second light beam, wherein the first light beam irradiates a first inspection plane to form first object-diffracted light; a light modulator for modulating the second light beam into reading light having a specific wavefront; a multiplexed holographic optical element, wherein the first object-diffracted light passes through the multiplexed holographic optical element, and the reading light is input into the multiplexed holographic optical element to generate a diffracted light beam as system reference light; and an image capture device for reading at least one interference signal generated by interference between the first object-diffracted light and the system reference light. The lensless holographic imaging system has a relatively small volume and relatively high diffraction efficiency.

A method for lens-free imaging of a sample or objects within the sample uses multi-height iterative phase retrieval and rotational field transformations to perform wide FOV imaging of pathology samples with clinically comparable image quality to a benchtop lens-based microscope. The solution of the transport-of-intensity (TIE) equation is used as an initial guess in the phase recovery process to speed the image recovery process. The holographically reconstructed image can be digitally focused at any depth within the object FOV (after image capture) without the need for any focus adjustment, and is also digitally corrected for artifacts arising from uncontrolled tilting and height variations between the sample and sensor planes. In an alternative embodiment, a synthetic aperture approach is used with multi-angle iterative phase retrieval to perform wide FOV imaging of pathology samples and increase the effective numerical aperture of the image.

The disclosed subject matter relates to a method for determining a three-dimensional particle distribution in a medium, comprising: emitting a coherent light beam to irradiate the sample; recording an interference image of the scattered light beam and a second part of the light beam that has not been scattered; computing, from the interference image, for each one of a plurality of virtual planes lying within the sample, a reconstructed image of the sample, generating for each reconstructed image, a presence image, wherein a value is assigned to each pixel of the presence images if the corresponding pixel of the reconstructed image has an intensity value exceeding a threshold value and if the corresponding pixel of the reconstructed image has a phase value with a predetermined sign.

A single-shot Fresnel non-coherent correlation digital holographic device based on a polarization-oriented planar lens, comprising: A polarization-oriented planar lens (1) for wavefront modulation and beam splitting, a focusing element (2), a half-wave plate (3) with a small hole and a polarization imaging camera (4). Incident light passes through the polarization-oriented planar lens (1) and the focusing element (2) and is divided into two beams with different polarizations, that is, focused and parallel or focused and divergent beams, wherein the focused beam passes through the small hole of the half-wave plate (3), the parallel or divergent beam passes through the half-wave plate (3), so as to make the polarization of the two beams consistent behind pass through the half-wave plate (3).

An optical apparatus comprising a plurality of lenses including a first lens affixed to an optics mount holder which is adjustably affixed to an alignment channel part is provided. The optical axis of the first lens passes through a hollow area of the alignment channel part. The lens is mounted on the optics mount holder which is adjustably affixed to one end of the alignment channel part with a plurality of adjustable fasteners. A method is provided for aligning the optical apparatus.

A method for three-dimensional imaging of a sample (302) comprises: receiving (102) interference patterns (208) acquired using light-detecting elements (212), wherein each interference pattern (208) is formed by scattered light from the sample (302) and non-scattered light from a light source (206; 306), wherein the interference patterns (208) are acquired using different angles between the sample (302) and the light source (206; 306); performing digital holographic reconstruction applying an iterative algorithm to change a three-dimensional scattering potential of the sample (302) to improve a difference between the received interference patterns (208) and predicted interference patterns based on the three-dimensional scattering potential; wherein the iterative algorithm reduces a sum of a data fidelity term and a non-differentiable regularization term and wherein the iterative algorithm includes a forward-backward splitting method alternating between forward gradient descent (108) on the data fidelity term and backward gradient descent (110) on the regularization term.

To obtain a more accurate image by improving a utilization efficiency of light energy while at the same time suppressing with a simpler method distortion that may occur in an inline hologram when a plurality of lights having different wavelengths are used, an observation device (1) according to the present disclosure includes a light source part (11) in which a plurality of light emitting diodes (101) having different light emission wavelengths with a length of each light emission point being smaller than 100λ (λ: light emission wavelength) are arranged such that a separation distance between the adjacent light emitting diodes is equal to or smaller than 100λ (λ: light emission wavelength); and an image sensor (13) installed so as to be opposed to the light source part with respect to an observation target object.