Method and equipment for printing 3-D stereograph

A negative detection device comprising the likes of a CCD camera and line sensors is incorporated in a 3D photographic printing apparatus in which a lenticular sheet is used. The negative detection device measures the positional shift of the key subject of the 2D negative. If the key subject shift exceeds a predetermined threshold value, a correction is introduced to regulate the spacial parallax of a background object. If the key subject shift is less than a predetermined threshold value a correction is introduced to regulate the spacial parallax of a foreground object. Exposure is performed after positional adjustments are made.

TECHNICAL FIELD 
This invention relates to methods and apparatuses for printing of three 
dimensional (3D) photographs. More particularly, the invention relates to 
means for executing exposure control and exposure-position rectification 
in methods and apparatuses for printing of three dimensional (3D) 
photographs, in accordance with the differences in spacial parallax. 
BACKGROUND ART 
As a general method for preparing 3D photographs, there is the indirect 
method in which a multiple of negatives are prepared in advance for a 
single object, that has a depth and that comprises a principal object, a 
foreground and background, using a camera containing more than three 
lenses, the negatives being repetitively printed for more than three times 
onto a photosensitive sheet containing a lenticular sheet and the 
photographic angle being changed for each negative. 
FIG. 1 illustrates the 3D photographic method. The figure shows the case of 
a triple-lens camera consisting of the lenses 1, 2 and 3, in which the 
arrows marked with L and L' show the spans between the observation points 
while X and Y show respectively the parallaxes between the principal 
object 5 and background 4 and the principal object 5 and foreground 6. 
For instance, if the principal object 5 and background 4 are compared, 
there are parallaxes of -X on the first print, 0 on the second print and 
+X on the third print for each of the photographing stations. If the 
principal object and foreground are compared, there are parallaxes of +Y 
on the first print, 0 on the second print and -Y on of the third print. 
Negatives that have different positions of the images of the principal 
object, foreground and background are prepared from the photographing 
stations that are located either on a straight line parallel to the object 
or a line drawn through the center of the object. 
The prepared negatives are projected and printed onto a photosensitive 
lenticular sheet, which consists of a sheet that acts as a lenticular lens 
and that is coated on the back side with a photosensitive material, from 
the side of lenticular lens in the order of photographic stations starting 
from one negative frame to the end of other frames. 
When printing is to be done, a part of the principal object is selected as 
the key-subject, and exposure is executed with positions adjusted so that 
the key-subject for the images in each negative are coincident. If 
printing is done with the photographic angle changed for each negative, 
the images in each negative become separated into a band pattern by the 
lenticular lenses, and an image band that has a width in proportion to the 
photographic angle is repetitively arranged in correspondence with the 
photographic direction. 
The formation of a three dimensional image is explained considering as an 
example the case of a 3D photograph, which was prepared by a single 
exposure, one each of the 3-frames of a negative being pictured with a 
triple-lens camera for 3D use. FIG. 2 illustrates an example of a 
conventional 3D photograph. 
The image band formed on the photosensitive layer as shown in the figure is 
expanded sideways by the lenticular lens and will be seen as a restored 
image, and different restored images of the two image bands corresponding 
to different photographic stations will reach the left and right eye of an 
observer. A three dimensional view is obtained from the superimposition of 
different image information reaching the left and right eyes of the 
observer. 
In the figure, the right eye receives the image 2 in the center while the 
left eye receives the image 1 on the right. The image band 2 covers 
9.degree. while the image bands of 1 and 3 each covers 7.degree. of the 
filed of view, and the three dimensional view is obtained in the 
23.degree. viewing region in front of the 3D photograph. 
The three dimensional effect will differ depending on which photographic 
station corresponds to the negative, the restored images of which will 
reach the left and right eyes of the observer. In the event when the 
photographic stations are different, namely when two image bands of larger 
observation spans are combined, the three dimensional effect will improve, 
but because the spacial parallax of the images that enter the left and 
right eyes is large, this large difference in the image information 
received by both eyes will be interpreted either as being out-of-focus or 
as a wrong vision and causes a degradation in the photographic quality. 
Consequently, the printing apparatus is arranged in such a manner as the 
image bands being seen by both of the eyes are ordinarily those that are 
printed at the bandwidth and band pattern at the photographic angle for 
which the combination of neighboring negatives have the least the 
observation span. In addition, one part of the principal object, which is 
more important in comparison with the background and foreground objects, 
is specified as the key-subject, and exposure is performed so that the 
key-subjects of each of the frames of a negative are coincident. 
