A totagram is produced by an iterative spectral phase recovery process resulting in complete information recovery using special masks, without a reference beam. Using these special masking systems reduce computation time, number of masks, and number of iterations. The special masking system is (1) a unity mask together with one or more bipolar binary masks with elements equal to 1 and −1, or (2) a unity mask together with one or more phase masks, or (3) a unity mask together with one pair of masks or more than one pair of masks having binary amplitudes of 0's and 1's, in which the masks in the pair are complementary to each other with respect to amplitude, or (4) one or more pairs of complementary masks with binary amplitudes of 0's and 1's without a unity mask.

A digital hologram is represented by a set of coefficients respectively associated with a plurality of definition wavelets each defined by a tuple of coordinates in a multidimensional space. A method for reconstructing the digital hologram in order to display it by a display, includes the following steps: depending on at least one data item representative of a characteristic of the display, determining a transformation of the multidimensional space; and generating a reconstructed hologram by assigning each coefficient of at least some of the coefficients to a reconstruction wavelet defined by an image reconstruction tuple by the predetermined transformation of the tuple of coordinates defining the definition wavelet associate with the coefficient in question. An associated display method, reconstruction device and system are also described.

A display system (300) comprising an optical system and a processing system. The optical system comprising a spatial light modulator (380), a light source, a Fourier transform lens, a viewing system (320, 330) and a processing system. The spatial light modulator is arranged to display holographic data in the Fourier domain, illuminated by the light source. The Fourier transform lens is arranged to produce a 2D holographic reconstruction in the spatial domain (310) corresponding to the holographic data. The viewing system is arranged to produce a virtual image (350) of the 2D holographic reconstruction. The processing system is arranged to combine the Fourier domain data representative of a 2D image with Fourier domain data representative of a phase only lens to produce first holographic data, and provide the first holographic data to the optical system to produce a virtual image.

The invention relates to a preprocessing circuit for at least one hologram computation circuit that comprises an input interface device for receiving data of a scene to be displayed, a processing device for defined processing of the received data and for converting the data into a system-independent format with incorporation of specific parameters required for displaying the scene, and an output interface device for outputting and transmitting the converted data to at least one hologram computation circuit. An apparatus for computing a hologram for displaying a scene by means of a holographic display apparatus is also disclosed. The apparatus comprises at least one spatial light modulation device and a preprocessing circuit as described, and at least one hologram computation circuit for computing a hologram and for encoding the hologram for the at least one spatial light modulation device.

A method for processing a three-dimensional holographic image includes obtaining depth images from depth data of a three-dimensional object, dividing each of the depth images into a predetermined number of sub-images, obtaining interference patterns of computer-generated hologram (CGH) patches corresponding to each of the sub-images by performing a Fourier transform to calculate an interference pattern in a CGH plane for object data included in each of the sub-images, and generating a CGH for the three-dimensional object using the obtained interference patterns of the CGH patches.

A method for processing a three-dimensional holographic image includes obtaining depth images from depth data of a three-dimensional object, dividing each of the depth images into a predetermined number of sub-images, obtaining interference patterns of computer-generated hologram (CGH) patches corresponding to each of the sub-images by performing a Fourier transform to calculate an interference pattern in a CGH plane for object data included in each of the sub-images, and generating a CGH for the three-dimensional object using the obtained interference patterns of the CGH patches.

A method for optimally producing a holographic image using a Holographic Optical Element (HOE) and the HOE meant for controlling directions and divergences of light beams to impart system compactness. The system uses concave and convex lenses and other beam expanding, splitting, modulating and combining optics for realization of compactness and high throughput. The thin laser beam is split using a holographic optical element and a conventional beam splitter. A neutral density filter adjusts the intensity of a reference beam to match the intensity of an object beam so that high quality digital holograms can be recorded. Effects of vibrations are minimized by the compact optical design, by anti-vibration mounts, by mounting all the opto-mechanical components on a single rigid platform and by enclosing the system. An electro-optical sensor array records holograms digitally and an algorithm numerically reconstructs and further quantifies the results using a personal computer/laptop/tablet etc.

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.

A holographic display with an illumination device, an enlarging unit and a light modulator. The illumination device includes at least one light source and a light collimation unit, the light collimation unit collimates the light of the at least one light source and generates a light wave field of the light that is emitted by the light source with a specifiable angular spectrum of plane waves, the enlarging unit is disposed downstream of the light collimation unit, seen in the direction of light propagation, where the enlarging unit includes a transmissive volume hologram realising an anamorphic broadening of the light wave field due to a transmissive interaction of the light wave field with the volume hologram, and the light modulator is disposed upstream or downstream of the anamorphic enlarging unit, seen in the direction of light propagation.

Method for obtaining an image of a sample (10), comprising: a) illuminating the sample using a light source (11); b) acquiring, using an image sensor (16), a first image (I.sub.1,P0) of the sample (10), said image being formed in the detection plane (P.sub.0), the first image being representative of an exposure light wave (14) propagating, from the sample, to the image sensor, along a first optical path (L.sub.1);
the method comprising, following b) c) modifying an optical refractive index, between the image sensor and the sample; d) following c), acquiring a second image (I.sub.2,P0) of the sample, said image being representative of the exposure light wave (14) along a second optical path (L.sub.2); e) implementing an iterative algorithm that combines the first and second images so as to obtain an image of the sample.