GB1596387A - Production of stereoscopic pictures - Google Patents

Description

(54) IMPROVEMENTS IN THE PRODUCTION OF STEREOSCOPIC PICTURES (71) We, WONDERVIEW OPTICAL INDUSTRIES OF CANADA LTD, a corporation organised and existing under the laws of British Columbia, Canada, of 991, Granville Street, Vancouver, British Columbia, Canada V6Z 1L3, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The present invention relates to a method of and apparatus for the production of a stereoscopic picture using a lenticular screen.

With the photographic apparatus for production of stereoscopic photographs which has been most commonly known, one and the same object to be photographed has usually been photographed simultaneously from two viewpoints spaced a predetermined distance from each other, using two photographic cameras juxtaposed, or a single photographic camera having two objectives. Right and left pictures thus separately obtained have been viewed with right and left eyes, respectively, through a special viewer. This invention, however, is concerned with single-picture stereoscopic (SPS) photographs, which can be viewed without an auxiliary device such as special glasses worn by the viewer and which are obtained by forming a plurality of images arranged in stripes of the object to be photographed as viewed from various angular positions through a lenticular screen.

The lenticular screen comprises a plurality of lenses or optical elements successively connected to one another, each of these optical elements being in the form of a part-cylinder having a diameter which may be as small as 0.1 mm to 2.0 mm, and said lenticular screen being located in front of the photosensitive surface. By visually converting said plurality of images arranged in stripes through another lenticular screen of the same optical arrangement as the first lenticular screen, a single-photograph stereoscopic picture is obtained.

These two types of stereograph are thus clearly to be distinguished from one another, not only with respect to the optical measures to obtain the desired pictures but also to the method of viewing the respective pictures. With an SPS picture of "directly viewable" type in which a plurality of images as viewed from different viewpoints are focussed on a single photo-sensitive material (film), a single objective is used for photographing so that an object to be photographed is projected and the film sensitized as a plurality of images which are not only laterally but also vertically reversed as in an ordinary photograph, and each image in the sensitive surface defined by each lenticular element is also laterally reversed in spite of the provision of the lenticular screen immediately in front of the focussing plane. In the sensitized picture comprising the reversed images thus obtained the picture section corresponding to the left side surface of the object to be photographed is opposed through the lenticular screen to the right eye while the picture section corresponding to the right side surface of the object is opposed through said lenticular screen to the left eye of the observer. Thus this socalled reversed stereoscopic picture can not be used directly viewed as a normal picture.

The reasons for this will be described in more detail later and are described in the Inventor's Japanese Patent Application No.

1971-20693 entitled "Photographic Apparatus for Obtaining Trivisional Picture" (unexamined Patent Publication No. 1972-37637) with reference to Figure 8 and in his Japanese Patent Application No. 1971-20694 similarly entitled "Photographic Apparatus for Obtaining Trivisional Picture" (unexamined Patent Publication No. 1972-37638) with reference to Figure 1.

According to these patent specifications, the desired SPS picture is obtained by a single exposure and improved photographic apparatus adapted to obtain the SPS pictures without the step of forming the reversely arranged image portions is proposed. According to the former of these patent specifications, the lenticular screen located in front of the photosensitive surface is displaced during exposure by an amount corresponding to the width of one of the lens elements thereof in synchronized relationship with movement of the camera shutter or slit over the distance required to cross the objective, and thereby the image which would otherwise be projected as a reversely arranged stereoscopic image is converted so as to be projected as the corresponding normally arranged image. According to the latter specification, a mask (or screen) having a slit is interposed between the lenticular screen and the photo-sensitive material, and is moved relatively to said photo-sensitive material for a time defined by a single opening of the shutter, so that the extent of movement of each member is a multiple of the unit width of the lens elements which constitute the lenticular screen, and thereby the reversely arranged image is converted into the corresponding normally arranged image.

An improved camera of this general type is described in our British Patent Specification No.

1,495,060.

With the photographic apparatuses for production of this improved stereoscopic picture, it is possible to obtain the desired SPS picture by a single exposure, instead of troublesome photographing measures, as have usually been necessary to obtain a stereoscopic picture of directly viewable type, such as many exposures repeated from the same camera position with respect to one and the same object to be photographed while said object is progressively rotated around itself or while the photographic camera is progressively moved along a circular arc around a fixed object to be photographed. However, even these improved photographic cameras are disadvantageous in that a relatively long exposure time is necessitated since these improved arrangements require a synchronous movement of the lenticular screen for every scanning during which the shutter completely crosses the objective and a synchronous relative movement of the lenticular screen, the mask with a slit, and the sensitive material. Also, no photographing operation is possible when the object to be photographed is moving, and these arrangements cannot be adapted for flash light exposures, particularly the momentary flash of Strobo light (electronic flash), in which a flash lamp having a light emission period usually shorter than the period during which each of said members moves is used.

