Journal of the Optical Society of America. A, Optics, image science, and vision
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J Opt Soc Am A Opt Image Sci Vis · Dec 2019
Paraxial lens design of double-telecentric anamorphic zoom lenses with variable magnifications or fixed conjugate.
This paper presents a paraxial lens design method for anamorphic zoom lenses with double telecentricity. Four types of such lens systems are provided, which are the Y-X-Y-Y type, the Y-Y-Y-X type, the Y-X-Y-X type, and the Y-X-X-Y type. ⋯ For each condition, given the optical power of each lens component and the design parameters, such as the total length, the magnifications in the tangential plane and the sagittal plane, and the anamorphic ratio, formulas determining the interval distances between lens components, the object position, and the stop position are provided. Eight examples of double-telecentric anamorphic zoom lenses are provided, and all the examples are tested in Zemax, which shows the validity of the proposed design method.
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J Opt Soc Am A Opt Image Sci Vis · Jan 2014
Estimating the eye aberration coefficients in resized pupils: is it better to refit or to rescale?
In order to work in a consistent way with Zernike aberration coefficients estimated in different pupils, it is necessary to refer them to a common pupil size. Two standard approaches can be used to that end: to rescale algebraically the coefficients estimated in the original pupil or to refit them anew using the wavefront slope measurements available within the new one. ⋯ In case of enlarging the pupil size, as it can a priori be expected, the opposite holds true. We provide explicit expressions to quantify the errors arising in both cases, including the expected error incurred when extrapolating the Zernike estimation beyond the radius where the measurements were made.
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J Opt Soc Am A Opt Image Sci Vis · Mar 2013
A reinterpretation of transparency perception in terms of gamut relativity.
Classical approaches to transparency perception assume that transparency constitutes a perceptual dimension corresponding to the physical dimension of transmittance. Here I present an alternative theory, termed gamut relativity, that naturally explains key aspects of transparency perception. Rather than being computed as values along a perceptual dimension corresponding to transmittance, gamut relativity postulates that transparency is built directly into the fabric of the visual system's representation of surface color. ⋯ Whereas brightness and lightness perception were previously reanalyzed in terms of the relativity of the achromatic color gamut with respect to illumination level, transparency perception is here reinterpreted in terms of relativity with respect to physical transmittance. The relativity of the achromatic color gamut thus emerges as a fundamental computational principle underlying surface perception. A duality theorem relates the definition of transparency provided in gamut relativity with the classical definition underlying the physical blending models of computer graphics.
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J Opt Soc Am A Opt Image Sci Vis · Oct 2011
Quantitative determination of dynamical properties using coherent spatial frequency domain imaging.
Laser speckle imaging (LSI) is a fast, noninvasive method to obtain relative particle dynamics in highly light scattering media, such as biological tissue. To make quantitative measurements, we combine LSI with spatial frequency domain imaging, a technique where samples are illuminated with sinusoidal intensity patterns of light that control the characteristic path lengths of photons in the sample. We use both diffusion and radiative transport to predict the speckle contrast of coherent light remitted from turbid media. ⋯ For polystyrene microspheres of radius 800 nm in water, the expected and fit D(b) using radiative transport were 6.10E-07 and 7.10E-07 mm²/s, respectively. For polystyrene microspheres of radius 1026 nm in water, the expected and fit D(b) were 4.7E-07 and 5.35 mm²/s, respectively. For scattering particles in water-glycerin solutions, the fit fractional changes in D(b) with changes in viscosity were all found to be within 3% of the expected value.