WO1999008154A1 - Camera avec systeme de relais de reduction d'image - Google Patents

Camera avec systeme de relais de reduction d'image Download PDF

Info

Publication number
WO1999008154A1
WO1999008154A1 PCT/NZ1998/000120 NZ9800120W WO9908154A1 WO 1999008154 A1 WO1999008154 A1 WO 1999008154A1 NZ 9800120 W NZ9800120 W NZ 9800120W WO 9908154 A1 WO9908154 A1 WO 9908154A1
Authority
WO
WIPO (PCT)
Prior art keywords
camera system
subsystem
camera
focal
aperture
Prior art date
Application number
PCT/NZ1998/000120
Other languages
English (en)
Inventor
Allan David Beach
Original Assignee
Industrial Research Limited
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 Industrial Research Limited filed Critical Industrial Research Limited
Priority to CA002300392A priority Critical patent/CA2300392A1/fr
Priority to NZ502447A priority patent/NZ502447A/xx
Priority to JP2000506564A priority patent/JP2001512853A/ja
Priority to AU86539/98A priority patent/AU732771B2/en
Priority to EP98937895A priority patent/EP1004054A1/fr
Publication of WO1999008154A1 publication Critical patent/WO1999008154A1/fr

Links

Classifications

    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G02B13/0095—Relay lenses or rod lenses