To solve such a problem, the present inventor has already proposed, in the specification of our British Patent Application No. 11223/76 (Serial No. 1,546,861), an improved method for obtaining SPS pictures by which a desired stereoscopic picture may be obtained even if the object to be photographed is moving, the strobo discharge is used as the illumination for photographing, and the operation of photographing occurs with use of a flash bulb, and also an improved photographic camera for obtaining SPS pictures adapted for said improved method. These prior inventions have had three basic objects, of which the first is to enable a good stereoscopic picture of directly viewable type to be surely obtained indepen dently of photographing requirements, the second is to simplify the mechanism of the photographic camera used to obtain such a stereoscopic picture of directly viewable type so that said stereoscopic picture of directly viewable type may be obtained even by those who are less skilled, using a photographic camera of relatively low cost and thereby the popularization of the stereoscopic picture of this type may be achieved, and the third is to enable reproduction of one and the same picture to be repeated from the picture photographed by said photographic camera of relatively low cost, whenever it is desired.

British Patent Application No. 11223/76 (Serial No. 1,546,861) is based on the idea that a reversely arranged stereoscopic image projected from one and the same original is converted through a special reversing measure into the corresponding normally arranged image and simultaneously printed. Said special reversing measure specifically comprises, under light projection, relatively moving the original and the fresh photo-sensitive material or printing paper, while keeping these two components in close contact with each other. This technically requires a substantial precision so that those less skilled cannot easily execute this reversing measure. In fact, the inventor initially intended to enable an original carrying thereon reversely arranged stereoscopic image portions to be prepared by a simplified photographic camera so that, when such a photographic camera of relatively low cost will have been adequately popularized, said original carrying thereon the reversely arranged image portions which has been obtained as a result of photographing by a user of said photographic camera may be sent to one of a number of special processing laboratories at which conversion of said reversely arranged image portions into the corresponding normally arranged image portions and printing thereof are simultaneously undertaken.

This object will be adequately achieved as long as the processing laboratory is equipped with the apparatus for image conversion and printing of high precision. Such a system through which the stereoscopic pictures are provided is, however, disadvantageous in that this system cannot necessarily adapt itself to the users' own wish for photographing in a faithful manner, and one of the most serious inconveniences lies in that this system can only provide the equivalent of contact printing, in which no variation occurs from the picture size on the original, and the other services such as enlargement, reduction and preparation of partially enlarged or reduced picture by trimming can never be provided by said system. Briefly, the processing laboratory as mentioned above has usually not been able to meet the needs for enlarged stereoscopic pictures and, also at the users' side, to make an enlargement has been practically impossible.

The present invention principally aims at reduction of these drawbacks and the most important significance thereof lies in the fact that not only said special processing laboratories but also the users themselves can easily achieve the conversion of the original carrying thereon the reversely arranged trivisional image portions and obtain an enlarged picture, although the method for preparation of said original carrying thereon the reversely arranged trivisional image portions and the photographic camera for execution of this method are similar to those of British Patent Specification No. 11223/76 (Serial No. 1,546,861).

The present invention is defined in the appended claims, to which reference should now be made.

The invention will now be described in more detail, by way of example, with reference to the accompanying drawings, in which: - Figure 1 schematically illustrates a principle on the basis of which the photographic camera used to execute the method for production of SPS pictures provides projection of a picture comprising reversely arranged trivisional image portions of an object to be photographed; Figure 2 is a rear view showing, in detail, the objective and the shutter of the photographic camera used to execute said method; Figure 3 is a plan view showing an important portion of the same members as shown by Figure 2; Figure 4 is a side view showing the important portion of the same members as shown by Figure 2; Figure 5 is a perspective view showing a preferred lens arrangement of the photographic camera used in the method; Figure 6 is a view similar to Figure 2 of an alternative objective and shutter for use when the lens arrangement as shown by Figure 5 is used; Figure 7 is a plan view showing, by way of example, a photographic camera adapted to be used in the execution of a method embodying the present invention; Figure 8 schematically illustrates a principle on the basis of which the reversely arranged SPS image portions carried on the original which has already been subjected to exposure and development are converted by the enlarging device into normally arranged SPS image portions; Figure 9 is a side view, partially given as an axial section, showing a light source housing, an original support and an optical system for projection, including an enlarging lens used in an actual enlarging device suitable for execution of a method embodying the present invention; and Figure 10 schematically illustrates how the enlarged picture obtained according to the principle illustrated by Figure 8 becomes an SPS picture of "directly viewable" type.

Figures 1 to 6 are similar to Figures 1 and 3 to 7 respectively of our British Patent Application No. 11223/76(Serial No. 1,546,861), but are included to enable a full understanding of the embodiment described.

