CA1052160A - Lenticular stereoscopic photography using changing projection angle - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

In the illustrative embodiments of the invention disclosed, autostereoscopic pictures are produced by taking a series of two-dimensional views of an object field and pro- .
jecting them in an enlarger onto lenticular print film.
Adjustable-focus and fixed-focus cameras are provided for taking the two-dimensional views, either simultaneously or sequentially, in a manner which automatically accounts for the effect of variation of the camera-to-object distance on the configuration of the enlarger-lenticular print film system, thereby allowing the parameters of the enlarger-print film system to be held constant. The number of enlarging lenses employed may correspond to the number of two-dimensional views to be projected, by virtue of which the stereoscopic picture may be composed in a single projection step, or a single en-larging lens may be used to project the two-dimensional views in sequence. As another feature of the invention, substantially uninterrupted and non-overlapping lineiform image bands of high image quality are formed on all areas of the lenticular film by scanning the projected images from each two-dimensional view over a predetermined distance along the photosensitive surface.

Description

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: BACKGROUND OF THE INVENTION
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ield of the Invention . The present invention relates generally to the -¦
. production of autostexeoscopic pic_ures of the type employing ;~
ienticular screens. More specifically, it concerns novel ~1 me~hods a~d apparatus for ta~in~ and composing such pictures which greatl~ simplify these processes relative to the prior ~ ~ .
state of the art.

. he Prior Art ` ;~
Le~ticular screen-type autostereoscopic pictures . .
are produced basically in two ways, the direct or ;'in camera`' technique, in which the taking and composing s~eps are both . ~-~
. ~ - carried out within the camera,-and the--indirect technique, in `~
~ which a number of two-dimensional.views.of an o~ject ~ield `i 20.- are made from different vantage points and the three-aimen~
.sional picture is subsequently composed by-projecting the ~
two-dimensional images through-a composing...lenticular scxeen. : ~m As practiced in th~ prior art, however, ~oth techniques ha~e ..
.: been subjec~-.to use, quality and/or cost limitations which `~` 25. have all but preclud~d their widesDread commercial applica~
l ~ion. .

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- , ~0 For example, the direct technlque typically requires a specially constructed camera, embodying a lenticular screen sheet located on the emul~ion side of the pho~ographic film, and an associated tracking mechanism which constrains movement of the camera to an arcuate path centered around a point in the ,~
scene to be photographed. During exposure, the camera ~s moved along the arcuate path defined by the tracXing mechanism and the lenticular screen is shifted relative to the photographic film by a total distance equal to one lenti~ule width. Thi~
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requires precision movements of the various camera and ~racking components, with attendant complexity of operation and c~nstruction. The apparatus moreover is quite bulky, which -;` limits its usefulness for location photography. The direct process also ~ecessitate~ exposure times of comparatively ` `;~
~ long duration, a rather severe llmitation, and has the f~rther I disadvantage o l~cklng good depth of ield. An additlonal drawback is that the final three-dimensional picture cannot be freely enlarged or reduced in size.
The indirect technique, by allowing the use of a conventional two-dimensional camera in photographing ~he object .
field or scene, eliminates most of ~he aforementioned drawback~
,' of-the dlrect techn~gus. Furthermore, r~cent developments by Lo and--~ims--rel~ting to the manner---of making the two-d~mensional i exposure~ ha~e ~gnif~cantly advanced the state o~ the ar~ of -.:~ the. lndirect te~hnique. .~;

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Limitations in the composing step have nevertheless continued to impede general usage of the indirect process. This has .
~een due chiefly to the need to produce the final image-bearing sheet (composed of interdigitated lineiform images . .~.
from the se~eral two-dimensional views) separately from the .
vie~ing screen and thereafter to laminate it to the screen :
. .with the lineiform images and screen lenticules in precise :~
; alignment. Since the image-bearing sheets frequently change size between composing and laminating, as a result ~or example .
of fluctuations in ambient temperature, humidity, etc., such alignment of the image sheet and the viewing screen is quite - . . laborious and costly and often cannot be satisfactorily :
attained. Eforts to apply mass production techniques~to the :
align~ent step, by means of litho or offset printi.~ of th~
i5 image sheet and forming the lenticular.screen directly on :
the image sheet for instance, not only do not adequately '.t,~ elimin.ate alignment problems b,ut create still othe~ ~ifficulties, .; such as poor color reproduction, fuxther change o~ dimension .` of the image sheet, low density o printing inks, low resolu- ~
; 20 tion of the printed imàge and the like, which further impair .~:
the picture quality.
; Attempts hav~ been made to overcome the lam~nating : ~
: and alignment problems of ~he indirect composing step by ~ :
; coating a photographic emulsion directly on the rear surface o~ a lenticular screen and using the "lentlcular film`' thus produced in composin~ the final three-dimensional picture ~.
. from the projected two-dimensional images; that is to say, the ; lenticular ~ilm is us~d in place of the separate composing lenticular screen and photosensitive sheet. Th~ two-.`''~ ' ' ~ .
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:, dimensional Yi~WS are projected sequentially or simultaneously through the lenticular screen to expose the photosensitive emulsion beneath the lenticules. A rudimentary composing system of this nature is described by N. A. Valyus at pages ~03-205 of "Stereoscopy", the Focal Press, London W.l, England (1966); see also U.S. patent No. 3,482,913, granted December 9, 1969, to W. E. Glenn, Jr. Although avoiding laminating and alignment problems, the prior art indirect ~-composing procedures employing lenticular print film have failed to overcome other problem areas in the composing step.
For example, autostereoscopic pictures thus produced have heretofore had limited viewing angles ana distances owing to the necessity of viewing the lenticular screen ~rom the same distance and position that the two-dimensional rames wexe projected during composing. This seriously detracts from the quality of the final picture. It is necesSaTy with known print film composing systems and processes, moreover, to make individual adjustments o~ the composing system bomponents, ` such as the distance between enlarging lenses, the projec-tion distance, etc., in order to obtain acceptable sharpness `
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in the three-dimensional picture. Often this is not pr~perly aon~, with resultant loss of picture quali~y, and in any event is a costly, time consuming operation. Such adjustments are -required, for instance, every time the distance between the camera and the center ~f interest of the object field, i.e., ;~
, the element or point to appear in the plane o~ the three-dimensional picture, is changed. As is developed in ~etail ~
hereinafter, this necessity compels a substantial number of ~` `;
interrelated adjustments. Hcretofore the prior art llas ;
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neither comprehended the ~ull nature of these adjustments ~ -nor provided an effective way of avoiding them or of imple-menting them in a simplified and reliable manner~ The end result has been that the prior art ~las ailed to provide .
indirect composing apparatus and procedures which are capable o producing high quality autos~ereoscopic pictures with effi-ciency and cost ~actors permissive of widespread commercial appIication of the technique.
: The foregoing and other re~uirements of the prior art are ~ulfilled by the present invention.

SU~RY OF THE INVENTION
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~. .In accordance with the invention, the relationships . . between thse taking and composing steps ref~uired to produce hi.gh ~:
. ,~ , quality stereoscopic pictures by use of the ind.irect technique lS 2re established and novel and advantageous forms of apparatus ~ .
embodying these relationships are provided. The result is an ` :~
overall integrated system wherein the various components of.the taking step and the composing step, i.e., the camera, the enlarger, and the lenticular screen, are so constructed and arranged, both individually and in relation to one another, as ;
to afford mar~ed advantages relative to prior art syst~ms in ~.
respect of pic~ure quality and economy.:
One e~bodiment of a camera constxucted in accordance with the.invention.includes a plurality N of lenses for takin~ ~ r a corresp~nding plurality N o~ two-dimensional ~fiews--of an `. object field. The lenses are arranged in a straight path.and -~
. are equi~iistantly spaced apart ~ith their-optical--axes-in~
:parallel. Means ar~ provided ~or ad justing the spacing be~ween '~ ~

