How Does Will Smith Upload Parallax 3d Images Without Losing Quality

With the principle of ray-tracing and the reversibility of light propagation, a new method of single-step full parallax constructed holographic stereogram printing based on constructive perspective images' division and mosaicking (EPISM) is proposed. The perspective images of the scene are outset sampled by a virtual camera and the exposing images, which are called synthetic constructive perspective images, are accomplished using the algorithm of effective perspective images' segmentation and mosaicking according to the propagation police force of light and the viewing frustum consequence of human eyes. The hogels are exposed using the synthetic constructive perspective images in sequence to form the whole holographic stereogram. The influence of modeling parameters on the reconstructed images are also analyzed, and experimental results have demonstrated that the total parallax holographic stereogram press with the proposed method could provide adept reconstructed images by unmarried-footstep printing. Moreover, detailed experiments with different holographic chemical element sizes, different scene reconstructed distances, and different imaging planes are also analyzed and implemented.

1. Introduction

With the express resolution power of human being eyes, holographic stereogram combines the principle of holography and binocular parallax together, and the stereoscopy vision is generated by a serial of superimposed plane images. Equally the wavefront needn't to exist reproduced accurately, the amount of data tin be reduced greatly in holographic stereogram, and holographic stereogram is considered as one of the most promising 3-dimensional (3D) brandish technology. Holographic stereogram has been widely used in various fields, such as in military, compages, commerce, automotive industry, entertainment, etc. [ane, 2].

Co-ordinate to the different sources of interference patterns and dissimilar approaches of recording, the printing of holographic stereogram can be categorized into three basic types: constructed holographic stereogram printing, computer-generated holographic stereogram printing, and wavefront printing [3,4]. In synthetic holographic stereogram printing, a spatial light modulator (SLM) is used to load and display sequential perspective images as the point beam. Afterward interfered with the reference beam, interference patterns are recorded on the holographic recording medium which is spatially segmented into multiple hogels (holographic elements) [5]. In reckoner-generated holographic (CGH) stereogram printing, interference patterns are offset calculated by the calculator, and so displayed on the SLM, scaled by the imaging lens and printed on the holographic recording medium [6–viii]. Wavefront printing is the integration of synthetic holographic stereogram press and CGH stereogram printing. The hologram calculated by computer is displayed on SLM, and illuminated past the reconstruction beam. Afterwards passing through a band-pass filter, the wavefront of the scene is achieved and it is considered as the signal beam, then interfered with the reference beam to form reflection hologram [9–12]. During the reproduction of holographic stereogram, the stereoscopy vision occurs when unlike perspective images with parallax information are viewed, and the parallax is changing when eyes are moving.

Compared with CGH stereogram printing as well equally wavefront press, there is no complicated diffraction adding in synthetic holographic stereogram printing. Synthetic holographic stereogram was commencement proposed by DeBitetto [xiii] and promoted by King et al. [14]. The Massachusetts Institute of Technology (MIT) media lab has committed to the development of digital synthetic holographic engineering since the 1990s, and studied on the principle of constructed holographic stereogram with big angle and broad view, as well every bit distortions and other issues [15, 16]. Zebra Imaging Inc. which was founded by MIT scientists successfully developed digital constructed holographic printers [2, 17]. Brotherton-Ratcliffe introduced a press technology for digital holograms with big surface area [18], and developed holographic printer with RGB pulse lasers [nineteen]. The bug like the design of printing system [20–22], printing efficiency [23–26], resolution in images [27, 28], color reproduction [29–31] and updatable holographic recording medium [32–34] are amid loftier-priority topics in synthetic holographic stereogram.

To achieve reconstructed images surfacing the recording medium, there are three types of the existing approaches for synthetic holographic stereogram printing, the two-step method [14], the infinite viewpoint photographic camera method proposed past MIT [16], and the single-step Lippmann holographic stereogram method based on figurer and paradigm-processing technologies proposed by Yamaguchi'due south group [35, 36]. In the two-pace method, the perspective images for exposing are acquired easily without transform processing, but there should exist twice exposures. Since information technology is difficult to achieve large-format collimating light, we can hardly make a large size hologram during the 2d exposure. Compared with the two-step method, there is simply once exposure either in the infinite viewpoint camera method or in the single-step Lippmann holographic stereogram method. However, in the infinite viewpoint camera method, the resolution of reconstructed images equals to the number of hogels and it is relatively low, specially for a small-scale size hologram. In the single-step Lippmann holographic stereogram method, the resolution of reconstructed images is relatively loftier, and a big size hologram is easily accomplished by increasing the number of hogels. Withal, the bespeak cloud data of the scene should be acquired and the occlusion relation of scene points in space should exist considered, leading to a complicated procedure. In this paper, a novel press method of synthetic holographic stereogram based on effective perspective images' segmentation and mosaicking (EPISM) is proposed. On the ground of ray-tracing principle and the reversibility of light propagation, the viewing frustum upshot of human being optics is analyzed and simulated. With the segmentation and mosaicking of effective perspective images, the synthetic visual information for a specific viewpoint tin can be extracted, and this visual data is exposed on a square surface area of holographic recording medium, i.due east., a hogel. After all the hogels are exposed successively, a holographic stereogram tin can be achieved. Compared with the existing approaches, the proposed EPISM method take some advantages. The full parallax holographic stereogram could exist printed by single-step exposure, and the resolution of reconstructed images is much higher than that of the space viewpoint camera method as information technology is adamant by the resolution of original sampled perspective images, not by the number of hogels. Moreover, the procedure of achieving exposing images is easier than that of the single-step Lippmann holographic stereogram method without because the occlusion relation of scene points, every bit the occlusion relation is embodied in the original sampled perspective images and the color and directional information is easily encoded by computing a virtual master hologram.

The rest of newspaper is organized as follows. In Section 2, the principles of previous methods are discussed and the principle of proposed method is introduced briefly. In Section 3, the realization of the proposed method is introduced in item. In Section four, the influence of modeling parameters on the quality of reconstructed images is analyzed. The principle of the proposed method is verified with experiments and the results are discussed in Section 5. The conclusions are presented in Section 6.

2. Principles

2.1. Previous methods

Two-step method

Ii-stride method includes three procedures: the acquisition of perspective images, the exposure of master hologram, and the reproduction of master hologram to transfer hologram, as shown in Fig. 1. Full parallax images of the scene are acquired nether breathless illumination, and Fresnel holograms of perspective images are recorded in different hogels successively, then the master hologram is generated (Fig. 1(a)). When viewing the main hologram, optics should be shut to the positions of aperture pupils, as shown in Fig. i(b). The master hologram is and then recopied to the transfer hologram with paradigm hologram photographing method (Fig. ane(c)), and the virtual aperture pupils are separated from the transfer hologram. When viewing the transfer hologram from unlike virtual student positions, different perspective images can be captured by man optics, and the stereoscopic vision is formed, as shown in Fig. i(d). For conveniences, the master hologram is called H₁ plate, and the transfer hologram is called H₂ plate in the post-obit pages. The size of the primary hologram should be much larger than that of the transfer hologram to ensure a same viewing angle.

Fig. 1 The production and reconstruction of ii-step method. (a)The production of principal hologram. (b)The reconstruction of primary hologram. (c)The reproduction of master hologram to transfer hologram. (d)The reconstruction of transfer hologram.

