The present invention relates to a system and method for high quality speckle-free phase-only computer-generated holographic image projection. The present invention more particularly relates to a holographic image display system comprising a spatial light modulator to phase modulate light from at least one light source configured to illuminate said spatial light modulator and to provide a phase hologram and projection optics to project said phase modulated light to generate an image formed by said displayed hologram onto an image plane.

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 logic circuit comprising a logic sub-circuit arranged to output a stream, S1, of Fresnel lens values, F(x), of a Fresnel lens for display on [m×n] pixels of a pixelated display device. In a first step, the logic circuit is arranged to set an initial data value stored in a first data register unit of the logic sub-circuit to (a−k).sup.2 and set an initial data value stored in a second data register unit of the logic sub-circuit to a.sup.2−(a−k).sup.2. In a second step the logic circuit is arranged to read the initial data value stored in the first data register unit and the initial data value stored in the second data register unit in a first iteration, and to read the data value stored in the first data register unit in the preceding iteration and the data value stored in the second data register unit in the preceding iteration, in a further iteration. In a third step, the logic circuit is arranged to sum the data value read from the first data register unit and the data value read from the second data register unit to form x.sup.2. In a fourth step, the logic circuit is arranged to calculate F(x) based on x.sup.2. In a fifth step, the logic circuit is arranged to output F(x) as the next value in the stream of F(x) values. In a sixth step, the logic circuit is arranged to write x.sup.2 to the first data register unit. In a seventh step, the logic circuit is arranged to add 2k.sup.2 to the value stored in the second data register unit. In an eighth step, the logic circuit is arranged to perform further iterations that repeat the second to seventh steps for x=a+k, a+2k, a+3k . . . a+(n−1)k, wherein a is the starting value of x, k is an increment in x and F(a) is the first value of stream, S1.

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 three-dimensional (3D) holographic display system includes a projector that generates an image with a form of spatially varying modulation on a light beam; holographic processor that performs a holographic method on the image generated by the projector; and memory device that stores holographic data generated in a process of performing the holographic method by the holographic processor. An amplitude of a light field is adaptively replaced by the holographic processor according to significance of respective areas of the image.

Disclosed are a holographic display method and a holographic display device. The holographic display method includes: acquiring an area of Nth diffraction order corresponding to an eye position; according to the area of Nth diffraction order, calculating a holographic complex amplitude distribution corresponding to a window of Nth diffraction order to obtain window hologram information, a function of the holographic complex amplitude distribution being expressed by C(m, n)=A(m, n)*exp[i(m, n)/N]; encoding the window hologram information; and according to the encoded window hologram information, loading the encoded window hologram information in the area of Nth diffraction order to display a hologram.

A holographic display apparatus capable of providing an expanded viewing window and a display method are provided. The holographic display apparatus includes an image processor configured to provide computer generated hologram (CGH) data to a spatial light modulator, wherein the image processor is further configured to generate a hologram data array comprising information of the holographic image to be reproduced at the first resolution or a resolution less than the first resolution, perform an off-axis phase computation on the hologram data array at the second resolution, and then, generate the CHG data at the first resolution.

Provided are methods of processing a holographic image and apparatuses using the methods. A method includes obtaining image data with respect to a three-dimensional (3D) object, obtaining interference patterns in a computer-generated hologram (CGH) plane by performing a Fourier transform on the image data, and generating a CGH with respect to the 3D object based on the interference patterns, wherein the Fourier transform is performed based on a focal length of an eye lens of an observer.

A method for observing a sample, the sample lying in a sample plane defining radial positions, parameters of the sample being defined at each radial position, the method comprising: a) illuminating the sample using a light source, emitting an incident light wave that propagates toward the sample; b) acquiring, using an image sensor, an image of the sample, said image being formed in a detection plane, the sample being placed between the light source and the image sensor; c) processing the image acquired by the image sensor, so as to obtain an image of the sample, the image of the sample corresponding to a distribution of at least one parameter of the sample describing the sample in the sample plane; wherein the processing of the acquired image comprises implementing an iterative method, followed by applying a supervised machine learning algorithm, so as to obtain an initialization image intended to initialize the iterative method.

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.