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-the lenses as a function of the distance from the lenses to the key subject matter element of the object field so as always to record the image of that element at a particular location on each two-dimensional view. The camera may be either of the adjustable-focus type or the ixed-focus type. : : :
In the former case, adjustment of the spacing between lenses carried out concurrently with focusing of the lenses. This adjustable lens feature.enables ~he spacing between the loca~
i tions ~rom which the respective two-dimensional views are pro- .. ;
jected during the composing step to be fixed irrespective of variation in the distance from the camera to the selected ele-ment of the object field, thereby eliminating many of the costly . and timè consuming adjustment steps required in pri~r ar~ sys- .
tems. Preferably, the spacing between adjacent projection locations is selected a~ a function of the parameters of tXe ;.:
lenticular screen so as to provide a proper image structure in ~ ~:
the stereoscopic pictureO Specifically, the projecting lens . spacing should be su~h ~hat the~N condensed images formed ..
~ beneath each lenticule are spaced apart by substantially w/N.
;~ ~20 Advantageously, though not necessarily, the spacing ~.
between adjacent projecting lens locations is also such that ~ ~ . . ..
- the required separation of the key subject matter element images ~ ~
,, .
; on adjacent two-dimensional views in the projection apparatus is . the same as thè spacing between adjacent image locations in the camera. If so, the ~ilm may be taken from the camera and, after :: ~
developing, placed dir~ctly in the.projection apparatus without : :

the necessity of cut~ting the film to adjust the spacing of the ~;:
individual views.
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In accordance with one broad aspect, the invention relates-to a picture of the type including an image layer containing a multiplic~ty of image bands, each of said image bands comprising a plurality N of condensed images formed by projecting elements of a corresponding plurality N of two dimensional views of an object field taken from spaced vantage points, and an overlying lenticular screen having a corresponding multiplicity of lenticules of width w aligned with the image :-bands, the improvement wherein each of said N condensed images :;
within each image band is of an expanded width greater than the : :
lineiform width m to which the element of the corresponding .
two-dimensional view projected to form said condensed image .
would be focused without expansion by the associated lenticule of the lenticular screen; and the image density of each of said N condensed images is substantially uniform across the ~idth ;~ `
thereof. :
In accordance with another aspect, the invention relates to an image array formed on the photosensitive surface of lenticular print film of lenticule width w, said image array :
consisting of a multiplicity of image bands each of which is :
aligned with a lenticule of the film and each of which comprises -N condensed Lmages formed by projecting through a pro~ecting .
lens and onto the aligned lenticule a portion of each of a corresponding N two-dimensional views of an object field taken .
from spaced vantage points, the improvement wherein each :
condensed image is formed by continuously changing the angle of ~:
projection of said portion of the corresponding two-dimensional :~ m~
view, while maintaining the projected image of a selected element o~ the two-dimensional view in reyistry with a reference point and while maintaining the ratio o~ the ~
distance between s~id selected element of the two-dimensional 3: :
Yiew and i~s pro~eCting lens and (2) the distance between ~ :
. . , : such projecting lens and the lentiGular print film substantially ~ -8- ` ;~

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constant, b~ an amount sufficient to scan the ima~e of said portion over a distance along the photosensitive surface such that said each condensed image occupies a width of substantially ~
w/N, whereby said scanning results in said each condensed image ~.
being greater in width than the ~idth m of an individual lineiform image formed by the aligned lenticule of said portion of the corresponding two-dimensional view, said each condensed ima~,e being substantially in focus and of substantially uniform : imag~ density across the full width w/N thereof.
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BRIEF DESCRIPTION OF THE . DRI~WINGS

For a better understanding of the invention, reference may be made to the ollowing description of exem-plary embodiments thereof, taken in conjunction with the figures of the accompanying drawings, in which: -Fig. 1 is a diagrammatic view of the overall indirect process fox the production of stereoscopic pictures, as practiced in the prior art; :~
. Fig. 2 illustrates certain basic relationships .10 between the el~ments of a photographic scene and the images ~ -: o those elements formed by a photographic lens;
Fig. 3 is a diagrammatic representation showing the'relationships between the taking and composing steps of ~he in~ire~t process;
~; 15 .Fig. 4.is a further combined representation of the taking and composing steps and also illustrating the ef~ect ~ . . of change in photographi,c distan~e on the xelationships between the various taking and composing components;
Fig, 5 depicts in plan an embodiment of a multi-lens adjustable-focus camera constructed in accordance with the ;~
~ invention;
- . Fig. 6 is a vertical sectio~al view taken along the ~:
:~ line 6-6 of Fig. 5; .
, ~ig. 7 is a plan view of a multi-lens ~ixed-focus camera constructed in accordance with the invention;
Fig. 8 portrays a representative single-lens composin~
': systcm according to the invention;

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~ig. 9 depicts the single lens system o~ Fig. 8 in another position of operation; and Figs. lOA~ lOB and lOC illustrate three forms of apparatus fox scanning the projected images from the two- ~
~imensional film frames along the photosensitive surface ~-o~ the lenticular film.

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DETAILED DESCRIPTION

Basic Indirect Process As alluded to above, the indirect process as prac-ticed in the prior art includes basically two distinct steps, a photographing or taking step and a composing step. These steps are illustrated diagrammatically in Fig~ 1 in the con-text of th~ overall indirect process. In the ta~ing step, a series of two-dimensional views o~ an object field, including ;
for example the elements A, K and B tshown fox`simplicity in a straight line), are taken from a corresponding number of photographic vantage points aligned transversely o~ the object ` field. The di~ferent photographic vantage points may be `
established by arranging a number o~ e~uidistantly spaced cameras o~ substantially identical optical characteristics 1~ along a path perpendicular to the optical axes of the cameras.
Alterhatively~ a single ~amera may be moved from vantage point , -to vantage point relative to the objec~ field (or the objec~ ;
field moved relative to a stationary camera), or a single camer~ having a number of objectives may be used. An illus-trative camera arrangement, there~ore, might take the ~orm ~ ~
illustrated in Fig~ 1, with five individual cameras 10, 12, 14, ~ "
16 and 18 positionad along a straight path 20 and centered relative to the objec~ ~ield elements A,--K and B~ Upon-exp~-sure, the cameras 1~-18 produce on the corresponding film ~5 frames 22, 24, 26, 28 and`30, ~espectively, lat~n~ images-of . ~ , .
the object ~ield elements A, ~ and B~ F~r~ clarity, only- the imàges X' produced by the cen~ral light rays tX) are aepicted in Fig. 1. The ~rames 22-30 are then--su-itably processed (developed, trimmed, e~c.) ~or use in the composing step.
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The processed frames (negatives or positi~es~ 22-30, ; bearing the developed images K', are placed in a corresponding number of projectors 32, 34, 36, 38 and 40 which are indepen-' dently adjustable for control of magnification and for align-ment of corresponding images of a selected object field ele- ~, '~ ment from the several negatives. The particular imases , ,` selected for registration during,composing will aetermine the object ~ield element that will appear to lie in the plane of the stereoscopic picture. Assuming in Fig. 1 that this is to ~-be the element K,,the projectors 32-40 are shifted relative ~, ;,, to one another until the projected K' images are aligned with ` a common point on the lenticular print ~îlm 42~ ~ny necessary -'adjus~men~ to establish commonality of magnifi~ation among '~
'~, the projectors 32-40 is also carried out. Thereafter, the prnjector~ are turned on and lineiform images ~'` corresponding to tne K' images from the frames 32-40 are ~ormed on the photo-` sensitive layer 44 o~ the lenticular ~ilm 42 in the well known manner. By ~irtue of the prior alignment of the projected K' ,~
~, images~,all,of *he X'' lineiform images will be formed beneath ,, 20 the same lenticule o~ the ~ilm 42, and indeed such registry of , ~
,, the-pxojected K-'-images-is ~acessary-if sharp-ste-reoscopic ','`~ ~, . pictures are to be obtained~'' ' ' -,',~ ,,~, : ~inally, the exposed le~icular film is suitably ' , processed to`pro~i-dè-~-he--~inal-stereoscopic picture 46 which, , `, 25 upon-viewing, affords t~ the observer an overall view of the !'`!~
~ object ~ield in relie~
,~ Althou~h, as previously not~d,-the ~oregoing-indixect '~ process obviates certain~o~ thè dif~iculties enc~untered with ' ~ ` stilI'earlier ster~oscopic procèduxes,-it-has h~retofore not ', : ~ . .. , ~ . ., .. ~ ~ . ' 1 .:- : -. . ,. . .- . . - .