Figure 1 illustrates the manner in which an image appears when an object is photographed by a photographic camera having a. lenticular screen located immediately in front of sensitive material. Referring to Figure 1, X designates the position of an object to be photographed Lo an objective, and So a shutter located behind said objective and adapted to be opened and closed transversely of the optical axis. Mo designates the lenticular screen and F0 the photosensitive material. The objective Lo to be used for photographing is preferably an objective as shown in Figure 5, which is cut along a pair of opposed planes extending parallel to the main optical axis of said objective. Correspondingly, it is preferred that the shutter So is, as shown by Figures 2 to 4 and Figure 6, adapted to be opened and closed transversely of the said cutting planes of the objective Lo extending parallel to each other and to form, when opened, a slit. In execution of the method, however, such a combination of objective and shutter as mentioned just above is not necessarily essential.

The lenticular screen Mo comprises a plurality of continuously arranged and assembled lenticular elements each having the form of a fine, vertically long part-cylinder which has a surface of circular arc in cross section and a uniform width as narrow as normally of the order of 0.2 mm to 5.0 mm. In Figure 1, these lenticular elements M1, M2, M3 .. ... are shown on a considerably enlarged scale. Accordingly, the boundary lines of the adjacent lenticular elements corresponding to opposite ends of each circular arc in cross section of the lenticular screen define a plurality of stripes extending parallel to one another and transversely of the said cutting planes of the objective which extend, in turn, parallel to each other when the objective as shown by Figure 5 is used. With such an optical system for sensitization, upon opening of the shutter So, the light rays coming from an object to be photographed pass through the objective Lo to the lenticular screen Mo and then pass through the latter to the photosensitive material Fo. In this passage, the light rays are subjected to refraction in the objective Lo and in the lenticular screen Mo.

The manner of image formation will now be considered with respect to the portion of an object to be photographed that lies between points P and Q in the figure. Imaginary points L, P, Q and R will be considered in the object plane defining sections containing threedimensional images Ao, B0 and C0 having image portions A-, A and A+; B-, B and B+; and C-, C and C+ respectively. The light rays coming from the point P and incident upon the objective Lo are included within a beam 61 covering the effective aperture of the objective L0 and the light rays coming from the point Q and incident upon the objective Lo are included within another beam 62 covering the effective aperture of the objective Lo Of these light rays included within these beams, only the portion that passes through a particular lenticular element M2 of the plurality of lenticular elements Ml, M2, M3 . successively arranged and assembled to form the image of said portion will be considered. The light rays coming from the points P and Q, and passing centrally through the objective Lo, form corresponding images at points P2 and Q2, respectively, on the photosensitive surface Fo. The light paths which are incident on the element M2 are shown by solid lines for better understanding. Of the beam 61 coming from the point P, the light rays which have been incident, not upon the lenticular element M2, but upon the lenticular element Ml adjacent said lenticular element M2 are subjected to refraction in passing through said element M1 and then form the image of said point P at a point P1 on the sentitive material surface F,, while the light rays of the beam 62 coming from the point Q which have been incident, not upon the lenticular element M2, but upon the lenticular element M3 adjacent said lenticular element M2, are subjected to refraction in passing through said element M3 and then form the image of the point Q at a point Q3 on the sensitive material surface Fo.

It might be thought from the drawing that all the light rays coming from the portion of the object to be photographed that lies between the points P and Q pass through only the three lenticular elements M1, M2 and M3 as shown, since each lenticular element of the lenticular screen is shown in a scale larger than it really is for convenience of illustration. However, besides said three lenticular elements M1, M2 and M3, these light rays coming from the portion of the object lying between the points P and Q really pass through a plurality of successive lenticular elements arranged symmetrically either side of said lenticular element M2 to form the projected image of said portion including the projected images of said points P and Q in each element, because each lenticular element has, as previously mentioned, a width as small as of the order of 2.0 mm to 5.0 mm.

It is known that an SPS photograph of directly viewable type is principally based on a plurality of projected images of the points P and Q formed by such a plurality of lenticular elements. However, the projected image thus formed in every lenticular element is a reversed image which cannot be directly viewed. The condition of the image formed in each lenticular element will now be considered again with respect only to the particular lenticular element M2. Images of surfaces B-, B and B+ of the three-dimensional object Bo to be photographed which lies between the points P and Q are formed in the order B'+, B' and B'- on the photosensitive material surface Fo. Thus, the image of the surface B+ is formed near the image point Q2 and the image of the surface B is formed near the image point P2. Such an image forma tion arrangement is true also with respect to the object Ao lying between point L and the point P, of which the image is formed in the adjacent lenticular element Ml, and with respect to the object C0 lying between the point Q and point R, of which the image is formed in the oppositely adjacent lenticular element M3.

