CN104199267B - Method for eliminating zero-order noise of pixel structure spatial light modulator - Google Patents

Abstract

The invention relates to a method for eliminating zero-level noise of a pixel structure spatial light modulator. The total transmittance of the spatial light modulator integrated with the micro-nano element can be adjusted by adjusting the pixel structure parameters of the micro-nano element and the spatial light modulatorAn excess function to enhance the contrast of the reproduced image, and ξ for adjusting₁,ξ₂And ξ₃The filling ratio of the spatial light modulator can be further modulated. Finally, the purposes of eliminating zero-order noise generated by the pixel structure spatial light modulator and improving the imaging quality of the system are achieved. The method can be widely applied to the holographic projection technology in the field of spatial light modulation.

Description

A kind of method eliminating dot structure spatial light modulator zero level noise

Technical field

The present invention relates to spatial light modulator field, particularly relate to a kind of dot structure spatial light modulator zero level that eliminates and make an uproar The method of sound.

Background technology

In the last few years, along with computer technology and the development of spatial light modulation device, line holographic projections showed gradually Become one of study hotspot of domestic and international 3D field of stereoscopic display.Line holographic projections shows by computer-generated hologram, then It is loaded in spatial light modulator and utilize laser diffraction to carry out imaging.It can complete documentation and the ripple of 3 d objects reconstruction Before, it is provided that the full depth information needed for human visual system, this is that other Projection Display modes are incomparable.Yet with Dot structure that spatial light modulator is intrinsic and limited fill factor, curve factor, the image that diffraction generates can exist obvious zero level to be done Disturbing, this carries out, also with commercial pixel type spatial light modulator, the typical problem that line holographic projections shows.Prior art proposes Hologram loads diverging spherical wave phase and linear phase, to reduce the zero order light impact on reproduction image.This is the most complete A kind of technical scheme that in breath Projection Display, the comparison of application is many.Owing to the space-bandwidth product of spatial light modulator is fixing, The extension of the spatial frequency spectrum width of additional diverging spherical wave phase and linear phase can reduce the imaging of system to a certain extent Quality.

Summary of the invention

(1) to solve the technical problem that

The technical problem to be solved in the present invention is how to provide a kind of dot structure spatial light modulator zero level that eliminates to make an uproar The method of sound, ensures not reduce the image quality of system simultaneously.

(2) technical scheme

In order to solve above-mentioned technical problem, the invention provides a kind of elimination dot structure spatial light modulator zero level noise Method, comprise the following steps:

Step one: integrated micro-nano element in spatial light modulator, the dot structure of described micro-nano element is adjusted with spatial light The dot structure one_to_one corresponding of device processed, micro-nano element meets d with the parameter of spatial light modulator_x>a_x>b_x,d_y>a_y>b_y；

Its spatial light modulator single pixel transmittance a size of a_x×a_y, the pel spacing in x direction and y direction is respectively d_xAnd d_y, the size on whole pel array surface is L_xAnd L_y；

Micro-nano element single pixel transmittance a size of a_x×a_y, the pel spacing in x direction and y direction is respectively d_xAnd d_y；

It is not b by the size of the active area of micro-nano elements modulate_x×b_y；

Step 2: calculate spatial light modulator not by absorbance S of the active region of micro-nano elements modulate_Preimage(x, y),

Step 3: calculate spatial light modulator active-surface by the transmittance factor S after micro-nano elements modulate_Differential(x, Y),

Wherein ,-j2 π (x+y) is the modulation function distribution of micro-nano element；

Step 4: calculate the transmission coefficient S in spatial light modulator dead band_{Dead band}(x,y)

Wherein A_{Dead band}(x,y)exp[iφ_{Dead band}(x, y)] it is the COMPLEX AMPLITUDE that causes of spatial light modulator dead band；

Step 5: obtain total transmittance function of the spatial light modulator of integrated micro-nano element

Step 6: regulation micro-nano element and the dot structure parameter of spatial light modulator, thus adjust that described integrated this is micro- Receive element spatial light modulator total transmittance function S (x, y), and ξ₁,ξ₂And ξ₃Ratio；

Wherein ${\mathrm{\ξ}}_1=\frac{b_x{b}_y}{d_x{d}_y},{\mathrm{\ξ}}_2\frac{a_x{a}_y-b_x{b}_y}{d_x{d}_y},{\mathrm{\ξ}}_3=\frac{d_x{d}_y-a_x{a}_y}{d_x{d}_y},$ And ξ₁+ξ₂+ξ₃=1, ξ₁+ξ₂For spatial light modulation The filling rate of device；

In above-mentioned steps, rect () is rectangular function,Representing convolution algorithm, (x, y) for being loaded into spatial light modulator for G The hologram distribution of active region.

