OSA's Digital Library

Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 20, Iss. 19 — Sep. 10, 2012
  • pp: 21137–21144
« Show journal navigation

3D objects enlargement technique using an optical system and multiple SLMs for electronic holography

Kenji Yamamoto, Yasuyuki Ichihashi, Takanori Senoh, Ryutaro Oi, and Taiichiro Kurita  »View Author Affiliations


Optics Express, Vol. 20, Issue 19, pp. 21137-21144 (2012)
http://dx.doi.org/10.1364/OE.20.021137


View Full Text Article

Acrobat PDF (2728 KB)





Browse Journals / Lookup Meetings

Browse by Journal and Year


   


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools

Share
Citations

Abstract

One problem in electronic holography, which is caused by the display performance of spatial light modulators (SLM), is that the size of reconstructed 3D objects is small. Although methods for increasing the size using multiple SLMs have been considered, they typically had the problem that some parts of 3D objects were missing as a result of the gap between adjacent SLMs or 3D objects lost the vertical parallax. This paper proposes a method of resolving this problem by locating an optical system containing a lens array and other components in front of multiple SLMs. We used an optical system and 9 SLMs to construct a device equivalent to an SLM with approximately 74,600,000 pixels and used this to reconstruct 3D objects in both the horizontal and vertical parallax with an image size of 63 mm without losing any part of 3D objects.

© 2012 OSA

1. Introduction

A wide range of research has been conducted for reconstructing 3D objects in video manner based on the holography principle [1

1. N. Peyghambarian, S. Tay, P.-A. Blanche, R. Norwood, and M. Yamamoto, “Rewritable holographic 3D displays,” Opt. Photon. News 19(7), 22–27 (2008). [CrossRef]

, 2

2. K. Yamamoto, T. Mishina, R. Oi, T. Senoh, and T. Kurita, “Real-time color holography system for live scene using 4K2K video system,” Proc. SPIE 7619, 761906, 761906-10 (2010). [CrossRef]

].One of the important topics for this kind of 3D display is how to enlarge the image size S for 3D objects, as well as how to enlarge the viewing-zone angle θ indicating the range where 3D objects can be seen. Naturally, it is desirable for both S and θ to be large. If we denote the number of pixels of SLM here by Nx horizontally and Ny vertically, the pixel pitch by px horizontally and py vertically, and the wavelength of the reconstructed light by λ, then the image size Sx and viewing-zone angle θx in the horizontal direction are given as follows.
Sx=Nxpx
(1)
θx=2sin1(λ/(2px))λ/px
(2)
Therefore, it is apparent that the product Sxθx is nearly proportional to Nx as shown in Eq. (3).
SxθxNxλ
(3)
In order to simultaneously increase Sx and θx, the number of pixels Nx must increase. Note that we only provided an explanation for the horizontal direction here since the vertical direction is exactly the same. All subsequent explanations will also only be given for the horizontal direction.

Although it is desirable to increase the number of pixels Nx, the maximum number is limited for a single SLM in practice. Therefore, a space-division multiplexing and time-division multiplexing have been investigated. The former one is to increase the number of pixels using multiple SLMs. If we denote the number of pixels in the horizontal direction of each SLM by Nx and denote the number of SLMs by Kx, then Nx=NxKx. The latter one is to change light path and update hologram data quickly to make it seem as if Nx were increased. Some methods for the latter one have been studied such as the method to use shutters [3

3. T. Mishina, F. Okano, and I. Yuyama, “Time-alternating method based on single-sideband holography with half-zone-plate processing for the enlargement of viewing zones,” Appl. Opt. 38(17), 3703–3713 (1999). [CrossRef] [PubMed]

, 4

4. T. Senoh, T. Mishina, K. Yamamoto, R. Oi, and T. Kurita, “Wide viewing-zone-angle full-color electronic holography system using very high resolution liquid crystal display panels,” Proc. SPIE 7957, 795709, 795709-12 (2011). [CrossRef]

] and the method to use a galvano mirror [5

5. Y. Takaki and N. Okada, “Hologram generation by horizontal scanning of a high-speed spatial light modulator,” Appl. Opt. 48(17), 3255–3260 (2009). [CrossRef] [PubMed]