Definitions

  • the present invention relates to high speed, high resolution camera systems.
  • this invention relates to a high speed, high resolution camera system which employs a conventional photographic camera subsystem and which is used with high resolution, solid-state image detectors such as CCDs, or the like.
  • Photographic camera systems are well known with many variations in existence. These camera systems are generally designed to produce an image of reasonably high resolution onto a photographic film, and to have as high a relative aperture, or smallest f-number value, as possible. Of course, there is a trade off between resolution and relative aperture. The optimum practical solution is achieved by considering the properties of the photographic film to be used with the camera. Of particular interest is the resolution of commonly used photographic film The resolution is limited by scattering within the film emulsion itself, and is typically approximately 20 microns. Simply put, the designers of these camera systems trade off resolution for relative aperture, whilst minimising cost, until the resolution of the image produced approaches the resolution of the film being used.
  • Photographic camera systems are available which are relatively cheap and of high quality. In particular, many relatively cheap systems are available in the industry standard 35 millimetre photographic film format. Also of interest is the type of film used. These vary in speed - the speed depending largely on the size of, for example, the silver halide crystals in the emulsion. Unfortunately, there tends to be a trade off between speed and resolution in film also.
  • Relative aperture D/f, where D is the diameter of the entrance pupil and f is the focal length.
  • Solid state electronic image detectors such as CCDs, or other semiconductor detectors, generally have higher resolutions than photographic films. Typically, the resolution of a CCD detector will be approximately 5 to 10 microns compared to approximately 20 microns for photographic film. Also, solid state detectors generally have a smaller area than the 35 millimetre film.
  • a camera system comprising:
  • a photographic camera subsystem having a characteristic first aperture and a focus at a first focal surface; a focal reducing lens relay subsystem having a characteristic second aperture and a focus at a second focal surface having a characteristic image diameter; wherein the focal reducing lens relay subsystem is arranged to reduce the image diameter of the photographic camera subsystem;
  • the camera system is arranged such that substantially the entire first aperture is mapped onto the second aperture.
  • this is effected by including a field lens subsystem in the camera system.
  • the camera system is adapted to be capable of incorporating an image detector.
  • the camera system is adapted to be capable of incorporating an electronic image detector at the second focal surface, the electronic detector having a characteristic pixel resolution and a characteristic effective detector area.
  • the camera system is adapted to be capable of incorporating an electronic image detector in the form of a semiconductor image detector.
  • the detector may be a charge coupled device array.
  • the camera system is arranged so that the first focal surface diameter is mapped onto the effective detector area of an image detector provided.
  • the focal reducing lens relay subsystem comprises a Hawkins and Linfoot arrangement modified to act as a focal reducing subsystem.
  • the Hawkins and Linfoot arrangement includes an aberration compensating means to compensate for aberrations introduced by the other parts of the Hawkins and Linfoot arrangement.
  • the aberration compensating means comprises a meniscus lens.
  • the Hawkins and Linfoot arrangement includes a chromatic distortion compensating means to compensate for chromatic distortion introduced by other parts of the Hawkins and Linfoot subsystem.
  • the chromatic distortion compensating means may be situated elsewhere in the optical system as would be evident to those skilled in the art.
  • the chromatic distortion compensating means comprises a lens doublet.
  • the chromatic distortion compensating means may comprise a lens triplet.
  • the focal reducing, lens relay subsystem may comprise any one of the following arrangements particularly adapted to act as a focal reducing system:
  • the camera system includes an adjustable aperture thereby allowing adjustment of the input aperture of the camera system.
  • the focal reducing, lens relay subsystem is arranged so that the image diameter of the photographic camera subsystem is reduced as much as possible before the resolution of the image at the second focal surface falls below that of the pixel resolution of the electronic detector provided.
  • aberrations introduced by the focal reducing lens relay subsystem cause an image formed by the camera system of a point source to be substantially the size of a pixel of an electronic image detector provided.
  • Figure 1 Schematically shows the configuration of an embodiment of the present invention.
  • Figure 2 Schematically shows the configuration of the original
  • FIG. 3 Schematically shows the configuration of a modified
  • Hawkins and Linfoot camera intended for finite conjugate imaging, and with an external focus.
  • FIG. 1 shows a camera system 1 according to an embodiment of the present invention.
  • the camera system 1 includes a standard photographic camera lens system 2 having a characteristic aperture 3 and a focus at the focal surface 4.
  • the focal surface is a plane, although it is also possible for this to be part of a sphere, parabola or some other type of surface.
  • the useable image projected onto the focal surface will typically have an industry standard useable diameter of 45 millimetres which is suitable for industry standard 35 millimetre camera format for which good quality, relatively cheap camera lens systems are readily available. Of course, other camera formats may alternatively be employed.
  • the resolution of the image at the focal surface of the photographic camera subsystem will typically be approximately 20 microns to match the resolution of typically used film.
  • the speed, or inverse of the relative aperture or f-number, of the photographic camera subsystem is denoted by f/D, where f is the focal length of the photographic camera subsystem and D is the diameter of the entrance pupil, which is determined by the diameter of the characteristic aperture 3.
  • f the focal length of the photographic camera subsystem
  • D the diameter of the entrance pupil, which is determined by the diameter of the characteristic aperture 3.
  • f/1 .4 lens system is said to be twice as fast as an f/2 lens (the area of the entrance pupil being proportional to the square of the pupil diameter).
  • the speed of the photographic camera subsystem may be determined by the relation 1 given above.
  • Figure 1 also shows a camera subsystem in the form of a focal reducing lens relay system 5.
  • a preferred arrangement for this focal reducing subsystem is the Hawkins and Linfoot camera modified to act as a focal reducer. Suitable modifications will be apparent to those skilled in the art.
  • other suitable focal reducing subsystems may consist of any one of the arrangements known in the art including: Schmidt; Bouwers; and Baker-Nunn. Other suitable arrangements, which are known to those skilled in the art, may also be used.
  • the preferred Hawkins and Linfoot arrangement shown in Figure 1 , includes a spherical mirror 7 and a meniscus lens 8, and is modified from the original ( 1 945) arrangement shown in Figure 2 so as to operate with a finite object conjugate.