Corresponding image points L1 and R3 are shown on the figure. From the fact that this image formation arrangement corresponds to the arrangement of surfaces of the object itself to be photographed, it might be wrongly con sidered as if the projected image as mentioned above could be directly viewed. When the projected image is viewed through the lenticular screen comprising a plurality of lenticular ele ments each having a part-cylindrical configur ation, however, the image cannot be viewed as a stereoscopic image. Namely, when viewed through such a lenticular screen, the left side surface B- of the object Bo to be photographed is formed as a left image B'-, and the right side surface B+ of said object Bo is formed as a right image B'+. Thus, the left image B' ? is opposed through the part-cylindrical lenticular lenses to the right eye and the right image B'+ is similarly opposed to the left eye of a person who directly views the projected images. Thus, the right eye views an enlarged image corresponding to the left image B'- and the left eye views an enlarged image corresponding to the right image B'+, respectively, through the lenticular screen. This relationship is true also with respect to the objects Ao and C0 so that the image obtained by the photographing operation as previously mentioned on the photo-sensitive material surface Fo is a reversed image.

Such reversed image portions are neverthe less intentionally obtained in the photographing step so that, using an original carrying thereon said reversed image portions as a complete pic ture, said reversed image portions are converted in a printing (or enlarging) step into the corres pending normal image portions so as to be directly stereoscopically viewed. lhe method for obtaining a stereograph comprises, therefore, the photographing step as above-mentioned which is adapted to obtain reversed SPS image portions and a method to convert said reversed image portions which are obtained by said photographing step into the corresponding normal SPS image portions in a printing step, using the original carrying thereon said reversed SPS image portions.

In the photographic camera adapted to obtain the reversed SPS image projected upon the photo-sensitive material, there is no noticeable feature with respect to the sensitive material surface, which is maintained stationary during exposure, and the lenticular screen also is stationarily placed immediately in front of the sensitive material. Accordingly, the section including these components will be described later in reference to Figure 7.

First of all, the section including the objective Lo and the shutter So adapted to provide a desired aperture for this objective during exposure will be described in detail. An objective as as shown by Figures 2, 3 and 4 in a rear view, a plan view partially given in section and a side view, respectively, may be employed in combination with a special shutter So which is suitable for use with this obective Lo. The photographic objective Lo is, in this embodiment, an objective of large diameter being circular as seen from the front (see Figure 2).

The shutter generally designated by So has a pair of blades 11, 12 each in the form of a slender rectangle and arranged transversely of stripe portions defined by boundary lines of the lenticular elements of the lenticular screen Mo placed immediately in front of the photosensitive surface, and these two blades are overlapped on each other along their edges near the optical axis to ensure a shielding effect. When the circular objective as shown is used, the black box of the photographic camera must be kept light-tight by coasting the objective over the area extending outward of the area defined by the chain-dotted lines in Figure 3, namely, extending upward of the upper chain-dotted line and downward of the lower chain-dotted line with shielding material or by covering said area with a suitable shielding member. Opposite ends of the respective blades 11 and 12 are pivotally supported at 20 by the camera body or a part of the shutter casing or held by links 13, 14 and 15, 16, respectively.

Although said blades 11 and 12 are also pivotally attached to the associated links, no reference is given in the figure to designate the respective pivots.

The upper blade 11 is moved from its closed position to its open position as the links 13 and 14 are rotated counterclockwise around the pivots 20, respectively, and similarly the lower blade 12 is moved from its closed position to its open position as the links 15 and 16 are rotated clockwise around the pivots 20, respectively. The outer ends of intermediate links 21 and 22 are pivotally mounted on the links 13 and 15 substantially at middle portions thereof, respectively, and said intermediate links 21 and 22 are, in turn, pivotally mounted at 19 on an end of a driving lever 18 adapted to be slidably moved centrally by an electromagnet 17 so that the links 13 and 15 may be rotated through the intermediate links 21 and 22 around the associated pivots 20 by movement of the driving lever 18 in the direction indicated by the arrows. Reference numeral 23 designates an armature of the electromagnet 17 and reference numeral 24 designates a restoring spring suspended between the pivots at which the outer ends of the intermediate links 21 and 22 are mounted on the links 13 and 15, respectively. There is no such linkage mechanism including the intermediate links for the links 14 and 16, since the links 13 and 15 are rotated around the respective pivots 20 through the intermediate links 21 and 22 as the armature 23 is attracted under excitation of the electromagnet 17 and, in response to this, the links 14 and 16 also are rotated around the respective pivots 20 so as to move the blades 11 and 12 apart and, conversely, the restoring spring 24 restores the links 13 and 15 upon de-excitation of said electromagnet 17 so that, accordingly, the links 14 and 16 rotate in the opposite directions and no restoring spring need be separately provided in practice between the links 14 and 16.

