Methods and apparatus to calibrate spatial light modulators are disclosed. Examples include processor circuitry to execute and/or instantiate instructions to provide a greyscale image to a spatial light modulator (SLM) to define voltages to be applied to individual pixels of the SLM. The voltages associated with pixel values in the greyscale image. The pixel values arranged in a double-slit grating pattern. The SLM to produce an interference pattern based on the double-slit grating pattern. The processor circuitry is to determine a phase difference between first and second gratings of the double-slit grating pattern based on the interference pattern. The processor circuitry is to generate a phase curvature based on the phase difference.

Methods of oil and gas exploration that may include: obtaining wavefield data representing recordings from a propagating wavefield through a geophysical volume; obtaining at least one reference digital image of a portion or all of the geophysical volume generated from the recorded wavefield data, wherein the reference image may have a reference sampling ratio and a reference image quality value; selecting a holographic computational method of imaging the wavefield data; selecting a data subset from the wavefield data based on one or more parameters selected from the group consisting of field sampling, imaging sampling, and image quality; decimating the data subset, wherein the decimated data subset may represent a sampling ratio less than the reference sampling ratio; and generating a new digital image based on the selected holographic computational method of imaging, the data subset, and parameters corresponding to the data sub set.

A data acquisition apparatus includes an illumination device, a first beam splitter, a measurement unit, and a photodetector. A measurement optical path and a reference optical path are positioned between the illumination device and the photodetector. In the first beam splitter, light traveling in a first direction and light traveling in a second direction are generated from incident light. The measurement optical path is positioned in the first direction, the reference optical path is positioned in the second direction, and the measurement unit is disposed on the measurement optical path. In the optical surface of the first beam splitter, an incident position of light emitted from the illumination device changes with time, and the angle formed by light propagating through the measurement optical path and the optical axis of the measurement optical path changes with change in the incident position.

Disclosed are optical interrogation apparatus that can produce lens-free images using an optoelectronic sensor array to generate a holographic image of sample objects, such as microorganisms in a sample. Also disclosed are methods of detecting and/or identifying microorganisms in a biological sample, such as microorganisms present in low levels. Also disclosed are methods of using systems to detect microorganisms in a biological sample, such as microorganisms present in low levels. In addition or as an alternative, the methods of using systems may identify microorganisms present in a sample and/or determine antimicrobial susceptibility of such microorganisms.

The invention discloses a digital laser holography-based rapid lens center offset detection device, which relates to the technical field of lens detection and includes a spherical wave emission device, a reticle, a lens to be detected, an image sensor and a computer. The device is simple and stable in structure, and a complex optical receiving system and mechanical scanning are avoided. A detection method is high in efficiency and measurement accuracy, a process is simple, and a lens with an infinitely great focal length may be detected.

A method and apparatus for monitoring particulate concentrations in ambient air use digital in-line holography and automated digital algorithms to classify and determine mass density and other characteristics of particles within a determined mass and size range. An embodiment provides a sampling plate on which particles are deposited at locations which depend on sizes and masses of the particles. A digital in-line hologram of the sampling plate is processed to obtain information about the particles. The method and apparatus have example application to environmental monitoring.

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.

Systems and methods are provided for a digital holography range Doppler receiver. The subject system transmits outgoing electromagnetic radiation to a target, and provides a first reference local oscillator (LO) beam to a first detector and a second reference LO beam to a second detector, based on the outgoing electromagnetic radiation. The system receives reflected electromagnetic radiation from the target through a first optical receiver and a second optical receiver having a smaller diameter, and determines range and velocity of the target simultaneously using an interference with the second reference LO beam. The system applies time and frequency offsets to the first reference LO beam based on the measured range and velocity to align the first reference LO beam with the reflected electromagnetic radiation, and produces an image of the target using the first reference LO beam having the applied time and frequency offsets.

Methods of identifying a flying object using digital imaging that may include: obtaining data of a propagating wavefield through a propagating volume that includes a volume above the earth's surface; 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; and determining a quantitative difference measure between the reference digital image and the new digital image, and image quality.

Methods of providing digital images of living tissue that may include: obtaining data of a propagating wavefield through living tissue; obtaining a reference digital image of the living tissue; 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; and determining a quantitative difference measure between the reference digital image and the new digital image based on the changing of one or more parameters selected from the group consisting of field sampling, imaging sampling, and image quality.