CN103871387A - Image sampling method based on liquid crystal display light modulation - Google Patents
Image sampling method based on liquid crystal display light modulation Download PDFInfo
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- CN103871387A CN103871387A CN201410131479.2A CN201410131479A CN103871387A CN 103871387 A CN103871387 A CN 103871387A CN 201410131479 A CN201410131479 A CN 201410131479A CN 103871387 A CN103871387 A CN 103871387A
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Abstract
The invention provides an image sampling method based on liquid crystal display light modulation. Elements of a liquid crystal display, a liquid crystal display driving control circuit, a Fourier lens and a photodiode are adopted in the method. The method comprises the following steps that light emitted by a measured object is imaged to the liquid crystal display through an optical imaging part, each pixel of the liquid crystal display is equivalent to a photoswitch, and the liquid crystal display driving circuit controls rotation of liquid crystal to change light transmittance of the liquid crystal, so that rays transmit through the liquid crystal display in a selective mode. A programmable measurement matrix is physically achieved through change of the light transmittance of the liquid crystal display. The rays transmitting through the liquid crystal display are emitted into the Fourier lens. The photodiode receives light intensity at the focus position of the lens, integration is conducted on the light intensity, and an obtained result is equivalent to an observed value in the compressive sensing theory. The image sampling method based on liquid crystal display light modulation is simple in structure and low in cost, and has good use value and wide application prospects in the fields of optical imaging and image acquisition.
Description
(1) technical field
The present invention relates to compressed sensing theory to be applied to the technical field of image acquisition, particularly a kind of new type of compression method of sampling of the physics realization mode using liquid crystal display as observing matrix.
(2) background technology
Traditional signals collecting is take nyquist sampling theorem as basis, and in the time obtaining signal, sample frequency must be greater than the twice of highest frequency in signal, could Accurate Reconstruction signal.But along with developing rapidly of science and technology, high-resolution digital equipment sampling has produced huge data, how processing more efficiently these data and saving storage and transmission cost is to greatest extent a great problem, propose requirements at the higher level to signal handling capacity, brought very big challenge also to corresponding hardware device.In fact, most of data that traditional sampling obtains are unessential, in the processing procedure of signal or image, only retain some important data, give up a large amount of redundant datas, and the signal after reconstruct or image can't cause visual difference.Because the data major part collecting is all unessential, can be dropped, can directly gather so part important, the last data that are not dropped, and accurately reconstruct original signal or image, this is the thought of compressed sensing theory.
Compressed sensing theory is formally to be proposed in 2006 on the basis of correlative study by Cand é s and Donoho.Its core concept is that compression is merged and carried out with sampling.First the non-self-adapting linear projection (measured value) of collection signal, then according to corresponding restructing algorithm by measured value reconstruct original signal.The advantage of compressed sensing is that the projection measurement data volume of signal is far smaller than the data volume that traditional sampling method obtains, and can suppress random noise.The first compression sampling of this principle, is shone upon measured signal it is sampled to low-dimensional by higher-dimension, chooses suitable rarefaction representation base Ψ, and making original signal f is sparse through Ψ conversion gained vector x.Then according to observation data y, observing matrix Φ and rarefaction representation base Ψ, choose special algorithm and solve y=Φ Ψ x, be finally finally inversed by original signal f by f=Ψ x.
Since compressed sensing proposes, scholars have carried out applied research widely in optical imaging field to it.As grain graininess measurement, single pixel camera, ultra-thin imaging system, the imaging of frequency multiplexing technique intelligence, multispectral imaging, the imaging of CMOS low data rate, Magnetic resonance imaging, astronomical sight etc.For example, patent (numbering: 201210058483.1) " photon counting compression sampling phased array laser three-dimensional imaging method " modulates laser illuminator with liquid crystal optical phased array, the measurement matrix used according to compression sampling irradiates target, convert in time by geiger mode avalanche photodiodes (APD) receiving target echoed signal and Single Photon Counting device the photon number of returning, finally by compression sampling recovery algorithms reconstruction of three-dimensional images.In above-mentioned patent, relate to measurement matrix and only realize the modulation of the signal to transmitting terminal, do not consider the compressed sensing implementation of receiving end signal.
Liquid crystal display with
liquid crystalmaterial is basic module, and filling liquid crystal material between two parallel plates changes the arrangement situation of liquid crystal material interior molecules by voltage, to reach the object of shading and printing opacity, show deep mixed, in picturesque disorder image.And as long as add the filter layer of three-primary colours between two flat boards, just can realize color display.Liquid crystal display power consumption is very low, and therefore extremely slip-stick artist favors, and is applicable to use the electronic equipment of battery.
The present invention adopts the liquid crystal display that removes the adjustable gray scale of monochrome backlight.Each pixel of liquid crystal display is equivalent to a photoswitch, and the torsion of liquid crystal display driving circuit control liquid crystal, to change its transmittance, makes light see through selectively liquid crystal display.Transmittance by liquid crystal display changes, and physically realizes a programmable observing matrix.
