EP2802919A1 - Systèmes optiques panoramiques - Google Patents

Systèmes optiques panoramiques

Info

Publication number
EP2802919A1
EP2802919A1 EP13702518.5A EP13702518A EP2802919A1 EP 2802919 A1 EP2802919 A1 EP 2802919A1 EP 13702518 A EP13702518 A EP 13702518A EP 2802919 A1 EP2802919 A1 EP 2802919A1
Authority
EP
European Patent Office
Prior art keywords
panoramic
optical system
panoramic optical
lens
lenses
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP13702518.5A
Other languages
German (de)
English (en)
Inventor
Stephen K. Eckhardt
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
EYESEE360 Inc
Original Assignee
EYESEE360 Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by EYESEE360 Inc filed Critical EYESEE360 Inc
Priority claimed from PCT/US2013/020826 external-priority patent/WO2013106427A1/fr
Publication of EP2802919A1 publication Critical patent/EP2802919A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/06—Panoramic objectives; So-called "sky lenses" including panoramic objectives having reflecting surfaces
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B17/00—Systems with reflecting surfaces, with or without refracting elements
    • G02B17/08—Catadioptric systems
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B17/00—Systems with reflecting surfaces, with or without refracting elements
    • G02B17/08—Catadioptric systems
    • G02B17/0852—Catadioptric systems having a field corrector only
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B17/00—Systems with reflecting surfaces, with or without refracting elements
    • G02B17/08—Catadioptric systems
    • G02B17/0856—Catadioptric systems comprising a refractive element with a reflective surface, the reflection taking place inside the element, e.g. Mangin mirrors
    • G02B17/086—Catadioptric systems comprising a refractive element with a reflective surface, the reflection taking place inside the element, e.g. Mangin mirrors wherein the system is made of a single block of optical material, e.g. solid catadioptric systems

