Abstract
A stereoscopic imaging display. A virtual field-of-view frame or reference window is set in a field of view of a stereo camera. Standard stereoscopic video data is sent. A stereo slide or a stereo photo print is formed with left and right images from the standard stereoscopic video data. Spacing D.sub.P2 between the left and right images is determined by the equation D.sub.P2=B(1−L.sub.2/L.sub.0), where B is a human interpupillary distance, L.sub.2 is a view distance, and L.sub.0 a distance from the human interpupillary distance to a reference dimension display screen which is equivalent to the reference window at the time of photographing being taken.
Claims
1. A stereo slide or stereo photo print fabricated with two left and right screens integrally placed side by side from standard stereoscopic video data, wherein with a human interpupillary distance being taken as B, a distance to a reference dimension display screen D.sub.0 being taken as L.sub.0, and a view distance of the stereo photo print or the stereo slide being taken as an arbitrary distance L.sub.2, the two left and right screens are disposed with a spacing between the two left and right screens, D.sub.P2, determined by an equation of D.sub.P2=B(1−L.sub.2/L.sub.0).
2. A method of fabricating a stereo slide or a stereo photo print with a left image and a right image integrally placed side by side on a piece of film from standard stereoscopic video data which corresponds to image data of a reference window at a time of photographing, the left image and right image of the stereo slide or stereo photo print having a lateral width W.sub.P2 and the stereo slide or stereo photo print being configured to be viewed at a view distance L.sub.2, wherein with a human interpupillary distance being taken as B and a distance from the human interpupillary position to a reference dimension display screen D.sub.0 which is equivalent to the reference window at the time of photographing being taken as L.sub.0, the images are disposed with a spacing, D.sub.P2, between the left end of the left image and the left end of the right image or between the right end of the left image and the right end of the right image, determined by an equation of
D.sub.P2=B(1−L.sub.2/L.sub.0)
3. The method of fabricating a stereo slide or a stereo photo print as in claim 2, wherein the width W.sub.P2 of the left and right images is determined by the equation W.sub.P2=W.sub.P0(L.sub.2/L.sub.0), where W.sub.P0 is the width of the reference dimension display screen.
4. The method of fabricating a stereo slide or a stereo photo print as in claim 2, wherein the human interpupillary distance B is taken to be a distance between 58 mm and 72 mm.
5. The method of fabricating a stereo slide or a stereo photo print as in claim 2, wherein the human interpupillary distance B is taken to be substantially 65 mm.
Description
BRIEF DESCRIPTION OF DRAWINGS
[0077] FIG. 1 is a conceptual diagram of stereoscopy of the present invention.
[0078] FIG. 2 is a diagram of a relation between a reference dimension display screen (a large-sized stereoscopic TV depicted) in FIG. 1 and a stereo camera that sends standard stereoscopic video data.
[0079] FIG. 3 is a detailed descriptive diagram of FIG. 1.
[0080] FIG. 4 is a descriptive diagram when wide-angle shooting lenses are mounted on the stereo camera of FIG. 2 (b).
[0081] FIG. 5 is a descriptive diagram when long-focus shooting lenses are mounted on the stereo camera of FIG. 2 (b).
[0082] FIG. 6 is a descriptive diagram of a stereo projector with two, left and right projection units provided side by side.
[0083] FIG. 7 is a descriptive diagram of a stereo projector with a single projection unit.
[0084] FIG. 8 is a descriptive diagram of a rear-projection-type stereoscopic television for linear polarization time-division display with a single projection unit.
[0085] FIG. 9 is a descriptive diagram of a rear-projection-type stereoscopic television for circular polarization time-division display with a single projection unit.
[0086] FIG. 10 is a descriptive diagram of a stereoscopic television camera allowing a stereoscopic image to be observed on a stereoscopic monitor and also an actual scene to be viewed at the same time.
[0087] FIG. 11 is an embodiment of a collimation pattern for display on the stereoscopic monitor.
[0088] FIG. 12 is a perspective view of a stereoscopic video displaying apparatus.
[0089] FIG. 13 is a section view of eyeglasses for field-of-view separation and eyeglasses for diopter correction for the stereoscopic video displaying apparatus of FIG. 12.