Reference numeral 25 (Figure 2) designates a diaphragm regulating lever serving as a control member disposed at its lower end in a range over which said armature 23 moves. A screw 27 threaded through parts 26 of the shutter casing so as to be suspended between these parts is threaded through the upper end of said diaphragm regulating lever 25 between said parts 26. The diaphragm regulating lever 25 is laterally moved by rotating the screw 27 threaded through said upper end to a desired position and the extent to which the armature 23 is moved by the attractive force occurring under excitation of the electromagnet 17 is regulated depending upon the position occupied by said diaphragm regulating lever 25. The larger is the extent to which the armature 23 moves under the magnetic attraction, the larger is the extent to which the blades 11 and 12 are moved away from each other in response to the movement of said armature 23 by the driving lever 18 and the intermediate links 13 and 15. The slit defined between the blades is held small, on the other hand, when the movement of said armature 23 under the magnetic attraction is restrained by the diaphragm regulating lever 25 at an initial stage of said movement.

Reference numeral 28 designates a diaphragm value regulating knob which is mounted on the outer end of said screw 27 and provided along its partial periphery with a diaphragm value index 29 adapted to index a diaphragm scale (not shown) provided along the rotating range of the diaphragm regulating knob 28 at a position to which said knob 28 has been rotated.

The diaphragm regulating lever 25 is thus arranged so that the opening extent of the shutter blades 11 and 12 adapted to define the aperture under excitation of the electromagnet 17 is controlled by a mechanism to activate the electromagnet 17 and thereby these blades 11 and 12 actually serve also as a diaphragm to control the amount of incident light. However, the measure by which the shutter blades 11 and 12 are enabled to serve also as the diaphragm is not necessarily limited to such a mechanism as shown by Figure 2. A mechanism shown by Figure 6 as one of the other possible embodiments may be also effective for this purpose.

The embodiment of Figure 6 may employ an objective in the form of a rectangular lens element as shown by Figure 5 and in this embodi ment, the extent to which the shutter blades 11 and 12 are moved in the direction in which the shutter is opened serves to restrain the shutter blades directly.

Referring to Figure 6, reference numeral 125 designates a screw serving to regulate the diaphragm, which is threaded through a part 126 of the shutter casing and has its upper end located in a range within which the blade 12 is moved. Reference numeral 128 designates a diaphragm value regulating knob mounted on the lower end of the diaphragm regulating screw 125 and, as in the previous embodiment, there is provided a diaphragm scale (not shown) along the range within which said diaphragm regulating knob is rotated so that a preset diaphragm value may be indicated by a diaphragm value index 129 arranged on a part of said knob 128 in cooperation with said diaphragm scale.

Accordingly, also in this embodiment, the diaphragm value regulating knob 128 may be turned so as to indicate a given diaphragm opposed directly to the objective Lo prior to exposure. The magazine is adapted to be removably mounted in said camera body 61. It will be understood that the front surface of the sensitive material Fo lies in a given focal plane when the magazine 62 accommodating said sensitive material is mounted in the camera body 61. Reference numeral 65 designates bellows to keep the sensitive material Fo lighttight in cooperation with the magazine 62 and as is well known the bellows 65 are adapted to expand and contract while keeping said lighttight relationship as the objective Lo is moved forward and backward along its optical axis by rotating a focussing button 66 to focus on an object to be photographed. Reference numeral 67 designates a storage lid adapted to fold said bellows 65, the objective Lo and the shutter together into the camera body 61 in cooperation with arms 68, and reference numeral 69 designates a grip by which the photographic camera can be held for photographing.

As a result of photographing with the photographic camera as mentioned above, an object image appears as the corresponding reversed image on the sensitive material Fo when the latter is subjected to a development process and the developed photo-sensitive material carrying thereon such an image is used as an original Fo in the subsequent enlarging process in the manner as will be described below.

Figure 8 illustrates an enlarging process which is carried out simultaneously with conversion from the reversed image portions on the original Fro ' to the corresponding normal image portions. In Figure 8, D designates a light source for enlarging, such as an incandescent or iodine lamp, and M and M' respectively designate separate lenticular screens so arranged that a series of part-cylindrical lens elements ml, m2, m3 . . . . of the lenticular screen M are opposed in contact at their part-cylindrical convexities with a series of parallel part-cylindrical lens elements ml, m2, m3 . . . of the other lenticular screen M' at their corresponding convexities. E designates an enlarging lens which is located immediately below these lenticular screens, and F a surface on which an image is projected. Although the lenticular screens M and M' are shown on an unpractically enlarged scale together with the respective three lens elements for convenience of better illustration and understanding of the principle of image conversion, it should be understood that the respective components are really arranged at a dimensional ratio quite different from that as shown, and the lenticular screens M and M' have substantially more than three lens elements between the light source D and the lens E, as shown by Figure 9.