Download Full Size | PPT Slide | PDF

Infinite viewpoint camera method

Infinite viewpoint camera method also includes three procedures: the acquisition of perspective images, the transformation from perspective images to parallax related images, and the printing of parallax related images. Perspective images of the scene are acquired by infinite camera offset and it tin be realized past orthogonal project in modeling software. The perspective images are and so transformed to parallax related images. When the altitude between the photographic camera and the holographic plate is far enough, the light arriving at the hogels tin can exist considered as bundles of parallel light approximately, and the transformation is but an operation on a series of arrays or stacks. The transformation principle of perspective images in space viewpoint camera method is shown in Fig. 2. Suppose in that location are s × t (s = 1, two, ⋯, M, t = ane, 2, ⋯, Northward) perspective images, and each paradigm contains i × j (i = one, two, ⋯, grand, j = 1, two, ⋯, n) pixels. The perspective prototype matrix is expressed as P _st (i, j). All the pixels at the same location of each P _st (i, j) are extracted to form a new matrix H _ij (due south, t), which denotes a parallax related prototype. Finally, the parallax related images are printed on the hogels. When taking infinite viewpoint camera method, the resolution of reconstructed images is equal to the number of hogels.

Single-step Lippmann holographic stereogram method

Single-step Lippmann holographic stereogram method also includes three procedures: the acquisition of signal cloud data, the adding of exposing images, and the printing of exposing images. The principle of this method is shown in Fig. 3. Compared with the two methods mentioned above, in this approach, the exposing images for hogels are acquired by perspective projection, not by camera sampling. Based on the center of each hogel, scene points are projected to the position of liquid crystal display (LCD) respectively (run across Fig. 3(a)). According to the viewer'due south position, the occlusion relation of scene points in space should be considered and the hidden surfaces should be removed. The calculated images are and then displayed on the LCD, converged through the lens, and recorded on the hogels (run into Fig. 3(b)). During the reconstruction of the scene, light rays are diffracted from each hogel in the same fashion as the prototype calculation, thus the viewer can perceive the scene (see Fig. 3(c)).

Fig. three Principle of the single-step Lippmann holographic stereogram method. (a) Calculation of an exposing image. (b) Optical setup of the method. (c) Reconstruction geometry for the holographic stereogram.

Download Full Size | PPT Slide | PDF

2.ii. Proposed EPISM method

We proposed a novel printing method of unmarried-pace full parallax holographic stereogram named EPISM. For convenience, the proposed unmarried-step method tin be comprehended equivalently as a 2-stride method. In conventional two-step method, the perspective images of the scene should be exposed on the principal hologram first, and so the principal hologram will be recopied to the transfer hologram. However, in our proposed method, there isn't an optical exposure of the main hologram. Generation of the master hologram is a virtual process and can exist implemented past computer rendering. The virtual master hologram is called virtual H₁ plate, meanwhile the size and the number of virtual hogels in it are controllable. The transfer hologram (i.e., the actually printed holographic stereogram) is also supposed to be composed of a lot of hogels. By simulating the propagation process of information from dissimilar perspective images during the reproduction of the master hologram to the transfer hologram, the exposing images for hogels in the transfer hologram tin can be achieved past computer rendering directly. The transfer hologram is called H_ii plate whose field of view (FOV) is adamant past both the limited resolution of holographic recording medium and the construction of printing organisation, and the FOV at whatsoever position is identical presumptively.

The virtual H₁ plate is composed of some virtual hogels, and each of them is corresponding to a specific perspective image. Suppose there is a specific hogel in H₂ plate, i.due east., hogel′, and the center of it is bespeak O. The primitive principle of the proposed method can be illustrated by taking the acquisition of exposing image for hogel′ as an instance (see Fig. four). The exposing image for hogel′ in H_two, named the synthetic effective perspective prototype, is comprised by the mosaicking of some specific constructive perspective images segments, and each effective perspective image segment is extracted from the specific perspective prototype respective to a virtual hogel in virtual H₁ plate. The extraction of effective perspective epitome segment is shown in Fig. four(a). Suppose the perspective epitome displayed on the LCD panel is exposed on a specific virtual hogel in virtual H₁ plate. With the principle of ray-tracing, when viewing virtual hogel from bespeak O in H₂ plate, the viewed constructive pixels of perspective image in LCD console are limited. The effective perspective paradigm segment is just a cross section between the perspective image displayed on LCD panel and the viewing frustum, whose vertex is signal O and concluding region is the purlieus of virtual hogel. That is to say, just the pixels within the cross section tin propagate to point O. Moreover, when viewing multiple virtual hogels from indicate O in H_two plate, the synthetic constructive perspective image mosaicked past effective images segments of multiple virtual hogels is shown in Fig. 4(b). Suppose there are due north × m virtual hogels amidst the FOV of point O, so all effective images segments of perspective images corresponding to these virtual hogels can be extracted and reassembled. The resulted mosaicked paradigm is the synthetic effective perspective image which is marked with dotted box (come across Fig. 4(b)), and it will be exposed on hogel′ in H₂ plate. In Fig. 4, to illustrate more clearly, at that place are gaps among the virtual hogels in virtual H₁ plate. However, gaps are not-existent in the actual printing. Similarly, the exposing images for the other hogels in H_two plate can be obtained in the same manner described above, and the single-step full parallax holographic stereogram can be obtained later press all the hogels in H₂ plate.

Fig. iv The archaic principle of the proposed method. (a) The extraction of constructive perspective paradigm segment corresponding to a single virtual hogel. (b) The constructed effective perspective image mosaicked by constructive images segments of multiple virtual hogels.

Download Full Size | PPT Slide | PDF

iii. Detailed principle of EPISM

The proposed EPISM method includes iii primal procedures: parameters determination of geometry, acquisition and choice of perspective images, segmentation and mosaicking of perspective images.

3.1. Parameters determination of geometry

The principle of effective pixels mosaicking for the hogel is shown in Fig. 5. For simplicity, just one-dimension instance (horizontal parallax) is analyzed. The virtual H_one plate, LCD panel and H_ii plate are placed parallelly along the z-axis, with the distances among them are L ₁, Fifty _two every bit shown in Fig. 5. The size of LCD panel is 50 _LCD. The viewing angle provided by H₂ plate is θ, and the range of sight in virtual H_one plate viewing from point O is l _MN.

Suppose the hogel in virtual H₁ plate facing and centering around bespeak O is virtual hogel₀, and the corresponding perspective prototype role displayed on LCD panel is segment AB. Based on ray-tracing principle, the effective pixels function of segment AB is only segment CD when point O is exposed past virtual hogel₀, i.e., only the perspective pixels information displayed on segment CD can propagate to point O. Similarly, for virtual hogel₁ below virtual hogel₀, the corresponding function of LCD panel is segment A′B′, and the effective pixels function of A′B′ contributing for betoken O is just segment DE. Regularly, corresponding to each virtual hogel in virtual H_ane plate, taking all these effective pixels segments CD, DE, ⋯ among the FOV of bespeak O together, the effective viewed pixels segment of point O can exist tiled and obtained. So this synthetic pixels segment can be recorded on the hogel centering around betoken O in H₂ plate. In the full parallax instance, the effective perspective pixels on LCD plough into the square effective perspective image which is the intersection region between the viewing frustum and the perspective image displayed on LCD, and the synthetic image tin can be obtained past mosaicking the resulted effective perspective images segments.

The determination of the viewing angle is shown in Fig. half-dozen. Virtual hogel in virtual H₁ plate can be regarded as single point approximately since its small size. The field angle between LCD panel and its corresponding virtual hogel in virtual H_i plate is θ′.