]. In addition, the Active TilingTM is a promising method that uses lens array and shutters to write hologram data on optically addressed SLM in sequence, which is also classable to time-division multiplexing [6

6. M. Stanley, R. W. Bannister, C. D. Cameron, S. D. Coomber, I. G. Cresswell, J. R. Hughes, V. Hui, P. O. Jackson, K. A. Milham, R. J. Miller, D. A. Payne, J. Quarrel, D. C. Scattergood, A. P. Smith, M. A. G. Smith, D. L. Tipton, P. J. Watson, P. J. Webber, and C. W. Slinger, “100 Mega-pixel computer generated holographic images from Active TilingTM – a dynamic and scalable electro-optic modulator system,” Proc. SPIE 5005, 247–258 (2003). [CrossRef]

]. Since it is known that the space-division and time-division multiplexing can be implemented together ingeniously [7

7. T. Senoh, T. Mishina, K. Yamamoto, R. Oi, and T. Kurita, “Viewing-zone-angle-expanded color electronic holography system using ultra-high-definition liquid crystal displays with undesirable light elimination,” J. Disp. Technol. 7(7), 382–390 (2011). [CrossRef]

], we deal with only a space-division multiplexing in this paper.

Various methods have been proposed for increasing the viewing-zone angle by a space-division multiplexing. These methods typically face with the problem that some parts of the viewing-zone angle are missing because it is physically impossible to locate the SLMs very closely together. Therefore, finding a means of eliminating this missing segment problem is a major issue. For example, a method of doubling the viewing-zone angle by using two SLMs and a beam splitter [8

8. T. Mishina, M. Okui, K. Doi, and F. Okano, “Holographic display with enlarged viewing-zone using high-resolution LC panel,” Proc. SPIE 5005, 137–144 (2003). [CrossRef]

] and a method of tripling it by using three SLMs and beam splitters [7

7. T. Senoh, T. Mishina, K. Yamamoto, R. Oi, and T. Kurita, “Viewing-zone-angle-expanded color electronic holography system using ultra-high-definition liquid crystal displays with undesirable light elimination,” J. Disp. Technol. 7(7), 382–390 (2011). [CrossRef]

] have been proposed. A method of enlarging the viewing-zone angle by a factor of 12 in the horizontal direction has also been proposed by locating SLMs in an arc shape to project onto a vertical diffusing screen; however this method loses vertical parallax [9

9. J. Hahn, H. Kim, Y. Lim, G. Park, and B. Lee, “Wide viewing angle dynamic holographic stereogram with a curved array of spatial light modulators,” Opt. Express 16(16), 12372–12386 (2008). [CrossRef] [PubMed]

]. Yet another method provides two sets of multiple SLMs located in arc shapes, which are combined using a beam splitter [10

10. F. Yaraş, H. Kang, and L. Onural, “Circular holographic video display system,” Opt. Express 19(10), 9147–9156 (2011). [CrossRef] [PubMed]

]. All of the methods unfortunately cannot control the image size at the same time.

Some methods have also been proposed for increasing the image size by a space-division multiplexing. In these methods, finding a means of eliminating missing image segments is also a major issue just like it is for the methods of increasing the viewing-zone angle. For example, a method of tripling the image size has been proposed by using three SLMs and a large beam splitter and lenticular sheet [11

11. N. Fukaya, K. Maeno, O. Nishikawa, K. Matsumoto, K. Sato, and T. Honda, “Expansion of the image size and viewing zone in holographic display using liquid crystal devices,” Proc. SPIE 2406, 283–289 (1995).

]. In this method, the image size of each SLM and the gaps between SLMs must be the same. A concept using multiple modules that combine an enlargement optical system and a resolution conversion technique has also been proposed [12

12. Y. Takaki and J. Nakamura, “Development of a holographic display module using a 4K2K-SLM based on the resolution redistribution technique,” OSA Tech. Digest DH, DM2C.5 (2012)

]. A problem with both of these proposals is that they only provide horizontal parallax.