The original F0 carrying thereon the reversely arranged image portions which has previously been mentioned with reference to Figure 1 corresponds, in Figure 8, to a developed original F0 ' located immediately above the lenticular screen M in close contact therewith, wherein said lenticular screen M is the one of the lenticular screens M and M' that occupies the upper position. With such an arrangement, the light beams coming from the light source D and passing through the left side image A'- of the left side object follows light paths within the lens element ml as shown in full lines, leave the latter, then enter the lens element m11 of the lenticuler screen M' which is located immediately below said lens element ml of the upper lenticular screen M, and, after being subjected thereby to refraction, are focussed on a position Ao-. Similarly, the light beams passing through the right side image A'+ of the left side object follow a light path within the lens element ml as shown in dashed lines, leave the latter, then enter the lens element mi' of the lenticular screen M' which is located immediately below said lens element ml of the upper lenticular screen M, and, after being subjected thereby to refraction, are focussed on a position Ao +. Likewise, the central image A' of said left side object is focussed on a position Ao, the left side image B'- of a central object is focussed on a position Bo-, the central image B' of said central object is focussed on a position Bo and the right side image B'+ of said central object is focussed on a position Bio+.

Similarly, respective images C'-, C' and C'+ of a right side object are focussed on positions C0-, C0 and CO+, respectively.

Thus, when two lenticular screens are opposed at their convexities of respective part-cylindrical lens elements in contact with each other and are subject to light projection, the respective objects on the original F0, placed in close contact with the lenticular screen M are focussed in a manner such that the positions of the details of each object are focussed and exchanged for one another with respect to the associated central image A', B' or C'. Accordingly, the respective images A'-, A', A'+; B'-, B , C'-, C', C'+ arranged in this order from the left on the original F0 ' as seen in Figure 8 are rearranged in the order of At +, Ao, Ao-; B0 +, Bo, Bo-; C0+, C0, C0- from the left on the lower surface of the lenticular screen M' in the projection light paths from the light source D, and such an arrangement of the respective images provides the desired arrangement of normal SPS image portions which, in turn, enables the picture to be "directly" viewed.

This fact means that photosensitive paper such as for contact printing may be placed on the lower surface of the lengticular screen to obtain a print carrying thereon the normally arranged SPS image portions, which is of the same size as the original Fol. Referring to Figure 8, G-G designates a plane in which the desired contact printing can be effectively achieved. The image arrangement thus converted and the image arrange on the image projection surface F (in the order of A+, A, A-; B+, B, B-; C+, C, C- from the right as seen in Figure 8) which has been enlarged and projected through the enlargement lens E, using the plane G-G as a secondary light source, are both the desired nor- mal SPS image arrangement enabling direct stereoscopic viewing for the reason as described hereinafter with reference to Figure 10.

Referring to Figure 10, ER designates the right eye and EL designates the left eye of an observer. Although a picture may be obtained through the usual development and finishing processing from the photographic printing paper which has been subjected to a printing in the place G-G or to an enlargement printing on the image projection surface F, this picture itself cannot be stereoscopically viewed by naked eyes. To be an effective SPS picture, a separate lenticular screen must be placed in close contact and preferably bonded with said picture so as to provide an SPS picture of "directly viewable" type. In the case of a picture which has been contact printed as the picture of the same size as the original Fro ', a lenticular screen which is identical to the lenticular screen Mo which was used in photographing process may be coordinately placed in contact with or bonded to said picture. In the case of an enlarged picture, however, the lenticular screen Mx to be placed in contact with or bonded to this picture must have a lens element width in accordance with the enlargement ratio used in the enlargement process. It should be noted here that the term "enlargement ratio" is used not with respect to the area of the original Fo' but with respect to the length thereof. More specifically, in the case of a picture Fx which was subjected to an enlargement so that this picture has a length n times the length of a particular image carried on the original Fol, the width of each lens element of the lenticular screen Mx to be placed in contact with or bonded to said pixture Fx must correspond to n times the width of each lens element of the lenticular screen Mo which was used in the photographing process.

In this manner, the light beam coming from the left side image of the left side object on the picture Fx thus obtained passes through the lens element of the lenticular screen Mx and enters the right eye ER of the observer, while the light beam coming from the right side image similarly passes through the lens element of said lenticular screen Mx and enters the left eye of the observer. Similarly, the light beam coming from the left side image of the right side object enters the right eye of the observer while the light beam coming from the right side image enters the left eye of the observer. Such a condition is identical to the condition of Figure 1 wherein, with respect to the objects Ao and CO to be photographed, the right side images A+ and C+ are viewed by the right eye while the left side images A- and C- are viewed by the left eye. It will be easily understood from the fact as men- tioned hereinabove that the lenticular screens M and M' opposed to each other as shown by Figure 8 can provide the picture carrying thereon normal images which are directly viewable by converting the reversely arranged images carried on the original Fro .