Contrary to conventional photography, in 3D photography, three dimensional 
effects are in demand more than such photographic characteristics as the 
color, contrast and sharpness. In order to obtain the three dimensional 
effect, although it is appropriate to increase the observation span, when 
an image with a large observation span enters both of the eyes it is 
likely that an out-of-focus situation or a wrong vision will occur. In 
conventional 3D photographic printing apparatuses, to prevent the 
out-of-focus situation and a wrong vision from occurring, the image band 
is formed so that a combination of negatives with the least observation 
span enters the left and right eyes of the observer. 
Using a multi-lens compact camera for 3D use where the lens spacing is 
fixed, and especially when a personnel having no special technical skill 
is photographing, a photographic composition of appropriate sense of depth 
of foreground and background is not always guaranteed and can even finish 
in one with a poor perspective. 
FIG. 3 shows an example of a conventional 3D photograph. Despite the fact 
that each of the frames of a negative are photographed with an appropriate 
spacial parallax, the right and left eyes of a observer will catch the 
image bands that are not neighboring and will not be able to appreciate 
the appropriate spacial parallax. If more than 4 image-bands are printed 
using a multiple of photographing stations from prepared negatives 
consisting of more than 4 frames, due to the fact that the view angle 
covered by a single image band is small, the right and left eyes of an 
observer will catch the image bands that are not neighboring depending on 
the observer's location, and that will result in an out-of-focus situation 
or a wrong vision. 
If an object of poor perspective effect or a small spacial parallax is to 
be photographed, a 3D photograph of the object prepared with conventional 
printing methods will not sufficiently produce a three dimensional effect. 
The present invention thus has the objective of realizing a 3D 
photographic printing method, wherein a desired spacial parallax is 
obtained, said photographic method producing 3D photographs of excellent 
three dimensional effects. 
Depending on the photographic object, not only the depths of the foreground 
and background, the relationship of the positions of the foreground 
object, the principal object and the background object will also be 
different, in addition the spacial parallaxes of the foreground, principal 
and background objects not being fixed. 
If for instance, a composition of the principal object located in the 
foreground is to be photographed, despite the fact that the parallax 
between the principal object and the foreground object is slight, that 
between the principal object and the background object is extremely large. 
In conventional 3D photographic printing apparatuses, where a part of such 
a principal object is selected as the key-subject and exposure is 
performed so as to make such key-subjects definitely coincident, the 
parallax of the background object will become too large that an 
out-of-focus situation will arise in the background. 
Contrarily, when a composition of the principal object located in the 
background is photographed, despite the fact that the parallax between the 
principal object and the background object is slight, that between the 
principal object and the foreground object becomes extremely large. When a 
part of such a principal object is selected as the key-subject and 
exposure is performed so as to make such key- subjects definitely 
coincident, the parallax of the foreground object will become too large 
that an out-of-focus situation will arise in the foreground. 
When a prepared 3D photograph is viewed in a situation where the parallax 
is extremely large as above, it is only possible to grasp distinctively 
the neighborhood of the key-subject of the principal object, and as a 
whole, the photograph will lose its finish and three dimensional effect. 
The present invention has the objective of providing 3D photographs of 
excellent finish by obtaining a 3D photographic printing apparatus that 
takes account of the differences in the spacial parallaxes among the 
foreground object, the principal object and the background object. 
DISCLOSURE OF THE INVENTION 
1) In order to obtain an excellent three dimensional effect, in the present 
invention the parallax of each of the frames of the negatives which 
construct a 3D photograph is measured for determining the depths of the 
foreground object, principal object and the background object resulting 
from the variation in the parallax due to the photographic location, and 
based on those results, an image band is prepared which has a bandwidth 
and band pattern resulting in the optimum three dimensional effect for the 
combination of the negatives which have different observation spans. 
In order to determine the spacial parallax, a negative-detecting device 
comprising a CCD camera and line sensors and the like is incorporated in 
the printing apparatus, and with each of the negative frames inserted the 
spacial parallax is determined from the specification of the coordinates 
on a TV monitor. 
In the event the variation in the spacial parallax due to the photographic 
location is small, an exposure pattern is obtained that forms an image 
band having a bandwidth and band pattern resulting in a three dimensional 
effect from the combination of negatives of large observation spans. 
In the event the variation of the spacial parallax is sufficient, exposure 
is performed at the regular bandwidth and band pattern for which the 
observation of 3D vision is possible for the combination of the negatives 
of small observation span obtained at adjoining photographic stations. 
2) In order to improve the finish of 3D photographs, in the 3D printing 
apparatus of the present invention, shift in the key-subject belonging to 
the principal object of each of the negatives is determined and corrected 
based on those results. In case the shift in the key-subject belonging to 
the principal object exceeds a threshold value, by judging the fact that 
the principal object is in the foreground a correction is introduced so as 
to regulate the parallax with the background object, and after position 
adjustments are made the exposure is performed. 
Contrarily, when the shift in the key-subject belonging to the principal 
object is below the threshold value, by judging the fact that the 
principal object is in the background a correction is performed so as to 
regulate the parallax with the foreground object, and after position 
adjustments are made, exposure is performed. Even in such photographs as 
scenic photographs where a principal object can not be specified, the 
correction is introduced by selecting an arbitrary position as the 
key-subject and measuring the shift. In order to measure the key-subject 
belonging to the principal object, a negative-detecting device that 
consists of such items as a CCD camera and line sensors and that is 
incorporated into the 3D photographic printing apparatus is used. 
1) Below is a description of printing methods and apparatuses of 3D 
photographs for excellent three dimensional effect. FIGS. 4 and 5 show the 
flow chart of the program to be incorporated in the present inventive 3D 
photographic printing apparatus. The flow charts of FIG. 4 and 5 are 
connected together at the symbol S. In this example, the parallax is 
estimated with reference to a single point on the principal object. 
As show in the figure, after establishing the initial settings of the 
positions of the CCD camera and exposure station, an image on one negative 
that is to become the reference image is photographed and the coordinates 
of the reference point are registered in memory. Next, the remaining image 
on the negative is photographed as the image for comparison, and the 
coordinates of the reference points for the images on each of the 
negatives are also registered in memory. In the event the shift in the 
positions of the reference points obtained from coordinates exceeds a 
preset threshold value, the observation span of adjoining negatives are 
large for the spacial parallax to be judged as adequate, and exposure is 
performed with the exposure pattern that will result in a three 
dimensional effect for the combination of the negatives of the adjoining 
photographic stations. 
In the event the shift in the positions of the reference points obtained 
from the coordinates is below the threshold value, the observation span of 
adjoining negatives are small and the spacial parallax is judged to be 
inadequate. Exposure is then performed with the exposure pattern that will 
result in a three dimensional effect for the combination of the negatives 
of far-apart photographic stations of the sequence so that the spacial 
parallax is larger and a photograph of excellent three dimensional effect 
is produced. 
FIG. 6 shows a schematic diagram of one example of the present inventive 3D 
photographic printing apparatus. The apparatus generally consists of: an 
exposure section that comprises such items as a light source, a lens, an 
exposure station and their driving devices; an image processing section 
that has such functions as photographing, processing and displaying 
functions; and a computer for control purposes comprising a CPU, ROM and 
RAM; and in addition an I/O, a circuit for the purpose of executing 
input/output dealings. 
The negative 7 is photographed using the CCD camera 11 and projected onto 
the television monitor 13 via the image processing section 12. Using a 
track ball 14 to move a cursor on the television monitor, it is possible 
to specify a position on the television monitor. The image processing 
section 12 transmits the coordinates specified by the cursor to a 
connected computer, where the shift in the image of each frame of the 
negative is computed and the spacial parallax determined. 
In the example shown in the figure, the exposure lens 15 and CCD camera 11 
are mounted on an identical plate, and connected to which are the two 
motors 16 and 17 that move the lens and the camera in two perpendicular 
directions. The exposure station 28 also is mobile and has a motor 18 for 
moving the same. The motors 16 and 17 for moving the lens and camera and 
the motor 18 for the exposure station are each connected via respectively 
the drive circuits 19 and 20 to the control computer comprising CPU 25, 
ROM 26 and RAM 27. In addition, the keyboard 24 that is used for operating 
the computer and the display 23 are each connected to the computer via the 
I/O ports 21 and 22 in the same manner as the drive circuits 19 and 20. 