In this paper, we propose a method for increasing the image size, and describe the device we developed on the method. The method locates an optical system containing a lens array and other components in front of multiple SLMs. It cannot only eliminate the missing image segments, but also control the balance between image size and viewing-zone angle by varying the focal length of lenses in the latter half within the optical system. In addition, it can exhibit parallax in both the horizontal and vertical directions unlike the methods mentioned earlier.

This paper is organized as follows. Chapter 2 describes the basic configuration of our method, Chapter 3 describes the particular specifications of the device and the experimental results, and Chapter 4 presents conclusions.

2. Configuration to eliminate the gaps between SLMs

Figure 1
Fig. 1 Configuration to eliminate the gaps between SLMs.
shows the configuration of this device. This figure only illustrates an example of the horizontal direction for the case Kx=3. First, parallel light from a coherent light source is incident perpendicularly on SLM C0 through beam splitter B0. Consequently, this is so-called in-line holography. The hologram data is displayed on C0. Note that the superscript at the top right of the letter represents the location within the array. Since the pixels are arranged in a grid pattern on a thin hologram, the light reflected on C0 contains a primary beam, conjugate beam, carrier beam and high-order beams of each of them. Since the object beam is generated as a primary beam, the other beams are unnecessary light and must be eliminated.

Here, let us simply denote the group of C0, B0, L00, F0 and L10 by partial optical system A0. By locating the partial optical system A0 and A2 adjacent to A1, the images due to C0, C1, and C2 will be tiled on plane P2 without gaps. As a result, the missing image segments due to the gaps between the SLMs will disappear.

The group of lenses L00, L01, and L02 forms a lens array L0 in practice as well as the group of lenses L10, L11, and L12 forms a lens array L1. F0 is a spatial filter for eliminating the conjugate beam, carrier beam, and high order beams, which are unnecessary light [13

13. K. Yamamoto, R. Oi, T. Mishina, and M. Okui, “Half-zone-plate processing for objects on both sides of hologram display,” Proc. SPIE 6912, 69120Q, 69120Q-10 (2008). [CrossRef]

]. The group of spatial filters F0, F1, and F2 forms a spatial filter array F in practice.

Finally, the light is incident on lens L2 and lens L3. By setting the focal length f2 of L2 and focal length f3 of L3 as follows, the image that had been enlarged at P2 will be returned to its original size at plane P3.

f3=(S'S'+T')f2
(6)

The image on C0 at P1 is enlarged and appears at P2without gaps. After that, the image at P2 is shrunk and appears at P3. The relation among viewing-zone angle θx, total image size and total gaps, i.e. total missing segments, is shown in Table 1

Table 1. Relation among viewing-zone angle, total image size and total gaps

table-icon
View This Table
| View All Tables
.

If you set a fixed value for Nxλ in Eq. (3) and you intend to vary the image size Sx and viewing-zone angle θx, you should set f2 and f3 to different values than in Eq. (6). Since that is a single optical axis, there also will be no missing image segments at P3, just like at P2. However, in this case, since the scaling factor in the optical axis direction differs from the scaling factor in other directions, you must provide hologram data that compensated for this discrepancy.

This configuration can exhibit parallax in both the horizontal and vertical directions. It can also control the balance between the image size Sx and viewing-zone angle θx according to the values of f2 and f3. By varying the focal lengths of lenses, you can configure the ratio between the image size of each SLM and the gap between SLMs. The image size Sx can be enlarged by increasing the number of SLMs Kx and using a large-aperture lens for L2. Unnecessary light can be eliminated by spatial filter F0. Those are some advantages of this configuration.

The Active TilingTM also includes lens array [6

6. M. Stanley, R. W. Bannister, C. D. Cameron, S. D. Coomber, I. G. Cresswell, J. R. Hughes, V. Hui, P. O. Jackson, K. A. Milham, R. J. Miller, D. A. Payne, J. Quarrel, D. C. Scattergood, A. P. Smith, M. A. G. Smith, D. L. Tipton, P. J. Watson, P. J. Webber, and C. W. Slinger, “100 Mega-pixel computer generated holographic images from Active TilingTM – a dynamic and scalable electro-optic modulator system,” Proc. SPIE 5005, 247–258 (2003). [CrossRef]

]. In that method, the lens array is used to write hologram data on optically addressed SLM in sequence. Our method uses lens array to eliminate the missing image segments for space-division multiplexing, which is different from Active TilingTM.