(3) summary of the invention
How compressed sensing is successfully applied in optical imagery, key is how correctly to obtain the compression sampling of image.From each formation method, except cmos imaging, all the other have all related to coding mode.Coding mode great majority are all to realize by optical system, once mask fabrication completes, its coding mode is also just fixing, cannot change.This programmable coding implementation of picture digital micro-mirror array (Digital Mirror Device, DMD), although flexible, being applied to imaging system can increase the complicacy of light path, affects system reliability.And DMD can only realize binary observing matrix.
The present invention proposes a kind of new compression sampling mode, adopts the physics realization mode of liquid crystal display as observing matrix Φ.
Element used comprises: liquid crystal display, liquid crystal display Drive and Control Circuit, fourier lense, photodiode.
The technical solution used in the present invention is: the light that object being measured is sent is imaged on liquid crystal display through optical imagery parts.Each pixel of liquid crystal display is equivalent to a photoswitch, and the torsion of liquid crystal display driving circuit control liquid crystal, to change its transmittance, makes light see through selectively liquid crystal display.Transmittance by liquid crystal display changes, and physically realizes a programmable observing matrix.The light that sees through liquid crystal display is injected fourier lense.Photodiode is at lens focus place receiving light power, and by light intensity integration, the result obtaining is equivalent to the observed reading y in compressed sensing theory.
The invention has the advantages that: the programmability with similar DMD element.And, because light is to see through liquid crystal display rather than enter lens after DMD element reflects, therefore each system element can be positioned on an optical axis, can directly fourier lense be positioned over to the liquid crystal display back side.The selection of the focal length of lens is just no longer subject to the restriction of light reflection angle like this, has reduced the complexity of light path.Meanwhile, overcome DMD and can only realize the shortcoming of scale-of-two observing matrix.And the price of liquid crystal display is comparatively cheap, reduce the cost of imaging system.
(4) accompanying drawing explanation
Below in conjunction with the drawings and specific embodiments, the present invention will be further described.
Fig. 1 is structural representation of the present invention.
Fig. 2 is the simulated experiment result of the embodiment of the present invention.
Accompanying drawing indicates
1, liquid crystal display 2, fourier lense 3, photodiode
(5) embodiment
In Fig. 1, liquid crystal display (1), fourier lense (2), photodiode (3) are positioned on an optical axis, fourier lense (2) is positioned between liquid crystal display (1) and photodiode (3), and photodiode (3) is positioned at the focus place of fourier lense (2).
Step 1: the light that object being measured is sent is imaged on liquid crystal display through optical imagery parts.Now the picture on liquid crystal display is original signal X
n × 1.
Step 2: the torsion of liquid crystal display driving circuit control liquid crystal, make Pixel arrangement on liquid crystal display in pseudo-random state i, wherein 1≤i≤M, their state has formed the capable h of i of observing matrix Φ
i(size is N).The signal that now will see through liquid crystal display is that X is at h
iunder value.
Step 3: the light that sees through liquid crystal display is injected fourier lense.Photodiode, at lens focus place receiving light power, by light intensity integration, obtains result y
i=h
ix
n × 1.
Step 4: repeat step above M time, M liquid crystal screen image element ordered state formed observing matrix Φ
m × N, M time measurement result forms observation data matrix Y=Φ X.
The mathematical model of compression sampling part is as follows:
One-dimensional discrete signal x can be expressed as
Wherein Ψ=[ψ
1| ψ
2| ψ
n], s is weighting coefficient s
i=<x, ψ
i>=ψ
i tn × 1 column vector of x.X and s are the equivalent representations of signal.If x is only the linear combination (K<N) of K base vector, claim that signal x is that K is sparse.In the time of K ∈ N, above-mentioned formula only has the large coefficient of minority and a large amount of little coefficients, and now signal x becomes compressible.
Consider a linear measurement process, calculate M x(M<N) and vector set
inner product, that is: y
i=<x, φ
j>.If measured value y
im × 1 vector forming is y, by
m × N the matrix forming as vector is Φ, has
y＝Φx＝ΦΨ＝Θs (2)
Wherein Θ=Φ Ψ is M × N matrix.Matrix Θ will meet constraint equidistant characteristics (restricted isometry property (RIP))
(1-ε)||v||
2≤||Θv||
2≤(1+ε)||v||
2 (3)
Be the length that matrix Θ must keep the sparse vector of specific K.Because Ψ fixes, make Θ=Φ Ψ meet constraint equidistant characteristics, can solve by design observing matrix Φ.The people such as Cand é s have proved in the time that Φ is gaussian random matrix, and matrix Θ can meet constraint equidistant characteristics with greater probability.Therefore can be by selecting Gauss's observing matrix that a size is M × N to obtain.