~ ~ ~ 1 219~6 'been susceptible of widespread commercial use, owing la~gely to ¢ost and quality limitàtion~ arising from the composing step The,,nature and extent of these limitations may be appreciated from an analysis of the'photographic and optical parameters o~ the indirect process. , Overall Indirect System By reference to Fig. ~, wherein a single taking lens or camera location (vantage point) is represented by the :. . . .
' lens 48, certain basic relationships of the taking step can be established. As before, the object field elements to be photographed are designated A, X and ~ and the images of those elements formed by the lens 48 on the film plane 50'are ~esig '~
nated A', ~' and B', respectively. The thin lens 48 is repxe-` sentative of the composite objective lens system of an actual ~'~
i5 camera~ h~ving an optical axis ~2. The line 54 indicates the path o~ alignmënt of the taking lenses or of movement o~ the ,;, ~;~ camera relative ko the ~bject fie~d, as drawn ~hrough the optical centèr of ~e le~s system. 'For conveniencer it is also , ,' assumed that the objects A, K and B are arranged in a straight ,`,~ '' line 56 parallel to and spaced a distance s from the optical ~
axis 52 of the lens 48 and that èlement ~ constitutes the "key ,`, subject matter" o~ the ~ieldO i.e., the element of the field whose image is to appear in the plane of the final stereo- l' ` scopic pictuxe, and hen~e the element on which the c~mera is ,1 focused. Element ~ will thus appear to ~e in the ~ore~round i~
of the final picture and element B in the bac~ground. ' By simple trigonometric relatio,ns, it may be seen ~
that: ~ , .," ~ . ~
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e = ~f~
k-rt _~ sft (2) . ~;
~ ''' a' = se = k k' t3 b7 = se = k k~ ~4) where: e is the distance from the objective plane to the ~ilm :~
plane; ~ ;~
ft ~ 8 the focal length of ~he ~aking lens; ~ .
~ a, k and b are the distances from the ob~ective plane ~
- to the object field ele~ent~ A, g and B, respectivelyJ and ~:
a', k' and b' are ~he distances along the ~ilm plane 50 :~
from the lens axis S2 to the images A', g' and B', respectlvely. :
Equations ~ 4) are applicable to all photographic ..
~antage~po~nts, i~e., to ~11 taking 3.en~ or camera po~ltlon~ -~:
: ~he characters ~ ~ , and ~XBg~ in Fig. 2 xepr~sent the .
. changes over the distance s in parallax, or parallax values~ ;
., along the`f~lm plane 50 bet~een the key subject matter alement .
image R' and the ~oxeground element image A', on the one hand~ ..
and be~een the key.sub~ect matter elemen~ ~mage Kl an~ the :~
background element image 8',-on the other. ~Xs~ i8 the tot~l ~: parallax value change over the distance ~. The v~lue~-of ~X8 "
, and ~ ~ KI are controlled within limits, ~ith ~XKA, and AX~K, preferably ma~e equal for op~imum clari~y and relie~ ~ ;;
effect in the ~t~reo~copio picture. .

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~ ~ ~ 21946 ., , ~laving established the foregoing ~aking-step rela-tionships, it is important to ascertain the interdependence of the taking and composing steps. These further relationships may be determined from Fig. 3, wherein, for clarity, the separate taking and composing steps are diagrammaticaily combined. The order of the two-dimensional views in the composing step of Fig.
3 is thus the reverse of what it actually would be i~ practice.
In Fig. 3, the taking step illustratively emhodies -i four objectives 58, 60, 62 and 64 and four corresponding film 1~ frames 66, 68, 70 and 72. Again, to avoid undue complexity, only the key subject matter element K of the object field is ~ ~
shown. Upon exposurç, the lenses 58-64 fo~m latent images X', ~;
together of course with images (not shown) of all other object ~`
field elements within the fields of view of the lenses, on ~5 'he respecti~e frames 66-7~
The~composing step, then, includes a ~ike number of enlarging (projecting) lenses 74, 7l6, i8 and 80 for projecting the K' images, etc., onto the surface o~ a lenticular print ~`~ilm 82. The lenticular film 82 is composed of the usual plano -~0 convex lenticu~ar screen 84 having coated on its base (the ~ocal plane of the screen) a pho~osensitive emulsion layer 86. The ;; composing screen and photosensitive layer could be separate if desired, or they could be formed separately and bonded or other-wisè affixed together prior to exposure. As is well known, `` 25 the lenticular screen 84 condenses the projected K' images from ~;
the respective frames 66-72 into a corresponding plurality of i ~ -;
linei~orm ima~es K " on ~he photos~nsitive layer 86 which, when the-fram~s and enlargin~---lenses-ar~--properly arra~ged, will be su~st~ntially e~uidis~antly spacçd beneath a sinqle lenticule 88 o~ ~he-scr~en 84. ~pon viewing the developed ~
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lenticular film 82 through the screen 8~, therefore, an observer will see a dif~erent llneiform image K'' with each eye, each o~ which K'` images will depict the key subject matter element X from a different photographic vantage point. --:
If all of the K' images from the frames 66-72 are projected in registry with a co~non reference point, the central pro~
jected rays (K') will pass through the center of curvature 90 o~ the same lenticule 88. The key subject matter element K
will then appear to lie in the plane of the stexeoscopic ~ ;~
picture. Imag2s of elements in the foreground and background ; of the object field, however, will not be projected in registry and will therefore be recorded beneath different lenticules of i the screen 84. Hence, the observèr will perceive those ob- ;;~-~
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jects as being either in front of or ~ehind the key subject ~ ;
matter element, as the case may be, and-consequently wiil appear to see the over~ll image of the ob~ect field in dimension. ; `~
Fig. 3 of course depicts the positional relationships between ~he key subject matter element ~, the taking lenses 58-~4, film frames 66-72, the enlarging lenses 74-80, and the ;
lenticular film 82 when all of those components are properly arranged to form on the photosensitive layer 86 all of the key subject matter element images K " beneath the same lenticule 88 -and spaced across substantially tha full width of and symmetri-cally within the lenticul~ If this arrangement is not sub-stantially achieved, loss of quality in the final picture, e.g., blurrAd images, limited ~i~wing angle, unsatisfactory ~hree-dimensional effect, etc., results. But the precise arrangement -'. ~

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of object fiela elements, taking components and composing components portrayed in Fig. 3 rarely exists in practice, necessitating the aforementioned complicated and laborious adjustments during the composing step. Moreover, ~he prior S art has not fully comprehended the nature and interdependency of the adjustments which must be made. In accordance with the present invention, the relationships ~derived below) existing between the various components when properly arranged ~as in Fig. 3) are utilized to provide improved t~cing and composing techniques and apparatus which overcome the limita~
tions of the prior art~
Returning to Pig. 3 and considering for convenience only the lenses 58, 60 and 62, the center-to-eenter spacing between lenses 58 and 60 is designated Tlt th~ center-~o-center spacing between lenses 6Q and 62 is designàted T2, and the spa~
ings between the corresponding K' images on ~rames 66, 68 and ~ ~
70 are designated Dl and D2, respectively. . `
By trigonome~ri~ relations it may be demonstrated that:
i~ ., :.', Di = Tl-k + e , and (5)

2 ~2 k k ~ (6) ` ' ' ' ! ' "
Where-the lenses 58,-60-and-62-are equidistantly spaced, Tl equals T~ and Dl-equals D2. Hence, the spacing ~ ,between the K' images on adjacent ~rames is equal among all 25 ~ of the frames 66-72 when th~ taking lenses 58-6~ a~e equi-distantly spaced. Th~s relationship exists as to the images of--a~l-object~ id-elements in the same plane--as-~the element :,;, :
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K, i.e., all such co-planar images will be spaced apart by .
; the same distance DK,. Accordingly, a general expression for the distance between the images on adjacent frames of ~-corresponding object field elements.co-planar with.the ele~
ment on which the taking lenses are focused, where the taking ~ .
lenses are equidistantly spaced apart by the distance T, may be derived from equations ~1) and (5) or (6) as~
. DK, = T k + e - T k ~7) Similarly, the spacings b`etween the adjacent images ~ ~.
~ any foxeground object element, e.g., element A in Fig. 1, ` :
~ or any background object element, e.g., element B in Fig. 1, ....
.~ and of any other ohject field elements in the same planes, can -~
~e express~d as.: .
DA~ ~ Te+ T r ft l k t8) I`l 15 D ~ ~ T ~ T ~ ft 1 k (9) ~~ ~tl `'; .
Turning brie~ly to the lenticular-~ilm--82~ the . pertinent parame~ers.o~ hè lenticules~_-according.. ~o wel-l:knQwn : 20- lénti~ular lens=theory; are--as follows:~
~ z = j~n ~10) P.= 1 (1 ,. w - ~ :
~1 r = j~l-l) (11) 0 = 2arctan.-nw-- .. (13 wher.e: ~ is:the-thickness o~ the--lentrcules;-- n is the index.. o~-re~ra~ion-of~the screen materinl;
`-; 25 . r i~ ~he radius o~ curvature o~ -theiindi-vidual-lcn~
. ticules;
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P is the number of lenticules or lines per inch;
a is the viewing angle of the lenticules;
z is the distance between the center of curvature ~ . . . .
of the lenticules and the ~ocal plane of the screen; and S w is the width of an individual lenticule.
Considering now the composing step, it can be estab-lished *hat the distance g ~etween the plane of the enlarging ;~
lenses 74-80 and the plane of the frames 66-72, the distance h between the enlarging lens plane and the lenticular film 82 (actually the plane of the centers of curvature of the lenti~
cules), the center-to-cènter spacing a between adjacent en-larging lenses, the focal length fe of tha enlarging lenses, ~, ,:, . . ......................... .. . ,. .
the size u of the usefùl image are`a of one of the rames in a - directior perpendicular to the lengt~wise extent of the lenti-~ules-ol the film 82, ana the corresponding size v of the final steraoscopic picture/ are related as ~ollows~
h + z = v/u (14) ,; . . ... ~ :. ~. .
.; ~ ., T~pically, h will be ver~ much greater than z, so that in effect h~g = v/u ~15) ;
Equation (15) gives the magnification factor or enlargement ratio, hereina~ter termed R, o~ the enlarging system.
Moreover, ~ and h are also constrained with fe in ;~ 25 ~ccordance with~
1 ~ 1 = 1 , or ;~
g :~ .
: . . . :: ~ -,., g h~e tl6) h ~ ~e ~
* ~,, I ' 219~6 ,_. .
~0~