3. The device we developed and experiments

We constructed a device with the parameters shown in Table 2

Table 2. Device parameters

table-icon
View This Table
| View All Tables
. This device, which uses an optical system and 9 SLMs, corresponds to a SLM with approximately 74,600,000 pixels. Figure 2
Fig. 2 Exterior view of the constructed device.
shows an exterior view of the constructed device. The arrows in the figure indicate the light path. We performed the following experiments using hologram data created by computer generated hologram (CGH) technology. Note that in this device, Tx is three times the size of Sx due to physical constraints of the SLMs. In other words, the missing area ((Sx+Tx)×(Sy+Ty)Sx×Sy) is 15 times larger than display area (Sx×Sy) as shown Fig. 3
Fig. 3 Display area and gap area.
. Therefore, observer cannot directly understand the reconstructed object, and an optical system like the one described here is required.

First, we confirmed the viewing-zone angle, the image size, and the fact that there were no missing segments. Figure 4
Fig. 4 Experimental results of simple graphic on hologram plane.
shows the experimental results. Figure 4(a) shows the design values of the displayed object on hologram plane. Figure 4(b), 4(c), and 4(d) show photographs that were taken of the reconstructed objects from locations 3.8 degrees to the right, directly in front, and 3.8 degrees to the left, respectively. It is apparent that the reconstructed objects can be observed in the designed viewing zone and missing segments that can be seen without the optical system are eliminated. In addition, Fig. 4(e) was photographed with real rulers located near the reconstructed objects. It is apparent that the reconstructed objects match the designed size, 9 times larger than the size of a SLM.

The dark area can be ideally eliminated perfectly; however the dark area exists in Fig. 4(b) and 4(d) a little in practice. This is caused by aberration of the lens array L0. Since it can be eliminated on theory, we could eliminate it if we could remove the aberration. In addition, we could eliminate it if we use f1 a little bigger than that of Eq. (4), which loses viewing-zone angle or image size a little but is practical.

Next, we confirmed that objects with different depths could be reconstructed. Figure 5
Fig. 5 Experimental results of 3D objects located at different depth.
shows the experimental results. Figure 5(a) shows the design values of the displayed objects. Figure 5(b) and 5(c) show photographs that were taken of the reconstructed objects focused on the earth in the front and the moon in the back, respectively. When the objects can be reconstructed at different depths, the moon should be blurry in Fig. 5(b) and the earth should be blurry in Fig. 5(c). From the experimental results and the description above, it is apparent that objects with different depths can be reconstructed.

Finally, we confirmed that a video could be reconstructed. Figure 6
Fig. 6 Experimental results of video sequence (Media 1).
shows the experimental results. Figure 6(a) shows the design values of the displayed objects. The letter “C” located 30 mm behind the hologram plane gradually moves forward until it is 30 mm in front of the plane and then gradually moves back until it is 30 mm behind the plane. The video sequence shows the letters “N,” “I,” and “T” also sequentially moving forward and back in a same manner. This experiment confirmed that this video sequence can be played smoothly at a frame rate of 60 frames per second [fps] for approximately 15 seconds.

Figure 6(b) shows a photograph that was taken of the reconstructed objects at the instant that the letter “C” is located 30 mm in front of the plane with the focus on the letters “N,” “I,” and “T,” while Fig. 6(c) shows a photograph that was taken with the focus on the letter “C.” It is apparent that depth can be reconstructed since letters at different depths are blurry. To see that this video can be played smoothly, see Media 1.

From the experiments described above, it is apparent that a video of 3D objects having an image size with a diagonal of 63 mm and a viewing-zone angle of 7.5 degrees can be played with frame rate of 60 fps using the proposed method.