DESCRIPTION OF NUMERALS
[0090] B human interpupillary distance [0091] L distance to a reference dimension display screen [0092] E.sub.L left eye [0093] E.sub.R right eye [0094] D display [0095] I.sub.∞ image at infinity [0096] W.sub.D width of the display [0097] E.sub.ref display of equivalent reference window (reference dimension display screen) [0098] W.sub.ref reference window [0099] W.sub.W reference window width [0100] S image pickup device [0101] I.sub.ref image in the reference window on the image pickup device [0102] a view angle [0103] F focal length [0104] W.sub.S width of the image pickup device [0105] D.sub.S spacing between left and right image pickup devices [0106] O.sub.∞ infinity body [0107] Φ optical axis of a stereo camera [0108] D.sub.0 display in reference dimensions [0109] D.sub.1 display smaller than reference dimensions within an overlap display range [0110] D.sub.2 display or stereo slide within a horizontal side-by-side display range [0111] W.sub.P0 width of the display Do [0112] W.sub.P1 width of (a part of) the display D.sub.1 [0113] W.sub.P2 width of each of the left and right displays [0114] D.sub.P1 spacing (picture distance) between left and right displayed on the display D.sub.1 [0115] D.sub.P2 placement spacing between the left and right displays or picture distance of the stereo slide [0116] L.sub.0 set distance in reference dimensions [0117] L.sub.1 distance to the display D.sub.1 [0118] L.sub.2 set distance to the display D.sub.2 or the stereo slide within the horizontal side-by-side display range [0119] L.sub.X boundary point (in principle) between the horizontal side-by-side display range and the overlap display range [0120] W.sub.ref′ matching point between left and right shooting fields of view when wide-angle lenses are mounted [0121] W.sub.ref″ matching point between left and right shooting fields of view when long-focus lenses are mounted [0122] P.sub.L display range of a left screen of a screen size larger than the reference dimensions [0123] R.sub.R display range of a right screen of a screen size larger than the reference dimensions [0124] S.sub.0 screen at a reference dimension display screen position [0125] S.sub.1 screen positioned at a short distance (1 meter) [0126] S.sub.2 screen positioned at a distance where left and right videos are placed side by side [0127] S.sub.3 screen positioned far away from the reference dimension display screen position [0128] 60 projector [0129] 61 projection lens [0130] 62 display [0131] D.sub.D spacing between the displays [0132] W.sub.D display width [0133] θ projection angle [0134] 71 screen equivalent to the reference dimension display screen [0135] 72 projection lens [0136] 73 display [0137] 0 point of application of the projection lens [0138] X position (optical-axis extending point) where a corresponding point of an image at infinity is to be displayed [0139] 81 DMD or LCOS display (projection) unit [0140] 82 projection lens [0141] 83 polarizing filter [0142] 84 transmission screen [0143] 85 eyeglasses for stereoscopic video viewing [0144] 91 DMD or LCOS display (projection) unit [0145] 92 projection lens [0146] 93 polarizing filter [0147] 94 liquid-crystal cell [0148] 95 λ/4 plate [0149] 96 transmission screen [0150] 97 circular-polarizing eyeglasses [0151] 100 reference window (virtual field-of-view frame) [0152] 101 stereoscopic monitor of the stereo TV camera [0153] 102 stereo TV camera [0154] 103 eyeglasses for stereoscopic video viewing [0155] 104 cameraperson [0156] CP collimation pattern [0157] 121 display [0158] 122 board [0159] 123 housing [0160] 130 eyeglasses for field-of-view separation [0161] 131 liquid-crystal plate [0162] 132 polarizing plate [0163] 133 eyeglasses for diopter correction
BEST MODES FOR CARRYING OUT THE INVENTION
[0164] A feature of the present invention is that stereoscopic video data can be shared for use even with different sizes of image pickup device of a stereo camera and different display ranges and screen sizes of stereoscopic displaying apparatus, and a reference window is set at the time of shooting so as to make a depth perception and dimensions of every stereoscopic video commonly recognized. And, this reference window is shot as field-of-view frames (left and right image frames), and is sent as reference stereoscopic video data necessary for display. Then, on a display side, the standard stereo video data is displayed on a screen in reference dimensions equivalent to the reference window on a shooting side, thereby reproducing a high-fidelity sense of stereoscopy.
[0165] For example, in FIG. 2, when it is assumed that a width of a reference window W.sub.ref . . . W.sub.W,
[0166] a width of an image I.sub.ref(L) and I.sub.ref(R) within the reference window projected onto the respective image pickup device having a width W.sub.S, and
[0167] a display screen width in reference dimensions . . . W.sub.D,
[0168] a shooting magnifying power r is r=W.sub.S/W.sub.W,
[0169] a display magnifying power R is R=W.sub.D/W.sub.S, and
[0170] r×R=1. According to the equations above, it can be understood that making image data sent from the stereo camera as standard stereoscopic video data is easy, irrespectively of the width Ws of the image pickup device.
First Embodiment
[0171] FIG. 1 is a conceptual diagram of stereoscopy. With a large-sized stereoscopic TV depicted in the drawing being taken as a television with a standard dimension display screen (a display width of 1800 mm), display screens of various sizes and their arrangement have a relation depicted in the drawing.
[0172] FIG. 3 illustrates dimensions and an arrangement relation in FIG. 1 in more detail. In FIG. 3, in contrast to an actual dimensional ratio, representation is shown at a dimensional ratio that increases as it is closer to the observer's position. This is to avoid congestion in plotting.
[0173] In FIG. 3, a distance Lx from the eyes of an observer to a boundary between a horizontal side-by-side display range and an overlap display range depicted in the drawing has a relation of L.sub.X=L.sub.0/(1+W.sub.P0/B), and
[0174] when it is assumed that L.sub.0=2500 mm and W.sub.P0=1800 mm and
[0175] when an interpupillary distance dimension is B=58 mm,
L.sub.X=2500/(1+1800/58)=78.04 mm, and
[0176] when the interpupillary distance dimension is B=72 mm,
L.sub.X=2500/(1+1800/72)=96.15 mm.
[0177] In the horizontal side-by-side display range, a barrier wall is required for partitioning into left and right fields of view, and an actual view distance has a limit of approximately 75 mm. Also, since 75 mm is very near compared with a distance of distinct vision, a loupe for diopter adjustment is required. A loupe with a focal length slightly longer than the viewing distance is proper. Therefore, in this case, an appropriate focal length of the loupe for use is approximately 80 mm.
[0178] Also, although the interpupillary distance dimension (on a stereo base) B varies to some degree among observers, when the view distance is long (overlap display range), some difference between the spacing between left and right corresponding points of an image at infinity and the interpupillary distance dimension B may be ignored.
[0179] And, in the horizontal side-by-side display range, although a margin of a difference with the interpupillary distance dimension B is small, the difference is mitigated by adjusting the spacing between diopter adjusting lenses.
[0180] A spacing between left and right screens, that is, a picture distance, has the following relation with the horizontal interpupillary spacing B and a distance L.sub.0 to a display D.sub.0 in reference dimensions. A picture distance D.sub.PN of a display D.sub.N disposed at an arbitrary distance L.sub.N has a value of D.sub.PN=B (1−L.sub.N/L.sub.0).