  • the meniscus 8 serves to correct for and minimise aberrations introduced by the spherical mirror 7.
  • the focal reducing subsystem may also include a chromatic distortion compensating system to compensate for chromatic distortion introduced by the meniscus 8.
  • This system may be a lens doublet, lens triplet or any other suitable system, which are commonly known in the art.
  • the chromatic distortion compensating means may be situated elsewhere in the optical system as would be evident to those skilled in the art.
  • the camera system may also be provided with an image detector 9.
  • the detector 9 will typically consist of an electrooptic image detector such a Charge Coupled Device (CCD) array, or some other semiconductor array, or an image intensifier tube. Any suitable electrooptic image detector known to those skilled in the art may be used.
  • a common size for a CCD array may have a diagonal dimension of 1 1 millimetres, which corresponds to approximately 2/3 inch. However, other available "standard video" sizes range from 1 /4 inch to 1 inch.
  • Image intensifier tubes range from 1 2 to 40 millimetres in diameter.
  • the image produced by the camera system will be improved if a field-curvature-correcting lens is bonded to the surface of the detector.
  • Suitable lenses and, indeed, alternative arrangements to such a lens for compensating for the curvature of the focused image will be apparent to those skilled in the art.
  • the camera system 1 also includes a field lens 10, which serves to match or couple the photographic camera subsystem aperture 3 to the focal reducing subsystem aperture 1 1 to reduce vignetting and also to ensure that the entire effective area of the detector 8 is utilised.
  • a field lens which serves to match or couple the photographic camera subsystem aperture 3 to the focal reducing subsystem aperture 1 1 to reduce vignetting and also to ensure that the entire effective area of the detector 8 is utilised. Any suitable alternative to a field lens which is known in the art may be used.
  • various photographic camera subsystems may be interchanged with the camera subsystem. These will correspondingly have various characteristic apertures. Therefore, various field lenses will need to be interchanged accordingly.
  • the focal reducing, relay lens subsystem acts to reduce the image created by the photographic camera subsystem to produce a smaller, brighter image at the focal surface 6 of the focal reducing subsystem.
  • This reduction in the focus, or image diameter corresponds to a larger relative aperture, or lower f- number for the camera system than the relative aperture of the photographic camera.
  • the focal reducing lens relay subsystem can be clearly demonstrated by considering an image produced by the photographic camera subsystem, and also the camera system as a whole, of a point source of light.
  • the point source typically will be imaged as a distorted, blurred spot having an average diameter of approximately 20 microns, for example.
  • the shape and diameter of this image will be a product of the aberration and chromatic distortion of the photographic lens system.
  • these aberrations have, simply put, been allowed to increase as a trade off for relative aperture of the subsystem to the point where the approximate size of the image approaches the minimum image size capable of resolution by the photographic emulsion for which the subsystem has been designed to be used.
  • the focused image of the point source focused at the focal surface of the photographic camera subsystem is reduced by the focal reducing subsystem onto the focal surface 6 of the focal reducing lens relay subsystem.
  • An ideal focal reducer would reduce the image diameter in accordance with its focal reducing ability. This would, of course, produce a reduced blur spot corresponding to a higher resolution image.
  • a real focal reducing, lens relay subsystem will itself introduce aberrations. These will primarily be high-order sphero-chromatic aberrations caused by the residuum of the aberration correction of the lens relay subsystem.
  • relation 1 given above the relative aperture of the camera system as a whole, will increase as the focal length is further reduced.
  • the aberrations introduced by the focal reducing subsystem will act to increase the minimum image size.
  • the optimum degree of focal reducing is where the size of an image of a point source approaches the minimum spot which can be resolved by the detector used with the camera system. In the case of a typical CCD, this will be approximately 5 to 10 microns.
  • the image produced at the focal surface 6 of the focal reducing, lens relay subsystem is reduced, and correspondingly brighter, with respect to the image produced by the photographic camera subsystem alone.
  • the camera system takes advantage of the higher resolution of the electrooptic detector to provide a faster imaging system.
  • Such a system can additionally be advantageous to the low light imaging properties of some electrooptic image detectors available.
  • any photographic camera arrangement may be used. These may include zoom, wide angle or even "fish eye” lenses.
  • the photographic camera arrangement may include any known devices or means to focus or vary the aperture of the photographic camera subsystem. It will also be apparent to those skilled in the art that the camera system may be arranged to have a variable input aperture.
  • Figure 3 shows an alternative focal reducing lens relay subsystem 1 1 which is, essentially a further modified Hawkins and Linfoot camera arrangement.
  • This alternative subsystem is primarily arranged for a finite object conjugate as in Figure 1 , but also so that the focal surface 1 2 to be conveniently positioned at the rear of the camera system.
  • This alternative arrangement replaces the focal reducing mirror 7 of the above-mentioned arrangement with a flat folding mirror 1 3 and spherical mirror 14. The action of these mirrors or further alternatives to these mirrors will be apparent to those skilled in the art.
  • the alternative arrangement 1 1 includes a chromatic distortion compensating doublet 1 5, a meniscus lens 1 6 and a field lens 1 7.
  • the meniscus lens 1 6 has been placed in front of the chromatic distortion compensated doublet 1 5, as opposed to the arrangement of Figure 2, so that the meniscus lens 1 6 is closer to the image thereby allowing a smaller meniscus lens 1 6 to be used. This is merely a constructional detail which will be apparent to those skilled in the art.
  • the focal reducing lens relay subsystem can be arranged to position the focal surface 1 2 at virtually any desired position by suitable arranging or substituting of optical elements.
  • Commercially available, high quality telephoto photographic camera subsystems may have a relative aperture of between f/2 and f/3.
  • a camera system in accordance with the present invention using such a telescopic lens will typically have a relative aperture of f/0.8. Therefore, it is clear that the present invention provides the advantage of an exceptionally high speed camera system. Due to the use of commercially available photographic camera subsystems, a camera system in accordance with the present invention will also be relatively cheap and/or easy to construct.
  • a system in accordance with the present invention also lends itself to employing relatively small, lightweight photographic camera subsystems which facilitate minimisation of the size and weight of the camera system as a whole.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Lenses (AREA)
  • Structure And Mechanism Of Cameras (AREA)
  • Cameras In General (AREA)