When the edge indicate of LCD panel, i.eastward., point B, is just on line MO, the information displayed on LCD panel could not propagate to bespeak O. Thus, there exists a critical relationship

Restricted by the limited viewing angle θ, only a few constructive pixels segments (corresponding to certain virtual hogels in virtual H_ane plate) tin contribute to each view indicate O in H₂ plate. For a certain view point in H₂ plate, as shown in Fig. 6, with paraxial approximation, the number of contributed virtual hogels in virtual H₁ plate is $\lceil \frac{\pi \theta (L_{\mathrm{i}}+L_{\mathrm{ii}})}{180{\mathrm{fifty}}_1}\rceil$ , where l _ane is the size of virtual hogel in virtual H₁ plate, and operator $\lceil \cdot \rceil$ denotes the operation of rounding downwards. Considering multiple viewpoints in H_two plate, they are all supposed to be located at the heart of each hogel in H_ii plate. The determination of the number of all the contributed virtual hogels in virtual H_one plate is shown in Fig. seven. Autonomously from the hogel in virtual H_one plate facing point O _#, the other contributed virtual hogels in virtual H_ane plate are distributed symmetrically on both sides of point O _#, and the number is denoted every bit n _hogel for either side presumptively. Nosotros accept

(2)

$$n_{\text{hogel}}=\lceil \frac{\pi \theta (L{}_{\mathrm{ane}}+L_2)}{360{\mathrm{50}}_1}\rceil -\mathrm{i},$$

and

(three)

$$N_{{\mathrm{H}}_{\mathrm{i}}}=2n_{\text{hogel}}+[l_2\times ({\mathrm{North}}_{{\mathrm{H}}_{\mathrm{ii}}}-1)+l_1]/l_{\mathrm{i}},$$

where fifty _two is the size of hogel in H₂ plate, $N_{{\mathrm{H}}_{\mathrm{one}}}$ and ${\mathrm{Due\; north}}_{{\mathrm{H}}_2}$ are the number of hogels in virtual H_i plate and H_two plate, respectively.

3.2. Acquisition and selection of perspective images

The one-dimension capture geometry of the perspective images is shown in Fig. 8. Perspective images of the scene are captured by simple camera in modeling software. The camera is moving along the movement plane, and the lens is perpendicular to the trace for photographing. The resolution of sampling images is limited to the pixel count of LCD. The FOV of camera equals to the angle θ′ as shown in Fig. 6. The sampling number coincides with the number of hogels in virtual H₁ plate, i.eastward., ${\mathrm{North}}_{{\mathrm{H}}_1}$ . The photographic camera's sampling interval satisfies the relationship of l _sap/fifty ₁ = Fifty _sap/L _ane, where l _sap is the sampling interval of the photographic camera, L _sap is the distance between the camera movement plane and the scene, l _i is the size of hogel in virtual H₁ plate, and 50 _i is the distance betwixt the LCD console and the virtual H₁ plate every bit mentioned to a higher place.

Every bit mentioned in Section 3.1, for any view point O in H₂ plate, the respective contributed hogels in virtual H_i plate are finite. Consequently, we have to select effective hogels in virtual H₁ plate and get their corresponding constructive perspective images segments for mosaicking. The corresponding human relationship between the hogel in H₂ plate and the effective contributed hogels in virtual H_one plate is shown in Fig. 9. For the specific hogel H _{i ′ j ′} in H_ii plate, hogels P _{south ′ t ′}in virtual H_one plate are effective, and with the following human relationship southward′ ∈ (i′, i′+ twonorthward _hogel), t′ ∈ (j′, j′ + twon _hogel) satisfied.

Fig. 9 The corresponding relationship betwixt the hogel in H₂ plate and the constructive contributed hogels in virtual H₁ plate.

Download Total Size | PPT Slide | PDF

3.3. Sectionalization and mosaicking of effective perspective images

The diagram of algorithm for segmentation and mosaicking of effective perspective images is shown in Fig. 10. Fig. 10(a) and Fig. 10(b) are the perspective view and front view with respect to the viewing direction, respectively. Additionally, in Fig. 10(b), the image displayed on LCD console, which is respective to the virtual hogel, is illustrated. The Cartesian coordinates of the point A, which is the upper left vertex of the kickoff row and get-go column hogel in virtual H_ane plate, are denoted equally A (0, 0, 0). In Fig. ten(a), the Cartesian coordinates of bespeak O are O (x ₀, y ₀, z ₀). To find the hogel ABCD from point O in virtual H₁ plate with a viewing frustum, the cross section in LCD panel is region A′B′C′D′, and its z-coordinate is z _one. Thus, we accept L ₁ = |z _ane| and L ₂ = |z ₀ – z ₁|.

Fig. 10 The diagram of precise algorithm in partitioning and mosaicking of perspective images. (a)The perspective view forth the gazing management. (b)The forepart view along the gazing direction.

Download Full Size | PPT Slide | PDF

In the front view with respect to z-axis (run into Fig. x(b)), the primal point of virtual hogel ABCD, point P, coincides with the center of LCD panel which projects perspective epitome to information technology. The boundary of perspective image is region A″B″C″D″ and it is North × N pixels. The overlapping region between A′B′C′D′ and A″B″C″D″, i.e., the intersection area betwixt the viewing frustum and the perspective epitome displayed on LCD, is constructive perspective image segment which should exist extracted. With view point O stock-still, and repeating above procedure for all the contributed virtual hogels in virtual H_one plate, the eventual effective perspective paradigm segment for point O, i.e., constructed effective perspective prototype, can exist achieved with all the effective perspective images segments reassembled. Since the resolution of LCD console is certain when it is selected, and ABCD and A″B″C″D″ have a common center point P, the extraction of all the pixels in the effective perspective image segment tin be calculated by locating this common center point. The heart indicate of A′B′C′D′ is denoted every bit P′.

The coordinates of the vertices of the (n, m) hogel in virtual H₁ plate are A (nl _ane − 50 ₁, ml ₁ − 50 ₁, 0), B (nl ₁, ml ₁ − l ₁, 0), C (nl _ane, ml ₁, 0) and D (nl ₁ − l ₁, ml ₁, 0). Thus, the coordinates of point P is P (nl ₁ − l _one/2, ml ₁ − l ₁/2, 0). Using the similar triangle, the width of the square region A′B′C′D′ is

(iv)

$${\mathrm{fifty}}_{{\mathrm{A}}^{\prime }{\mathrm{B}}^{\prime }}=l_{{\mathrm{B}}^{\prime }{\mathrm{C}}^{\prime }}=l_{{\mathrm{C}}^{\prime }{\mathrm{D}}^{\prime }}=l_{{\mathrm{D}}^{\prime }{\mathrm{A}}^{\prime }}=\frac{Z_0-Z_{\mathrm{one}}}{Z_0}{l}_1.$$

The line OP′P passes through points O (x ₀, y ₀, z ₀) and P (nl _ane − l _ane/ii, ml ₁ − 50 _one/two, 0), therefore, the coordinates of signal P′ can be calculated as

(five)

$${\mathrm{P}}^{\prime }\left({\mathrm{ten}}_{{\mathrm{P}}^{\prime }}=\frac{z_{\mathrm{ane}}-z_0}{z_0}\left(x_0-\frac{2n{l}_{\mathrm{i}}-{\mathrm{50}}_1}{2}\right)+x_0,y_{{\mathrm{P}}^{\prime }}=\frac{z_{\mathrm{one}}-z_0}{z_0}\left(y_0-\frac{2\mathrm{thousand}{l}_{\mathrm{i}}-l_{\mathrm{i}}}{\mathrm{ii}}\right)+y_0,z_{{\mathrm{P}}^{\prime }}=z_1\right).$$

Since the ten-axis coordinate of point P is x _P = nl ₁ − l ₁/ii and the size of LCD console is fifty _LCD, the x-axis coordinate of point A″ tin can be obtained as

(half-dozen)

$$x_{{\mathrm{A}}^{″}}=x_{\mathrm{P}}-\frac{{\mathrm{fifty}}_{\text{LCD}}}{\mathrm{two}}=\frac{2n{l}_{\mathrm{ane}}-l_{\mathrm{ane}}-{\mathrm{fifty}}_{\text{LCD}}}{2}.$$

Combined Eq. (4) and Eq. (v), we have

(7)

$${\mathrm{10}}_{{\mathrm{A}}^{\prime }}=x_{{\mathrm{P}}^{\prime }}-\frac{{\mathrm{50}}_{{\mathrm{A}}^{\prime }{\mathrm{B}}^{\prime }}}{\mathrm{ii}}=\frac{z_1}{z_0}(x_0-\mathrm{northward}{\mathrm{fifty}}_{\mathrm{ane}}+{\mathrm{50}}_1)+n{l}_{\mathrm{one}}-l_1,$$

where x _A′ is the 10-centrality coordinate of bespeak A′.

