Holographic projection method

A technology of holographic projection and holographic surface, applied in the field of holographic projection, can solve the problems of complex measurement and application, and achieve the effect of breaking through the limitation of imaging distance

Active Publication Date: 2012-10-24
SOUTHEAST UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

For the projection of Fresnel holograms, although the lens factor can be introduced into the calculation to project the image on a plane with different distances without adjusting the focal length, the introduction of the lens factor is very complicated for calculation and application.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment

[0050] Embodiment: the monochromatic green light with a wavelength of 532 nanometers emitted by the monochromatic laser 5 is used for projection; the phase spatial light modulator 1 adopts the phase spatial light modulator produced by the U.S. BNS company, and its specification is 512 × 512 pixels, and the pixel The spacing is 15 microns; the focal length f of the lens 3 is 0.5 meters.

[0051] Three screens are arranged behind the lens 3 , which are respectively a projection screen 4 , a second projection screen 8 and a third projection screen 9 .

[0052] The corresponding order of projection screen 4 is a 1 =1.1 fractional Fourier transform, the corresponding order of the second projection screen 8 is a 2 =1.25 fractional Fourier transform, the corresponding order of the third projection screen is a 3 =1.4 fractional Fourier transform. According to the order and distance formula z=f tan(aπ / 4) sin(aπ / 2), it is easy to know that the positions of the reconstructed images of...

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Abstract

The invention discloses a holographic projection method which comprises the following steps of: (10) laying projection devices: successively laying a phase spatial light modulator, a beam splitting prism, a lens and a screen, laying a mono-color laser and a polarizing film on the same side of the beam splitting prism, and connecting the phase spatial light modulator with a computer; (20) measuring the distance of an imaging face; (30) measuring and calculating the relationship between the focal length of the lens and the distance of the imaging face; (40) after determining the order of fractional Fourier transformation in the system, and carrying out iteration by using the fractional Fourier transformation formula and the inverse transformation formula to obtain the phase of a two-dimensional image; and (50) transmitting the phase hologram to the phase spatial light modulator via the computer, and projecting the phase hologram onto the screen in the specific location by using the phase spatial light modulator. With the holographic projection method, the holographic reconstructed two-dimensional image can be projected onto any plane behind the lens, and the focal length of the lens does not need to be changed to control the distance of imaging.

Description

technical field [0001] The invention relates to a holographic projection method. The holographic projection method controls the imaging distance of projected images by utilizing the optical characteristics of fractional Fourier transform. Background technique [0002] For traditional holographic projection, the phase hologram is generated using the classic Gerschberg-Saxton (GS) iterative algorithm, which is an iterative algorithm based on Fourier transform. The process of hologram projection is to use the lens to light field Perform Fourier transform or Fresnel diffraction to reproduce the light field of a two-dimensional image. For the projection of Fourier holograms, the projection imaging distance is related to the focal length of the lens. According to the Fourier transform characteristics of the lens, the imaging is always formed on the back focal plane of the lens, and the imaging distance is also the focal length of the lens. Therefore In order to project images on ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G03B21/00G03H1/22
Inventor 常琛亮夏军
Owner SOUTHEAST UNIV
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