Definitions

  • the present invention relates to panoramic optical systems, and in particular, it relates to catadioptric panoramic optical systems comprising a mirror and multiple
  • panoramic lenses Many rotationally symmetric lenses have been described over the years, and most of them are capable of imaging an azimuthal field of 360° about the axis of rotation, also called the optical axis. What distinguishes panoramic lenses is that their field of view is not measured from 0° at the optical axis to their maximum field, rather their field of view is measured with respect to a plane perpendicular to the optical axis. This plane is often referred to as the horizontal plane. For example, for a panoramic lens, the field of view may be referred to as +5°/-20°, which means that the picture includes up to five degrees above the horizontal and twenty degrees below.
  • Optical systems may be divided into three categories: dioptric, catoptric and catadioptric.
  • dioptric contains all optical systems that have only transmissive elements.
  • catoptric optical systems have only reflective elements.
  • Catadioptric optical systems have both transmissive and reflective elements, and may be divided into two subcategories.
  • One of these subcategories includes all optical systems that have within them a single element that both reflects and transmits light, while the other is restricted to elements that either reflect or transmit, but not both.
  • the latter subcategory includes optical systems that have mirrors that transmit light either around their periphery or through a hole, as long as that light is not refracted by the mirror substrate.
  • Dioptric wide angle lenses such as fisheye lenses
  • fisheye lenses have been known to achieve larger than hemispherical fields of view, with half field angles up to 140°, measured from the optical axis.
  • Such lenses are frequently described by their full field angle, so a lens with the half field angle of 140° would be called a 280° fisheye.
  • As a panoramic lens it would be described as a +90°/-50° lens.
  • fisheye lenses often have significant image compression (distortion) at the edge of the field of view, resulting in decreased resolution in the portion of the field near the horizontal plane.
  • U.S. Pat. No. 5,185,667 to Zimmerman describes the use of a fisheye lens as a panoramic lens.
  • Catoptric optical systems have also been proposed as panoramic lenses.
  • U.S. Pat. No. 5,920,376 to Bruckstein et al. describes cameras that are purely catoptric, consisting only of one or more mirrors and a pinhole camera arrangement.
  • a significant problem with this type of system is that a pinhole does not allow much light to get to the image.
  • the pinhole is generally required to reduce aberrations to an acceptable level.
  • Another way to express this problem is that catoptric panoramic lenses are generally restricted to large F-numbers or small numerical apertures by their aberrations.
  • Catadioptric panoramic optical systems with only reflecting or transmitting elements are known. Multiple-catadioptric systems may be capable of high performance, but suffer the difficulty of aligning the mirrors and keeping them in alignment.
  • One example of a complex mirror alignment is disclosed in U.S. Pat. No. 5,627,675 to Davis et al. Although blur sizes of less than 10 microns at F/1.5 are shown, the optical arrangement is extremely complex.
  • Monochromatic aberrations are typically divided into primary and higher order aberrations.
  • Primary aberrations include spherical aberration, which introduces a blur to the image that is constant across the field of view.
  • Coma and astigmatism blur the image with a magnitude that varies linearly and quadratically with field angle, respectively.
  • Field curvature causes the best image not to lie on a plane, so that an image formed on a flat piece of film or a flat array detector is blurred. Distortion does not blur the image, but causes a magnification that varies as the cube of the field angle, so that the image of a square has curved sides.
  • the present invention provides periscopic lens systems with a single mirror designed to minimize astigmatism.
  • Simple, highly manufacturable lens systems are provided for capturing and/or projecting a 360-degree panoramic scene that requires only a single miiTor.
  • the lens systems are designed to be used at fast speeds, e.g., faster than F/10.
  • an ellipsoidal mirror is used to minimize astigmatism in combination with a dioptric lens group that counterbalances the aberrations introduced by the ellipsoidal mirror.
  • An aspect of the present invention is to provide a panoramic optical system comprising an ellipsoidal mirror, and an astigmatism reducing lens system comprising a series of lenses arranged to transmit images from the ellipsoidal mirror, wherein the lens system has an F/number faster than F/10 and reduces astigmatism to less than ⁇ 500microns, for example, ⁇ 200 microns.
  • Fig. 1 is a partially schematic cross-sectional view of a panoramic optical system including an ellipsoidal mirror and a series of lenses in accordance with an embodiment of the invention.
  • Fig. 2 is an astigmatism plot for the panoramic optical system of Fig. 1.
  • Fig. 3 is a distortion plot for the panoramic optical system of Fig. 1.
  • Fig. 4 is a polychromatic diffraction modulation transfer function (MTF) plot for the panoramic optical system of Fig. 1.
  • Fig. 5 is a partially schematic cross-sectional view of a panoramic optical system including an ellipsoidal mirror and a series of lenses in accordance with another embodiment of the invention.
  • the panoramic optical system of the present invention comprises an ellipsoidal mirror and multiple dioptric lens elements.
  • the ellipsoidal mirror is designed to minimize astigmatism and the dioptric lens elements counterbalance aberrations introduced by the mirror.
  • a panoramic optical system 20 in accordance with an embodiment of the present invention includes a single ellipsoidal mirror 1 and a dioptric group or lens system 21.
  • the mirror 1 is elliptical in form to minimize astigmatism, compared to spherical, parabolic or hyperbolic mirrors that introduce significantly more astigmatism.
  • the dioptric group 21 includes a multiplicity of dioptric elements 2-6 and 8-11 and an aperture stop 7. Light enters the dioptric group 21 after reflecting from the mirror 1. As it passes through the dioptric group 21 it passes through the aperture stop 7, which limits the F/number of the beam.