[0181] A width W.sub.P0 of each of left and right screens is proportional to the distance from the eyes of the observer. Since left and right visual angles α depicted in the drawing formed by interposing the display D.sub.0 between light beams entering each eye are the same, respective apparent screen widths depicted in FIG. 3 have a relation of W.sub.P0=W.sub.P1=W.sub.P2, and therefore the screens can be viewed as having the same size.
[0182] As described above, by displaying standard stereoscopic video data on a TV with the reference dimension display screen (a large-sized TV depicted in FIG. 1) in a relation and arrangement depicted in FIG. 1, common data can be used in all display ranges from the overlap display range with left and right images superposed thereon to the horizontal side-by-side display range having separate left and right display surfaces. In this case, on each display depicted in the drawing, it is enough to only arrange and display the standard stereoscopic video data (at a position and with a width) under conditions independently defined for left and right.
[0183] FIG. 2 is a diagram for describing a stereo camera as a means obtaining stereoscopic image data in the relation and arrangement depicted in FIG. 1. FIG. 2(a) is a diagram of a state exactly the same as the state of stereoscopy of FIG. 1, and FIG. 2(b) is a relation diagram in the case of using a stereo camera. Now, when it is assumed that a display E.sub.ref of an equivalent reference window depicted in FIG. 2 (a) is a display of the television with a reference dimension display screen of FIG. 1 (the large-sized stereoscopic TV depicted in FIG. 1), a reference window W.sub.ref is set to the stereo camera of FIG. 2(b), and the spacing between left and right shooting lenses of the camera is the interpupillary distance dimension B, a conjugate relation establishes between a distance from the display E.sub.ref of the equivalent reference window of FIG. 2 (a) to left and right eyes E.sub.L and E.sub.R of the observer and a distance from the reference window W.sub.ref having a width W.sub.W to left and right shooting lenses L.sub.L and L.sub.R. Therefore, image data on the image pickup device disposed in each of the left and right view angles α is the same as that when a person actually observes the television with the reference dimension display screen of FIG. 1 (the large-sized stereoscopic TV depicted in the drawing). Also, the size (width) of the image pickup device disposed in the view angle α is determined by the position of the image pickup device in an optical-axis direction.
[0184] In FIG. 2(b), the width Ws of the image pickup device is calculated by W.sub.S=W.sub.W×f/L. Also, the spacing between the left and right image pickup devices (picture distance in an inverted image state), that is, D.sub.S depicted in the drawing, is calculated by
[0185] D.sub.S=B(1+f/L), which is longer than the spacing between the left and right shooting lenses=human interpupillary width B.
[0186] An image projected on each image pickup device is in an inverted state. When the image is rotated at 180 degrees at each of the left and right positions for erection, the spacing between the left and right screens, that is, the picture distance (on a display side=an erect image state), becomes shorter than the human interpupillary distance B. Also, two triangles (two triangles partially overlapping each other) each configured of the reference window W.sub.ref depicted in FIG. 2 (b) and lines each passing through a principal point of a corresponding one of the left and right shooting lenses, the lines between which the window W.sub.W of the reference window W.sub.ref is interposed, and two triangles configured of lines each passing though the principal point of a corresponding one of the left and right shooting lenses, the lines between which both ends of a corresponding one of the left and right image pickup devices S, and a surface of the image pickup device itself are similar figures symmetric with respect to the principal point of a corresponding one of the left and right shooting lenses. Also, since left and right units are symmetric with reference to a center line 0 depicted in the drawing, when the drawing is folded along the center line 0 on the paper as a folding line, left and right optical axes Φ(L) and Φ(R) match each other, and the left and right axes overlap each other. Therefore, stereoscopic videos shot by the stereo camera of FIG. 2(b) are displayed at the same screen position on the TV with the reference dimension display screen of FIG. 1 (the large-sized stereoscopic television depicted in the drawing) alternately in a time-division manner or in a manner such that they are simultaneously superposed by polarization or the like, and when the left and right screens are viewed with the left and right eyes through eyeglasses for field-of-view separation, the corresponding points of the image at infinity are displayed by itself at the human interpupillary distance. Thus, stereoscopic video in an optimum state can be reproduced. Here, for projection at the same position with reference dimensions, no special measures are required, and it is enough to display an image on the image pickup device S depicted in FIG. 2 (b) at a display magnifying power of W.sub.D/W.sub.S, which is a simple ratio between the screen width W.sub.D of the display D and the width W.sub.S of the image pickup device.
[0187] Also, each of the left and right screen widths of respective sizes depicted in FIG. 1 is determined at a ratio between a distance of arrangement of each displaying apparatus and a distance to the TV with the reference dimension display screen (in FIG. 3, L.sub.1/L.sub.0=W.sub.P1/W.sub.P0). Therefore, since the left and right display screen widths are easily calculated because of having a simple ratio.
[0188] And, as depicted in FIG. 1, in stereoscopic video, the corresponding points at infinity should be displayed in all regions with the human interpupillary distance spacing. Thus, infinity=interpupillary distance=distance between optical axes of the left and right shooting lenses and, since light beams from the corresponding points at infinity entering the left and right shooting lenses of the stereo camera are parallel to each other, the corresponding points of the image at infinity projected onto the image pickup devices have a space equal to the distance between optical axes. Therefore, even with any display size, the spacing between the corresponding points at infinity between the left and right display screens=the human interpupillary distance can be set only by setting a corresponding center position of the optical axis of each of the left and right shooting lenses on the left and right image pickup devices at a position so that the spacing between the left and right positions on the display screen is equal to the human interpupillary distance spacing. That is, even with a stereoscopic displaying apparatus of any screen size, with reference to the left and right optical axes of the stereo camera, a spacing corresponding to the spacing between the left and right optical axes of the imaging unit is displayed on left and right of a reproduction screen so as to have a dimension equal to the human interpupillary distance.