4. Conclusions

A problem encountered when increasing the image size by using multiple SLMs is that some parts of 3D objects are missing due to the gap between SLMs. In this paper, we propose a method without missing image segments by locating an optical system containing lens arrays and other components in front of multiple SLMs. Advantages of our method are that parallax can be exhibited in both the horizontal and vertical directions, the balance between the image size and viewing-zone angle can be controlled, the device can be configured without regard to the ratio between the image size of each SLM and the gaps between SLMs, the image size can be increased by increasing the number of SLMs, and unnecessary light can be eliminated. We applied the method to 9 SLMs to realize an image size with a diagonal of 63 mm, a viewing-zone angle of 7.5 degrees, and a frame rate of 60 fps.

References and links

1.

N. Peyghambarian, S. Tay, P.-A. Blanche, R. Norwood, and M. Yamamoto, “Rewritable holographic 3D displays,” Opt. Photon. News 19(7), 22–27 (2008). [CrossRef]

2.

K. Yamamoto, T. Mishina, R. Oi, T. Senoh, and T. Kurita, “Real-time color holography system for live scene using 4K2K video system,” Proc. SPIE 7619, 761906, 761906-10 (2010). [CrossRef]

3.

T. Mishina, F. Okano, and I. Yuyama, “Time-alternating method based on single-sideband holography with half-zone-plate processing for the enlargement of viewing zones,” Appl. Opt. 38(17), 3703–3713 (1999). [CrossRef] [PubMed]

4.

T. Senoh, T. Mishina, K. Yamamoto, R. Oi, and T. Kurita, “Wide viewing-zone-angle full-color electronic holography system using very high resolution liquid crystal display panels,” Proc. SPIE 7957, 795709, 795709-12 (2011). [CrossRef]

5.

Y. Takaki and N. Okada, “Hologram generation by horizontal scanning of a high-speed spatial light modulator,” Appl. Opt. 48(17), 3255–3260 (2009). [CrossRef] [PubMed]

6.

M. Stanley, R. W. Bannister, C. D. Cameron, S. D. Coomber, I. G. Cresswell, J. R. Hughes, V. Hui, P. O. Jackson, K. A. Milham, R. J. Miller, D. A. Payne, J. Quarrel, D. C. Scattergood, A. P. Smith, M. A. G. Smith, D. L. Tipton, P. J. Watson, P. J. Webber, and C. W. Slinger, “100 Mega-pixel computer generated holographic images from Active TilingTM – a dynamic and scalable electro-optic modulator system,” Proc. SPIE 5005, 247–258 (2003). [CrossRef]

7.

T. Senoh, T. Mishina, K. Yamamoto, R. Oi, and T. Kurita, “Viewing-zone-angle-expanded color electronic holography system using ultra-high-definition liquid crystal displays with undesirable light elimination,” J. Disp. Technol. 7(7), 382–390 (2011). [CrossRef]

8.

T. Mishina, M. Okui, K. Doi, and F. Okano, “Holographic display with enlarged viewing-zone using high-resolution LC panel,” Proc. SPIE 5005, 137–144 (2003). [CrossRef]

9.

J. Hahn, H. Kim, Y. Lim, G. Park, and B. Lee, “Wide viewing angle dynamic holographic stereogram with a curved array of spatial light modulators,” Opt. Express 16(16), 12372–12386 (2008). [CrossRef] [PubMed]

10.

F. Yaraş, H. Kang, and L. Onural, “Circular holographic video display system,” Opt. Express 19(10), 9147–9156 (2011). [CrossRef] [PubMed]

11.

N. Fukaya, K. Maeno, O. Nishikawa, K. Matsumoto, K. Sato, and T. Honda, “Expansion of the image size and viewing zone in holographic display using liquid crystal devices,” Proc. SPIE 2406, 283–289 (1995).

12.

Y. Takaki and J. Nakamura, “Development of a holographic display module using a 4K2K-SLM based on the resolution redistribution technique,” OSA Tech. Digest DH, DM2C.5 (2012)

13.