  • the aperture stop 7 may be made of a single part, such as a sheet of metal, for example, or may be adjustable.
  • a single part such as a sheet of metal, for example, or may be adjustable.
  • One example of an adjustable aperture stop is an iris diaphragm, but other adjustable apertures known in the art may be used.
  • a conventional imaging device such as film or an electronic detector, for example a CCD or CMOS array, may be placed in the vicinity of the image plane to receive the image.
  • the panoramic lens may be used as a projection lens, in which case the film to be projected or an electronic imaging device for imprinting an image on a beam of light, such as an LCD or a micromirror device, for example a DLP, available from Texas Instruments, Inc. of Richardson, TX, USA, may be placed in the vicinity of the image plane.
  • Light from a light source shined through or reflected from the imaging device could then be projected onto a screen, which may be cylindrical, spherical or some other shape.
  • the first column lists the element numbers shown in Fig. 1, as well as the mirror surface and lens element surfaces, listed as A-Q. The object and the image are also listed in Table 1.
  • the second column in Table 1 is the surface curvature, which is the reciprocal of the radius of curvature.
  • the numbers represent the distance to the next surface.
  • Glass types displayed in the fourth column are commercially available from Ohara Corporation, Collinso Santa Margarita, CA. All of the elements in this lens are rotationally symmetric, so the fifth column lists the distance from the optical axis to the periphery of the element.
  • the number in the last column represents the conic constant of the mirror.
  • a conic surface is described by the following equation: where z is the distance from a plane tangent to the surface at its intersection with the optical axis, c is the curvature of the surface (the reciprocal of its radius of curvature), y is the distance from the optical axis to the point at which z is to be calculated and k is the conic constant.
  • a conic constant may be used by lens design programs, such as Zemax,
  • conic constant shown in Table 1 is -0.742, other conic constants may be used.
  • a conic constant equal to 0 represents a sphere
  • a conic constant equal to -1 represents a parabola with values between these limits representing an ellipse.
  • an elliptical conic constant between -0.01 and -0.99 may be used in accordance with the present invention, typically between -0.3 and -0.9.
  • the conic constant is between -0.6 and -0.85. It is also possible to use an ellipsoidal mirror with aspheric terms in addition to the conic constant.
  • a user of the Zemax program would describe this surface as an even asphere or an odd asphere or a Q-type asphere.
  • Such a mirror may be used in accordance with the present invention to reduce astigmatism.
  • a feature of the ellipsoidal mirrors according to this invention is that the shape generally lies between that of a sphere and a parabola with the same curvature, at least within the used area.
  • the panoramic field of view in this embodiment may be at least ⁇ 50°, as measured from a plane perpendicular to the optical axis.
  • the field of view may be symmetric about the horizontal plane, for example, ⁇ 30° or ⁇ 40°, or
  • the field of view can be chosen to be smaller, to maximize the resolution for a given number of pixels on the detector, or larger, to maximize the amount of space observed.
  • Fig. 2 is a plot of the parabasal astigmatic field curves for the embodiment shown in Fig. 1 and described in Table 1. These curves show that the astigmatism has been reduced to less than ⁇ 200 microns, which is veiy well controlled for many applications.
  • astigmatism is calculated as the differences between the sagittal and tangential foci, based on tracing Coddington rays. This calculation is described in optics texts, for example, Rudolf Kingslake, "Lens Design Fundamentals", Academic Press, New York, 1978. It can be measured by using an industry standard target such as the US Air Force 1951 three-bar target. Such targets may be purchased from, for example, Edmund Optics, Barrington, New Jersey.
  • F-theta distortion is based on the assumption that an angle in object space will be mapped to a distance on the image. It is measured as the distance between the actual image point and one calculated based on constant magnification and expressed as a percentage difference between the two distances from the center of the image. Distortion of less than 5% is sufficiently well controlled to be hard to notice, and certainly small enough to enable electronic correction.
  • Fig. 4 plots the MTF of the embodiment shown in Fig. 1 and described in Table 1. Aberrations in this embodiment are small enough for use with a pixelated detector with pixels of less than 10 micron pitch.
  • the embodiment shown in Fig. 1 and described in Table 1 may be useful as fast as F/5.6.
  • the F/number may be as fast as F/10, or F/8, or F/4 or F/2.8.
  • the F/number values are determined by standard methods known in the art in which the focal length of a lens is divided by the entrance pupil diameter. Lower F/numbers correspond to lenses that allow more light to the image plane, so lower F/numbers are more desirable for situations with dimmer lighting or when faster shutter speeds are required to stop motion.
  • Fig. 5 illustrates another panoramic optical system 120 in accordance with an embodiment of the present invention, which is further described in Table 2.
  • the first optical element 100 referred to as the ball in Table 2
  • the outer surface A may be a sphere, as described in Table 2, or it may be aspheric.
  • the mirror surface B is, according to this invention, elliptical in cross-section.
  • the exit surface C may be spherical, as shown in this example or it may be aspherical. All of the other surfaces D-0 in the embodiment shown in Fig.
  • the system 120 includes a lens system 121 comprising a series of lenses 102, 103 and 105- 108, having the surfaces D-0 labeled in Fig. 5 and listed in Table 2.
  • This panoramic lens is designed to operate as fast as F/2.8 but could be modified for other F/numbers.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Lenses (AREA)

