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Wavelength scanning digital holography using laser diode current modulation is presented. A series of holograms are recorded while the phase of hologram is swept through wavelength scanning. The object wave component is extracted from recorded holograms by applying temporal frequency analysis to each pixel of the holograms. The proposed technique allows us to record a large object as digital hologram...
Ray-Space/Light Field is a novel representation of 3-D visual information that enables 3D/free-viewpoint photorealistic image generation. Although it is based on a clear and simple concept, and hence, it is expected to be a basic representation for 3D end-to-end systems, it has the problem that there exists no easy way to obtain Ray-Space data efficiently. In this paper, we first describe the basic...
Multi-aperture imaging provides a variety of modalities in object observation. A compound-eye camera called TOMBO is an effective platform for computational imaging based on multi-aperture imaging. As an example of medical application, a TOMBO imaging system was applied to 3D shape measurement of teeth and gingivae and to estimation of gingival tissue composition for odontotherapy. Lastly, an imaging...
Holographic display is considered to be one of the most ideal three-dimensional display modalities. However, there are still some crucial problems to be resolved. The narrow viewing zone angle and the smallness of reconstructed images are one of them. There is a trade-off relation between the viewing zone angle and the size of the reconstructed image. The only way to improve both two properties is...
The wavelength margin is a very important characteristic which can make a laser diode to be used possible as a light source in a holography storage system. In this paper, we studied an expending method to decrease bit error rate by adjusting the focal length of the lens to compensate the wavelength drift in the collinear holographic storage system.
We investigated phase distribution of normal and malignant lymphoma cells by using digital holography. The experimentally obtained phase image revealed distinct texture that has potential to be applied to malignant lymphoma identification.
We propose a method for efficient calculation of hologram using ray-sampling (RS) plane from orthographic projection images. This algorithm enables us to synthesize hologram with the large RS plane efficiently. Accelerated calculation is compared with the conventional RS plane based method was experimentally verified.
The line thickness of lines consisting of the line pattern of VZFO in contact-type 3-D displays is a major clue of simulating the color moirés in the displays. The thicknesses of the lines and the period of the line pattern are virtually chirped due to refraction caused by the VZFO thickness. This chirping and the line thickness are the main source of the color moirés. This color moirés can be used...
We propose an aerial projection system for reconstruction of floating 3D images based on computer-generated image holograms (CGIHs). The proposed system consists of a spatial light modulator (SLM) and two concave mirrors. The SLM displays CGIHs, and a reconstructed 3D image is formed near the SLM plane. Because the two concave mirrors are set face to face, the floating image of the reconstructed 3D...
A hybrid digital holographic microscopic system that enables simultaneous detection of 3D phase and fluorescence images is proposed. The proposed microscopic system is designed by combination of a transmission type off-axis digital holographic configuration and a reflection type Fresnel incoherent holographic configuration, aimed for biological application. Owing to the single acquisition, signal...
Fast measurement system of a moving three-dimensional phase object using digital holographic microscopy is presented. In the fabricated system, a three-dimensional phase object is put on a fast movable stage. Under the CW laser illumination, the holograms of the phase object are superimposed. We experimentally investigated the effect of the speed of the movable stage on the reconstructed data.
Besides bar coding and fingerprinting objects of the physical world, we introduce here the idea of patterning codes i.e. of making patterns from codes in imitation of a process of pattern formation compatible with physics. The case of images of paper patterns at cm scale is considered to illustrate. Starting from an approach where codes are viewed as part of the initial conditions of a Turing process,...
We propose a kind of steganography that features decoding by photographing an LED screen. Our proposed steganography employs a high-frame-rate LED display to embed a secret image in successive 4 fields that are changed at 480 Hz. We have investigated display sequences of the encoded images by changing the exposure time of a camera. Experimental results show the displayed sequence that contains three...
We report on deterministic femtosecond multi-filamentation in fused silica by encoding a diffractive microlens array into a spatial light modulator. The efficiency and focal length of each microlens are electronically controlled. Even for an input inhomogeneous irradiance distribution, this allows for a precise control of the energy coupled to the filaments and the spectra of the generated supercontinuum...
As one of the wave-splitting phase-shifting digital holography, single-exposure generalized phase-shifting digital holography has been proposed. In the digital holography, the phase-shift quantity, which corresponds to the difference between the phase quantities of the reference wave on the adjacent pixels, is not restricted but generalized. Owing to the generalized phase-shifting, a random-phase...
Super-resolution holographic data storage allows us to record and retrieve a data page with a smaller aperture than a Nyquist aperture. This system has a potential to realize a high-density recording compared with a conventional holographic storage system. Recording a phase data page in super-resolution holographic data storage to improve light efficiency is proposed. The phase data page is designed...
The proposed holographic Shack-Hartmann wavefront sensor can measure a wavefront aberration with large dynamic range. It is realized by introducing a holographic optical element and pattern matching technique. To confirm the flexibility of the sensor, measurements of the wavefronts with various aberrations are numerically demonstrated.
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