Similarly, the y-centrality coordinate of betoken A′ is

(8)

$$y_{{\mathrm{A}}^{\prime }}=y_{{\mathrm{P}}^{\prime }}-\frac{{\mathrm{50}}_{{\mathrm{A}}^{\prime }{\mathrm{B}}^{\prime }}}{2}=\frac{z_1}{z_0}(y_0-\mathrm{yard}{\mathrm{fifty}}_1+l_1)+m{l}_{\mathrm{i}}-l_1.$$

The altitude between indicate A′ and betoken A″ forth 10-axis is

(9)

$$l_{x_{{\mathrm{A}}^{\prime }{\mathrm{A}}^{″}}}=|x_{{\mathrm{A}}^{\prime }}-x_{{\mathrm{A}}^{″}}|=|\frac{z_1}{z_0}({\mathrm{ten}}_0-n{\mathrm{50}}_1+l_1)-\frac{{\mathrm{50}}_1}{\mathrm{ii}}+\frac{l_{\text{LCD}}}{\mathrm{ii}}|.$$

Similarly, the distance along y-axis is

(10)

$${\mathrm{50}}_{y_{{\mathrm{A}}^{\prime }{\mathrm{A}}^{″}}}=\left|\frac{z_1}{z_0}(y_0-m{l}_{\mathrm{i}}+{\mathrm{50}}_1)-\frac{l_{\mathrm{ane}}}{2}+\frac{l_{\text{LCD}}}{2}\right|.$$

Then, the indices of the pixels for the effective perspective prototype segment tin exist obtained by mapping the coordinates to the pixels indices. Since the perspective image corresponding to the virtual hogel in virtual H₁ plate is N × N pixels and is displayed on the LCD panel whose size is l _LCD, the pixel number of unit length in LCD console is N _uni = N/l _LCD. Suppose the pixel alphabetize of point A″ are (1, one), with Eq. (9) and Eq. (10), the pixel indices of vertices for region A′B′C′D′ can exist calculated every bit follows:

(11)

$${\mathrm{A}}^{\prime }\left(\left|\frac{z_1}{z_0}(x_0-n{l}_1+{\mathrm{fifty}}_{\mathrm{ane}})-\frac{{\mathrm{50}}_1}{\mathrm{ii}}+\frac{l_{\text{LCD}}}{2}\right|\times \frac{N}{l_{\text{LCD}}}+1,\left|\frac{z_{\mathrm{one}}}{z_0}(y_0-\mathrm{chiliad}{l}_1+l_1)-\frac{{\mathrm{fifty}}_{\mathrm{one}}}{2}+\frac{l_{\text{LCD}}}{\mathrm{ii}}\right|\times \frac{N}{l_{\text{LCD}}}+1\right),$$

(12)

$${\mathrm{B}}^{\prime }\left(\left|\frac{z_{\mathrm{i}}}{z_0}({\mathrm{ten}}_0-n{l}_1+{\mathrm{fifty}}_1)-\frac{l_1}{2}+\frac{{\mathrm{50}}_{\text{LCD}}}{2}\right|\times \frac{N}{l_{\text{LCD}}}+\frac{z_0-z_1}{z_0}\times \frac{\mathrm{Due\; north}{l}_1}{{\mathrm{fifty}}_{\text{LCD}}},\left|\frac{z_1}{z_0}(y_0-m{l}_{\mathrm{i}}+l_1)-\frac{l_{\mathrm{one}}}{2}+\frac{l_{\text{LCD}}}{\mathrm{two}}\right|\times \frac{N}{l_{\text{LCD}}}+1\right),$$

(13)

$${\mathrm{C}}^{\prime }\left(\left|\frac{z_{\mathrm{i}}}{z_0}(x_0-n{l}_1+l_{\mathrm{i}})-\frac{l_1}{2}+\frac{{\mathrm{fifty}}_{\text{LCD}}}{\mathrm{ii}}\right|\times \frac{\mathrm{Due\; north}}{{\mathrm{fifty}}_{\text{LCD}}}+\frac{z_0-z_{\mathrm{ane}}}{z_0}\times \frac{\mathrm{Northward}{\mathrm{fifty}}_1}{{\mathrm{fifty}}_{\text{LCD}}},\left|\frac{z_{\mathrm{one}}}{z_0}(y_0-m{l}_1+{\mathrm{50}}_1)-\frac{l}{2}+\frac{{\mathrm{50}}_{\text{LCD}}}{2}\right|\times \frac{N}{l_{\text{LCD}}}+\frac{z_0-z_1}{z_0}\times \frac{N{l}_{\mathrm{one}}}{l_{\text{LCD}}}\right),$$

(xiv)

$${\mathrm{D}}^{\prime }\left(\left|\frac{z_{\mathrm{one}}}{z_0}(x_0-\mathrm{northward}{l}_1+l_1)-\frac{l_{\mathrm{ane}}}{2}+\frac{{\mathrm{50}}_{\text{LCD}}}{2}\right|\times \frac{\mathrm{Northward}}{l_{\text{LCD}}}+1,\left|\frac{z_1}{z_0}(y_0-m{l}_1+l_1)-\frac{l_{\mathrm{i}}}{2}+\frac{l_{\text{LCD}}}{\mathrm{two}}\right|\times \frac{N}{l_{\text{LCD}}}+\frac{z_0-z_1}{z_0}\times \frac{\mathrm{North}{l}_{\mathrm{ane}}}{l_{\text{LCD}}}\right).$$

And so the pixels' indices in region A′B′C′D′ can be extracted from the perspective image, and the effective perspective image segment contributed past virtual hogel ABCD is obtained.

For view indicate O (x ₀, y ₀, z ₀), we tin extract all these pixels corresponding to every contributed virtual hogels in virtual H₁ plate and reassemble these pixels together (i.e., mosaicking all the effective perspective images segments), and then the synthetic constructive perspective prototype for bespeak O (x ₀, y ₀, z ₀) is obtained. This rendering algorithm of segmentation and mosaicking can be implemented by the computer. Repeating the same algorithm for all the viewpoints in H₂ plate, the image consequences for the exposure of hogels on the terminal full parallax holographic stereogram can exist prepared.

4. The influence of modeling parameters on the reconstructed images

As a blazon of holographic stereogram, the proposed EPISM based synthetic holographic stereogram also employs the principle of holography and binocular parallax together, where the stereoscopy vision is generated by a series of mosaicked effective perspective images segments. Therefore, the reconstructed performance is affected significantly with the parameters chosen in EPISM. Improper parameters may upshot into serious reduction of reconstruction quality, such equally the flipping effect, low resolution, etc.

four.ane. The flipping effect

The size of hogel, the depth of scene, and the distance from the scene to the holographic plate have been demonstrated to play important roles on the flipping effect in traditional holographic stereogram [37]. In the proposed EPISM based synthetic holographic stereogram, these parameters also affect the flipping effect. The diagram for analyzing the flipping of the image is shown in Fig. 11. l denotes the size of hogel. L denotes the distance between the image plane and the hologram, and information technology tin can be regarded as the distance from the scene to the holographic plate. ΔFifty is the depth of the scene. Suppose there is a scene point Q, and it is L_d abroad from the image plane.