Hence, by combining equations (15~ and tl6). h -' may be expressed in terms of the focal length fe of the - enlarging lenses and the enlargement ratio R: ' -~ h = ~e(R + 1) ' -~17) ' -~
'' ' . ' '''';'- ;`'~. '.
' 5 For the combined taking-composing condition o~ Fig. '` '

3, i.e., where the taking lenses 58-64, the frames 66-72 and ''`~ ' the enlarging lenses 74-80 are àlL arranged so as to register each of the K' images with a common reference point, the respec-; tive spacings ~ and D of'the enlarging lenses and K' images are ~ 10 related according to~
; d = Dh ' (18) '' h ' Incorporating equations (7) ànd ~18):
.``~ d - T 1 + e/k ~ (19) 1 ~ g/h -~
It is apparent from equation ~19) that even where : ' '15 e o~ the camera and ~ and'h of tha ~nlarging system are held constant,'the xequired spacing d o~ the enlarging lenses will ' still vary with the photog'raphic distance k to the key subject -ma~ter element K and the spacing T o~ the taking lenses. 'In normal photographic usa~e, k is o~ course almost infinitely variable. For widespread application of the indirect techni~uer ... ..
therefore, appropriate provision must be made to take this ' factox into account in a rapid yet reliable and economi~ manner.
',! It may further be demonstrated ~rom consideration ' of Fig. 3 that the optimum lenticule width w of the lenticular `~ .25 ~'screen 84 also vAri~s as a fu;nction o~ the enlarging lens "~
;~ spacin~ d and ~l~ncc of the photographic distance k. Desirably, ;~
.,., . '~
'~

, -20- ~
,. 1~ ~ `

~ 46 ," (~ (' '' . ~ .
~Z~

when a stereoscopic pictuxe is viewed through the viewing . screen there should be no discontinuities cr interruptions in .. the overall image o~ the object field (resulting, or example, from gaps between adjacent lineiform images or ~rom over-lapping lineiform images) presented to the observer regardless :
of the position from which he views the picture. That is to `:
say, the images of correspondin~ elements from the respectivP
two-dimensional frames condensed beneath each lenticule should .. :
just fill up the.area beneath the lenticule without overlapping; ..
The relationships productive of this image arrangement may be .~
. . .
seen by reference to Fig. 3 and by consideration of the linei- :
form images o~ the key subject matter element K and of other :~ -alements in~the same plane as the element K.
`` In Fig. 3, the distance spanned b~ the images K'' .-.~ 15 beneath the lenticule 88 is given by ' `: i . x = zd N ~ o) .~ `:
. ., : . . , . :`. ', where: N is t~e number o~ two-dimensional frames.. ~ . :
~hen, let L' represent the element image on the ; frames (shown only on frame 66 in Fig. 3 for clarity) whi~h is focused through the lenticu-le-92--next *o lenticule 8~ so as to form thereun-der--the lineiform image L " . The spacing I between the K " image.and..the L'' image-~rom the same frame, e.g., . :
frame---66,-is given by: ~ `. ~:~
:, .
I = wtl ~ z) ~1) ., . ~ :
To avoid im~e discontinuities and overlappin~ in :
the composed stereoscopic pictur-c, each.lineiform imag~ on the . : .photosensi~ivè-sur~ace 86 ideally-wilI occupy---~ distan~e - .. .~;
. ' . ., " '.';
`''~

; -2~- .:
' ~
.
.

, .

x,J (N-l) . The pre~erred value of I would thus be: :
X = N x t22) .
N~

'; The optimum lenticule wid~h w is'then that w which satisfies equation ~22). This can be had by combining equations t20), (21) and (22): -w~l~z~ = Ndz/~ .
h and, since h is much greater than z, for prac~ical purposes: ', , w - Ndz/h = Ndj/nh S23~ -; It may be appreciated that i~ w is selected according ~`:
to e~uàtion (23), the'entixe area of the lenticular film will ~e filled with lineiform image elements which are.contiguous but which do not overlap, and that a c~ntinuous unintarrupted . view of the ~bject field will thus be presented to the observer.
. ~ . ,: .
' Howaver., it follows from e~uation~ (23~ and (l9) that the ' i~-,', 15 optimum value of w vàries with d, an~ thus with k, so that "~
it is not only necessary to account for the change in d . occasioned by chan~e in k, but to account as well for the ., .~
; accompanying change in the'required value of w. -Otherwise, ,~
the--linei~orm--images K! '., etc., will .no.t~bP properly placed ~ -to provide the aesired uninterrupte,d picture configuration.
' Although for p~rpos2s of illustration the indi-,.: :
vi~ual ~"~and L" linai~orm images are shown-in Fig. 3 as . , .
` ~ully-coverin~ the distAnco I/N (i.e.j- w~N), these image~ -:~ ~ .
are in faot well-~ocused and condensed by the enlarging lenses ~ :
and the lenticular scre~n. In the ,usual case,tlley are , ' : `
' ~
-2~ : :
` , , - - ~ ,. ~ ~

:
`~

~5~

in reality very narrow line (`'lineiform") images o considerably less width than that depicted in Fig. 3. To avoid discontinu-ities between lineiform images, therefore,.it is desirable to expand or scan the individ~al lineiform images over the dis-tance x - m, where m is the width of each unexpanded linei-form image. As one feature of the invention, metho~s and apparatus are pxovided for this purpose, as is described herein- -. .
after. Also, it is possible to select the parameters of thelenticular screen and to arrange the enlarging system such that stereoscopic pictures of acceptable quality are provided without -expansion of ~he individual lineiform images. Generally, there- .
fore, the invention a~fords improved apparatus and methods for implementing the indirect process whether or not image expansion is utilized in the composing stage, although for maximum advan-~ tage it preferably is. - .

- . Adjustabl~ Camera The invention provides, ~s one way of overcoming the aforementioned prior art limitations, a multi-lens camera in which the focus and spacing of the lenses are simultaneously ad]usted so as always to maintain the proper image relation- ;~
ship among the several film ~ram~s for allowing composing o ~.-a stereoscopic picture to be carried out without necessitating adjustment of the enlarger components or of the lenticular film . : :
paramaters regardless o~ change in the.~photographic distance k. .~ ~
~, ,That is to say, the camera permits the photographer.to focus on 'r'' '`~
any object ~ield element o$ his choice without requiring adjust~

ment or red~si~n of the ~nlar~ing-lenticular film system for ~:
each ind~idu~l value o~ the photographic dis~nce-k.
:-".. ..
t ~

t - 23~
. ' '- ~ . , ~ :, ,.
; . 1:,.
"

21946 ,.~
f ~:

~, , 1~)5'~3L60 .
locations Oll the respective two-climensional frames 106-112. .
This in turn requires certain adjustments in the camera 96, the nature of which may be more fully appreciated by con-sideration of what happens when the photographic distance k S is changed without such adjustments being made. ~.
~ssuming the camera is to be focused on an object :
field element K2 ~see ~ig. 4) spaced a distance k~ from the . objective plane 94, it may be seen that the objec~ives 98- ;`
104 will have to be moved a distance ~e (greatly exaggerated ~or clarity) from the plane ~4 in which they wer~ located when . focused on element Kl in ordèr to bring the images of the element K2 into sharp focus on the ~ilm plane 127. If e ~.. .~.
alone is changed, however, the images K2 of the element X2 (considaring~now only the ric3ht hand frames 110 and 112 and assumin~ ~oth are lar~e enough to receive the K2 images~ ~'7i not fall on the same locations`on the frames 110 and 112 as .
did ~he images Xl. Hence, they will not be in the proper positional relationship relative to the enlarging lenses 118 and 120 for registry w.ith the center of curvature 128 of the 20 lenticùle 124 and will be projected instead through the point ~ :
130. This departure ~rom the correct locations o~ ~he K' images may be avoided, according to~the invention, by ad~usting the.spacing ~ be~ween-adjacen~ objectives 98-104-of-th-e--~c~m~ra 96 i-n correspondence-~ith-t~e adjustment in e. This further adjustment is illustratad in the left hand side o~ Fig. ~
; Assuming a~ain that.the camera is to b~ ocused on -`~ X2 and the o~j~c~iv~s 98 -~nd 100 are.moved fo~ard by-~e t~ :~
: bring the imag~s X2-o~--that elament into sharp ~ocus on the frames 106 and 108, it will be apprcciated that in order to . ., - -25~

` - . . -.... . .- . . ` . - ~ .