[0189] FIG. 4 is a diagram of a state when the shooting lenses of the camera in the state depicted in FIG. 2 are replaced by wide-angle shooting lenses. To shoot a subject of the same size at a wide angle, the working distance is short. Also, to form an image on an image pickup device of the same size, the focal length of each shooting lens is short. As depicted in FIG. 4, when the lenses are replaced by shooting lenses of a short focal length, the distance at which left and right fields of view match each other in stereoscopy is also short. If an actual scene is directly viewed by the naked eye, when infinity (infinity in a sense of photo shooting) is included in a field-of-view frame W.sub.ref′ at a position depicted in FIG. 4 with a broken line, it is impossible to view a near-distance subject and a long-distance subject at the same time in stereoscopy (when a person views an actual scene, it seems that a narrow field of view is instantaneously viewed at every moment for intracerebral process, thereby allowing viewing in practice, but this causes fatigue to optic nerves). However, when stereoscopic image data shot by a camera in this state (shooting is performed by shooting lenses of a short focal length and the left and right fields of view match each other at a short shooting distance) is viewed with a stereoscopic television with a reference dimension display screen depicted in FIG. 1, the state of stereoscopy is excellent. When the reference window W.sub.ref′ depicted in FIG. 4 with the broken line is set, if an actual scene is directly viewed from that window, which is assumed to be real, parallax between a near-distance scene and a long-distance scene is large, and therefore it is impossible in stereoscopy to view the left and right fields of view as one. However, this stereoscopic video data is viewed with each displaying apparatus in the state of settings depicted in FIG. 1, the reference window W.sub.ref′ depicted in FIG. 4 with the broken line can be viewed as being far away to a position of a reference window W.sub.ref depicted in the drawing with a solid line, thereby allowing stereoscopy normally. Therefore, the use of wide-angle shooting lenses is advantageous because shooting can be performed in a narrow place by getting closer to a subject.
[0190] FIG. 5 illustrates an example of the use of lenses with a long focal length, conversely to the case of FIG. 4. When the focal length of the shooting lenses is long, the left and right shooting fields of view match each other at a position far away from a standard view distance (a position represented by a broken line). Also in this case, however, when viewing is performed with the displaying apparatus depicted in FIG. 1, the reference window W.sub.ref″ actually positioned far away at the position represented by the broken line can be viewed as being near a position of the field-of-view frame W.sub.ref represented by the solid line.
[0191] According to the description based on FIG. 4 and FIG. 5 above, the use of zoom lenses can be naturally implemented. Even when the focal length of the shooting lenses is varied anyway, the width and spacing of the image pickup devices fitting to the reference dimension display screen calculated by the above equations based on FIG. 2 suffice (in practice, a largish width of the image pickup devices may be used to set a read range). Then, even when the focal length of the shooting lenses of the stereo camera is changed, it is enough to only set, for example, each condition depicted in FIG. 1, in a predetermined state in the stereoscopic television on a viewing side. This is because light beams entering the left and right shooting lenses from the corresponding point at infinity are parallel to each other and also the distance between the optical axes of the shooting lenses is set at the human interpupillary distance. For this reason, the spacing between the corresponding points at infinity projected onto the left and right image pickup devices is equal to the human interpupillary distance.
[0192] Even when the focal length of the shooting lenses is changed with respect to the same stereo camera, the width of and spacing between the paired left and right image pickup devices are constant. Therefore, when the focal length of the shooting lenses is changed, the shooting distance where the left and right fields of view match each other is changed. In stereoscopic video, in any cases, a shooting state in which a subject at a distance shorter than the distance where the left and right fields of view match each other is within a shooting field of view is not preferable in general. In a stereo camera, even if a finder is subjected to stereoscopy, it is extremely difficult to visually recognize whether or not a subject within a shooting field of view is within a distance where the left and right fields of view match each other. By displaying collimation patterns depicted in FIG. 11 on the left and right screens of the finder in a superposed manner, viewability can be improved.
[0193] A stereo projector 60 depicted in FIG. 6 includes a pair of left and right projection lenses 61L and 61R set with a human interpupillary distance spacing. Furthermore, displays 62L and 62R having a width W.sub.D are placed with a spacing D.sub.D slightly longer than the spacing of the left and right projection lenses 61, thereby matching left and right projection screens each other on a screen S.sub.0 equivalent to the reference dimension display screen. Thus, only with focusing on the screen at an arbitrary distance, the projected images are displayed under the same conditions as those in the state depicted in FIG. 1, and a sense of stereoscopy can be obtained by observing from an appropriate viewing distance.
[0194] As long as the positions of the displays 62L and 62R are each at a position of an angle of projection θ depicted in the drawing, the size of the width W.sub.D of the display 62 is not restricted, and is determined by a sum of a focal length f and a focus control amount Δf of the lenses, that is, f+Δf, from screens S.sub.0 to S.sub.3 of the projection lenses, that is, at the entire projection distance. Therefore, the angle of projection θ depicted in FIG. 6 is set at the same angle as the angle of view α depicted in FIG. 2(b), it is not necessary to set the width Ws of the image pickup devices S depicted in FIG. 2 (b) and the width W.sub.D of the display 62 depicted in FIG. 6 at the same width.
[0195] However, in the drawings, in practice, the placement position (distance) of the projector and the view distance become equal to each other, and the projector itself becomes an obstruction. This can be solved by multiplying the placement distance (screens S.sub.0 to S.sub.3) of the projector by n (n>1). Therefore, the relation between the angle of projection θ and the angle of view α depicted in FIG. 2(b) described above is not θ=α, but a relation of θ<α holds.
[0196] FIG. 7 is a descriptive diagram when the stereo projector of FIG. 6 in which two projection units are placed side by side is modified with a single unit. Left and right videos displayed on left and right displays 73L and 73R depicted with broken lines form an image by left and right projection lenses 72L and 72R represented by broken lines on a screen 71, with left and right width directions being matched each other. The left and right projected screens match each other on the screen 71 although a distance between optical axes of the left and right projection lenses is set at 65 mm, which is equal to the dimension of a human interpupillary distance, because the spacing between the left and right displays 73L and 73R is set longer than the distance between the optical axes.
[0197] A triangle a, O.sub.(R), b and a triangle f, O.sub.(R), e depicted in FIG. 7 with broken lines are similar figures with the point O.sub.(R) as a point of symmetry. Similarly, a triangle a, O.sub.(L), b and a triangle d, O.sub.(L), c depicted with broken lines and a triangle a, O.sub.(C), b and a triangle h, O.sub.(C), g depicted with solid lines are similar figures, respectively, with the point O.sub.(L) and the point O.sub.(C) each as a point of symmetry. Therefore, line segments c-d, g-e, and e-f are equal to each other. Therefore, when the left and right projection lenses 72.sub.(L) and 72.sub.(R) depicted with broken lines are moved to an intermediate position of 72.sub.(c) represented by a solid line, the displays 73.sub.(L) and 73.sub.(R) depicted with the broken lines are superposed with an intermediate position 73.sub.(c) represented by a solid line. Also, as for left and right videos to be displayed on the displays 73.sub.(L) and 73.sub.(R), the left and right videos are displayed alternately in a time-division manner by using a single projection unit formed of the projection lens 72.sub.(C) and the display 73.sub.(C), this is equivalent to a projector with two left and right projection units placed side by side. And, an image X.sub.L on the display 73.sub.(L) and an image X.sub.R on the display 73.sub.(R) each with respect to a corresponding point of an image at infinity formed on the screen 71 with a dimension equal to the distance between the optical axes of the left and right projection lenses are alternately displayed on the display 73.sub.(C) so as to have a positional relation represented by .fwdarw.. The left and right positions are reversed because an inverted image is displayed on a display for displaying an original image in the projector and is reversed by the projection lenses.
[0198] Here, the corresponding points of images at infinity are depicted so as to be viewed at a horizontally symmetric position as depicted, that is, at a screen center position in a state of stereoscopy. However, an actual image at infinity is not restricted to be at the screen center, and this plotting is for convenience of description. However, light beams emitted from the same point of a subject at infinity enter the left and right eyes so as to be parallel to each other. Therefore, even this plotting is assumed to be understood in general.
[0199] FIG. 8 illustrates an example of application of the stereoscopic video displaying apparatus with a single projection unit described above with reference to FIG. 7. A stereoscopic video displaying apparatus 80 (stereoscopic television) is of a rear projection type for projecting video to be displayed on a DMD 81 by a projection lens 82 onto a transmission screen 84 (rear surface). On a front surface of the projection lens 82, a polarizing plate 83 is placed. In this state, when left and right videos are alternately displayed by the DMD 81 in a time-division manner, the left and right videos are alternately displayed on the transmission screen 84 in time series with the same state of polarization. When this stereoscopic video is viewed with the eyeglasses for stereoscopic video viewing described above, stereoscopy can be achieved with the left and right fields of view separated from each other.
[0200] Also, when LCOS is used as a display device in place of DMD, since light beams reflected on LCOS are polarized, the polarizing plate 83 depicted in FIG. 8 is not required.
[0201] FIG. 9 illustrates a stereoscopic video displaying apparatus 90 (stereoscopic television), in which a DMD rear projection unit 91 has a projection lens 92 with its front surface having a polarizing plate 93 placed thereon, and with its front surface having a liquid-crystal cell 94 placed thereon, and further with its front surface having a λ/4 plate 95 placed thereon, thereby alternately displaying stereoscopic left and right videos on the DMD 91 based on standard stereoscopic video data and driving the liquid cell in synchronization with the display image of the DMD 91 for control so that light enters with a relation in which a polarizing direction with respect to a fast axis of the λ/4 plate 95 is 45 degrees and −45 degrees, thereby alternately displaying stereoscopic video on the transmission screen 96 with circular polarization in clockwise and counterclockwise directions. In this case, by using circular-polarizing eyeglasses for viewing, no crosstalk occurs even when the eyeglasses are tilted.
[0202] Also, in the apparatus 90 described above, when LCOS is used in place of DMD, the polarizing plate 93 is not required.