When viewing bespeak Q at neighboring hogels H _i , _j and H _{i +ane, j} , eyes will perceive point Q _i , _j and point Q _{i +1, j} on the paradigm plane. The aperture between reconstructed images of neighboring hogels won't be observed if the minimum distance of parallax movement δ = |Q _i , _j Q _{i +1, j} | on prototype plane is small enough. With Fig. 11, we have

We tin can neglect the flipping effect when the distance δ is smaller than the limited resolution of the observing system, namely,

where

In Eq. (17), λ is the wavelength, α is the diameter of the smallest pupil in the observing system. The educatee diameter of homo eyes is a, when it is smaller than l,α = a, whereas α = fifty.

Substituting Eq. (15) and Eq. (17) into Eq. (16), nosotros have

(18)

$$-\frac{1.22\lambda L^{\mathrm{ii}}}{\mathrm{50}\alpha +\mathrm{i.22}\lambda \mathrm{50}}\le L_d\le \frac{\mathrm{one.22}\lambda L^2}{\mathrm{50}\alpha -1.22\lambda \mathrm{50}}.$$

With Eq. (18), the depth of scene which stereogram holographic could provide is

(19)

$$\mathrm{\Delta }L=\frac{\mathrm{one.22}\lambda L^2}{l\alpha -\mathrm{i.22}\lambda L}+\frac{\mathrm{ane.22}\lambda L^{\mathrm{ii}}}{\mathrm{fifty}\alpha -\mathrm{one.22}\lambda L}.$$

Generally, lα ≥ ane.22λL, then Eq. (19) can be rewritten equally

(20)

$$\mathrm{\Delta }L\approx \frac{\mathrm{ii.44}\lambda L^{\mathrm{ii}}}{\mathrm{fifty}\alpha }=\{\begin{array}{l}\frac{2.44\lambda {\mathrm{50}}^2}{l\alpha },\text{when}a\le l\\ \frac{\mathrm{two.44}\lambda L^2}{l^2},\text{when}a>l\end{array}.$$

Eq. (xx) shows that, at that place is a constraint among the depth of scene ΔFifty, the size of hogel l, and the altitude from the scene to the holographic plate L. When the depth of scene and the size of hogel remain the same, the altitude from the scene to the holographic plate must exist longer than a certain value. Otherwise, the flipping effect will occur, namely, discontinuity of the reconstructed images will be observed when moving the heart from one hogel to the next. This flipping effect will disturb the viewer and reduce the reconstruction quality.

4.2. The resolution of synthetic effective perspective image

We can also analyze the resolution of constructed effective perspective image nether the condition of different system parameters. The effective length of LCD panel (the segment CD as shown in Fig. v) for each perspective epitome is

The respective pixel count is

The resolution of constructed effective perspective prototype is

Substituting Eq. (21) and Eq. (22) into Eq. (23), nosotros have

(24)

$$M=\frac{N_{\text{uni}}\times (2n_{\text{hogel}}+\mathrm{one})\times {\mathrm{fifty}}_1\times L_2}{L_1+{\mathrm{50}}_{\mathrm{ii}}}.$$

Eq. (24) shows that, when the LCD is selected and the parameters of geometry are adamant, the resolution of synthetic effective perspective image can be calculated. With Eq. (24), the reward of our proposed method over the infinite viewpoint camera method, i.e., a higher resolution of reconstructed images, will be illustrated in the following experiments.

four.3. The size of the scene

To record all the information of the scene, the virtual camera needs to thoroughly cover the scene when sampling. Combing Fig. five, Fig. six and Fig. 7 together, at that place exists a relationship between the size of scene and the size of holographic plate equally follows

(25)

$$2{\mathrm{50}}_1\times \tan \frac{{\theta }^{\prime }}{2}+L_{H_1}-l_1>L_{\mathrm{O}},$$

(26)

$$L_{H_{\mathrm{ane}}}=2(L_1+{\mathrm{50}}_2)\times \mathrm{t}\mathrm{a}\mathrm{n}\frac{\theta }{2}+L_{H_2}-l_2,$$

where $L_{{\mathrm{H}}_{\mathrm{i}}}$ , ${\mathrm{Fifty}}_{{\mathrm{H}}_2}$ , L _O are the size of virtual H_i plate, H_two plate and the scene, respectively. Eq. (25) and Eq. (26) volition be helpful to design the scene model, as the size of the scene is confined by the size of holographic plate we could utilize.

4.iv. The influence of LCD parameters

The selection of LCD console will also affect the reconstructed effect. With Eq. (one), when fifty ₁, l ₂, L ₁ and L ₂ keep unchanged, the larger l _LCD is, the larger θ volition be, and information technology will be more user-friendly for viewing. With Eq. (24), when the resolution of LCD panel is higher, i.e., N _uni is bigger, the resolution of constructed effective perspective image will be higher, i.e., the reconstructed image will exist clearer. Meanwhile, when the pixel count of constructed constructive perspective prototype is sure, the area of image in LCD panel as well as the diameter of illumination beam required is smaller. Consequently, the light amplification by stimulated emission of radiation energy is more full-bodied, and it can reduce the exposure time and raise the printing rate.

5. Experiments and discussions

A LCD panel (VVX09F035M20) produced by Panasonic was used. The LCD panel was 8.9 inches with 1920 × 1080 pixels, and 1000 × m pixels of information technology were used and the corresponding effective displaying size was ten cm × 10 cm, i.e., l _LCD = x cm, and N _uni = Due north/l _LCD = 100 pixels/cm. A teapot model with 6.iv cm width, three.2 cm height and 4 cm depth was utilized equally the 3D scene, and it was tipped 45°. The FOV of sampling camera was set as thirty°, i.e., θ′= 30°. With Eq. (1), there was L ₁ = l _LCD/[2tan (θ′/2)] = 18.6 cm. When simulating the generation of virtual H_one plate, Fifty = Fifty _i = 18.6 cm, ΔL = 6.4/sin 45° = 4.5 cm and λ = 639 nm. These parameters were substituted into Eq. (20) and result in l = 1.1 mm. However, when the sampling interval of original perspective images was selected every bit i.i mm, the sampling number was so large that the calculation load was besides heavy. By the simulation, a good mosaicking effect could be achieved for synthetic constructive perspective images when fifty = ii.5 mm. Consequently, we assumed that L ₁ = 18.6 cm and l ₁ = 2.five mm for all the next experiments. Moreover, the altitude from the scene to H₂ plate was assumed to be 11.4 cm, i.e., Fifty = L ₂ = 11.4 cm, then we had l = 0.67 mm from Eq. (xx). Due to the limited power of the laser nosotros used, the cost of exposure fourth dimension was and so high if such a minor size of hogel was adopted. We assumed that l ₂ = ane cm. The size of holographic plate we used was 8 cm × 8 cm, then N _H2 = 8/l ₂ = 8. With Eq. (1)–Eq. (3), we had θ ≈ 30°, north _hogel = 31 and $N_{{\mathrm{H}}_1}=91$ . The 3D modeling software Blender was used for the virtual capture of perspective images of 3D scene, and the virtual camera was put xviii.6 cm laway from the median airplane of teapot. Substituting all the parameters above into Eq. (24), at that place was M = 599 pixels. In the infinite viewpoint camera method, the resolution equated to the sampling number of virtual H_i plate, i.e., $N_{{\mathrm{H}}_1}$ . Since $M\gg N_{{\mathrm{H}}_{\mathrm{one}}}$ , the proposed method could amend the resolution of image drastically. Substituting all the parameters in a higher place into Eq. (25) and Eq. (26), the atmospheric condition for virtual H₁ plate to record the consummate information of the scene could also be satisfied. When l ₁ < l _ii, 50 ₁ adamant the mosaicking effect of constructive perspective images, and fifty _ii adamant the flipping consequence.