Preferably, between pel array surface and the described spatial light modulator pixel array surface of described micro-nano element Distance is below 2cm.

Preferably, described micro-nano element snug space light modulator pixel array surface is placed.

Preferably, the edge of the described each pixel of micro-nano element is fixing numeric distribution, can be to active-surface portion Divide the modulation realizing-j2 π (x+y).

Preferably, the described effective modulating part of micro-nano element is that the edge of each pixel, width and length are respectively (a_x- b_x)/2 and (a_y-b_y)/2, remainder modulation degree is zero or is constant.

(3) beneficial effect

A kind of method eliminating dot structure spatial light modulator zero level noise of the present invention, collects in spatial light modulator Become micro-nano element, and be calculated total transmittance function of the spatial light modulator of integrated micro-nano element.Integrated micro-nano element Total transmittance function of spatial light modulator can strengthen reproduce image contrast, then with regulation spatial light modulator filling Rate combines, and reaches to eliminate the purpose of the zero level noise that dot structure spatial light modulator produces, improves the image quality of system.

Accompanying drawing explanation

In order to be illustrated more clearly that the embodiment of the present invention or technical scheme of the prior art, below will be to embodiment or existing In having technology to describe, the required accompanying drawing used is briefly described, it should be apparent that, the accompanying drawing in describing below is only this Some embodiments of invention, for those of ordinary skill in the art, on the premise of not paying creative work, it is also possible to Other accompanying drawing is obtained according to these accompanying drawings.

The dot structure parameter schematic diagram of the spatial light modulator of Fig. 1: prior art；

The structural parameters schematic diagram of the spatial light modulator of a kind of integrated micro-nano element that Fig. 2: the present invention provides.

Detailed description of the invention

With embodiment, embodiments of the present invention are described in further detail below in conjunction with the accompanying drawings.Following example are used for The present invention is described, but can not be used for limiting the scope of the present invention.

The present invention provides a kind of method eliminating dot structure spatial light modulator zero level noise, comprises the following steps:

Step one: integrated micro-nano element in spatial light modulator, the dot structure of described micro-nano element is adjusted with spatial light The dot structure one_to_one corresponding of device processed, micro-nano element meets d with the parameter of spatial light modulator_x>a_x>b_x,d_y>a_y>b_y；

Its spatial light modulator single pixel transmittance a size of a_x×a_y, the pel spacing in x direction and y direction is respectively d_xAnd d_y, the size on whole pel array surface is L_xAnd L_y, as shown in Figure 1；

Micro-nano element single pixel transmittance a size of a_x×a_y, the pel spacing in x direction and y direction is respectively d_xAnd d_y, not It is b by the size of the active area of micro-nano elements modulate_x×b_y, as shown in Figure 2；

Step 2: calculate spatial light modulator not by absorbance S of the active region of micro-nano elements modulate_Preimage(x, y),

Step 3: calculate spatial light modulator active-surface by the transmittance factor S after micro-nano elements modulate_Differential(x, Y),

Wherein ,-j2 π (x+y) is the modulation function distribution of micro-nano element；

Step 4: calculate the transmission coefficient S in spatial light modulator dead band_{Dead band}(x,y)

Wherein A_{Dead band}(x,y)exp[iφ_{Dead band}(x, y)] it is the COMPLEX AMPLITUDE that causes of spatial light modulator dead band；

Step 5: obtain total transmittance function of the spatial light modulator of integrated micro-nano element

Step 6: regulation micro-nano element and the dot structure parameter of spatial light modulator, thus adjust that described integrated this is micro- Receive element spatial light modulator total transmittance function S (x, y), and ξ₁,ξ₂And ξ₃Ratio；

WhereinAnd ξ₁+ξ₂+ξ₃=1, ξ₁+ξ₂For spatial light modulation The filling rate of device；

By regulation micro-nano element and the dot structure parameter of spatial light modulator, integrated micro-nano element i.e. can be adjusted (x y), thus strengthens the contrast reproducing image to total transmittance function S of spatial light modulator；ξ can be regulated again₁,ξ₂And ξ₃ Ratio, and then can reach to modulate the purpose of filling rate of spatial light modulator.It is finally reached elimination dot structure spatial light The zero level noise that manipulator produces, improves the purpose of the image quality of system；

In above-mentioned steps, rect () is rectangular function,Representing convolution algorithm, (x, y) for being loaded into spatial light modulator for G The hologram distribution of active region.

Wherein, described micro-nano element snug space light modulator pixel array surface is placed

The edge of the wherein said each pixel of micro-nano element is fixing numeric distribution, not with spatial light modulator active area Load the change of numerical value and change, active-surface part can be realized the modulation of-j2 π (x+y).