~L05~

The manner in which thii~ is accomplishea is portrayed in.Fig. 4, which also il~ustrates the consequences of ~ailure. ~ :
to make such adjustment of the camera lenses. .:
~ In Fig. 4, Kl is ~ key subject matter element located .~ .5 a distance kl from the objective plane 94 of a camera 96 in- ;
cluding, illustratively, four objectives 98, 100, 102 and 104 centered on the element Xl. It is assumed that with the objec-tives 98-104 in the positions indicated in solid in Fig. 4 t the camera 96 is focused on the element Kl so as to form on the film ~rames 106, lOB, 110 and 112 sharply focused images K
; of that element. As previously shown,.if the objectives 98-104 ~`.
: . are uniformly~spaced by a distance Tl~ the images Ki on the : film ~rames 106-112 will be uniformly spaced apart by a dis~
. tance D, The enlarging lenses 11~, 116, 118 an~ 120 of ~h~ : :
S . erlarger 1~2 will then be corxe~pond.in~ly spaced apart b~ a dis. ance d so as to form the lineiform images Kl' evenly oYer . the width w of a lenticule 124 of the lenticular film ~26, as ,~
previously explained~ In accordance with the invention, all ~ . .. .
. ......... components:from the frames 106-112 on back are held in fixedposition regardless o~ variation in the photographic distance ..... ~:
k;-that is to say, the parameters o~ the enlargex-lenticular ~ ~ilm system, e.g. d, ~, h,--w, r, z and i~ remain cons~ant . `.~:
r regardles-~ of change.in the photo~raphic' distan~e.k~ thereby ; eliminating-the trQub-lesome-adju`stments he-E~tofore foun~
nece~sary in the composing s~ep.
.~ It-is clear from~inspeGtion of ~ig. 4 tha~ in order ..
~or the e~larger-lenticular ~ n system to bet in ~f~ct, stan~
dardized in this way, the im~ges ~' of the key subjec~ m~tt~x element (the -projected imaS~ hich are to be held ~ in registry 30--- during-enl-argement) must-a-l-ways--be--~ecorded-at-the-~m~
., .

;~ 2~
: ' ` 1 -::
: j.

l 219~6 :, , ' ' . ', form the images K2 at the same-locations on th,e film .frames 106 and 108,as were the Kl images the spacing between the ,objectives 98 and 100 must be changed ~rom Tl to T2. In other'words, the objectives 98 and 100 must be moved from ~' the positions shown in solid to the positions shown in dashed ' , lines in the le~t hand si~e of Fig. 4. The distances by '.
which the objectives 98 and 100, and the correspondingly ~' .
~ ' located objectlves 102 and 104, must be moved may be appre~
: ciated from consideration of equation ~19): :
d - T 1 ~ e (19) .',` 1 ~ g ' " ~, h ' With a fixed enlarying system, ~,' h and d are con~
'j , stant regardless of variation in k. ilence, for all ~alu~s of ,~
.' k the quantity T(l ~ e/k) must also be constant. As k~w, t~e ~ :
quantity T(l + e/k) also -3T~, so that ~or T~ equation (19) ~ ;
. . becomes: -,, , d - T~tl-~e/h) = T~ (24) ~
~ g7h ~,, ., ' . ~
Since a remains constant for all values of T, the : 20 taking lens spacing T may ~e expressed, combining equations ~
. . (19) and (24), as ~ollows. ,. :, . . T = T~ = T~k ~25) ~ ,~
: 1 ~ e/~ k ~ e . '~ ~:

Then i~ the change ~T in lens spacing is defined 25. , as T~-T:
k ~ e ~- ~6') ,~ ,~

' -26-., . 1`--:
~:
. ~........ . , . , . -and the several taking lenses must be moved accordingly to effect the necessary change in T. ~or example, in Fig. 4, where thexe are our lenses g8-104, and assuming that the distance kl = ~ so that Tl = T~, the distance o by which the objectives 100 and 102-must be moved cin opposite directIons) is AT/2 and the distance p by which the ob~ectives 98 and 104 must be moved is 3~T/2. The distance of movement of the indi-vidual taking lenses is of course dependent upon the number ~;
of lenses employed in the camera and their locations relative ~ :
to the center line of the lens array. In any event, the spacing ~ :
T between adjacent lenses is changed in correspondence with the change in k and the change in e so as always to form the images K' o the ob;ect field element K on which the camera is focused at the same location~ on the film frames, ther`eby always . ~
maintaining the images K' in the proper positional relationship ~
relative to the enlarg~ng lenses for correct c~mposing............... i;.~ .;
Considering now ~e with more particularity and recalling e~uation (1), it will be appreciated that even for .
short photographic distances, e.g. k = 4 feet, k will be much ~
-20 greater-than--ft,.e.g. 25 mm, and therefore that: ~ :
~-: e Y ft(l ~ ft/k) Y ft ~ ft / :~
Since.e = ft when.k = ~, the.change ~e from the smallest value e~ to some larger value e required in order .
: to focus an object ~ield--element=-at--a distance k on-the ~ilm ;
.~ plane of-the camera is:
~e = e - e~ Y ft2/k (28~ ~
. , :`'' ` '~' -,,^,~
: . . '.'''~' ' ' 30 - ::. :
` `;- ~ ?

:~ . .~ :-, -27- . ~ ~
.~i ~
. ~, ~: ~
:' . 1.~

~u~
Hence, ad~us~ment of the camera len~es both ~or focus (~e~ and for horizontal sp~cing (~T1 in accordan~e wi~h variation in photographic diatance k to the o~ec~ field element focused on may readily be achieved by means of any convenience mechanical lmplementation of equa~ions t26) and (28). Advantageously, though not necessarily, ~oth adjustments are carried out simultaneously, as for example through a mechanism linked to the rangefinder of the camera. Representative apparatus for this purpose is illustrated in Figs. 5 and 6.
Figs. 5 and 6 depic~ in diagrammatic form a camera 132 including five obje~tives 134, 136, 138, 140 and 142 arranged w~th their optical axes parallel and their opt~cal centers in a common plane. It will ag~in be understood that the thin objective lenses illustrated are illustrative only and that composite lens systems would normally be employed. The camera may be provided with any ~ppropriate film ~dvanoe system for advancing ~ive fllm frames lnto registry with tha object~ves 134- l~
142. Likewise~ the CamerA i8 provided with a suitable shutter ~:
system, indicated ~chematically ~t 14~ in Fig. 5, which may for .
. . . . ~
exzmple be of the blade-type. ~lternatively, individual shutter~; preferably electron~cally controlled, may be provided.
The shutt~r eystem ln el~h~r case may be ~rranged to make ~11 :~
ive exposures-simul~aneously-to allow selective exposure o~ the-several lenses.

~,.; . : ~ .

~; ,.

. ~
,~
:. -28-.,': , .
~, . '~:
.' . .'~
;.~ ::

~ 05~

The lenses 134-1~2 are individually carried by mounting blocks 146, 148, 150, 152 and 154, respectively, -which, in accordance with the invention, are mounted within the camera 132 ~or movement both in the piane of the lenses and perpendicular to the plane of the lenses. To that end, the blocks 146-154 are captured between an upper cam plate 156A and a lower plate 156B which are fixed to the camera housing. The cam platçs 156A and 156B are formed with ver~ r tically aligned cam slots 160A and 160B, 162A and 162B, 164A
and 164B, 166A and 166B and 168A and 168B,and the lens mounting blocks 146-154 carry upper and lower lugs or cam ~ -followers 170A and 170B, 172A and 172B, 174A and 174B, 176A
and 176B and 178A and 178B which are received within the~ -corre~ponding cam slots 160A and 160B - 16~A and 168B, respec- `
tively. ~s all of the lenses 134-142 move the same distance l-tow~rd ar.d away from the ~ilm plane and certain of the lenses ,-~
move through different distances parallel ~o the ~ilm plane, the cam slots must be inclined acc~rdingly. For example, ~or t,``~
the five lens arrangement of Figs. 5 and 6, wherein the end- t~
2~`- most lenses 134 and 142 move la~erally twice as ~ar (2~T) as the inner lensès 136 and 140 (~T) and the center lens 150 j~
does not move laterally at all, the endmost cam slots 160A
and l60B and 168A and 1688 are inclined relative to ~he objec~
tive plane at half ~he angle o~ inclination of ~he inn~r ~am j-~
slots 162A and 162B and 166A and 166B. The central cam slot 164A is o~ course perpendicular to the objecti~e plane.
Since the lenses 134 and 136 move in ~he opposit~
direction ~rom that of lenses 140 and 142,-*he cam slots 160 and 160B and 1~2A-=and=162B ar~ oppositely--inclin~d rel~ive ~-2~- .