In numerical simulation, some original perspective images and synthetic constructive perspective images corresponding to specific viewpoints are shown in Fig. 12. The index (x, y) in Fig. 12(b) denote the xth row and yth column'southward hogel in H_two plate. Obviously, the synthetic constructive perspective images are observed much larger than original perspective images. The reason is that the viewing distance is 11.4 cm for synthetic effective perspective images, and it is smaller than 18.half dozen cm for original perspective images. Moreover, comparing Fig. 12(a) with Fig. 12(b), the synthetic effective perspective images are pseudoscopic images, and the depth inversions can be observed clearly from teapot lid and teapot lesser. The essence of the proposed EPISM method is to reach pseudoscopic images of the scene when viewing at different positions, thus the reconstructed scene is a real scene in right depth.

Fig. 12 The numerical simulation of perspective images in different viewing positions. (a)The original perspective images. (b)The constructed effective perspective images.

Download Full Size | PPT Slide | PDF

The optical setup of the synthetic holographic stereogram printing arrangement is shown in Fig. 13. A 400 mW 639 nm unmarried longitudinal mode and linear polarization solid-state cherry laser (CNI MSL-FN-639) was used as the laser source, and an electrical shutter (Sigma Koki SSH-C2B) was used to command the exposure time. The light amplification by stimulated emission of radiation beam passed a non-polarizing beam splitter (NPBS) and was divided into two beams, i.e., the signal axle and the reference axle, and the intensities of them were both adjusted past attenuators. Synthetic constructive perspective images were loaded onto the LCD panel. The backlight module and ii polarizers of the LCD were removed. The illuminated beam passed through the LCD console after expanded past a convex lens with f = 75 mm, then transmitted a diffuser and arrived at the holographic plate. The diffuser plate used for diffused manual was placed just in forepart of the LCD console to diffuse the object light to fill the discontinuity of the hogel. The reference beam passed through a spatial filter comprised of a 40 × objective and a fifteen μgrand pivot-pigsty to filter out the higher spatial frequency. A collimating lens with f = 150 mm was used to collimate the focused light amplification by stimulated emission of radiation and to get a uniform plane reference wave. The distance betwixt the LCD panel and the holographic plate was 11.4 cm. The signal axle and the reference beam were interfered from different sides of the holographic plate and the interference fringes were recorded on the holographic motion-picture show. There were ii apertures close to the holographic plate from both side to ensure only the square surface area of the holographic plate (i.eastward., the hogel) exposed. The holographic plate was installed on a motorized KSA300 X-Y stage whose positioning precision was both along the horizontal and vertical directions. The motorized X-Y stage was driven by a programmable MC600 controller. In our system, the distance between the LCD panel and the holographic plate was set as 50 ₂, and the displacement of motorized X-Y stage for every spatial footstep was l _ii. The LCD panel, the electric shutter and the motorized Ten-Y stage were time-synchronously controlled by a computer.

It should be noted that, the synthetic effective perspective images were tiled by the original perspective images, whose exposure management was from the LCD panel to the virtual H_i plate, and information technology was contrary to the exposure direction from the LCD panel to the H₂ plate. Consequently, the synthetic effective perspective images should be flipped horizontally before loaded onto the LCD panel.

The exposure fourth dimension tin can be expressed as T _exp = E/(P _sig + P _ref), where E was the light sensitivity of holographic plate, P _sig and P _ref were the free energy intensity of betoken beam and reference beam illuminated on the holographic plate, respectively. In the experiment, the holographic plate was developed past ourselves, and for red light amplification by stimulated emission of radiation at 639 nm, E = 1250 μJ/cm². To reduce exposure time, the energy ratio between the bespeak axle and the reference beam was gear up as i:30, so P _sig = 10 μJ/cm², P _ref = 300 μJ/cm². The exposure time was calculated equally T _exp = 4 s. Waiting time was causeless as T _sti = sixteen south to eliminate the vibration resulted from the motion of the shuttle and the motorized X-Y stage. Consequently, the total press time was $T\approx (T_{\exp }+T_{\text{sti}})\times N_{{\mathrm{H}}_{\mathrm{ii}}}\times N_{{\mathrm{H}}_{\mathrm{two}}}=1280\mathrm{s}$ .

Since the energy ratio between the signal beam and the reference beam was far from 1:1, the diffraction efficiency was relatively low. The reconstructed event was not so good in white light reconstruction, so the laser reconstruction was utilized. The schematic for reconstruction is shown in Fig. 14. The holographic plate was illuminated by the conjugate beam of the original collimated reference wave, and a real image could be viewed perpendicularly to the holographic plate. A Catechism EOS 550D photographic camera with a 100 mm focus lens was put virtually 45 cm in forepart of the holographic plate to capture the reconstructed images, and it was moved along the track every bit indicated in Fig. fourteen.

It should exist pointed out that, for the conventional hologram with a sure size, a longer reconstructed distance 50 _ii is always referred to a smaller viewing zone range. However, in our EPISM based holographic stereogram printing, the determination of viewing zone range is different from that of the conventional one. According to our EPISM method, the selection of proper geometric parameters is to ensure a aforementioned perspective relation in sampling and printing processes, i.e., the size of the hologram should satisfy a certain relation with the value of 50 ₂. Consequently, the viewing zone range in our EPISM method is fixed, i.e., it is adamant by the value we supposed, not by the size of the hologram. Specifically, the viewing zone range is adamant by the FOV of whatsoever viewing point used in capturing of perspective images and printing of hogels, which is supposed to be 30° in our experiment.

The photographs of optical reconstruction from different perspectives are shown in Fig. 15. It can be seen that the proposed EPISM based holographic stereogram tin can nowadays right total parallax data, and the reconstructed 3D scene is well agreed with the original i. Still, when the observation directions are close to the limited directions (i.east., ±fifteen°), original sampled perspective images of the teapot scene are incomplete, so does the reconstructed scene. Furthermore, the situation mentioned above is more obvious in horizontal direction than that of the vertical direction since the teapot is with six.4 cm width and three.two cm acme. Therefore, photographs with complete teapot scene are selected to capture, so the viewing zone range shown in Fig. 15 is less than xxx°. The relatively depression contrast ratio is resulted from the minor energy ratio P _sig/P _ref. In Fig. 15, the center of the teapot is brighter than the other sections, which dues to the direction of the lighting in modeling software, and information technology shows that the hologram tin can display the gloss of the scene.

To indicate the reconstructed real scene out of the holographic plate, one ruler was placed parallel to the holographic plate, and the other one was placed 11.four cm ahead. A camera was put well-nigh 45 cm in front of the holographic plate to capture the reconstructed images. The photographs captured at different focus depths are shown in Fig. 16. The spatial position relation is shown in Fig. sixteen(a). In Fig. 16(b), both the correct ruler and the median surface of teapot are articulate simultaneously while the groundwork was blurred, and a blurred lattice structure on the purlieus among different hogels tin be observed. In Fig. 16(c), both the left ruler and the holographic plate are clear simultaneously, and the printed hogels can be observed clearly, while the 3D scenes are blurred.