Figure 9 shows, by way of example, an actual printing device adapted to effect the image arrangement conversion on the basis of the principle as illustrated by Figure 8. In Figure 9, the same members or parts as those in Figure 8 are designated by the same reference numerals as used in Figure 8. In Figure 9, however, the enlarging device is only schematically illustrated, omitting the table onto which the picture is enlarged and projected, particularly as an actual enlarging device exclusively for coloured photographs. H designates a lamp housing to accommodate a light source D for enlarging purpose such as an incandescent or iodine lamp. Condenser lenses K, K are located just below the light source D to condense the light rays emitted from said light source D accommodated within the lamp housing H. Between the condenser lenses K, K and an original Fol, there are located a filter T known as the colour conversion filter to adjust the colour temperature and the wavelength balance of the light source colour and a light diffusing plate V known by the name of diffuser, in this order from the upper side. Said filter T may be, depending upon the colour reproduction characteristic of the original F0, as a colour negative, of various kinds which are exchangeable, or a combined filter of several, most often three kinds may be inserted. The light diffusing plate V, on the contrary, is usually fixed particularly in a manner that the light rays projected onto said table are not subjected to a partial variation.

w designates bellows wnicn light-tlghtly expand and contract as the enlarging lens E moves along the optical axis with respect to the body of the enlarging device. In an actual enlarging device, said lenticular screens M and M' are preferably joined together in a frame so that no relative movement occurs therebetween and the original Fo' is held by a suitable holder against the upper surface of said pair of integrally combined lenticular screens M and M'. This holder may be a clip or holder as commonly used in ordinary enlarging devices.

Thus, in the method for production of SPS photographs the object is photographed by the camera, at the start, to prepare the original Fo carrying thereon the reversely arranged SPS image portions of said object. The original Fo' corresponding to the first-mentioned original F0 - carrying thereon the reversely arranged image portions having been subjected to the development processing is now projected through the pair of lenticular screens held in close contact with each other and thereby the image arrangement is converted in the simplest manner without any movable member. Therefore, even those not so skilled can make the SPS photograph of directly viewable type.

The method described enables the flash light photographing to be effectively performed using a strobo discharge or a flash bulb, and an SPS picture to be momentarily obtained even with respect to a moving object to be photographed.

Said single photographing operation provides an exposure picture formed as reversely arranged SPS image portions and when an enlarged pic- ture is prepared from an original carrying said reversely arranged SPS image portions, the latter are converted into the corresponding normally arranged image portions. To obtain a desired trivisional picture through a single exposure, an objective of relatively large diameter should be used as described in the specifications of the previously mentioned Japanese Patent Applications Nos. 1971-20693 and 1971-20694.

With such prior arrangements, however, the respective mechanisms of the photographic camera itself must be synchronously moved by a predetermined amount. Such a photographic camera would become too bulky to be easily carried and result in a too high cost to be com- monly used. The photographic camera described herein, on the contrary, provides an epochmaking improvement in that the photographing operation is achieved in the ordinary manner so far as a lenticular screen is located immediately in front of the photo-sensitive material or a camera previously provided with such a lenticular screen is used, since, as described in detail in our British Patent Application No. 11223/76 (Serial No. 1,546,861), it is assumed that the reversely arranged SPS image portions are intentionally formed on the sensitive material and the camera contains therein no member which must be simultaneously moved by a predetermined amount as previously mentioned, and, from the original thus prepared, the desired enlarged picture which can be directly viewed is obtained by an enlarging operation.

It should be understood that the respective embodiments which have been illustrated and described hereinabove are merely preferable embodiments of the present invention, and depending upon particular manners and purposes of the pictures to be photographed, such as ray photographs and astronomical photographs, various dependent changes in the design details are possible to adapt the arrangement for particular purposes, within the scope of the claims.

WHAT WE CLAIM IS: 1. A method of making a single-photograph stereographic (SPS) picture the method comprising (a) a photographing step in which, using a system comprising a stationary photo-sensitive material, a lenticular screen having elongate lenticular elements and fixed in front of the stationary photo-sensitive material in close contact therewith, an objective having an effective aperture extending transversely of the longitudinal direction of the lenticular elements of the screen, and a shutter, an object is photographed to form reversely arranged image portions of the object on said stationary photosensitive material, and (b) a printing step in which an original obtained by processing the photo-sensitive material is photographically printed through a pair of lenticular screens arranged with their lenticular surfaces closely opposed to each other and with their lenticular elements parallel to each other and to the image portions in the original to provide a picture consisting of an SPS image which can be directly viewed through a further lenticular screen placed in close association with the picture.

2. A method of making a single-photograph stereoscopic picture, substantially as herein described with reference to the accompanying drawing.

