A measuring arrangement having an illuminating arrangement to emit coherent light; a cuvette defining an inner volume for receiving a fluid possibly comprising microscopic objects of foreign origin, the cuvette being arranged to receive the coherent light and let it exit therefrom through opposite entrance and exit openings, the entrance opening being closed by an entrance window. The possible microscopic objects present in the fluid scatter part of the light, the scattered and non-scattered light interfering to form interference fringes. An image sensor is configured to capture a hologram digital image frame by receiving the light propagated across the cuvette. An exit window is arranged to close the exit opening of the cuvette. The image sensor is mounted in direct contact with the cuvette.

A method is presented for determining a phase of an input beam (110, E.sub.in) without a reference ray. In the method, an input beam (110, E.sub.in) having a plurality of input rays is split into a main beam (112, E1) and a reference beam (114, E2) in such a way that each input ray is split into a main ray of the main beam (112, E1) and a comparative ray of the reference beam (114, E2). The main beam (112, E1) is propagated along a first interferometer arm, and the reference beam (114, E2) is propagated along the second interferometer arm. The propagated main beam (112, E1) and the propagated reference beam (114, E2) are superposed to form an interference beam having a plurality of interference rays. The propagation along the first and second interferometer arms is carried out such that at least one interference ray of the interference beam is a superposition of a main ray of the propagated main beam (112, E1) assigned to a first input ray of the input beam (110, E.sub.in), and of a comparative ray of the propagated reference beam (114, E2) assigned to a second input ray of the input beam (110, E.sub.in) different from the first input ray.

Some embodiments are directed to a system for measuring vibrations of a surface of a mechanical part, by digital holography. The system includes a source of radiation emitting in a predetermined range of frequencies, a first separator element configured to define a first incident ray and a reference ray, a module for shaping a second incident ray from the first incident ray, and an optical element configured to make the reference ray and a radiation produced by a reflection of the incident ray on the surface of the mechanical part interfere. The module for shaping the second incident ray includes diffracting optical elements having a diffraction structure to diffract the incident radiation. The structure is from a polymer, sol-gel or photoresin material resting against a glass substrate, the structure including elements etched in a plane parallel and/or orthogonal to the substrate, with dimensions from 100 nanometres to 100 micrometres.

A differentiation system for differentiating cells includes an input device configured to receive holographic image data of a microscopic particle in suspension, holographic image data processing logic for converting the holographic image data to the frequency domain by performing a Fourier transform of the holographic image data, and a recognizer configured to determine characterization features of the holographic image data of the microscopic particle in the frequency domain for characterization of the microscopic particle, the characterization features comprising rotationally invariant features.

A label-free bio-aerosol sensing platform and method uses a field-portable and cost-effective device based on holographic microscopy and deep-learning, which screens bio-aerosols at a high throughput level. Two different deep neural networks are utilized to rapidly reconstruct the amplitude and phase images of the captured bio-aerosols, and to output particle information for each bio-aerosol that is imaged. This includes, a classification of the type or species of the particle, particle size, particle shape, particle thickness, or spatial feature(s) of the particle. The platform was validated using the label-free sensing of common bio-aerosol types, e.g., Bermuda grass pollen, oak tree pollen, ragweed pollen, Aspergillus spore, and Alternaria spore and achieved >94% classification accuracy. The label-free bio-aerosol platform, with its mobility and cost-effectiveness, will find several applications in indoor and outdoor air quality monitoring.

The invention is a method for estimating a representative volume of particles of interest (10 i) immersed in a sample, the sample extending in at least one plane, referred to as the sample plane (P 10), the sample comprising a sphering agent, capable of modifying the shape of the particles, the method comprising the following steps: a) illuminating the sample by means of a light source (11), the light source emitting an incident light wave (12) propagating towards the sample (10) along a propagation axis (Z); b) acquiring, by means of an image sensor (16), an image (I 0) of the sample (10), formed in a detection plane (P 0), the sample being arranged between the light source (11) and the image sensor (16), each image being representative of a light wave (14) referred to as an exposure light wave, to which the image sensor (16) is exposed under the effect of illumination; c) using the image of the sample (I 0), acquired during step b), and a holographic propagation operator, to calculate a complex expression (A (x, y, z)) of the exposure light wave (14) in different positions relative to the detection plane; the method comprising a step of estimating the representative volume (AA) of the particles of interest (10 i) depending on the complex expressions calculated during step c).

A method for observation of a sample, the sample comprising microorganisms immersed in a nontransparent culture medium, the culture medium being favorable to the development of the microorganisms, the sample being arranged between a light source and an image sensor, the method comprising: a) illuminating the sample with the light source, the light source emitting light propagating along an axis of propagation; b) acquiring an image of the sample by the image sensor; c) from the image acquired, characterization of the microorganisms; the method being characterized in that: the culture medium extends, parallel to the axis of propagation, to a thickness of less than 500 m.

A method of generating a color image of a sample includes obtaining a plurality of low resolution holographic images of the sample using a color image sensor, the sample illuminated simultaneously by light from three or more distinct colors, wherein the illuminated sample casts sample holograms on the image sensor and wherein the plurality of low resolution holographic images are obtained by relative x, y, and z directional shifts between sample holograms and the image sensor. Pixel super-resolved holograms of the sample are generated at each of the three or more distinct colors. De-multiplexed holograms are generated from the pixel super-resolved holograms. Phase information is retrieved from the de-multiplexed holograms using a phase retrieval algorithm to obtain complex holograms. The complex hologram for the three or more distinct colors is digitally combined and back-propagated to a sample plane to generate the color image.

An image creation unit of a server creates and stores a plurality of phase images or the like having different resolutions on the basis of holographic data collected by a measuring terminal. In response to an image transmission request according to an operation, an image transmission processing unit of the server extracts data of an image corresponding to an observation range after the movement from an image of an appropriate resolution and transmits the data to the browsing terminal. In the browsing terminal, a display image is formed by overlaying a high-resolution phase image corresponding to only an observation range to be displayed on low-resolution phase image of an observation target area.

A method is disclosed for classifying and/or counting objects (for example, cells) in an image that contains a mixture of several types of objects. Prior statistical information about the object mixtures (class proportion data) is used to improve classification results. The present technique may use a generative model for images containing mixtures of object types to derive a method for classifying and/or counting cells utilizing both class proportion data and classified object templates. The generative model describes an image as the sum of many images with a single cell, where the class of each cell is selected from some statistical distribution. Embodiments of the present techniques have been successfully used to classify white blood cells in images of lysed blood from both normal and abnormal blood donors.