. ~

: .~ :: : . ::. . .

t 2l946 ~5;~

.
; to the cam slots 166A and 166B and 168A and 168B. Preferably, . the lengths of the cam slots are such that their ends define the desired limits of travel of the l~nses 134-142. These may readily be determined from equations (26) and (28) once T ~ ft and the minimum desired value of k are selected. The inclination of the inner cam slots 162A and 162B and 166A
and 166B needed to provide the appropriate incremental change in for each incremental change in T may be determined by solving each of equations (26) and (28) for k,~equating them and rearranging the terms as: ;
e = ft _ ~29) The inclination o~ the endmost slots would then ~ -simply be hal~ that of e~uation (29). :
.` To effect the desired incremental changes in the -camera foous and lens spacing with variation in the photo~
graphic distance k, each o~ the lens mounting blocks 146-154 is carried b~ an adjustmen~ control rod 180 having ~t one end an adjustment control knob 182 for manipulation by the photog~
xapher. The endmost blocks 146 and 154 and the inner bloc~s 2Q 148 and 152 are threaded internally to receive correspondingly threaded portions of the rod 18Q. So that the endmost blocks ~`
146 and 154 will be moved laterally twice as far as the inner i blocks 148 and 1~2, the pitch of the endmost threaded portions , 184 ~only the left-hand portion is shown for clari~y) is twice ~5 as great as the pitch of the inner threaded portions 186 and 188. Tha threaded portions on either side of the central lcns 138 arc of course o~ op~osite lead. The central mounting block 150 is not ~hread~d to the rod 1$0 bùt preerably is -.. . ~: -: _ 1.

fitted closely thereto for rigidity. The thread pitches employed may be selected according to the fineness of the adiusbment desired; e.g., the outer threaded portions may have a pitch o 1/28th inch and the inner two portions of 1/56th inch.
The adjustment control rod 180 is linked to the . .~ ,, - camera rangefinder, conveniently of the coincidence-type com~ined rangefinder-viewfinder. This may be done in any `~
suitable manner well known in the art. For example, the movable element 200 of the rangefinder could be coupled through a cam plate 202 to a cam ~04 carried by the control rod 180. This linka~e would be arranged such that when the ~ ~-camera is focused a~ infinity the spacing T between lenses would be at the maximum and e would be at a minimum, i.e., T - T~ and e ~ ft. Thus when the camera i5 focused on any object closer than i~finity, by manipulatîon of the control ~ ~-knob 182 as governed-by-the range~inder 190, the camera ~
.::
objectives 134-142 would be moved :Laterally and forward in accordance with equation (29) so as always to maintain the de~ired image positions on the respective-=~-ilm-planes. It will be_appreciated that wh~rever the rod-180 passes through~

., a structural-member of-the-camera housing, the housing will .
be appropriately slotted to accommodate forward and rea~Yard movement of the rod.
.
~ 25 -- Fo~-simpler cameras i-n--which fo~usin~ control ~ ~
., ov~r a range-o~ photo~raphic distances is not required, ~ ~; ~
as fo~ instance in a genaral usa~e snapshot-typ~ camera ~ ;

~ having a comparatively shor~ ~oc~l }en~h lcns, the ~ocus~
; ing adjustment featur~ may be eliminat~*-an`~-the -desired- `~

.' :
! ' i~

- 2]946 ~;~5;~l6~
image relationship among the film frames maintained by cont~ol of lateral ~ovement o~ the lenses alone. A fixed-focus camera of this cons ruction is depicted in Fig. 7, and may generally be o~ the same construction as the camera of Figs. 5 an~ 6 e~cept that the cam slots for guiding movement of the lenses ;-are oriented parallel to the objective plane o the camera.
Thus, in Fig. 7, th~ upper cam plate 206A ana the lower cam plate 206B are provided with endmost slots 208A and 208B and 210A and 210B of twice the lateral length of the inner cam slots 212A and 212B and 214A and 214B. In this case, the central lens is fixed against both lateral and focusing move-ment.
Since there is no change in e in the Fig. 7 embodi-ment, e baing selected to focus the lenses at some preferred distance, say 10 ft, the total change ~T in the Iens spacing from ~ to some smaller valua of ~ corresponding to a photo~
yraphic distance k ~f less than inf:;nity will b~ slightly smaller than in the embodiment o Figs. 5 and 6. For the . .
- fixed-focus camera, ~ becomes, modifying equation (26):
/~T = T~ f . :
t (30) k ~ f~

The endmost lenses in Fig. 7 would therefore be moved laterally a maximum o~ 2~T -from equation t30) and the inner lenses would be moved a maximum of ~T from equation ~30), 2S and ~he cam slots-208A and 20~B 214A and 214B preferably are ~;~
; correspondingly sized and looated relative to the calibration of the range~inder 216 to de~ine these limits of travel. The ~ "
values o~ ~T ~rom equation~ ~2~3 and (30)- will be vir~ually -`~
the same ~or short focal length lenses or for compa~a~ively ~' ., ` . . ',~
-32- ~
1,,,,~. .

~ LO~
long minimum k distances, and equation (,26~ could be used in these 'circumstances bvth ~or the adjustable-focus and the ixed-focus cameras. At short key sub~ect matter distances and/or with 'lon~ I'ocal length cameras, equation ~30~ will afford more accurate spacing control.
If an illustrative ~alue of Tco ~or the ad~ustable-focus `~ ~
camera of Figs. 5 and 6 is 22.0 mm and ~he minimum key subject `' ~ ' matter distance k of interest is taken to be 6 ft, values of ~T
and ~e are (from equations ~26) and (28~ assuming ~t is 25mm) ' 0.301mm and 0.342mm, respectively. The range~i:nder' linkage to the adjustment control rod 180 and the threaded connections !~
be;_ween the rod and the lens mounting blocks would thus be designed to move the endmost objectives 134 and 142 through the "' ~' lateral distance 0.602mm and the inner objectiv~3s 136 and 140 ,-through the distanoe 0.301nUn upon mov~nent o the focusing control knob from the position corresponding to infinity to the ' ?~
position corresponding to 6 ft. Simi:larly, the 'cam slots 160A ;'-and 160B, 162A and 162B, 1661~ and 166B and 168A and 168B would '',;~
.... .
be inc~ined relative to the objee:ti~e 'plane so as 'to produce a 20 corresponding change in e from eCO of ~5mm to e ~or 6 ft of ,~ ~25.3421ran, with incremental changes in e and T over these maximum ~,. ~
distances being related in accordance, with equation (29). ",~
For the fixed-focus camera of Fig., 7, a representative ~
- initial or maximum len~ spacing T~ may be 22.0 mm. For this ,' value, and again assuming an ~ oE 25mm and a minimurr~ k o~ 6 ~t, , the magni~ude ~T rom eqùation ~30) is 0.297mm. The rangefinder ' ~
and adjustment control rod 180 would in this case be linked to ~';;
`' provide lateral '~

~:~ . ,:
`, ~`''' ,' ., '.',' ' ~ .. -:
33- ;'', ''~ ~'' ,' ' . : . ,,'' ~ .

- 1~5~;f~
movement of the endmost lenses over the total distance O.594mm and of the inner lenses over the total distan~e 0.297mm, with . appropriate incremental control thereover.

` ~' .

.. , ~ .

:. , '.. , :
:.` ,,.;. ::
!:~
~:: 20 :~:

, ~ .
01. :; :

. ',', ~ ~"~
~,, ` ,: , :i 30 .'.
:

, -` : -3~-. 1,~

~ ` -ilL~5 Extended Enlarger Lens Spac`in~
.
If it is deslred to use a lenticular screen having a viewing angle greater than that which will be accommodated by :
the maximum permissible or desired camera lens spacing, or, for example, where a single lenticular film configuration is to be used with cameras having different lens spacings, a single-step :
projection system construc~ed generally in accordance with Fig. 4, but having an extended spacing d between adjacent lenses, .
.may be used. ~his is done by increasing the spacing d by the distance , ~ ' : ?

"'',''~

~0 ....