3. An SPS picture produced by the method of claim 1 or claim 2.

4. Apparatus for use in the method of claim 1, comprising (a) a photographic camera having a location for including therein a stationary photo-sensitive material, a lenticular screen fixed in front of the stationary photo-sensitive material location in close contact therewith, an objective having an effective aperture extending transversely of the longitudinal direction of the lenticular elements of the screen, and a shutter, and (b) a photographic printer including therein a pair of lenticular screens in close association with a location for receiving an original obtained by processing photo-sensitive material exposed with the aid of the camera, the screens being arranged with their lenticular surfaces closely opposed to each other and with their lenticular elements parallel, and means for photographically printing from an original through the pair of lenticular screens.

5. Apparatus according to claim 1, including a magnification varying optical system arranged to enlarge or to reduce the print image formed in the printer.

6. A photographic printer for use in step (b) of the method of claim 1, comprising a light source, an originalwreceiving position, a pair of lenticular screens in close association with the original-receiving position and with their lenticular surfaces closely opposed to each other and their lenticular elements parallel, an objective lens system, and an image receiving position, arranged sequentially on a common optical axis.

7. A photographic printer substantially as herein described with reference to Figure 8 of the accompanying drawings.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (7)

**WARNING** start of CLMS field may overlap end of DESC **. photographing to be effectively performed using a strobo discharge or a flash bulb, and an SPS picture to be momentarily obtained even with respect to a moving object to be photographed. Said single photographing operation provides an exposure picture formed as reversely arranged SPS image portions and when an enlarged pic- ture is prepared from an original carrying said reversely arranged SPS image portions, the latter are converted into the corresponding normally arranged image portions. To obtain a desired trivisional picture through a single exposure, an objective of relatively large diameter should be used as described in the specifications of the previously mentioned Japanese Patent Applications Nos. 1971-20693 and 1971-20694. With such prior arrangements, however, the respective mechanisms of the photographic camera itself must be synchronously moved by a predetermined amount. Such a photographic camera would become too bulky to be easily carried and result in a too high cost to be com- monly used. The photographic camera described herein, on the contrary, provides an epochmaking improvement in that the photographing operation is achieved in the ordinary manner so far as a lenticular screen is located immediately in front of the photo-sensitive material or a camera previously provided with such a lenticular screen is used, since, as described in detail in our British Patent Application No. 11223/76 (Serial No. 1,546,861), it is assumed that the reversely arranged SPS image portions are intentionally formed on the sensitive material and the camera contains therein no member which must be simultaneously moved by a predetermined amount as previously mentioned, and, from the original thus prepared, the desired enlarged picture which can be directly viewed is obtained by an enlarging operation. It should be understood that the respective embodiments which have been illustrated and described hereinabove are merely preferable embodiments of the present invention, and depending upon particular manners and purposes of the pictures to be photographed, such as ray photographs and astronomical photographs, various dependent changes in the design details are possible to adapt the arrangement for particular purposes, within the scope of the claims. WHAT WE CLAIM IS:

1. A method of making a single-photograph stereographic (SPS) picture the method comprising (a) a photographing step in which, using a system comprising a stationary photo-sensitive material, a lenticular screen having elongate lenticular elements and fixed in front of the stationary photo-sensitive material in close contact therewith, an objective having an effective aperture extending transversely of the longitudinal direction of the lenticular elements of the screen, and a shutter, an object is photographed to form reversely arranged image portions of the object on said stationary photosensitive material, and (b) a printing step in which an original obtained by processing the photo-sensitive material is photographically printed through a pair of lenticular screens arranged with their lenticular surfaces closely opposed to each other and with their lenticular elements parallel to each other and to the image portions in the original to provide a picture consisting of an SPS image which can be directly viewed through a further lenticular screen placed in close association with the picture.

2. A method of making a single-photograph stereoscopic picture, substantially as herein described with reference to the accompanying drawing.

3. An SPS picture produced by the method of claim 1 or claim 2.

4. Apparatus for use in the method of claim 1, comprising (a) a photographic camera having a location for including therein a stationary photo-sensitive material, a lenticular screen fixed in front of the stationary photo-sensitive material location in close contact therewith, an objective having an effective aperture extending transversely of the longitudinal direction of the lenticular elements of the screen, and a shutter, and (b) a photographic printer including therein a pair of lenticular screens in close association with a location for receiving an original obtained by processing photo-sensitive material exposed with the aid of the camera, the screens being arranged with their lenticular surfaces closely opposed to each other and with their lenticular elements parallel, and means for photographically printing from an original through the pair of lenticular screens.

5. Apparatus according to claim 1, including a magnification varying optical system arranged to enlarge or to reduce the print image formed in the printer.

6. A photographic printer for use in step (b) of the method of claim 1, comprising a light source, an originalwreceiving position, a pair of lenticular screens in close association with the original-receiving position and with their lenticular surfaces closely opposed to each other and their lenticular elements parallel, an objective lens system, and an image receiving position, arranged sequentially on a common optical axis.

7. A photographic printer substantially as herein described with reference to Figure 8 of the accompanying drawings.