[0203] In a stereo camera for television broadcasting, it is preferable to be able to observe a shooting field of view reflected on a stereoscopic finder and directly view an actual at the same time. To achieve such a stereoscopic finder (monitor), for example, the liquid-crystal display of a 12-inch width depicted in FIG. 1 is mounted on a stereoscopic television camera. The 12-inch-size monitor is among large ones as a camera monitor but, as depicted in the drawing, viewing can be made from a position of 350 mm. In this case, left and right images are alternately displayed in a time-division manner. At the same time, infrared rays for synchronization are sent from a synchronizing signal sending apparatus mounted on the display (not shown). And, on the left and right sides of eyeglasses for stereoscopic video viewing in which left and right fields of view are separated, left and right polarizing plates identical to each other are mounted, respectively. Furthermore, on its front surface, a liquid-crystal plate is mounted. Also, on the eyeglasses, a tilt-angle sensor is mounted. Left and right light beams alternately discharged from the LCD described above are polarized light beams identical to each other and in a predetermined direction. When the polarizing plates of the eyeglasses described above are set in a direction orthogonal to a direction of interrupting the polarized light beams discharged from the LCD, the left and right fields of view of the eyeglasses are closed to become dark. The state of the fields of view is changed in a manner such that a polarizing direction of incident light from the LCD is optically rotated by 90 degrees or 270 degrees by the liquid-crystal plate mounted on the front surface to cause both of the left and right fields of view to be in an open state and viewed brightly. When a voltage is alternately applied to the liquid-crystal plates mounted on the front surface of the eyeglasses with infrared rays sent in synchronization with a display image on the LCD, the liquid crystal becomes in a tension state with that voltage. As for polarized light discharged from the LCD, the polarizing direction is kept as it is, and light-shielding is made by the liquid-crystal plates of the eyeglasses to cause the fields of view to be dark. At the same time, when a voltage is alternately applied to the liquid-crystal plates of the eyeglasses in synchronization with the LCD with infrared rays, the left and right fields of view are alternately opened and closed, and the left and right fields of view for viewing the LCD is separated, thereby allowing stereoscopy. Also, when the eyeglasses are tilted, a relative directional relation between the LCD and the polarizing direction of the eyeglasses is distorted to cause crosstalk. The crosstalk is prevented by controlling and correcting the applied voltage with the tilt-angle sensor. Here, in the electronic imaging apparatus, the finder is not required to be integrated with the camera. For example, when a stereo camera configured of a pair of left and right shooting lenses and a pair of left and right image pickup devices and a notebook personal computer are connected to each other via a USB cable or the like, the PC itself serves as a finder.
[0204] FIG. 10 illustrates an embodiment of the stereoscopic television camera described above, and a two-dot-chain line 100 depicted in the drawing represents a reference window, which has been described above. This reference window is substantially a field of view of the camera, and is a field-of-view frame virtually set on an actual scene to be shot by the stereo camera. This virtual field-of-view frame represents a state equivalent to a state of viewing outer scenery from, for example, a house window or the like. However, since no frame is present in an actual scene, as a matter of course, a cameraperson 104 directly views, through eyeglasses for stereoscopic video viewing 103 over a stereoscopic television camera 102, not only a shooting field of view (the reference window 100 depicted in the drawing) but also a scene outside the shooting field of view. Then, when casting an eye onto a monitor 101, the person can view stereoscopic video of the same size and same sense of distance (the video can be viewed as such, although the actual display dimensions are different) as those of the reference window 100 on (in) the monitor 101.
[0205] A relation between the width of the monitor-purpose display 101 of FIG. 10 and an appropriate viewing distance is such that, when it is assumed in FIG. 3 that L.sub.1=350 mm, left and right display screen widths are:
[0206] for W.sub.P1, W.sub.P1=W.sub.P0×L.sub.1/L.sub.0, and
[0207] when it is assumed that W.sub.P0=1800 mm and L.sub.0=2500 mm,
[0208] each of the left and right display screen width W.sub.P1 is
W.sub.P1=1800×350/2500=252 mm.
[0209] A spacing between the left and right screens, that is, a picture distance, is represented by D.sub.P1 in FIG. 3, and
[0210] when D.sub.PN=B(1−L.sub.N/L.sub.0) represented above, and
[0211] D.sub.P1=B(1−L.sub.1/L.sub.0), and when the interpupillary distance is B=65 mm,
D.sub.P1=65(1−350/2500)=55.9 mm
[0212] The distance between the centers of the left and right image display screens, that is, the picture distance, is as described with FIG. 3 for display, and the spacing between the corresponding points of images at infinity is set at 65 mm, which is equal to the human interpupillary distance, for display. In FIG. 3, D.sub.P1(R) represents a screen for right and D.sub.P1(L) represents a screen for left. At this time, the size (entire width) of the display D.sub.1 is:
[0213] a total of W.sub.P1 and D.sub.P1, and W.sub.P1+D.sub.P1=252+55.9=307.9 mm
[0214] This dimension is slightly longer than 12 inches, that is, 12×25.4=304.8 mm, because the viewing distance itself is processed as a numerical value in steps of 10 mm for representation. Also, in practice, a bit longer viewing distance poses no problem.
[0215] Also, conversely, when the viewing distance L.sub.1 is calculated from the display size,
when it is assumed in FIG. 3 that L.sub.1=L.sub.0(W.sub.P1+D.sub.P1−B)/(W.sub.P0−B),
W.sub.P1+D.sub.P1=12″=304.8 mm,
[0216] B=65 mm,
[0217] W.sub.P0=1800 mm, and
[0218] L.sub.0=2500 mm, the viewing distance L.sub.1 is
L.sub.1=2500(304.8−65)/(1800−65)=345.53 mm.
[0219] Furthermore, to facilitate viewability of stereoscopy of the monitor of the stereoscopic television camera, a collimation pattern mainly formed of vertical lines is superposed and displayed by software on each of the left and right images to be displayed. FIG. 11 is a detailed diagram of a monitor 101 of the stereoscopic television camera 102 of FIG. 10. On the monitor 101 (display D.sub.1), a collimation pattern is displayed by software at a position so that each pattern and the left and right images superpose each other. As a matter of course, the collimation patterns are displayed only on the finder, and image data sent from the stereo camera is imaged image data only.