Abstract

La présente invention concerne des systèmes optiques panoramiques (20, 120) comprenant un miroir ellipsoïdal (1, 101) et un système de lentilles (21, 121) qui réduit l'astigmatisme. Les systèmes de lentilles (21, 121) peuvent fonctionner à des vitesses rapides. L'invention concerne des systèmes de lentilles simples et faciles à fabriquer destinés à la capture et/ou à la projection de scènes panoramique à 360 degrés de haute qualité.
EP13702518.5A 2012-01-09 2013-01-09 Systèmes optiques panoramiques Withdrawn EP2802919A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US201261584566P 2012-01-09 2012-01-09
PCT/US2013/020826 WO2013106427A1 (fr) 2012-01-09 2013-01-09 Systèmes optiques panoramiques

Publications (1)

Publication Number Publication Date
EP2802919A1 true EP2802919A1 (fr) 2014-11-19

Family

ID=51690159

Family Applications (1)

Application Number Title Priority Date Filing Date
EP13702518.5A Withdrawn EP2802919A1 (fr) 2012-01-09 2013-01-09 Systèmes optiques panoramiques

Country Status (1)

Country Link
EP (1) EP2802919A1 (fr)

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO2013106427A1 *

Similar Documents

Publication Publication Date Title
US9229200B2 (en) Panoramic optical systems
US10649185B2 (en) Imaging system and imaging optical system
EP3454104A1 (fr) Système optique de projection et dispositif de projection
US7245443B2 (en) Panoramic attachment optical system, and panoramic optical system
CN102177468A (zh) 三反射镜全景相机
CN114859559A (zh) 光学镜头
EP3990960B1 (fr) Système optique catadioptrique compact pour téléphones mobiles
CN117761874A (zh) 定焦镜头
CN111474689B (zh) 广角镜头及全景摄像系统
JP4648758B2 (ja) 光学系
CN109324395A (zh) 一种定焦无畸变玻塑镜头
US7616389B2 (en) Optical system
JP6004073B2 (ja) 光学系及び撮像装置
JP5839135B2 (ja) 全天球型光学系及び撮像装置
JP5783314B2 (ja) 全天球型光学系および撮像システム
JPH09509265A (ja) 高シンメトリー光学システム
JP4855076B2 (ja) 光学系
JP4908853B2 (ja) 光学系
JP2007127703A (ja) 光学系
JP4869712B2 (ja) 光学系
EP2802919A1 (fr) Systèmes optiques panoramiques
JP2006126322A (ja) 光学系
JP4648757B2 (ja) 光学系
JP4451271B2 (ja) 光学系
CN110261996B (zh) 基于数字光处理的成像镜头及增强现实设备

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20140722

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

DAX Request for extension of the european patent (deleted)
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN

18D Application deemed to be withdrawn

Effective date: 20170801