Fig. 2 is the simulated experiment result of the embodiment of the present invention.Fig. 2 (a) is original image, and size is 100 × 100, is gray level image.The energy of each frequency range of this pictures is all very abundant, the mixing of appropriateness details, smooth region, shade and texture, thereby can well test various image processing algorithms, be the standardized test chart of widespread use in Research on Image Compression Algorithm.Fig. 2 (a) is equivalent to image in step 1 the original signal X on liquid crystal display
10000 × 1.Observing matrix Φ chooses the scale-of-two stochastic matrix of size for M × 10000.Y=Φ X has just formed the observation data matrix obtaining after M sampling in step 4 like this.In the simulated experiment of the present embodiment, choose minimum full variational method solving equation Y=Φ X.The result X ' going out through this Algorithm for Solving forms reconstruction image.Fig. 2 (b) gets the image reconstructing at 4000 o'clock for sampling number M.
The minimum full variational method is that Cand é s etc. is sparse angle from the discrete gradient of a large amount of natural images, the image reconstruction algorithm that is more suitable for reconstruction of two-dimensional images putting forward.The full Variation Model of compression of images is as follows
minTV(f) s.t. y＝Φf (4)
Objective function TV (f) is image discrete gradient sum,
Claims (4)
1. a compressive sampling method that carries out optical modulation with liquid crystal display, is characterized in that: the light that object being measured is sent is imaged on liquid crystal display through optical imagery parts.Each pixel of liquid crystal display is equivalent to a photoswitch, and the torsion of liquid crystal display driving circuit control liquid crystal, to change its transmittance, makes light see through selectively liquid crystal display.Transmittance by liquid crystal display changes, and physically realizes a programmable observing matrix.The light that sees through liquid crystal display is injected fourier lense.Photodiode is at lens focus place receiving light power, and by light intensity integration, the result obtaining is equivalent to the observed reading in compressed sensing theory.It comprises the following steps:
Step 1: the light that object being measured is sent is imaged on liquid crystal display through optical imagery parts.Now the picture on liquid crystal display is original signal X
n × 1.
Step 2: the torsion of liquid crystal display driving circuit control liquid crystal, make Pixel arrangement on liquid crystal display in pseudo-random state i, wherein 1≤i≤M, their state has formed the capable h of i of observing matrix Φ
i(size is N).The signal that now will see through liquid crystal display is that X is at h
iunder value.
Step 3: the light that sees through liquid crystal display is injected fourier lense.Photodiode, at lens focus place receiving light power, by light intensity integration, obtains result y
i=h
ix
n × 1.
Step 4: repeat step above M time, M liquid crystal screen image element ordered state formed observing matrix Φ
m × N, M time measurement result forms observation data matrix Y=Φ X.
2. the compressive sampling method that carries out as claimed in claim 1 optical modulation with liquid crystal display, is characterized in that: adopt and without the liquid crystal display of the adjustable gray scale of monochrome backlight, original image signal is carried out to optical modulation, the physics realization mode by liquid crystal display as observing matrix.
3. the compressive sampling method that carries out as claimed in claim 1 optical modulation with liquid crystal display, is characterized in that: photodiode is at fourier lense focus place receiving light power, and the light signal after liquid crystal display modulation is carried out to integration.
4. the compressive sampling method that carries out as claimed in claim 1 optical modulation with liquid crystal display, is characterized in that: M time liquid crystal screen image element ordered state has formed observing matrix Φ, and M time measurement result forms observation data matrix Y=Φ X.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105508909A (en) * | 2014-10-15 | 2016-04-20 | 固安翌光科技有限公司 | Plane illumination light source adjustable in brightness of two sides |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4481510A (en) * | 1980-12-23 | 1984-11-06 | Thomson-Csf | Electrooptical switching device |
| US20040239831A1 (en) * | 2003-06-02 | 2004-12-02 | Palumbo Perry A. | Display backlight device |
| CN101893552A (en) * | 2010-07-06 | 2010-11-24 | 西安电子科技大学 | Hyperspectral imager and imaging method based on compressive sensing |
| CN102608619A (en) * | 2012-03-07 | 2012-07-25 | 北京航空航天大学 | Three-dimensional laser imaging method based on photon counting compressive sampling phased array |
| CN103326780A (en) * | 2013-06-21 | 2013-09-25 | 中国科学院空间科学与应用研究中心 | Free space optical-communication APT system and method based on compressive sensing receiver |
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2014
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4481510A (en) * | 1980-12-23 | 1984-11-06 | Thomson-Csf | Electrooptical switching device |
| US20040239831A1 (en) * | 2003-06-02 | 2004-12-02 | Palumbo Perry A. | Display backlight device |
| CN101893552A (en) * | 2010-07-06 | 2010-11-24 | 西安电子科技大学 | Hyperspectral imager and imaging method based on compressive sensing |
| CN102608619A (en) * | 2012-03-07 | 2012-07-25 | 北京航空航天大学 | Three-dimensional laser imaging method based on photon counting compressive sampling phased array |
| CN103326780A (en) * | 2013-06-21 | 2013-09-25 | 中国科学院空间科学与应用研究中心 | Free space optical-communication APT system and method based on compressive sensing receiver |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105508909A (en) * | 2014-10-15 | 2016-04-20 | 固安翌光科技有限公司 | Plane illumination light source adjustable in brightness of two sides |
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