An optical device is formed by hot stamping a demetallized hologram to an optically variable foil or to a coating of optically variable ink. In another embodiment a hologram is hot stamped to a banknote or document printed with a color-shifting ink.

A method of imaging includes illuminating a sample spaced apart from an image sensor at a multiple distances. Image frames of the sample obtained at each distance are registered to one another and lost phase information from the registered higher resolution image frames is iteratively recovered. Amplitude and/or phase images of the sample are reconstructed based at least in part on the recovered lost phase information.

A method of imaging includes illuminating a sample spaced apart from an image sensor at a multiple distances. Image frames of the sample obtained at each distance are registered to one another and lost phase information from the registered higher resolution image frames is iteratively recovered. Amplitude and/or phase images of the sample are reconstructed based at least in part on the recovered lost phase information.

A 3D optical microscope device of a small form factor optical system is disclosed. A transmission optical system device comprises a first lens having a left side disposed in contact with an input plane, and a second lens having a right side disposed in contact with a rear focal plane and disposed at a position spaced apart by a focal length of the first lens. The first lens and the second lens Fourier-transform a light signal incident on the input plane and output the transformed signal to the rear focal plane.

A lens-less system for holographic imaging or a holographic imaging device is provided. The method/device includes a stationary image sensor to capture an image of a sample illuminated by light from a stationary illumination source. A reference lens-less holographic image may be captured and used as a base line to reduce image artifacts and/or remove noise from the lens-less holographic image. Since real wavefronts produced by a diverging point source are neither perfectly spherical nor planar but a combination of both qualities, theoretical estimates for wavefront reconstruction based on perfectly planar or spherical incident waves cannot be applied accurately. The method/device here provides a solution by performing a calibrated wavefront reconstruction based on equations governing coherent light propagation for both spherical waves and planar waves with a mathematical correlation between numerical magnification and propagation depth to produce accurate three-dimensional details of the object.

A lens-less system for holographic imaging or a holographic imaging device is provided. The method/device includes a stationary image sensor to capture an image of a sample illuminated by light from a stationary illumination source. A reference lens-less holographic image may be captured and used as a base line to reduce image artifacts and/or remove noise from the lens-less holographic image. Since real wavefronts produced by a diverging point source are neither perfectly spherical nor planar but a combination of both qualities, theoretical estimates for wavefront reconstruction based on perfectly planar or spherical incident waves cannot be applied accurately. The method/device here provides a solution by performing a calibrated wavefront reconstruction based on equations governing coherent light propagation for both spherical waves and planar waves with a mathematical correlation between numerical magnification and propagation depth to produce accurate three-dimensional details of the object.

A microscopy system and method use super-resolution to generate the equivalent of a digital holographic image. Through super-resolution, images of nanoscale sized objects may be captured without interrupting the object (for example, a virus) or the object's environment. The information gathered through super-resolution techniques may be transformed into holographic replications of the object which may be analyzed with greater accuracy of the object.

A deep learning framework, termed Fourier Imager Network (FIN) is disclosed that can perform end-to-end phase recovery and image reconstruction from raw holograms of new types of samples, exhibiting success in external generalization. The FIN architecture is based on spatial Fourier transform modules with the deep neural network that process the spatial frequencies of its inputs using learnable filters and a global receptive field. FIN exhibits superior generalization to new types of samples, while also being much faster in its image inference speed, completing the hologram reconstruction task in 0.04 s per 1 mm.sup.2 of the sample area. Beyond holographic microscopy and quantitative phase imaging applications, FIN and the underlying neural network architecture may open up various new opportunities to design broadly generalizable deep learning models in computational imaging and machine vision fields.

A method for aquatic microplastic identification is provided. The method includes steps as follows: emitting a laser beam from a laser source, such that the laser beam passes through a liquid sample with MP samples in a sample channel and then a polarizer and is received by polarization camera; capturing a sample image of the MP samples by the polarization camera, wherein the sample image comprises interference patterns resulting from superposition of object and reference waves; and feeding the interference patterns into a morphology analyzing module for real-time tracking and analyzing by using a lightweight convolutional neural network (CNN) model, so as to classify the MP samples.

A lens-less system for holographic imaging or a holographic imaging device is provided. The method/device includes a stationary image sensor to capture an image of a sample illuminated by light from a stationary illumination source. A reference lens-less holographic image may be captured and used as a base line to reduce image artifacts and/or remove noise from the lens-less holographic image. Since real wavefronts produced by a diverging point source are neither perfectly spherical nor planar but a combination of both qualities, theoretical estimates for wavefront reconstruction based on perfectly planar or spherical incident waves cannot be applied accurately. The method/device here provides a solution by performing a calibrated wavefront reconstruction based on equations governing coherent light propagation for both spherical waves and planar waves with a mathematical correlation between numerical magnification and propagation depth to produce accurate three-dimensional details of the object.