The apparatus of the present invention captures each of the frames of 
negatives, computes the changes in the coordinates of a reference point 
specified by a cursor on the screen of a television monitor, and changes 
the photographic angel and the printed band pattern in the event the 
parallax is judged to be small so that the combination of the negatives 
having a larger observation span is used to produce three dimensional 
effect. 
For example, in the case of 3D photographic preparation in which a negative 
of 3-frames each having a small spacial parallax is photographed 3 times, 
exposure is executed in the exposure pattern for which the bandwidth 
between the two extreme image bands become larger. 
FIG. 7 shows a diagram for explaining one example of a photograph printed 
with the present inventive 3D photographic printing apparatus. As shown in 
the figure, due to the fact that the image bands of the two extremes (1) 
and (3) easily contain the optic angle, when viewed from the front, both 
eyes will receive restored images of (1) and (3), which are due to the 
combination of negatives of larger observation span and an excellent 3D 
photograph is produced. 
In addition, as shown above in FIG. 3 as another example, considering the 
case of 3D photographic preparation in which a negative of 4-frames is 
photographed 6 times to prepare 6 image bands, with conventional printing 
methods the image bands (1) and (3), which are not adjoining, will reach 
both eyes of the observer although each frame has an appropriate spacial 
parallax, and exposure is performed by having changed the exposure pattern 
even if an out-of-focus situation is to occur. 
FIG. 8 shows a diagram for explaining yet another example of a photograph 
printed with the present inventive 3D photographic printing apparatus. By 
changing the band patterns of FIG. 3 to those in FIG. 8, the restore 
images of the image bands (2) and (3) will reach the eyes of the observer 
and an excellent three dimensional photograph is obtained. Contrarily, 
when the spacial parallax of each of the frames is too small, a band 
pattern such as that in FIG. 3 is printed, and the restored images of the 
image bands (1) and (3) are made to reach the eyes of the observer to 
obtain an excellent 3D photograph. 
(2) Below is a description of printing methods and apparatuses for 
obtaining 3D photographs of excellent finish. FIGS. 9 and 10 show the flow 
chart of the program for the detection of negatives and the control of 
exposure station position in the present inventive 3D photographic 
printing apparatus. The symbol S in the figures indicates the fact that 
the flow charts are connected. 
Threshold value of the shift and the origin of the coordinate axes are 
specified as the initial settings, and having specified the key-subject 
position of the reference image the coordinates and the data at the 
key-subject position are input. From the comparison image, the image at 
the key-subject location is referenced and the coordinates of the 
key-subject of the comparison image obtained. By comparing the coordinates 
of the key-subjects of the reference image and image of comparison, the 
amount of shift is computed, and if the threshold value has been exceeded, 
a uniform value of correction is added to the each of the shifts and the 
exposure position recalculated. Complied with the corrected exposure 
position, the lens, negative and the exposure station or the like are 
moved, and the exposure is appropriately done. 
One example of the method used for computing the correction in the present 
inventive 3D photographic printing apparatus is described. When 3-frame 
negatives are arranged with 18.5 mm pitch, the correction is performed 
based on the fact that the shifts greater than 1 mm or less than 0.3 mm 
constitute the impermissible range of shifts. When the condition, 0.3 
mm.ltoreq.1 (the horizontal distance between the key-subject of the 
reference image and the key-subject of the comparison 
image)--18.5.vertline..ltoreq.1 mm is satisfied, the amount of shift is 
considered to be permissible, and the exposure is performed without any 
correction, coinciding the key-subjects. 
When the condition, .vertline. (the horizontal distance between the 
key-subject of the reference image and the key-subject of the comparison 
image)--18.5.vertline.&gt;1 mm is satisfied, by considering the horizontal 
distance between the key-subject of the reference image and the 
key-subject of the comparison image as 19 mm the superimposing is 
executed. When the condition, .vertline. (the horizontal distance between 
the key-subject of the reference image and the key-subject of the 
comparison image)--18.5.vertline.&lt;0.3 mm is satisfied, by considering the 
horizontal distance between the key-subject of the reference image and the 
key-subject of the comparison image as 18.8 mm the superimposing is 
executed. 
One example of printing using the present inventive 3D photographic 
printing apparatus is described. As shown in FIG. 11, when viewed from the 
camera 30 the principal object 31 is extremely close and the key-subject 
position on each image will vary markedly resulting in a large shift. 
