Miniaturization of zoom lenses with a single moving element

Demenikov, Mads; Findlay, Ewan; Harvey, Andrew R.

doi:10.1364/oe.17.006118

Cited by 45 publications

(17 citation statements)

References 15 publications

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“…The proper choice for V1 and V2 improves the quality of the restored images of a given optical system in terms of focal range, signal to noise ratio and maximum spatial frequency, among other parameters [4,20,21]. Thus, controlled rotation of these elements will suffice in optimizing the system if conditions or performance demands change, as for instance, change in zoom lenses from infinite conjugate imaging to finite conjugate imaging [6].…”

Section: Methodsmentioning

confidence: 99%

“…One clear example of the need for this hybrid solution is the control of thermally induced aberrations in IR imaging systems due, for instance, to the dramatic change in the refractive index of commonly used materials such as germanium as well as other geometrical and mechanical changes in optical set-ups. A recent application for zoom lenses is another example of the potential applicability of the method [6].…”

Section: Introductionmentioning

confidence: 99%

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Adaptive phase plates for optical encoding systems invariant to second-order aberrations

Acosta

2011

Optics Communications

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Adaptive phase plates for optical encoding systems invariant to second-order aberrations

Acosta

2011

Optics Communications

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“…The seminal 1995 paper by Dowski and Cathey [2] showed that a cubic optical phase function introduced into the exit pupil of an imaging system yields a point-spread function (PSF) that is approximately invariant to defocus, exhibits no nulls in the MTF, and therefore enables digital recovery of a high-quality image for an extended DOF [3]. Control of focus-related aberrations is a major challenge in lens design, and so hybrid imaging using cubic or other antisymmetric phase functions such as trefoil [4] has been exploited for simplification of lens design and manufacture in miniaturization of zoom lenses [5] and thermal imaging [6], particularly for infinite-conjugate imaging.…”

Section: Introductionmentioning

confidence: 99%

Extended depth-of-field imaging and ranging in a snapshot

Zammit¹,

Harvey²,

Carles³

2014

Optica

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Traditional approaches to imaging require that an increase in depth of field is associated with a reduction in numerical aperture, and hence with a reduction in resolution and optical throughput. In their seminal work, Dowski and Cathey reported how the asymmetric point-spread function generated by a cubic-phase aberration encodes the detected image such that digital recovery can yield images with an extended depth of field without sacrificing resolution [Appl. Opt. 34, 1859(1995]. Unfortunately recovered images are generally visibly degraded by artifacts arising from subtle variations in point-spread functions with defocus. We report a technique that involves determination of the spatially variant translation of image components that accompanies defocus to enable determination of spatially variant defocus. This in turn enables recovery of artifact-free, extended depth-of-field images together with a two-dimensional defocus and range map of the imaged scene. We demonstrate the technique for high-quality macroscopic and microscopic imaging of scenes presenting an extended defocus of up to two waves, and for generation of defocus maps with an uncertainty of 0.036 waves.

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“…Many applications may benefit from extended DOF capabilities in macroscopic imaging, for example in surveillance, machine vision or biometrics problems where the DOF extension is a clear advantage [2,3]; but the technique can also be used to reduce system complexity [4] or for athermalisation and achromatisation of infrared imaging systems [5].…”

Section: Introductionmentioning

confidence: 99%

Design and implementation of a scene-dependent dynamically selfadaptable wavefront coding imaging system

Carles

Ferran

Carnicer

et al. 2012

Computer Physics Communications

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A computational imaging system based on wavefront coding is presented. Wavefront coding provides an extension of the depth-of-field at the expense of a slight reduction of image quality. This trade-off results from the amount of coding used. By using spatial light modulators, a flexible coding is achieved which permits it to be increased or decreased as needed. In this paper a computational method is proposed for evaluating the output of a wavefront coding imaging system equipped with a spatial light modulator, with the aim of thus making it possible to implement the most suitable coding strength for a given scene. This is achieved in an unsupervised manner, thus the whole system acts as a dynamically selfadaptable imaging system. The program presented here controls the spatial light modulator and the camera, and also processes the images in a synchronised way in order to implement the dynamic system in real time. A prototype of the system was implemented in the laboratory and illustrative examples of the performance are reported in this paper. The program implements an enhanced wavefront coding imaging system able to adapt the degree of coding to the requirements of a specific scene. The program controls the acquisition by a camera, the display of a spatial light modulator and the image processing operations synchronously. The spatial light modulator is used to implement the phase mask with flexibility given the trade-off between depth-of-field extension and image quality achieved. The action of the program is to evaluate the depth-of-field requirements of the specific scene and subsequently control the codifing established by the spatial light modulator, in real time.

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Miniaturization of zoom lenses with a single moving element

Cited by 45 publications

References 15 publications

Adaptive phase plates for optical encoding systems invariant to second-order aberrations

Adaptive phase plates for optical encoding systems invariant to second-order aberrations

Extended depth-of-field imaging and ranging in a snapshot

Design and implementation of a scene-dependent dynamically selfadaptable wavefront coding imaging system

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