The described effective modulating part of micro-nano element is that the edge of each pixel, width and length are respectively (a_x-b_x)/2 He (a_y-b_y)/2, remainder modulation degree is zero or is constant.

In the present embodiment, as a example by Fourier hologram, when being integrated with the spatial light modulator of micro-nano element with this to entirely When breath figure carries out diffraction imaging, (u v) is transmission function S (x, Fourier transformation y) to COMPLEX AMPLITUDE g of imaging plane

Wherein

Wherein f (u, v) is original image, f'(u, v) is the derivative of original image, F (u, v) be dead band produce zero level noise；

The COMPLEX AMPLITUDE of imaging plane also can be written as

Wherein f (u, v)+f'(u, v) be our target image of wanting, and contrast increases relative to original image, with Time can by regulation ξ₁,ξ₂And ξ₃Size make the Section 2 in its braces

$-({\mathrm{\ξ}}_1+{\mathrm{\ξ}}_2)\sin c({\mathrm{ua}}_x,{\mathrm{va}}_y)\mathrm{comb}({\mathrm{ud}}_x,{\mathrm{vd}}_y)\⊗[f^{\′}(u,v)+F(u,v)]$

And Section 3Cancel out each other, thus eliminate zero level noise, carry The image quality of high system.

The present invention can be used for pure phase type spatial light modulator, net amplitude type spatial light modulator, combined modulation spatial light Manipulator and complex amplitude modulation spatial light modulator, DMD etc..

Embodiment of above is merely to illustrate the present invention, rather than limitation of the present invention.Although with reference to embodiment to this Bright be described in detail, it will be understood by those within the art that, technical scheme is carried out various combination, Amendment or equivalent, without departure from the spirit and scope of technical solution of the present invention, all should contain the right in the present invention and want Ask in the middle of scope.

Claims (5)

1. the method eliminating dot structure spatial light modulator zero level noise, it is characterised in that comprise the following steps:

Step one: integrated micro-nano element in spatial light modulator, the dot structure of micro-nano element and the picture of spatial light modulator Element structure one_to_one corresponding, micro-nano element meets d with the parameter of spatial light modulator_x＞ a_x＞ b_x,d_y＞ a_y＞ b_y；

Its spatial light modulator single pixel transmittance a size of a_x×a_y, the pel spacing in x direction and y direction is respectively d_xWith d_y, the size on whole pel array surface is L_xAnd L_y；

Micro-nano element single pixel transmittance a size of a_x×a_y, the pel spacing in x direction and y direction is respectively d_xAnd d_y；

It is not b by the size of the active area of micro-nano elements modulate_x×b_y；

Step 2: calculate spatial light modulator not by absorbance S of the active region of micro-nano elements modulate_Preimage(x, y),

Step 3: calculate spatial light modulator active-surface by the transmittance factor S after micro-nano elements modulate_Differential(x, y),

Wherein ,-j2 π (x+y) is the modulation function distribution of micro-nano element；

Step 4: calculate the transmission coefficient S in spatial light modulator dead band_{Dead band}(x,y)

Wherein A_{Dead band}(x,y)exp[iφ_{Dead band}(x, y)] it is the COMPLEX AMPLITUDE that causes of spatial light modulator dead band；

Step 5: obtain total transmittance function of the spatial light modulator of this micro-nano element integrated

Step 6: regulation micro-nano element and the dot structure parameter of spatial light modulator, thus adjust described this micro-nano unit integrated Total transmittance function S of the spatial light modulator of part (x, y), and ξ₁,ξ₂And ξ₃Ratio；

WhereinAnd ξ₁+ξ₂+ξ₃=1, ξ₁+ξ₂For spatial light modulator Filling rate；

By regulation ξ₁,ξ₂And ξ₃Size make WithCancel out each other, thus eliminate zero level noise, improve the one-tenth picture element of system Amount；

In above-mentioned steps, rect () is rectangular function,Expression convolution algorithm, and G (x, y) active for being loaded into spatial light modulator The hologram distribution in region.

Method the most according to claim 1, it is characterised in that the pel array surface of described micro-nano element and described space Distance between light modulator pixel array surface is below 2cm.

Method the most according to claim 2, it is characterised in that described micro-nano element snug space light modulator pixel array Surface is placed.

Method the most according to claim 1, it is characterised in that the edge of the described each pixel of micro-nano element is fixing number Distribution value.

Method the most according to claim 1, it is characterised in that the described effective modulating part of micro-nano element is each pixel Edge, width and length are respectively (a_x-b_x)/2 and (a_y-b_y)/2, remainder modulation degree is zero or is constant.