[0220] When the liquid-crystal monitor 101 of the stereoscopic television camera 102 described from p. 36, l. 20 to p. 40, l. 8 of Specification is stereoscopically viewed through the eyeglasses for stereoscopic video viewing 103, the state of adjusting the sense of stereoscopy can be visually recognized. And, the stereoscopic video viewed on the monitor of this stereoscopic television camera allows the sense of three dimensions in exactly the same state as that of a viewer receiving stereoscopic broadcasting shot and sent by this stereoscopic television camera and viewing stereoscopic television.
[0221] Furthermore, whether in mono or stereo, when moving pictures are shot, it is important to know the progress of situations simultaneously at the time of shooting. Therefore, an operational effect of this television camera configured so as to allow an actual scene to be always viewed while monitoring is enormous.
[0222] The stereoscopic video imaging apparatus described in an embodiment above is extremely effective, but the finder (monitor) portion is large, posing problems in hand-held shooting, portability, and others. Also, light shielding of the finder portion is incomplete, posing a problem in which it is difficult to view a finder image in a bright shooting environment.
[0223] FIG. 12 is a perspective view of a stereoscopic finder with eyeglasses for field-of-view separation fixed on a display, in which a display 121 of a stereoscopic finder 120 and a board 122 holding eyeglasses for field-of-view separation 130 are fixed by a casing 123. The display 121 is an LCD, for example, and alternately displays left and right videos so as to display the left video at a P.sub.L portion on a screen width W.sub.D depicted in the drawing and the right video in a P.sub.R portion thereon depicted in the drawing and separates the left and right fields of view in synchronization with the eyeglasses for field-of-view separation 130 for stereoscopy. Since the field of view is light-shielded from external light with the casing 123, the display can be clearly viewed even under a bright environment outdoors. Also, since the eyeglasses for field-of-view separation is fixed to the display, there is no fear of crosstalk even when the observer tilts his or her head.
[0224] Irrespectively of either large or small size as described with reference to FIG. 3, the finder (display) can be viewed equivalently to the reference dimension display screen, depending on how to display and the viewing distance. However, in consideration of tilt ability, a smaller display size is preferable. When the display size is small, the distance of viewing the display is shorter than the distance of distinct vision. When the observation distance is shorter than the distance of distinct vision, a diopter correction lens (plus diopter) depicted in FIG. 13 is required even for a person with normal vision. Also, with a movement (not shown) of a diopter correction lens 133 in an optical axis direction, adjustment can be made according to the diopter of the observer.
[0225] FIG. 13 is a configuration diagram of the eyeglasses for field-of-view separation 130 of the stereoscopic video displaying apparatus 120 of FIG. 12 depicted above, and the eyeglasses are mainly formed of a polarizing plate 132 and a liquid crystal plate 131. When the display 121 of the stereoscopic video displaying apparatus 120 of FIG. 12 is an LCD, display light is polarized light, and when the polarizing plate 132 depicted in FIG. 13 is placed (on both left and right) in an orthogonal direction in a state of light-shielding the polarized light mentioned above with respect to amplifying direction of display light, the field of view is closed. And, when the liquid-crystal plate is placed ahead of the polarizing plate 132 depicted in the drawing, display light of the LCD is rotated by 90 degrees or 270 degrees to be in a state of opening the field of view. In this state, when a voltage is applied to the liquid crystal plate 131, the twisted liquid crystal is linearly strained and light passes though as it is without being rotated by the liquid-crystal plate 131, and therefore light is shielded by the polarizing plate 132 to close the field of view. By applying a voltage to the liquid-crystal plate 131 depicted in FIG. 13 in synchronization with display of the display 121 depicted in FIG. 12, the left and right fields of view are separated for stereoscopy. Here, in the description above, although the field of view is in a closed state when a voltage is applied to the liquid-crystal plate 131 depicted in FIG. 13, if the polarizing plate 132 is placed in the same direction as that of a polarizing plate on the surface of the display (LCD) 121 depicted in FIG. 12, the field of view is in an open state when a voltage is applied to the liquid-crystal plate 131.
[0226] Here, when a non-polarizing material, such as an organic EL, is used as a display, if so-called shutter eyeglasses with one more polarizing plate further added to the front surface of the liquid-crystal plate 131 of FIG. 13 are used, the operation goes the same. Also, when a discharge lamp that lights at commercial frequencies is viewed with the shutter eyeglasses, flicker occurs. However, the finder 120 of FIG. 12 is shielded from external light. Since light beams viewed through the eyeglasses for field-of-view separation 130 are light beams of the display only, even if the eyeglasses for field-of-view separation 130 is shutter eyeglasses, flicker does not occur.
[0227] Here, in the description from an embodiment previously descripted above, the finder of the stereoscopic imaging apparatus is assumed, but this is merely an embodiment of the stereoscopic video displaying apparatus of another embodiment, and can be used as a normal stereoscopic video displaying apparatus. Also, the casing 123 of the stereoscopic video displaying apparatus 120 depicted in FIG. 12 may be other than that depicted in the drawing. For example, bellows, a foldable focusing hood as seen in conventional cameras, and others may be used (not shown).
[0228] In the case of a stationary-type stereoscopic video displaying apparatus, the display size is desirably large to some extent. This is because, in general, the larger the display size, the easier to increase resolution. When a large screen is viewed, if each observer uses eyeglasses for field-of-view separation, many people can advantageously view at the same time. However, in consideration of a sanitation problem of reusing eyeglasses used by others in public environment, a technique of mounting eyeglasses onto a display for peering still has an advantage. Even in this case, the display is desirably large to same extent. And, when the position where the display is placed, that is, the view distance, is desirably at a distance longer than the distance of distinct vision. At a distance longer than the distance of distinct vision, the diopter correction lens 133 depicted in FIG. 13 is not required, and diopter correction eyeglasses normally used by each observer may be used, or no eyeglasses may be worn, according to situations similar to those at the time of usually viewing something.
