Engineering Optics

Iizuka, Keigo

doi:10.1007/978-3-540-36808-3

Cited by 87 publications

(84 citation statements)

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“…A similar discussion in Fourier space leading to the same result can be found in Ref. 14 The monochromaticity restricts the possible wave vectors k i to those fulfilling ͉k i ͉ = c with the angular frequency and c the vacuum speed of light, and therefore the corresponding three-dimensional wave field is only nonzero on the surface of a sphere with radius ͉k͉. Expressing the wave vector k i by deviations q i from a reference vector k 0i the latter pointing in main beam direction, written in components…”

Section: ͑2͒supporting

confidence: 72%

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Magnified x-ray phase imaging using asymmetric Bragg reflection: Experiment and theory

et al. 2006

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X-ray imaging using asymmetric Bragg reflection in the hard x-ray regime opens the way to improve the spatial resolution limit below 1 m by magnifying the image before detection, simultaneously providing a strong phase contrast. A theoretical formalism of the imaging process is established. Based on this algorithm, numerical simulations are performed and demonstrate that both Fresnel propagation and Bragg diffraction contribute to contrast formation. The achievable resolution of this technique is investigated theoretically; the results obtained can be used to improve future experimental setups. Furthermore, the minimum detectable phase gradient is estimated, for comparison with other phase sensitive imaging techniques. Results from biological objects demonstrate that the technique is viable for imaging both in two and three dimensions. Refraction contrast images are extracted from experimental projection images by an algorithm similar to diffraction-enhanced imaging ͑DEI͒, and used to achieve three-dimensional tomographic reconstruction.

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Section: ͑2͒supporting

confidence: 72%

“…8͑b͔͒. We have used 2 14 up to 2 17 sample points in Fourier space in order to avoid numerical artifacts. Different types of test amplitudes corresponding to increasingly realistic model samples will be discussed in the subsequent sections.…”

Section: Numerical Simulationmentioning

confidence: 99%

Magnified x-ray phase imaging using asymmetric Bragg reflection: Experiment and theory

et al. 2006

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“…The second is a /2 phase step for the positivevalued coordinates and a À/2 phase step for the negatives ones. This is required to attain the correct mask sign and also the imaginary unit (Iizuka 1987). Consequently, the first derivative is performed along the mask slope direction.…”

Section: Optical Differentiation Techniquementioning

confidence: 99%

Pure Amplitude Masks for Exoplanet Detection with the Optical Differentiation Coronagraph

Oti

Canales

Cagigal

2007

ApJ

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The optical differentiation coronagraph relies on the optical differentiation technique implemented on a standard coronagraph. The use of a coronagraphic mask to estimate the first derivative of the incoming field shows high starlight suppression (theoretically infinite), but it is highly sensitive to pointing errors and suffers from monochromaticity drawbacks. In order to overcome these limitations, we generalize the optical differentiation concept to higher order derivatives. Here we describe a novel set of coronagraphic masks that estimate the second derivative of the incoming field. A mathematical description of the optical differentiation coronagraph is presented. These new masks also achieve a theoretical perfect suppression of the on-axis light, and furthermore, they are less sensitive to pointing errors (fourthorder sensitivity to tip/tilt error leakage). Moreover, they are pure amplitude masks, and hence they do not require a complementary phase mask, which represents an additional advantage. The use of a Gaussian roll-off helps to concentrate the diffracted starlight near the pupil borders, where it could be removed more efficiently by a Lyot stop, and transforms the coronagraph into a nearly band-limited coronagraph.

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“…The display industry is seeking various methods to realize three-dimensional (3d) display. Many of them rely on our illusion (Iizuka 2008) and others try to reproduce volumetric light source in the real 3d space. Input and output devices go hand in hand.…”

Section: Introductionmentioning

confidence: 99%

Detection of Finger Height for a Multi-Touch Mouse

Fujieda¹,

Okuda²,

Inoue³

et al. 2010

International Journal of Optomechatronics

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An image of multiple fingers is acquired by an input system that consists of a camera with a fisheye lens, infrared LEDs, and a transparent shell. When the LEDs illuminate fingers uniformly, the distance between the fingertips and the lens can be deduced by analyzing the intensity of the fingertip regions and/or the size of the fingers in the image. Azimuth and polar angles of the fingertips are obtained from the image directly. Repeating this process provides a series of three-dimensional coordinates of multiple fingertips. Such information might be useful for realizing a multi-touch mouse with height detection capability.

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Engineering Optics

Cited by 87 publications

References 0 publications

Magnified x-ray phase imaging using asymmetric Bragg reflection: Experiment and theory

Magnified x-ray phase imaging using asymmetric Bragg reflection: Experiment and theory

Pure Amplitude Masks for Exoplanet Detection with the Optical Differentiation Coronagraph

Detection of Finger Height for a Multi-Touch Mouse

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