JPS586934B2 - Lenticular screen adjustment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lenticular screen method for creating a stereoscopic photograph in which two originals of the same subject are photographed from the left and right eye positions and are printed using a slit screen.

Conventional lenticular screen method To create stereoscopic photographs, two original plates taken of the same subject from different positions are used, a lenticular screen is layered on photographic paper or film, and printed from two directions, then separated and developed. By processing, a print is created in which the image to be delivered to the right eye and the image to be delivered to the left eye are converted into striations arranged alternately, and this print and the lenticular screen are connected in accordance with the direction of the striations in the print and the lenticular direction. There is a known method of creating a three-dimensional photograph by bringing the semi-cylindrical lens of the screen into close contact again so that the cylinder axis direction is parallel to the screen.

However, the streaks printed by this method are extremely thin, and the viewing position where stereoscopic viewing is possible is also limited to an extremely narrow range, which has the drawback that the image becomes invisible even if you deviate slightly from the found viewing position where stereoscopic viewing is possible.

To do this, the striations are expanded into stripes by moving the relative positions of the original plate, lens, lenticular screen, photographic paper, etc. during exposure, or by using a printing lenticular screen with a thickness different from that of the viewing lenticular screen. It would be impractical to create prints with no gaps, but this is not only complicated, but because a lenticular screen is used to create the print, the printed strips are subject to optical aberrations from the lenticular screen. This included size adversely affects stereoscopic vision.

In order to solve the above problem, there is a method of using a slit screen consisting of a transparent part and a black striped part instead of a lenticular screen when making a print.

That is, a slit screen with a transparent part having a width of 1/2 of the pitch P of the lenticular screen is created, and the first original plate is printed with this slit screen and photographic paper or film in close contact with each other. Move the slit screen by P/2 and cover the exposed area with the black stripe 2
Alternating P/2 obtained by printing the second original plate
This is a method to obtain a three-dimensional photograph by placing the print, which is filled with images on the left and right sides of the width without any gaps, in close contact with a lenticular screen.

The 3D photographs created by this method not only have the advantage of being able to expand the width of the image at the same time as printing, which required complicated work when creating 3D photographs using the lenticular screen. Since a lenticular screen is not used in the image, the aberration of the lenticular screen is not included in the image at all, and its adverse effects can be completely avoided.

However, the 3D effect of this 3D photograph is limited to a limited range on the screen, and outside this range a 2D image or an inverted 3D image is observed.

To explain this with reference to FIG. 1, when an observer who is directly facing the center of the screen at a distance D from the screen observes through the unit lenticular lens 1 at the center of the screen, the right eye sees only the right-eye image r1, and the left eye sees only the right-eye image r1. sees only the left eye image l1.

Next, when you move your line of sight sequentially to the left unit lens without moving your eye position and observe the image belonging to each unit lens through each unit lens, your line of sight will move to the right until it reaches unit lens 2, which is directly below your left eye. Stereoscopic vision is possible because the eyes and left eye see within the range of the right eye image and left eye image, respectively, but when they reach the unit lens 2, both the right eye and the left eye observe the right eye image r2. Therefore, it becomes a two-dimensional image, and the most 3D image becomes visible.

When the line of sight further moves to the left and the right eye sees the adjacent left-eye image, that is, the unit lens 3 is reached, the right eye sees the left-eye image l4 of the unit lens 4, and the left eye sees the left-eye image l4 of the unit lens 3. Since the right eye image r3 is viewed, it becomes an inverted stereoscopic image.

Similarly, the same phenomenon as above occurs when the line of sight is sequentially moved to the right.

Therefore, the stereoscopic viewing range of the entire screen, which is a combination of the stereoscopic viewing range for the left half of the screen and the stereoscopic viewing range for the right half, is limited to the area directly below the width of the viewing eyes, and the entire screen can be viewed simultaneously in stereoscopic viewing. I can't see it.

This phenomenon occurs because the pitch of the slit screen used to create the image is equal to the pitch of the lenticular screen, and in order to create a 3D photo that allows you to view the entire screen in 3D at the same time, you need a slit screen with an appropriate pitch. It turns out that we have to correct the pitch of the image using

Therefore, in the method for creating a stereoscopic photograph using a lenticular screen according to the present invention, by setting the pitch of the slit screen to an appropriate value larger than the pitch of the lenticular screen, the image pitch increases as the distance from the center of the screen of the stereoscopic photograph increases. By increasing the sum of the changes, even if the image is located far from the center of the screen, the right eye image can be seen by the right eye, and the left eye image can be seen by the left eye, so that the entire screen can be seen. It is characterized by enabling clear stereoscopic vision.

In the present invention, O1, O2 and O5 in FIG.
The center of curvature of the unit lens 5 at the edge of the image is taken as the point M, which is the usual viewing distance D for observing a stereoscopic photograph from O1 on the perpendicular line MO1 erected at the center of the screen, and the extension of MO1, MO2, and MO5 is the lenticular screen. A1 is the point that intersects with the bottom of
, A2, A5 and MA1, MA2, MA5 as left and right dividing lines, right eye images r1, r2, r5 and left eye images l1, l2, observed through unit lenses 1, 2, 5.
15 is arranged closely on the left and right sides of A1, A2, and A5.