Fig. sixteen The photographs in unlike focus depths. (a)The spatial position relation of rulers and holographic plate. (b)Focused on the right ruler. (c)Focused on the left ruler(Fifty ₂ = 11.4 cm, l _two = 1 cm).

Download Total Size | PPT Slide | PDF

From the analysis in Section 4.one, the flipping effect volition be decreased when the hogel size decreases while the other parameters keep unchanged. In the farther experiment, l ₂ was adjusted to 0.v cm, and so the number of printed hogels was 16 × 16 = 256. In the contrast experiments, the size of hogel size was selected as l ₂ = ane cm and fifty ₂ = 0.5 cm, and the video of motion parallax was recorded as shown in Visualization 2 and Visualization 3, respectively. Information technology tin can be seen that the motility parallax is smoother with a smaller hogel size.

With the fixed distance between LCD panel and holographic plate (kept as 11.four cm), the press organization can also realize different reconstructed distances. When nosotros need the reconstructed scene in different depths, i.due east., the value of Fifty ₂ is variable, the synthetic effective perspective images should be scaled starting time, as shown in Fig. 17.

Suppose the synthetic effective perspective prototype generated by the proposed EPISM is Thousand × M pixels, then the image loaded onto the LCD panel should be scaled to M′ × M′ pixels, and $M^{\prime }=\frac{11.4}{L_2}M$ .

In experiment, L _ii was selected equally viii.4 cm and 50 ₂ = 0.five cm, then we had Thousand = 440 pixels, and Thou′= 598 pixels. The 440 × 440 pixels constructed effective perspective image was enlarged to 598 × 598 pixels and loaded onto the LCD panel for printing. In the reconstruction, 1 ruler was placed parallel to the holographic plate, and the other one was 8.4 cm ahead. The photographs in different focus depths are shown in Fig. eighteen. Both the right ruler and the median surface of teapot are clear simultaneously in Fig. xviii(a), while both the right ruler and the holographic plate are clear simultaneously in Fig. eighteen(b), and the dim hogels in Fig. 18(b) are without information recorded because of the vibration during the exposure. Information technology can be seen that with the scaling of synthetic effective perspective images, the press organisation can realize different reconstructed distances when the distance betwixt LCD console and holographic plate is fixed.

Fig. 18 The photographs in different focus depths. (a)Focused on the right ruler. (c)Focused on the left ruler(L ₂ = 8.4 cm, 50 ₂ = 0.five cm).

Download Full Size | PPT Slide | PDF

When we need a much shorter distance of reconstructed scene, i.e., much smaller Fifty ₂, the size of hogel should exist much smaller as shown in Eq. (20), and the number of hogels volition be increased profoundly. All the same, this will issue in a dramatically increasing of printing time considering of the express power of the light amplification by stimulated emission of radiation. Otherwise, if the hogels' size is not diminished along with the decrease of L _two, the reconstructed quality of scene will decline. An experiment was conducted to illustrate this problem. When L ₂ was shorten to 6 cm while l ₂ was yet kept as 0.5 cm, in the reconstruction, ane ruler was placed parallel to the holographic plate, and the other one was 6 cm ahead, the reconstructed scene was with poor quality as shown in Fig. 19.

Fig. xix The photographs in unlike focus depths. (a)Focused on the right ruler. (c)Focused on the left ruler(L ₂ = half dozen cm, l ₂ = 0.5 cm).

Download Full Size | PPT Slide | PDF

Co-ordinate to the principle of synthetic holographic stereogram, the sampling plane of the 3D scene is the clearest reconstructed aeroplane when the sampling plane of scene and the LCD plane are identical, since the curvature baloney is arisen when the other planes are loaded onto the LCD console. An experiment using 3D scene with three playing cards were implemented. They were placed one cm autonomously respectively forth z-axis, and disposed staggeredly along x-axis and y-axis. The distances between the sampling camera and the kickoff playing carte were 18.6 cm, 17.half-dozen cm and 16.six cm, respectively (Fig. 20). During the generation of synthetic constructive holographic stereogram, the distance between virtual H₁ plate and LCD panel was supposed as 18.six cm. The optically reconstructed images with dissimilar clearest imaging planes are shown in Fig. 21. In Fig. 21(a), Fig. 21(b) and Fig. 21(c), the playing bill of fare of the front, the middle, and the rear ane is clearest, respectively. Nosotros take the eye card as an instance to describe the difference between reconstructed planes. In each subfigure of Fig. 21, a same surface area is marked with a green rectangle, and this area is clearest in Fig. 21(b), merely distorted in Fig. 21(a) and blurred in Fig. 21(c).

Fig. 21 The optically reconstructed images with different clearest imaging planes. The clearest imaging plane is (a)the front carte du jour, (b)the middle card and (c)the rear card while (d) is the original model.

Download Full Size | PPT Slide | PDF

half dozen. Conclusion

In this newspaper, nosotros propose a press method of single-step full parallax constructed holographic stereogram based on effective perspective images' segmentation and mosaicking (EPISM). The perspective images of 3D scene were offset sampled past a virtual camera, then the effective perspective image segment was extracted from the perspective image of virtual hogel according to the propagation law of light and the viewing frustum effect of man optics. Using the EPISM algorithm, the constructed effective perspective images for the printed hogels were achieved past mosaicking the constructive perspective images segments of the contributed virtual hogels. The influences of modelling parameters on the reconstruction quality, such as the flipping effect, the reconstructed images' resolution, were besides analyzed. The proposed method was verified experimentally and discussed, and the experimental results indicated that the EPISM based single-step full parallax holographic stereogram could behave skillful reconstruction quality every bit well every bit a compact configuration. Even so, the pocket-size hogel size is required to forestall the flipping effect, especially for the 3D scene with a big depth and the reconstructed scene with a brusque distance, and this will result in a meaning increasing of printing time. The improved EPISM method with better reconstruction quality as well as efficient printing rate will exist investigated in the time to come.

Funding

Foundation for the Writer of National Excellent Doctoral Dissertation of the People's Republic of China (FANEDD) (201432); Natural Scientific discipline Foundation of Beijing Municipality (4152049); Beijing NOVA plan (Z1511000003150119).

References and links

1. M. Lucente, "The commencement 20 years of holographic video - and the next 20," in SMPTE 2d Annual International Conference on Stereoscopic 3D for Media and Entertainment - Society of Move Motion-picture show and Television receiver Engineers(SMPTE), 2011.

ii. H. I. Bjelkhagen and D. Brotherton-Ratcliffe, "Ultrarealistic imaging: the future of display holography," Opt. Eng. 53(11), 112310 (2014). [CrossRef]

3. Grand. Yamaguchi, "Light-field and holographic three-dimensional displays [Invited]," J. Opt. Soc. Am. A 33, (12)2348–2364 (2016). [CrossRef]

4. Y. Takaki and Yard. Taira, "Speckle regularization and miniaturization of computer-generated holographic stereograms," Opt. Express 24(6), 6328–6340 (2016). [CrossRef] [PubMed]

v. H. Kang, E. Stoykova, Northward. Berberova, J. Park, D. Nazarova, J. S. Park, Y. Kim, S. Hong, B. Ivanov, and N. Malinowski, "Three-dimensional imaging of cultural heritage artifacts with holographic printers," Proc. SPIE 10226, 102261I (2017). [CrossRef]

six. H. Kang, E. Stoykova, and H. Yoshikawa, "Fast stage-added stereogram algorithm for generation of photorealistic 3D content," Appl. Opt. 55(iii), A135–A143 (2016). [CrossRef] [PubMed]

7. H. Yoshikawa and T. Yamaguchi, "Review of Holographic Printers for Computer-Generated Holograms," IEEE T. Ind. Inform. 12(iv), 1584–1589 (2016). [CrossRef]

8. C. Pei, 10. Yan, and X. Jiang, "Computer-generated phase-modulated full parallax holographic stereograms without conjugate images," Opt. Eng. 53(x), 103105 (2014). [CrossRef]

9. T. Yamaguchi, O. Miyamoto, and H. Yoshikawa, "Book hologram printer to record the wavefront of three-dimensional objects," Opt. Eng. 51(seven), 075802 (2012). [CrossRef]

ten. H. Kang, East. Stoykova, H. Yoshikawa, Southward. Hong, and Y. Kim, "Comparison of organisation backdrop for wave-front holographic printers," in Fringe 2013, Westward. Osten, ed. (Springer-Verlag, 2014), 851–854. [CrossRef]

11. 1000. Wakunami, R. Oi, T. Senoh, H. Sasaki, Y. Ichihashi, and K. Yamamoto, "Wavefront printing technique with overlapping arroyo toward high definition holographic image reconstruction," Proc. SPIE 9867, 98670J (2016).