. ']
,~

30 ~

; ~ _35 necessary to satiqify equation (23) :Eor the lenticular screen at hand.
Exten~ion of the enlarger lens spacing in a multi-lens systemi such as that depiated in Fig. 4 of course necessitates a co~r2sponding extension of the spacing D between adjacent film frames, as provided by equation (18). This may readily be accomplished by cu~ting the two-dimensional film strip and pla~ing the individual film frames in the proper position relative to each enlarging lens. ~:
: 10 S~n~le Lens Enlarger As an alternative to a projection system having a number of lenses corresponding to the number of lenses in the camera, a system employing a single projecting lens may be us~d.
Such a system is illustrated in Figs. 8 and 9, wherein a projection housing 21~ supports an enlarging lens 218, a negative carrier 220 and a lamp chamber 222. A film strip 224 from one ;~ o the previously described multi-lens cameras, bearing, for :~
example, four two-dimensional frames 226, 228, 230 and 232 is ,~
~ 20 .. ~ ,~,.
`~

i~ 3~ ~ ~
~` ':"
i~ . ~.
. , ~. , .
., ~ ~`

'i,i . . '~

~ ~t4b . ' ~ ' ,, '~
9~5;~

supported by the carrier ~20 in any convenient fashion. A ~' single-lens system of this nature is especially useful, for ~, example, when the viewing an~le ~ of the lenticular film re-quires an extended projection lens s,pacing and it is not desirable to cut the film strip for individual placement of the several film frames. The embodiment of'Figs. B and 9 depicts this situation. ' ' ',~- ?
At the beginning of thè composing step, the carrier --220 is positioned relative to the enlarging lens 218 and the ~
lamp chamber 222 such that the projected image of the X' image ~' -'on the first frame 226 is projected in registry with the pre~
' selected reference point. Hence, prbjection of frame 226 will ~' i,' '`, result in the recordation of a corresponding image K'' benea~th ' '~
- lenticule ~34 of the lenticular film 236. As the two-dimensional ;';'~
is frame 226 represents one endmost view of the object field, the ' ~ -, imase K'' is,recorded adjacen~ one edge of the lenti~ule 234. ~
: . . .
After projection of fràme 226, th,e Iamp chamber 222 is turned off and the housing 216 is shifted i`n.the direction of arrow ~;
238, as for' example by means of step,ping motor 240 coupled to , ,~
the housing by an appropria~e mechanical linkage 242, by a distance sufficient to move the lens--218 from the position ,"' sho~n in ~ull lines-at 244 in Fig. 8 to the position shown in "~
phantom lines at 246. That is to say, the lens 218 is shifted ,"' ', through-the distance d so ~hàt it-will be in the proper position ~
~or projection o~ the K' image on the next frame 2~8 through ~ ,, the center of curva~ure of len~icule 234. The shifting distance d of the lens 218 is detcrmined in-the same manner-as-with the m~lti-lens enlargor--~f Fig.'4 and, once determined, need not ;~'~

be-changed dur-ing composin~.
' .. ,. :' ;~
' . ~, ~37 ,' . i. .- .: . . . . : . ~ . -j 219~6 The lamp chamber 222 and the film strip carrier 220 are also moved in the direction of arrow 238 along with the housing 216 and, upon completion o:E such movement, are in the positions illustrated in Fi~. 9. In order to maintain the proper positional relationship between the frame 228 and the lens 218, however, the film carrier 220 must be shifted in the . direction of arrow 248 through the distance D between the R' images on the ad~acent frames 226 and 228. The value of D in this .
` instance is determined by the ~amera lens spacing and may be : 10 ~ound fxom equation ~24~. A stepping motor 250 and mechanical . .
linkage to the carrier 220 may be provided for this purposè.
When the lens 218, lamp chamber 222 and fr~me 228 -~
are positioned as in Fig. 9; the lamp chamber 222 is tùrned on ~: and the im~ge of frame 228 is projeoted onto the len~icular :. 15 film 236, thereby forming a second lineiform image K " beneath ~he lenticule 23~ spaced by substantially w/N from the ~re~
vi~usly ~ormed image ~ " from frame 226.
~hereafter, the fore~oing procedure is repeated for :. .
:: frames 230 and 232 until ~our lineiform images K'' have been recorded benPath the lenticule 2i~. Of course, lineiform images ' of other elements o~ the two-dimensional frames will be recorded ~:
~ beneath other lenticules of t~e lenticular film 236.
: If desired, the fore~oing singLe lens composing pro-cedure may be fully automa~ed; i~cluding the feeding and with- :~
drawal o~ film strips to and ~rom the ~ilm strip caxrier 220 and ::.

the feeding and withdrawal ~of lenticular film to a~d ~rom the . :`~
- exposure station. Also, additional film strips may be-axranged : ; .
: in parallel on ~he carrier 2~0 and proje~ted by use o~ a c~mmon lamp housing 22~ In ~his case, additional enla~ging lcnses .
:~ :
~ _. ~` :
.. . ~
. ` 38- ~ `

. ~ ~

~s~
and lenticular ~ilms would also be arranged in parallel, thereby enabling s~multaneous composing o~ plural sterebscopic pictures.
Such pictures may be of the same photographic scene or of - different photographic scenes, as will be determined by the ~: image in~ormation on the two-dimensional film strips. In a like manner, automatically controlled parallel film frames, enlarging lenses and lenticular films could be used in the multi~lens composing system of Fig. 4.
~echanical arrangements of the s~ngle-lens system .
' 10 other than that illustrated in Figs. 8 and 9 may also be : employed. For instance, instead of a movable lamp chamber ~ -222, a series of appropriately loca~ed, ~i~ed lamps could be :~ .
used, or a common large lamp chamber might be employed.
Sin~le Lens ~amera '~
As a further feature of the invention, signi~icant :~
' advantages relati~e-~o--~he-pri-or-art-may---~e-real~zed.by use'of . '~
.. either the multi-lens composing-procedure or the single~lens . composing procedure described above to compose stereoscopic ;'~ pictures from two-dimensional views taken with a conventional ;~
'. 20--; single-lens camera. -In this..case,-the sequence of-.two~
' dimensional views-is--preferably:taken by.moving.thè'camera along "`~
., ~ .;,: ~ .
a straight path-transverse -to the-obj-e~t-field. . ~'; '~

For the-:-purposes of-composing a stereoscopic picture '-.. '';~.. .

from two-dimensional ~rames taken.with a single~lens camera-~

` the film feeding characteristiss-Qf the:camer-a-must be taken .1 , .'' ' ., 1 . : ~

. ,~
30- --, ~ '"
' ; ~ ' .,'' ., ~ ~
'~:

into account in determining the spac~ng d o~ the enlarging lenses. The center-to~center spacing o~ the film frames within the camera is not To as in the cam~ras o~ Figs. 5~7, but is instead a value TS determined ~y the film feeding ~-characteristics of the camera. The corresponding spacing, here denoted Ds, between the K' images on adjacent frames is therefore equal to the value ~ TS plus the distance which the : K' image shifts along the film frame between adjacent two vantage points. Thus, Ds = Ts ~ T ft (31) k ~ ft where the last term represents the distance which the K' image shifts, and is readily determined from equation ~2~ by substituting T, the distance between camera locations along the straight path, for the term s of that equation.
; This change in the relationship of adjacent K' images on the film frames requires associated changes in the relationships between the various components of the enlarging syste~ which depend upon the magnitude of the K' image spacing ~ -on the film rames-.- Hence, the enlarging lens spacing ds for -the multi-lens enlarging system is, from equation (18~:
s = Ds h and ~ (32 the corresponding lenticule width w5, previously determined from equation (23), is given by: ``
s N ds ~ (33) ~;

Like-Ghanges are requ~red for the single-lens enlarging system-of Figs. 8 and 9.

"~
~40~ , '~

: . ~ : .. .

105~
Linei~o~m Im~e -~cah~ih~ ~nd ~al~it~ ~ontrol ~s ment~oned, in order to pres'ent a noninterrupted ::
picture to the o~server, the area benea~h each'lenticule of the v~ewi'ng lenticular scraen sho'uld be'completely filled with lineiform images of the objec't field. .For hi~h quality, it is likewise des~rable 'tnat ad~'acent li~ne~orm images do nst ;~
overlap apprec'~a~ly and that all o~ the''~mages be'o~
substantially uni~orm density. -To minimize variation among the lineiform images because i 10 of projection of the two-dimensional views through different : .
areas of the enlarging lenses, light transmission filters are preferably utilized in con~unction with'the enlarging lenses. .; ' Suitably, the'~ilters have'light transmission chàracteristics which are the converse of those'of the`'enlarging lenses. Thus, . . : .
whereas the intensity of light transmitted by ~ typical lens characteristically falls off with'distance from its optical : ,:. ;, :
'' axis, the filters would have increasin~ light transmission ef~iciency ~ith'd~stance'from the`ir centerc:~ The'filters would therefore coact with the lenses to provide lineiform images of ;' ' - 20 substanti~lly uniform density. '~ .
It may also be desirable, particularly whe`re short ~o~al length-~enses--are-u~ed,-to--employ taking-or enlarging -lenses of '~
~I different focal lengths at t~e'lens locations spaced ~rom the ''~
central axis.of the.:camera:~-or enlarger-to reduce distortion-~' which otherwise might occur at the edges of the stereoscopic :~
picture due to lack of ~ocus. Fox example, in the ~ive lens .
camera illus~rated'-~in Figs. 5 and 6, ~he two endmost lenses .
134 and 142 migh~.ea~ have a focal Iength of '' .
'' ~: :
' ' ;' ,. ': ~
.. , ~:, .. , .-, : . ~, ~:

- . , '' ~
.. ..... . . .. .. ., .. . . , . . , . . ~ ~ .