Therefore, in this state, the right and left eyes of an observer who faces the center of the screen and observes the left side of the screen from a position at the normal viewing distance D will receive right-eye images on the left and right of the left-right dividing lines MA1, MA2, and MA5, respectively. r1, r2, r5 and left eye images l1, l2
, 15 must be seen.

Similarly, when observing the right side of the screen, the right eye must view the right eye image, and the left eye must view the left eye image, so in addition to the case of the left side, it is within the entire range of the stereoscopic photograph. All images can be clearly viewed in 3D.

Further, according to the present invention, it is possible to continue stereoscopic viewing even when the observation position is moved not only from the fixed observation position but also within a range corresponding to the vicinity thereof.

The moving range in which the entire screen can be viewed stereoscopically even if the viewing position is moved will be explained below with reference to FIGS. 3 and 4.

First, in Fig. 3, a straight line connecting both outer ends of the images rl and l1 and the center of curvature O1 of the unit lens 1, and a line MO drawn from O1 to the bottom of the lenticular screen are parallel to each other, spaced apart from each other, on both sides of the perpendicular line MO. Let G and I be the points that intersect the two straight lines GH and IJ, then the range surrounded by HGO1M and MO1IJ is the area where the right eye receives the r1 image and the left eye receives the l1 image through the unit lens 1 when the lenticular lens has no aberration. As shown in the figure, H'G'KI'
J' is the range of movement of the observation position represented by the midpoint M between the left and right eyes that can be used for stereoscopic vision.

Next, use the same method to find the movement range of the observation position for unit lens 1 to find the movement range for all the unit lenses, and find the common part of these. This is the movement range that allows stereoscopic viewing of the entire screen. is ultimately the same as the common part of the movement ranges of the unit lenses at both ends.

That is, in FIG. 4, the leftmost and rightmost unit lenses are 5 and 6, respectively, the left and right dividing lines for unit lenses 5 and 6 are MO5 and MO6, and the images belonging to unit lenses 5 and 6 are r5, l5 and r6, l6. Then, in the same way as the movement range of the observation position capable of stereoscopic vision for the unit lens 1 in FIG. The range surrounded by diagonal lines obtained as follows indicates the movement range of the observation position where the entire screen can be viewed stereoscopically.

Originally, if a lenticular screen was used to create prints and the position of the enlarger lens was appropriately selected, the pitch of the image would be corrected automatically, but as mentioned above, the negative effects of aberrations of each unit lens cannot be avoided, and the observation position There is a problem in enlarging the image, and printing the image using a slit screen is far superior, but in order to create a print that can be viewed in three dimensions at the same time, the pitch of the slit screen must be modified, as shown in Figure 2. It is necessary to satisfy the relationship.

In Figure 5, the center of curvature of the unit lens in the center of the screen is O
1. Li is the distance from O1 to the center of curvature Oi of the i-th unit lens, and the point where the extension of the left-right dividing line MOi intersects with the bottom surface of the lenticular screen, that is, the image for the right eye and the image for the left eye belonging to the i-th unit lens The boundary point of the image is Ai, the intersection of the perpendicular line drawn from the center of curvature Oi to the bottom surface with the bottom surface is Bi, AiBi is Xi, and the thickness of the lenticular screen is T.
, if the radius of curvature of the lens part is R and the pitch is P, then Xi=AiBi=OiBiLi/D=(TR)Li/
D, which is the sum of changes in image pitch from the center of the screen to the i-th unit lens.

Therefore, the change amount ΔX in the image pitch for one pitch of the lenticular screen can be obtained from the following equation.

△X=Xi-Xi-1 Therefore, the image pitch (slit screen pitch) P
′ can be expressed as follows.

P' = P + △ It is possible to create lenticular screen-type stereoscopic photographs that have little aberration and allow stereoscopic viewing of the entire screen over a wide range.

[Brief explanation of the drawing]

Fig. 1 is a principle diagram when the pitch of the image is equal to that of the lenticular screen, and the entire screen cannot be viewed stereoscopically. Fig. 2 shows an embodiment according to the present invention, in which the pitch of the image is set to an appropriate value different from the pitch of the lenticular screen. The principle diagram when the entire screen can be viewed stereoscopically, Figures 3 and 4
The figure is an explanatory diagram of the movement range that allows stereoscopic viewing of the entire screen even if the observation position is moved, and Figure 5 is an explanation of how to find the perfect image pitch that allows stereoscopic viewing of the entire screen. It is a diagram. 1, 2, 3, 4... unit lens.

Claims (1)

[Scope of Claims] 1. The surface is divided into a large number of longitudinal force direction stripes, and an image to be delivered to the right eye and an image to be delivered to the left eye are alternately printed on adjacent strips. In stereoscopic photography, which is placed in close contact with the back surface of a lenticular screen so that the direction of the band and the axis of the semi-cylindrical lens of the lenticular screen are parallel to each other, the printing of the image consists of a transparent part and a black striped part. Using a slit screen, when the usual viewing distance for observing stereoscopic photographs is D, the pitch and thickness of the lenticular screen are P and T, respectively, and the radius of curvature of the unit lens is R, the pitch of the slit screen is P.
' is P'=P+(T-R)P/D, and when Li is the distance from the center of curvature of the unit lens at the center of the screen to the center of curvature of the i-th unit lens,
A lenticular screen method for creating a stereoscopic photograph, characterized in that pressure is applied so that the sum of changes in image pitch Xi from the center of the screen to the i-th unit lens becomes Xi=(TR)Li/D.