12. L. Cao, Z. Wang, H. Zhang, G. Jin, and C. Gu, "Book holographic printing using unconventional angular multiplexing for 3-dimensional brandish," Appl. Opt. 55(22), 6046–6051 (2016). [CrossRef] [PubMed]

13. D. J. Debitetto, "Holographic panoramic stereograms synthesized from white light recordings," Appl. Opt. 8(eight), 1740–1741 (1969). [CrossRef] [PubMed]

14. Yard. C. Rex, A. M. Noll, and D. H. Berry, "A new approach to computer-generated holography," Appl. Opt. 9(2), 471–475 (1970). [CrossRef] [PubMed]

15. M. W. Halle, "The generalized holographic stereogram," Proc. SPIE 1461, 142–155 (1991). [CrossRef]

sixteen. M. W. Halle, "The generalized holographic stereogram," Ph. D. thesis, Massachusetts Institute of Technology (1993).

17. C. Newswanger and Thousand. Klug, "Holograms for the masses," in 9th International Symposium on Display Holography(ISDH), (IOP Publishing, 2013), 012082.

xviii. D. Brotherton-Ratcliffe, "Large format digital colour holograms produced using RGB pulsed light amplification by stimulated emission of radiation technology," in, 7th International Symposium on Brandish Holography, H. I. Bjelkhagen, ed. (River Valley, 2006), 200–208.

19. D. Brotherton-Ratcliffe, S. J. Zacharovas, R. J. Bakanas, J. Pileckas, A. Nikolskij, and J. Kuchin, "Digital holographic press using pulsed RGB lasers," Opt. Eng. 50(ix), 091307 (2011). [CrossRef]

20. Yard. Yamaguchi, T. Honda, N. Ohyama, and J. Ishikawa, "Multidot recording of rainbow and multicolor holographic stereograms," Opt. Commun. 110(5–half-dozen), 523–528 (1994). [CrossRef]

21. Due south. Maruyama, Y. Ono, and 1000. Yamaguchi, "High-density recording of full-colour full-parallax holographic stereogram," Proc. SPIE 6912, 69120N (2008). [CrossRef]

22. B. Lee, J. -H. Kim, Yard. Moon, I. -J. Kim, and J. Kim, "Holographic stereogram printing nether the non-vibration environs," Proc. SPIE 9117, 911704 (2014). [CrossRef]

23. M. Yamaguchi, H. Endoh, T. Koyama, and North. Ohyama, "High-speed recording of full-parallax holographic stereograms past a parallel exposure system," Opt. Eng. 35(6), 1556–1559 (1996). [CrossRef]

24. 10. Rong, X. Yu, and C. Guan, "Multichannel holographic recording method for iii-dimensional displays," Appl. Opt. 50(seven), B77–B80 (2011). [CrossRef] [PubMed]

25. A. V. Morozov, A. North. Putilin, Due south. Southward. Kopenkin, Y. P. Borodin, V. 5. Druzhin, Southward. E. Dubynin, and G. B. Dubinin, "3D holographic printer: fast printing approach," Opt. Limited 22(3), 2193–2206 (2014). [CrossRef] [PubMed]

26. Y. Im, West. Moon, J. Roh, H. Kim, and J. Hahn, "Direct laser writing of estimator-generated hologram using pulse light amplification by stimulated emission of radiation system," in Digital Holography and Three-Dimensional Imaging, (Optical Society of America, 2014), paper JTu4A.27.

27. Grand. Hong, Due south. -g. Park, J. Yeom, J. Kim, N. Chen, K. Pyun, C. Choi, S. Kim, J. An, H. -S. Lee, U.-i. Chung, and B. Lee, "Resolution enhancement of holographic printer using a hogel overlapping method," Opt. Express 21(12), 14047–14055 (2013). [CrossRef] [PubMed]

28. T. Utsugi and M. Yamaguchi, "Reduction of the recorded speckle noise in holographic 3D printer," Opt. Limited 21(1), 662–674 (2013). [CrossRef] [PubMed]

29. M. Takano, H. Shigeta, T. Nishihara, M. Yamaguchi, Southward. Takahashi, Due north. Ohyama, A. Kobayashi, and F. Iwata, "Full-color holographic 3D printer," Proc. SPIE 5005, 126–136 (2003). [CrossRef]

xxx. H. I. Bjelkhagen and Due east. Mirlis, "Color holography to produce highly realistic 3-dimensional images," Appl. Opt. 47(4), 123–133 (2008). [CrossRef]

31. F. Yang, Y. Murakami, and M. Yamaguchi, "Digital color management in full-color holographic three-dimensional printer," Appl. Opt. 51(xix), 4343–4352 (2012). [CrossRef] [PubMed]

32. S. Tay, P. -A. Blanche, R. Voorakaranam, A. Five. Tunç, W. Lin, S. Rokutanda, T. Gu, D. Flores, P. Wang, G. Li, P. St Hilaire, J. Thomas, R. A. Norwood, Thou. Yamamoto, and N. Peyghambarian, "An updatable holographic iii-dimensional display," Nature 451(7179), 694–698 (2008). [CrossRef] [PubMed]

33. P. -A. Blanche, A. Bablumian, R. Voorakaranam, C. Christenson, W. Lin, T. Gu, D. Flores, P. Wang, West. -Y. Hsieh, K. Kathaperumal, B. Rachwal, O. Siddiqui, J. Thomas, R. A. Norwood, M. Yamamoto, and N. Peyghambarian, "Holographic three-dimensional telepresence using big-area photorefractive polymer," Nature 468(7320), fourscore–83 (2010). [CrossRef] [PubMed]

34. Northward. Tsutsumi, G. Kinashi, Thou. Tada, K. Fukuzawa, and Y. Kawabe, "Fully updatable 3-dimensional holographic stereogram display device based on organic monolithic compound," Opt. Express 21(17), 19880–19884 (2013). [CrossRef] [PubMed]

35. Grand. Yamaguchi, Due north. Ohyama, and T. Honda, "Holographic three-dimensional printer: new method," Appl. Opt. 31(2), 217–222 (1992). [CrossRef] [PubMed]

36. M. Yamaguchi, H. Endoh, T. Honda, and N. Ohyama, "High-quality recording of a full-parallax holographic sterogram with a digital diffuser," Opt. Lett. 19(2), 135–137 (1994). [CrossRef] [PubMed]

37. T. Yatagai, "Stereoscopic arroyo to 3-D display using computer-generated holograms," Appl. Opt. xv(xi), 2722–2729 (1976). [CrossRef] [PubMed]

bormannhentown.blogspot.com

Source: https://opg.optica.org/abstract.cfm?uri=oe-25-19-23523

Share this post