Abstract

Le système de lentille (5) réduisant la focale réduit le diamètre image d'un système de lentille (2) traditionnel photographique de façon à augmenter l'ouverture relative et par conséquent la vitesse de ce système (2). Un détecteur d'image haute résolution tel qu'un détecteur CCD peut être placé au niveau du plan focal (6) du système de lentille (5) réduisant la focale, ce dernier étant réalisé à partir d'un système de lentilles Hawkins et Linfoot modifié comprenant un ménisque convergent (8) et un miroir sphérique (7) ou à partir de systèmes de lentilles Schmidt, Bouwers ou Baker-Nunn.
PCT/NZ1998/000120 1997-08-12 1998-08-12 Camera avec systeme de relais de reduction d'image WO1999008154A1 (fr)

Priority Applications (5)

Application Number Priority Date Filing Date Title
CA002300392A CA2300392A1 (fr) 1997-08-12 1998-08-12 Camera avec systeme de relais de reduction d'image
NZ502447A NZ502447A (en) 1997-08-12 1998-08-12 High speed, high resolution camera with an image reduction relay system
JP2000506564A JP2001512853A (ja) 1997-08-12 1998-08-12 像縮小リレーシステムを持つカメラ
AU86539/98A AU732771B2 (en) 1997-08-12 1998-08-12 Camera with image reduction relay system
EP98937895A EP1004054A1 (fr) 1997-08-12 1998-08-12 Camera avec systeme de relais de reduction d'image

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NZ32854097 1997-08-12
NZ328540 1997-08-12

Publications (1)

Publication Number Publication Date
WO1999008154A1 true WO1999008154A1 (fr) 1999-02-18

Family

ID=19926400

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/NZ1998/000120 WO1999008154A1 (fr) 1997-08-12 1998-08-12 Camera avec systeme de relais de reduction d'image

Country Status (5)

Country Link
EP (1) EP1004054A1 (fr)
JP (1) JP2001512853A (fr)
AU (1) AU732771B2 (fr)
CA (1) CA2300392A1 (fr)
WO (1) WO1999008154A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002093231A1 (fr) * 2001-05-15 2002-11-21 Industrial Research Limited Systeme imageur optique a elements de correction d'aberration

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103064171B (zh) * 2012-09-29 2014-11-19 北京空间机电研究所 一种高分辨率大视场光学成像系统

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4823199A (en) * 1986-03-11 1989-04-18 Minolta Camera Kabushiki Kaisha Still video adapter device detachable to a camera body
US4862293A (en) * 1986-08-30 1989-08-29 Minolta Camera Kabushiki Kaisha Still video adapter
WO1992007504A1 (fr) * 1990-10-31 1992-05-14 Occipital, Inc. Appareil photographique a couplage de charge et procede d'imagerie du fond de l'×il
WO1995034013A1 (fr) * 1994-06-07 1995-12-14 Industrial Research Limited Systeme optique grande vitesse
EP0690327A2 (fr) * 1994-06-30 1996-01-03 Mantis Wildlife Films Pty. Limited Système optique à grand angle, à grand profondeur de champ et à courte distance focale
US5499069A (en) * 1994-05-24 1996-03-12 Eastman Kodak Company Camera system and an optical adapter to reduce image format size
US5587766A (en) * 1995-02-13 1996-12-24 Nikon Corporation Camera which sets an internal aperture value in accordance with a converted photographic lens aperture value

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4823199A (en) * 1986-03-11 1989-04-18 Minolta Camera Kabushiki Kaisha Still video adapter device detachable to a camera body
US4862293A (en) * 1986-08-30 1989-08-29 Minolta Camera Kabushiki Kaisha Still video adapter
WO1992007504A1 (fr) * 1990-10-31 1992-05-14 Occipital, Inc. Appareil photographique a couplage de charge et procede d'imagerie du fond de l'×il
US5499069A (en) * 1994-05-24 1996-03-12 Eastman Kodak Company Camera system and an optical adapter to reduce image format size
WO1995034013A1 (fr) * 1994-06-07 1995-12-14 Industrial Research Limited Systeme optique grande vitesse
EP0690327A2 (fr) * 1994-06-30 1996-01-03 Mantis Wildlife Films Pty. Limited Système optique à grand angle, à grand profondeur de champ et à courte distance focale
US5587766A (en) * 1995-02-13 1996-12-24 Nikon Corporation Camera which sets an internal aperture value in accordance with a converted photographic lens aperture value

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
S.F. RAY, "Applied Photographic Optics", 2nd Edition, Published 1994 by FOCAL PRESS (OXFORD), pages 394-396. *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002093231A1 (fr) * 2001-05-15 2002-11-21 Industrial Research Limited Systeme imageur optique a elements de correction d'aberration
WO2002093230A1 (fr) * 2001-05-15 2002-11-21 Industrial Research Limited Systeme d'imagerie optique a etendue optique elevee

Also Published As

Publication number Publication date
CA2300392A1 (fr) 1999-02-18
JP2001512853A (ja) 2001-08-28
AU732771B2 (en) 2001-04-26
EP1004054A1 (fr) 2000-05-31
AU8653998A (en) 1999-03-01

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