[0229] Conventionally, the electronic stereoscopic video imaging and display apparatuses and stereo photographs with two screens placed side by side have pursued different paths. However, in recent years, with advance of electronic video (image) machines, there is a demand for handling both as one, but it has not yet been fulfilled to date. To respond to this demand, the invention described in an embodiment of the present application is directed to a technique capable of fabricating a stereo photo print of two-screen side-by-side mode from one frame (paired left and right screens) projected on an electronic stereoscopic video displaying apparatus (for example, stereoscopic television) or freely fabricating a stereo slide of two-screen side-by-side mode from standard stereoscopic video data shot by a digital stereo camera.
[0230] According to FIG. 1, when left and right images are placed in a horizontal side-by-side display range depicted in the drawing and viewed (requiring diopter correction lenses because the viewing distance is extremely shorter than the distance of distinct vision), left and right fields of view match each other at the position of the large-sized television depicted in the drawing, and it looks as if a large-sized television exists at the display position depicted in the drawing. FIG. 3 is a detailed diagram of FIG. 1. When standard stereoscopic data is displayed on left and right screens (D.sub.2(L) and D.sub.2(R) depicted in the drawing) placed side by side for display on the reference display Do, the display screen becomes small, as a matter of course. Although the size of the display screen is a matter of general concern even in conventional mono video, the problem that has not been considered is how to determine the spacing between the left and right screens According to FIG. 3, when it is assumed that the placement distance of the display D.sub.0 of a reference dimension display screen is L.sub.0, the position of the stereo print (slide) D.sub.2 where left and right images are placed side by side (viewing distance) is L.sub.2, and a human interpupillary distance is B, the spacing between the left and right screens (D.sub.P2 depicted in the drawing) of the stereo print (slide) is determined as D.sub.P2=B(1−L.sub.2/L.sub.0).
Second Embodiment
[0231] The present invention actualizes stereoscopic television broadcasting and, in addition to that, allows stereoscopic video to be put on the Internet to present stereoscopic video of products for mail-order selling or the like. Also, describing about handling of products with their stereoscopic video is more effective than demonstration of actual products. This is because actual products have to be exhibited even some of them are unmarketable, which poses a problem in space efficiency and, even if many products are exhibited, products actually marketable are usually very limited, thereby causing a risk of obsolescence of unsold inventory. With an exhibition with stereoscopic video, the number of products to be actually displayed in stores can be significantly reduced.
[0232] Other than that, for the purpose of sale, it is effective to use stereoscopic video also for sale of automobiles and furniture. It is extremely effective not only for a salesperson to bring recorded video for demonstration but also for over-the-counter sale. The reason for this is that, since automobiles, furniture, and others require a vast exhibition space, many products cannot be exhibited. Also, it is economically impossible to prepare many high-priced products for exhibition and, furthermore, it may be impossible to present an actual use scene of some actual products. This goes the same for sale of apparel and others, and a fashion show can be presented as stereoscopic video.
[0233] Still further, in the example of sale of commodities described above, mobile exhibition is possible even for a large product, but in housing-related exhibition, such as the one for a room of an apartment, mobile exhibition of an actual product is impossible. In this case, the present invention is very effective.
[0234] Described above are sales-related examples of application. Other than that, the present invention is very effective when used as a guide for sightseeing.
[0235] Furthermore, an example of application unique to stereoscopic video is a educational training system. Description of various mechanical instruments and the structure and handling of aircraft is easier to understand with explanation with real pictures and stereoscopic animation rather than with explanation of an actual instrument or aircraft.
[0236] Still further, an example of most effective application is in the field of medical education. For example, a first step in surgery as an intern is to look at an operation near a person conducting it. In practice, however, it is impossible to place many onlookers around an operating table and the place may not be able to be actually viewed clearly even by looking nearby. In this case, a commentator describes video shot by a stereo camera (moving pictures are shot and recorded, and a necessary portion is advanced frame by frame to be repeatedly viewed in slow motion), and medical students can view it stereoscopically on a display of a personal computer on each desk or on a large-sized TV. In a conventional projection-type stereoscopic screening system, clear images cannot be obtained without a dark environment, and therefore it is required to reduce lighting or shield light from a window, which is not appropriate in an educational site. According to a stereoscopic television system of the present invention, sharp stereoscopic video can be viewed even under a bright environment.
[0237] Still further, in medical care, support from a medical specialist can be obtained with stereoscopic video through a communication line from a remote place, which contributes to telemedicine.
[0238] Here, in an example of medical application, a connection with a stereoscopic endoscopic camera allows stereoscopic viewing of the inside of a body cavity. In this case, a feature of the stereoscopic television system of the present application is such that, during stereoscopic viewing with a television (display), a line of sight can be moved to a surrounding environment with the state unchanged (without removal of eyeglasses for stereoscopy). Also, according to the liquid-crystal display, viewing can be made without reducing lighting.
[0239] Still further, stereoscopy is required especially in the field of atomic energy. To protect operators and surrounding environments from radioactivity, the present invention is expected to be applied to a monitor for remote control and monitoring.
[0240] Here, the present invention can be variously modified as long as modifications do not deviate from the spirit of the invention and, as a matter of course, the present invention covers these modifications.
INDUSTRIAL APPLICABILITY
[0241] The present invention is used for making video (image) stereoscopic in the field of transmission and reception of images using television broadcasting and communication lines and other fields, by utilizing the same video data even with different models of displaying apparatus.