- -:~S~
ilm while holding the enlarging lens or lenses stationary, or (3I shi~t~ng the enlarg~ng lens or lenses and the lenticular film while keeping the film framP or frames stationary. All three are e~uivalent and result in the des~red relative movemen~
between projected images from the two~dimensional views and the photosensiti~e sur~ace of the lent~cular ilm. Accordingly, when ~he lenticular width w is properly selected and there are N frames, the total distance occupied by the expanded lineiform images, or image bands, beneath each lenticule will lQ just ~ill up the lenticule.
The three basic ways of scanning are illustrated in Figs. 10A, 10~ and 10C. Only one film frame and its associated enlarging lens are depicted in each instance, but it will be understood that in the case of a multi-lens enlarger the scanning relationships developed hereina~ter apply to all frames and lensesO ~`
Considering first Fig. 10A, it will be seen that if the condensed image R'' is to be scannèd o~er the distance x ) - m, the enlarging lens 254A must move a distance Ql and the film ~
frame 256A must move a distance Ml, both in the opposite -~ direction (to the left~in Fig. 10A) from that in which the image ~`
i K'' is to be expanded. By trigonometric relations and by -~ reference to equations (18) and (20)-~23~, it can be demonstrated ~;
` -~hat: j Ml = D - m~g ~ h) Y D t41) .. ~ Z . '~:
` and that:
Ql = ~ - m h ~ d t42) ~
z ., :-~3~
I

~5~
_ The shi~ting o~ the lens 254A and the ~ilm frame 256A ~ ' through.the distan.ces Ql and Ml, respectively, may conveniently ~e impl~mented b~ me~`ns of an arm 26Q~ pi~voted to the lenticular film easel 262A in the plane of the centers of curvature of the lenticules and slidably coupled at the other end to the enlarging ~
lens carrier 264A and the ~ilm frame carrier.266A. ~ stepping ~.
.- motor 268A suitably coupled to the arm 260A may be used to pivot : ;. tha arm.
In the second form of scanning, depicted in ~ig. lOB, lQ the enlarging lens 254B remains stationary wh~le the film frame ; ..
256B is moved in one direction (to the left in Fig. lOB) ~y the distance M2 and the lenticular film 258B is moved in the opposite direction (~o the right in Fig. lOB) through the dis~ance W2. By trigonometric relations, it may be seen that: .. ;

W2 = Ql ' d - m h ~ d (43~ ~ .:
. and that .

, M2 g (~ m)_ g ~ (44~ .
~he required shifting of the film frame 256B and the .~ ~ .
.. ~
. lenticular film 258B may readily be accomplished by a common arm 260B pivoted to the lens carrier 264B and slidably coupled -at-itS--Opposite ends-to the lenticular film easel 262B and the .
film strip carxier 266B. As before, a stepping--mot~r 268B.. may - .
be.used to operate the arm 260B.- ~: :
According to~the-third basic scanning techni~ue, ~
~` illustrated in Fig~ lOC, the enlarging lens ~54C i~ shifted by :.
a distance Q3 and ~he lenticular fi~m 258C shifted ~y.a distance ~:~
W3, both in the same direction (for example, to ~he ...
, . .
, . .:
' ~

30. .
., . .
.' '. ,', ;`~' ~_ ': ~
~:

219~6 ~0~

right as seen in Fig. lOC)~ In this case, it may be shown that the lens shifting distance Q3 is given byO
[h Z~ h ~45) and that the lenticular film shifting distance W3 is equal -~o~
W3 = D - m L ~ ~ ~ D (46) z , Here, again, shifting of the enlarging lens or lenses and the lenticular film may be effected by use of a single arm 260C, ~ the arm in this instance being pivoted to the film frame `l 10 carrier 266C and slidably coupled at appropriate points along its length to the enlaxging lens carrier 264C and the lentic~
ular film easel 262C. A stepping motor 268C may conveniently . ~- ~
be used to actuate the arm. . -;. Scanning of the indiviaual lineiform images through ;;~
~ 15 the distance X - m along the pbotosensitive surfa~e may .~, b~ carried out continuously or in~ermittently. Continuous ~ ;.
.~,. scanning.has the advantage ~ speed, thus reducing composing time, and also provides a ~moother image over the scanned area. ~.
~ . As will be appreciated, scanniny o~ the lineiform images in~
.~' 20 any one of the foregoing three ways will produce beneath éaGh i lenticula a nun~er of condensed images corresponding in number 1 to the number N o~ two-dime~sional ~rames projected, each of `1 which condcnsed images will occupy substantially w~N o~ the .~ area beneath the lenticule. Upon completion of scanning, the -, .25 projection angle ~ lsee Fi~ 4) o~ the enlarging system wilL
~' be subst~ntially equal to th~ vie~ing an~le ~ o~ the lenti~ular .'~ screen. The projection ~nglo ~ ~s the an~le subtend~d by the s endmost projection lens location~. The entire lenticulc will -45 :

5~
therefore be completel~ filled with images~ Moreover, since each condensed Image'is ~ormed ~y traver's~ng the projected ';~-image over the photosensi~ive sur~ace, ther'e'~s substantially no variation in density of the ~mage 'across the extent of the image. This, coupled with the fact that each condensed image ' depicts only an expanded image'of the'same'element of a single two-dimens;onal view, a~fords a stereoscop~c picture of high viewing quality. The quality of the image bands, and hence of the final picture, may be even further enhanced ~y also using the aforementioned light transmission filters and, where~ '~
; appropriate, taking or composing lenses of different focal ~ ;
lengths. '~
Although the in~en~ion has been described and illustrated 1~ ' with respect to speci~ic embodiments thereof, many modifications 1 ;' '' and variations of such embodiments may be made by one skilled ¦'' ;~ in the art without departing from the inventive concepts disclosed. For example, the foregoing taking and composi~g 1` ~
1 procedures could be used to produce an animated pàcture by taking -' ., ~.-~seque~tial ~wo-dimensional views of a changing ob~ect field ; 2Q- or to produce a changing picture by taking each two-dimensional 1~`

- view (or pair of views) with different objects in the object '`

f.ield or even of different object fields in their entirety.

~ ikewi-se, the-two-dimensional-views need not be taken directly ''from the ob~ect field itself, bu~ may instead-be-made from a i~
. , .
~ransmi~ted image of the object ~ield, such as is produced, ~or example, by the image intensi~ier screen o~ an x-ray unit or an ''elec~ron microscope. Again, although the invention has ~een ~ '~

described herein primarily in connection with camer~s ha~ing ad~ustable lens- spacings~ it will be ~46- `
~ :

~L~5'~

understood that the invention is equally applicable in certain respects, and particularly in regard to the teachings dealing.
with proper camera lens spacings and with image scanning during th~ composing step, to cameras in which the lenses are fixed in pl~ce and where adjustments are made in the composing step.
Accordingly, all such modifications and variations are intended ~ .
to be included within the spirit and scope of the appended claims.
. ' ~" .

..~ ' ':', , , , ~ ''~', ' ,, '' `~ ' ` ` ~' . ' .' ~ ,:

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.~ ' , ' . ' . ~' :
;.` ., &

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.,. . ': ~;

Claims (3)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. In a picture of the type including an image layer containing a multiplicity of image bands, each of said image bands comprising a plurality N of condensed images formed by projecting elements of a corresponding plurality N of two-dimensional views of an object field taken from spaced vantage points, and an overlying lenticular screen having a corres-ponding multiplicity of lenticules of width w aligned with the image bands, the improvement wherein each of said N condensed images within each image band is of an expanded width greater than the lineiform width m to which the element of the corresponding two-dimensional view projected to form said condensed image would be focused without expansion by the associated lenticule of the lenticular screen; and the image density of each of said N condensed images is substantially uniform across the width thereof.

2. The picture of claim 1 wherein the width of each of said N condensed images is substantially w/N.

3. In an image array formed on the photosensitive surface of lenticular print film of lenticule width w, said image array consisting of a multiplicity of image bands each of which is aligned with a lenticule of the film and each of which comprises N condensed images formed by projecting through a projecting lens and onto the aligned lenticule portion of each of a corresponding N two-dimensional views of an object field taken from spaced vantage points, the improvement wherein each condensed image is formed by continuously changing the angle of projection of said portion of the corresponding two-dimensional view, while maintaining the projected image of a selected element of the two-dimensional view in registry with a reference point and while maintaining the ratio of (I) the distance between said selected element of the two-dimensional view and its projecting lens and (2) the distance between such projecting lens and the lenticular print film substantially constant, by an amount sufficient to scan the image of said portion over a distance along the photosensitive surface such that said each condensed image occupies a width of substantially w/N, whereby said scanning results in said each condensed image being greater in width than the width m of an individual lineiform image formed by the aligned lenticule of said portion of the corresponding two-dimensional view, said each condensed image being substantially in focus and of substantially uniform image density across the full width w/N thereof.