As shown in FIG. 12, despite the fact that the frames of the negative have 
a pitch of 18.5 mm, the decision is made to introduce a correction 
because, with respect to the reference image the key-subject of the 
comparison image is either located at a position below the initial 
input-setting, 17.5 mm (namely, .vertline.17.5-18.5.vertline.&gt;1 mm), or at 
a position exceeding 19.5 mm (namely, .vertline.19.5-18.5&gt;1 mm). 
When printing is performed using a conventional 3D photographic printing 
apparatus, as shown in FIG. 13, parallax of the background becomes so 
large that an out-of-focus situation will arise. When printing is 
performed using the present inventive 3D photographic printing apparatus, 
as shown in FIG. 14 the photographic finish will improve because it is 
possible in the present invention to regulate the spacial parallax as a 
whole becoming extremely large. 
As shown in FIG. 15, in the case when the principal object is in the 
extreme background, the key-subject position in each of the images does 
not vary and the shift is hardly existent. As shown in FIG. 16, despite 
the fact that the frames of the negative have a pitch of 18.5 mm, the 
decision is made to introduce the correction because, with respect to the 
reference image the key-subject position of the comparison image is 
located within the threshold range, 18.2 to 18.8 (namely, 
.vertline.18.2-18.5.vertline.&lt;0.3 mm or .vertline.18.8-18.5.vertline.&lt;0.3 
mm). 
When printing is performed using a conventional 3D photographic printing 
apparatus, as shown in FIG. 17, the parallax of the foreground becomes so 
large that an out-of-focus situation will arise. When printing is 
performed using the present inventive 3D photographic printing apparatus, 
as shown in FIG. 18, the photographic finish will improve because it is 
possible in the present invention to regulate the spacial parallax as a 
whole becoming extremely large. 
In situations where the principal object can not be specified as in scenic 
photographs, the amount of shift is measured by specifying an arbitrary 
position as the key-subject. Generally, it is appropriate to specify the 
key-subject on the foremost object in the fore-sight out of the entire 
objects. In addition, it is also appropriate to fix the key-subject in 
advance, and in which case it is effective to place the key-subject in the 
central image region. 
As described above, by using an exposure pattern consisting of image 
bandwidth and band pattern that differ in accordance with the spacial 
parallax of the image obtained at each of the photographic station, it is 
possible in the present inventive 3D photographic printing apparatus to 
prepare a photograph that create a restored image having a suitable 
spacial parallax in the eyes of an observer. 
The out-of-focus condition resulting from spacial parallax being extremely 
large is resolved, and three dimensional effects can be controlled by 
supplementing the inadequacies in the depth of the background and 
foreground. Additionally, utilization of the present inventive printing 
apparatus has the advantage that 3D photographs emphasizing the 3D effect 
can be produced. 
By utilizing the present inventive 3D photographic printing apparatus, it 
is possible to produce photographs with a minor focal-point blurring by 
means of regulating to a suitable value the spacial parallax of either the 
background or the foreground that results when the principal object is 
located more closer to foreground or to the background. Although there was 
a tendency in 3D photography for photographing only objects of a specific 
composition, the present invention has the advantage that, irrespective of 
the positions of the principal object, background object and the 
foreground object, excellent 3D photographs can be produced by using the 
present inventive 3D photographic printing apparatus, even of the likes of 
scenic views.

BEST MODE FOR CARRYING OUT THE INVENTION 
The embodiments of the present inventive three dimensional (3D) printing 
apparatus are explained with reference to illustrations. As shown in FIG. 
20, a negative 34 inserted in the negative mask 33 is captured by a CCD 
camera, and the central frame of a three-frame negative is displayed as 
the reference image, as shown in FIG. 21, on a television monitor 35. In 
this embodiment, the television monitor 35 is connected to an image 
processing section and a CPU, and by the manupulation of a track-ball 38 
and the cursor 37 can be moved. 
When a principal object can be specified, the position of a key-subject 36 
on the screen is specified by the cursor 37. In the image processing 
section, the coordinates and the image of the key-subject specified are 
captured, and based on the captured image information, the CCD camera 
scans and determines the key-subjects on the comparison images. 
As shown in FIG. 22 by the arrows A and B, the distances between the 
key-subjects of the comparison images and that of the reference image are 
obtained, and an amount of correction is determined with reference to a 
threshold value that is preset.