K. Yamamoto, R. Oi, T. Mishina, and M. Okui, “Half-zone-plate processing for objects on both sides of hologram display,” Proc. SPIE 6912, 69120Q, 69120Q-10 (2008). [CrossRef]

OCIS Codes
(090.1760) Holography : Computer holography
(090.2870) Holography : Holographic display
(070.6120) Fourier optics and signal processing : Spatial light modulators

ToC Category:
Holography

History
Original Manuscript: June 11, 2012
Revised Manuscript: August 26, 2012
Manuscript Accepted: August 26, 2012
Published: August 31, 2012

Citation
Kenji Yamamoto, Yasuyuki Ichihashi, Takanori Senoh, Ryutaro Oi, and Taiichiro Kurita, "3D objects enlargement technique
using an optical system and multiple SLMs
for electronic holography," Opt. Express 20, 21137-21144 (2012)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-20-19-21137


Sort:  Author  |  Year  |  Journal  |  Reset  

References

  1. N. Peyghambarian, S. Tay, P.-A. Blanche, R. Norwood, and M. Yamamoto, “Rewritable holographic 3D displays,” Opt. Photon. News19(7), 22–27 (2008). [CrossRef]
  2. K. Yamamoto, T. Mishina, R. Oi, T. Senoh, and T. Kurita, “Real-time color holography system for live scene using 4K2K video system,” Proc. SPIE7619, 761906, 761906-10 (2010). [CrossRef]
  3. T. Mishina, F. Okano, and I. Yuyama, “Time-alternating method based on single-sideband holography with half-zone-plate processing for the enlargement of viewing zones,” Appl. Opt.38(17), 3703–3713 (1999). [CrossRef] [PubMed]
  4. T. Senoh, T. Mishina, K. Yamamoto, R. Oi, and T. Kurita, “Wide viewing-zone-angle full-color electronic holography system using very high resolution liquid crystal display panels,” Proc. SPIE7957, 795709, 795709-12 (2011). [CrossRef]
  5. Y. Takaki and N. Okada, “Hologram generation by horizontal scanning of a high-speed spatial light modulator,” Appl. Opt.48(17), 3255–3260 (2009). [CrossRef] [PubMed]
  6. M. Stanley, R. W. Bannister, C. D. Cameron, S. D. Coomber, I. G. Cresswell, J. R. Hughes, V. Hui, P. O. Jackson, K. A. Milham, R. J. Miller, D. A. Payne, J. Quarrel, D. C. Scattergood, A. P. Smith, M. A. G. Smith, D. L. Tipton, P. J. Watson, P. J. Webber, and C. W. Slinger, “100 Mega-pixel computer generated holographic images from Active TilingTM – a dynamic and scalable electro-optic modulator system,” Proc. SPIE5005, 247–258 (2003). [CrossRef]
  7. T. Senoh, T. Mishina, K. Yamamoto, R. Oi, and T. Kurita, “Viewing-zone-angle-expanded color electronic holography system using ultra-high-definition liquid crystal displays with undesirable light elimination,” J. Disp. Technol.7(7), 382–390 (2011). [CrossRef]
  8. T. Mishina, M. Okui, K. Doi, and F. Okano, “Holographic display with enlarged viewing-zone using high-resolution LC panel,” Proc. SPIE5005, 137–144 (2003). [CrossRef]
  9. J. Hahn, H. Kim, Y. Lim, G. Park, and B. Lee, “Wide viewing angle dynamic holographic stereogram with a curved array of spatial light modulators,” Opt. Express16(16), 12372–12386 (2008). [CrossRef] [PubMed]
  10. F. Yaraş, H. Kang, and L. Onural, “Circular holographic video display system,” Opt. Express19(10), 9147–9156 (2011). [CrossRef] [PubMed]
  11. N. Fukaya, K. Maeno, O. Nishikawa, K. Matsumoto, K. Sato, and T. Honda, “Expansion of the image size and viewing zone in holographic display using liquid crystal devices,” Proc. SPIE2406, 283–289 (1995).
  12. Y. Takaki and J. Nakamura, “Development of a holographic display module using a 4K2K-SLM based on the resolution redistribution technique,” OSA Tech. Digest DH, DM2C.5 (2012)
  13. K. Yamamoto, R. Oi, T. Mishina, and M. Okui, “Half-zone-plate processing for objects on both sides of hologram display,” Proc. SPIE6912, 69120Q, 69120Q-10 (2008). [CrossRef]

Cited By

Alert me when this paper is cited

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.

Supplementary Material


» Media 1: MOV (2446 KB)     

« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited