WO2018176996A1 - 全息图像生成方法、处理器及全息图像显示装置、设备 - Google Patents

全息图像生成方法、处理器及全息图像显示装置、设备 Download PDF

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WO2018176996A1
WO2018176996A1 PCT/CN2018/073111 CN2018073111W WO2018176996A1 WO 2018176996 A1 WO2018176996 A1 WO 2018176996A1 CN 2018073111 W CN2018073111 W CN 2018073111W WO 2018176996 A1 WO2018176996 A1 WO 2018176996A1
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image
holographic
reconstructed image
phase
target
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PCT/CN2018/073111
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French (fr)
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李科
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深圳市美誉镜界光电科技有限公司
李科
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Publication of WO2018176996A1 publication Critical patent/WO2018176996A1/zh
Priority to US16/576,986 priority Critical patent/US11480921B2/en

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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
    • G03H1/26—Processes or apparatus specially adapted to produce multiple sub- holograms or to obtain images from them, e.g. multicolour technique
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
    • G03H1/04—Processes or apparatus for producing holograms
    • G03H1/10—Processes or apparatus for producing holograms using modulated reference beam
    • G03H1/12—Spatial modulation, e.g. ghost imaging
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/01—Head-up displays
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/01—Head-up displays
    • G02B27/017—Head mounted
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/10—Beam splitting or combining systems
    • G02B27/1006—Beam splitting or combining systems for splitting or combining different wavelengths
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
    • G03H1/02—Details of features involved during the holographic process; Replication of holograms without interference recording
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
    • G03H1/04—Processes or apparatus for producing holograms
    • G03H1/08—Synthesising holograms, i.e. holograms synthesized from objects or objects from holograms
    • G03H1/0808—Methods of numerical synthesis, e.g. coherent ray tracing [CRT], diffraction specific
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
    • G03H1/04—Processes or apparatus for producing holograms
    • G03H1/16—Processes or apparatus for producing holograms using Fourier transform
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
    • G03H1/22—Processes or apparatus for obtaining an optical image from holograms
    • G03H1/2202—Reconstruction geometries or arrangements
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
    • G03H1/22—Processes or apparatus for obtaining an optical image from holograms
    • G03H1/2294—Addressing the hologram to an active spatial light modulator
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
    • G03H1/02—Details of features involved during the holographic process; Replication of holograms without interference recording
    • G03H2001/0208—Individual components other than the hologram
    • G03H2001/0224—Active addressable light modulator, i.e. Spatial Light Modulator [SLM]
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
    • G03H1/04—Processes or apparatus for producing holograms
    • G03H1/08—Synthesising holograms, i.e. holograms synthesized from objects or objects from holograms
    • G03H1/0841—Encoding method mapping the synthesized field into a restricted set of values representative of the modulator parameters, e.g. detour phase coding
    • G03H2001/085—Kinoform, i.e. phase only encoding wherein the computed field is processed into a distribution of phase differences
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
    • G03H1/22—Processes or apparatus for obtaining an optical image from holograms
    • G03H1/2202—Reconstruction geometries or arrangements
    • G03H1/2205—Reconstruction geometries or arrangements using downstream optical component
    • G03H2001/2207—Spatial filter, e.g. for suppressing higher diffraction orders
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
    • G03H1/22—Processes or apparatus for obtaining an optical image from holograms
    • G03H1/2202—Reconstruction geometries or arrangements
    • G03H2001/2244—Means for detecting or recording the holobject
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H1/00—Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto
    • G03H1/22—Processes or apparatus for obtaining an optical image from holograms
    • G03H1/2294—Addressing the hologram to an active spatial light modulator
    • G03H2001/2297—Addressing the hologram to an active spatial light modulator using frame sequential, e.g. for reducing speckle noise
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H2222/00—Light sources or light beam properties
    • G03H2222/10—Spectral composition
    • G03H2222/17—White light
    • G03H2222/18—RGB trichrome light
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03H—HOLOGRAPHIC PROCESSES OR APPARATUS
    • G03H2270/00—Substrate bearing the hologram
    • G03H2270/55—Substrate bearing the hologram being an optical element, e.g. spectacles

Definitions

  • the present invention relates to the field of imaging display, and in particular, to a holographic image generation method, a processor, and a holographic image display device and device.
  • holograms and holographic projections have broad application prospects in our daily life and work production.
  • holograms and holographic projections can be widely used in image display, optical storage encryption, diffraction element design, optical communication, lithography, and the like.
  • the energy utilization rate of hologram and holographic projection is much higher than that of traditional projection, and it has the advantages of high brightness, small size, simple structure, no image dead pixels and good stability. Therefore, holograms can be used. Achieve large-screen 2D/3D projection, car head-up display, head-mounted augmented reality, etc.
  • the traditional holographic image generation method utilizes the Gerchberg-Saxton (GS) algorithm, the Iterative Fourier Transform Algorithm (IFTA) algorithm, the Simulated Annealing algorithm, etc.
  • GS Gerchberg-Saxton
  • IFTA Iterative Fourier Transform Algorithm
  • Simulated Annealing algorithm etc.
  • the common disadvantage is that the effect is affected by the number of iterations, and the calculation amount is too large. After iterating several times, it is easy to stagnate, the error does not continue to converge, resulting in reduced image quality, more noise, longer computing time, etc., and even if the number of iterations continues to increase, the noise cannot be reduced, the reconstructed image quality is poor, and the real-time image cannot be realized. display.
  • the visual residual effect can be utilized, the hologram is quickly superimposed in a short time to reduce the noise, but the effect is still insufficient.
  • the present invention has been made in order to provide a holographic image generating method, a processor, and a holographic image display apparatus and apparatus that overcome the above problems or at least partially solve the above problems.
  • a holographic image generating method comprising:
  • the amplitude phase of the reconstructed image corresponding to the target image is constrained, and the image is continued to be iterated based on the amplitude phase constrained image.
  • a signal processor comprising:
  • a holographic conversion module configured to perform holographic transformation on a target amplitude phase distribution based on the target image to obtain a holographic phase image corresponding to the target image
  • phase quantization module configured to perform phase quantization on the holographic phase image to obtain a quantized holographic image
  • An inverse holographic transformation module configured to perform inverse holographic transformation on the quantized holographic image to obtain a reconstructed image corresponding to the target image
  • a determining module configured to determine whether the holographic phase image meets a preset condition, and when the reconstructed image satisfies a preset condition, determining that the quantized holographic image is a target holographic image
  • a complex amplitude constraint module configured to constrain an amplitude phase of the reconstructed image corresponding to the target image when the reconstructed image does not satisfy a preset condition, and return the holographic transform module for the holographic transform module to be based on The image after the amplitude phase constraint continues to iterate.
  • a holographic image display apparatus comprising the signal processor, a light source device, a spatial light modulator SLM, a Fourier lens, a spatial filter, and a projection objective lens as described above, wherein the spatial light is provided
  • the modulator SLM is configured to apply the target holographic image obtained by the signal processor as an image source to the light beam incident by the light source device, and perform diffraction transmission transformation and selection by the Fourier lens and the spatial filter.
  • a holographic reconstructed image is obtained, and the holographic reconstructed image is projected and enlarged by the projection objective to form a corresponding enlarged display image.
  • a holographic image display apparatus comprising the signal processor, a light source device, a spatial light modulator SLM loaded with digital spherical phase modulation, a spatial filter, and a projection objective as described above, a spatial light modulator SLM loaded with digital spherical phase modulation is used for taking a target holographic image obtained by the signal processor as an image source, applying a light beam to the incident light beam of the light source device for diffraction transmission transformation, and filtering through the spatial filtering After the selection process is performed, a holographic reconstructed image is obtained, and the holographic reconstructed image is projected and enlarged by the projection objective to form a corresponding enlarged display image.
  • the present invention also provides a wearable device comprising a wearable device and a display screen disposed on the wearable device and a holographic image display device as described above, the display screen being plated with a reflective film or a holographic optical element The film forms a virtually magnified image with the projected display image generated by the holographic image display device.
  • the present invention also provides a vehicle head-up display device comprising a display screen and a holographic image display device as described above, the display screen being plated with a reflective film or a holographic optical element film for generating the holographic image display device
  • the projected display image forms a virtually magnified image.
  • the holographic image generating method, the processor and the holographic image display device and the device provided by the embodiments of the present invention can realize high-contrast and low-noise real-time holographic image processing and display quickly and efficiently by determining whether the reconstructed image satisfies a preset condition. Moreover, any adjustment of the imaging distance can be achieved.
  • FIG. 1 is a flowchart of a holographic image generating method according to an embodiment of the present invention
  • FIG. 2 is a flowchart of a holographic image generating method according to another embodiment of the present invention.
  • FIG. 3 is a flowchart of a holographic image generating method according to another embodiment of the present invention.
  • FIG. 4 is a schematic structural diagram of a signal processor according to an embodiment of the present invention.
  • FIG. 5 is a schematic structural diagram of a signal processor according to another embodiment of the present invention.
  • FIG. 6 is a schematic structural diagram of a signal processor according to another embodiment of the present invention.
  • FIG. 7 is a schematic diagram of a specific chip structure of a signal processor according to an embodiment of the present invention.
  • FIG. 8 is a schematic structural diagram of a holographic image display device according to an embodiment of the present invention.
  • Figure 9 is a schematic diagram of a monochrome holographic image display device
  • Figure 10 is a schematic diagram of a color holographic image display device
  • FIG. 11 is an imaging schematic diagram of a wearable device
  • Figure 12 is an imaging schematic diagram of a vehicle head-up display device.
  • Fig. 1 schematically shows a flow chart of a holographic image generating method of one embodiment of the present invention.
  • a holographic image generating method according to an embodiment of the present invention specifically includes the following steps:
  • Step S11 performing holographic transformation based on the target amplitude phase distribution of the target image to obtain a holographic phase image corresponding to the target image.
  • the holographic transformation can be implemented by using Fourier transform, Fresnel transform, fast Fourier transform, fractional Fourier transform and angular spectrum spatial transform.
  • the 3D holographic imaging display for different distances can be implemented by using a Fresnel transform, a fractional Fourier transform, an angular spectrum spatial transform, or the like.
  • Step S12 Perform phase quantization on the holographic phase image to obtain a quantized holography image.
  • Step S13 performing inverse holographic transformation on the quantized holographic image to obtain a reconstructed image corresponding to the target image.
  • Step S14 if the reconstructed image satisfies a preset condition, determining that the quantized holography image is a target holographic image;
  • Step S15 If the reconstructed image does not satisfy the preset condition, the amplitude phase of the reconstructed image corresponding to the target image is constrained, and the image is continued to be iterated based on the amplitude phase constrained image.
  • step S10 is further included:
  • Step S10 Acquire a target image, perform phase distribution calculation on the target image, and obtain a target amplitude phase distribution of the target image.
  • the method further includes step S121:
  • Step S121 If the phase-quantized holographic phase image has a vortex, the vortex of the quantized holographic image is subjected to neighborhood interpolation or replaced with a preset value to obtain a corrected quantized holography image. Correspondingly, performing inverse holographic transformation on the quantized holographic image to obtain a reconstructed image corresponding to the target image, specifically performing inverse holographic transformation on the corrected quantized holographic image to obtain reconstruction corresponding to the target image image.
  • Target image amplitude I(p) is the target light intensity distribution
  • the pixel size M*N the signal window magnification Mag
  • the weighting factor ⁇ 1 , ⁇ 2 precision ⁇
  • total iteration number N max total iteration number
  • GS algorithm iteration number N GS compensation factor ⁇ k
  • escape factor ⁇ escape factor
  • the method before performing the phase distribution calculation on the target image, includes: adjusting a size of a corresponding color pixel in the target image according to a wavelength of the different color laser.
  • the images reconstructed by the RGB lasers can be resized to realize color holographic display.
  • the number of red and green image pixels can be adjusted based on the blue image pixel size.
  • the target amplitude phase distribution is obtained by performing phase distribution calculation on the target image.
  • the target amplitude phase distribution F k (p) is holographically transformed by diffraction transmission, and its phase is obtained to obtain a hologram ⁇ k (r).
  • Holographic transformation (diffraction propagation function) It can be a Fourier transform, a Fresnel transform, a fast Fourier transform, a fractional Fourier transform, an angular spectrum spatial propagation, and the like.
  • angle() is the complex angle.
  • the fast Fourier transform can be implemented by FFT ⁇ , IFFT ⁇ , and the Fresnel transform can be implemented by the Fresnel diffraction formula:
  • the Fresnel transform can be used to make a holographic lensless system, thereby reducing the volume and aberration of the system.
  • U I (x, y) is the complex amplitude distribution of the holographic surface light field
  • U O (u, v) is the complex amplitude distribution of the image plane light field
  • k is the wave number
  • z is the propagation distance of the holographic surface to the image plane
  • f u , f v is the spatial frequency.
  • the angular spectrum space transfer formula is:
  • U I (x, y) is the complex amplitude distribution of the holographic surface field
  • U O (u, v) is the complex amplitude distribution of the image plane light field
  • H(f u , f v ) is the angular spectrum propagation function
  • k is Wavenumber
  • z is the propagation distance from the holographic surface to the image plane
  • f u , f v is the spatial frequency.
  • fractional Fourier transform can be expressed as:
  • the fractional Fourier transform can calculate the plane of light diffraction propagation from the back surface of the lens to infinity, which is more extensive than the traditional Fourier transform can only calculate the light field distribution on the back focal plane. Scope and flexibility.
  • U I (x, y) is the complex amplitude distribution of the holographic surface light field
  • U O (u, v) is the complex amplitude distribution of the image plane light field
  • a is the order, due to the periodicity of the trigonometric function
  • the order a The value range is 0-2.
  • k is the wave number
  • z is the propagation distance from the hologram to the image plane.
  • ⁇ k (r) Q ⁇ k (r) ⁇ .
  • ⁇ k (r) implements iterative quantization of the hologram phase using 256-order phase quantization in one embodiment. Specifically, there are multiple implementations of 256-order phase quantization.
  • the quantization operator Q ⁇ is defined as:
  • the method comprises: determining a quantization order and a quantization range of the lasers of the respective colors according to wavelengths of the lasers of different colors. Specifically, for a color RGB holographic display hologram, since the SLM has different gamma response curves for different wavelengths, the quantization in actual use is also different.
  • phase delay formula of the liquid crystal spatial light modulator is:
  • n o is the ordinary light refractive index of the liquid crystal molecule
  • n e is the extraordinary refractive index of the liquid crystal molecule
  • h is the thickness of the SLM
  • ⁇ For the wavelength.
  • the quantization height of the gamma response curve at 533 nm green light is [0, 2 ⁇ ], and the quantization step is [0, 255].
  • the quantization height of 650 nm red light is [0, 1.7 ⁇ ]
  • the quantization step is [0, 255]
  • the quantization height of 450 nm red light is [0, 2 ⁇ ]
  • the quantization step is [0, 217].
  • the neighborhood interpolation operator M ⁇ is defined as:
  • the de-zero value can be performed in the previous quantization process, and the quantization is prevented from being 0 in the quantization process.
  • the modified quantized hologram is subjected to inverse holographic transformation, and the reconstructed image f' k (p) is obtained by diffraction transmission.
  • Inverse holographic transformation (diffraction propagation function) It can be a Fourier inverse transform, a Fresnel inverse transform, an inverse fast Fourier transform, a fractional inverse Fourier transform, an angular spectral inverse propagation transform, and the like.
  • abs() is the modulus of the complex number.
  • Fig. 3 is a flow chart schematically showing a hologram image generating method of another embodiment of the present invention.
  • the holographic image generating method of the embodiment of the present invention specifically includes the following steps:
  • Step S30 Acquire a target image, perform phase distribution calculation on the target image, and obtain a target amplitude phase distribution of the target image.
  • Step S31 performing holographic transformation based on the target amplitude phase distribution of the target image to obtain a holographic phase image corresponding to the target image.
  • the holographic transformation comprises Fourier transform, Fresnel transform, fast Fourier transform, fractional Fourier transform and/or angular spectrum spatial propagation transform.
  • Step S32 performing phase quantization on the holographic phase image to obtain a quantized holography image.
  • Step S321 If there is a vortex in the phase-quantized holographic phase image, the vortex of the quantized holographic image is subjected to neighborhood interpolation or replaced with a preset value to obtain a corrected quantized holography image;
  • Step S33 performing inverse holographic transformation on the corrected quantized holographic image to obtain a reconstructed image corresponding to the target image.
  • Step S34 determining whether the error of the reconstructed image is less than a preset accuracy threshold, or whether the number of iterations corresponding to the reconstructed image is equal to a preset total number of iterations threshold; if yes, proceeding to step S35, otherwise, performing step S36;
  • Step S35 Determine that the corrected quantized holography image is a target holography image.
  • step S36 it is determined whether the number of iterations corresponding to the reconstructed image is greater than a threshold of the number of iterations of the preset GS algorithm; if the number of iterations corresponding to the reconstructed image is less than or equal to the threshold of the number of iterations of the preset GS algorithm, step S37 is performed, otherwise Go to step S38;
  • Step 37 Perform a first type of amplitude constraint on the reconstructed image according to the GS algorithm according to the target amplitude; and return to step S31 to process the reconstructed image of the first type of amplitude constraint as a target image of the new round of iterative processing, and update The number of iterations is counted until the error of the obtained reconstructed image satisfies the preset accuracy threshold, or the current iteration number is equal to the preset total iteration number threshold.
  • Step 38 If the number of iterations corresponding to the reconstructed image is greater than the preset GS algorithm iteration number threshold, determine whether the error of the reconstructed image converges; if the error of the reconstructed image converges, perform step S39, otherwise perform steps S311;
  • Step S39 Perform a second type of amplitude constraint on the amplitude of the reconstructed image according to a preset target image and a weighting factor corresponding to the reconstructed image, and a compensation factor, to accelerate error convergence of the reconstructed image.
  • the second type of amplitude constraint includes an amplitude compensation constraint and an energy conservation constraint.
  • Step S310 and performing compensation constraint according to the compensation factor; and returning to step S31, processing the reconstructed image of the second type of amplitude constraint as a target image of the new round of iterative processing, and updating the iteration count until the obtained reconstruction
  • the error of the image satisfies the preset precision threshold, or the current iteration number is equal to the preset total iteration number threshold.
  • Step S311 performing a third type of amplitude or complex amplitude constraint on the reconstructed image, so that the amplitude or complex amplitude of the reconstructed image jumps out of a local extremum;
  • Step S312 resetting the compensation factor to an initial value; and returning to step S31, processing the reconstructed image that jumps out of the local extremum as a target image of the new round of iterative processing, and updating the iteration count until the obtained reconstructed image is obtained.
  • the error satisfies the preset accuracy threshold, or the current iteration number is equal to the preset total iteration number threshold.
  • ⁇ k the role of ⁇ k is to ensure energy conservation during the calculation process.
  • the loop is continued. GS and determines whether k exceeds the number of iterations N GS, i.e. meets k ⁇ N GS.
  • a second type of amplitude constraint is imposed on the amplitude of the reconstructed image signal window to accelerate the convergence constraint.
  • the amplitude of the noise window is preserved and the phase is unchanged, ie:
  • ⁇ 1 , ⁇ 2 are the weighting factors of the target image and the reconstructed image, respectively, and the effect is to separately control the energy of the target image and the reconstructed image.
  • ⁇ k is a compensation factor, and the effect is to compensate the reconstructed image according to the energy distribution of the reconstructed image relative to the target image.
  • ⁇ k The role of ⁇ k is to ensure energy conservation during the calculation.
  • W signal and W noise are the signal window and the noise window, respectively.
  • the compensation factor ⁇ k is adjusted to perform feedback constraint.
  • ⁇ k is a compensation factor, initially 1 , and the function is to compensate the reconstructed image according to the energy distribution of the reconstructed image relative to the target image.
  • a third type of amplitude or complex amplitude constraint is performed to reduce the constraint on the reconstructed image and make iterative Jump out of the local extremum and the regression converges.
  • Method 1 Constrain the amplitude of the reconstructed image signal window to the target amplitude, retaining the amplitude of the noise window, and the phase is unchanged.
  • Method 2 Constrain the amplitude of the reconstructed image signal window to a target amplitude with relatively reduced energy, and preserve the amplitude of the noise window, then the noise window energy is relatively increased and the phase is unchanged, namely:
  • ⁇ is the escape factor, ⁇ 1, which acts to reduce the weight of the signal window energy, reduce the constraint on the target, and make the iterative regression converge.
  • Method 3 The amplitude constraint of the reconstructed image is the same as the amplitude constraint of the second type, and then a random perturbation is added to the phase to make the iterative jump out of the local extremum.
  • the holographic image generating method, the processor and the holographic image display device and the device provided by the embodiments of the present invention generate holograms by initial parameter setting; diffraction transmission; iterative quantization of hologram phases; and inverse diffraction transmission to obtain reconstructed images; Satisfy the accuracy or the total number of iterations; whether it exceeds the number of GS iterations; whether the error converges when the number of GS iterations exceeds; the amplitude constraint within the GS iteration number; the amplitude constraint that exceeds the GS iteration number and the error converges; the compensation factor constraint; When the number of iterations, and the error does not converge, the amplitude or complex amplitude constraint of the local extremum is jumped out; the compensation factor constraint is a series of processing flows.
  • the accelerated iterative convergence is realized effectively, and the local minimum is jumped out, thereby realizing high-contrast, low-noise real-time fast
  • FIG. 4 is a schematic block diagram showing the structure of a signal processor 10 according to an embodiment of the present invention.
  • the signal processor of the embodiment of the present invention specifically includes a holographic transformation module 101, a phase quantization module 102, an inverse holographic transformation module 103, a determination module 104, and a complex amplitude constraint module 105, wherein:
  • the holographic conversion module 101 is configured to perform holographic transformation on a target amplitude phase distribution of a target image to obtain a holographic phase image corresponding to the target image;
  • the phase quantization module 102 is configured to perform phase quantization on the holographic phase image to obtain a quantized holographic image
  • the inverse holographic transformation module 103 is configured to perform inverse holographic transformation on the quantized holographic image to obtain a reconstructed image corresponding to the target image;
  • the determining module 104 is configured to determine whether the holographic phase image meets a preset condition, and when the reconstructed image satisfies a preset condition, determine that the quantized holographic image is a target holographic image;
  • the complex amplitude constraint module 105 is configured to constrain an amplitude phase of the reconstructed image corresponding to the target image when the reconstructed image does not satisfy a preset condition, and return the holographic transform module for the The holographic transformation module continues to iterate based on the amplitude phase constrained image.
  • the signal processor further includes a phase calculation module 100, and the phase calculation module 100 is configured to perform holographic transformation on the target amplitude phase distribution based on the target image. Previously, the target image is acquired, and the target image is subjected to phase distribution calculation to obtain a target amplitude phase distribution of the target image.
  • the signal processor further includes a pixel adjustment module not shown in the drawing, the pixel adjustment module, configured to perform laser according to different colors before performing holographic transformation on the target amplitude phase distribution based on the target image The wavelength of the corresponding color pixel in the target image.
  • phase quantization module 102 is further configured to determine quantization orders and quantization ranges of lasers of different colors according to wavelengths of lasers of different colors before performing phase quantization on the holographic phase image.
  • the signal processor further includes a correction module 106, and the correction module is configured to perform phase-quantized holography after the phase quantization of the holographic phase image.
  • the correction module is configured to perform phase-quantized holography after the phase quantization of the holographic phase image.
  • the phase image has a vortex
  • the vortex of the quantized holographic image is subjected to neighborhood interpolation or replaced with a preset value to obtain a corrected quantized holography image.
  • the determining module 104 is specifically configured to determine whether the error of the reconstructed image meets a preset accuracy threshold, or whether the number of iterations corresponding to the reconstructed image reaches a preset total iteration number threshold; The error of the reconstructed image is less than a preset precision threshold, or the number of iterations corresponding to the reconstructed image is equal to a preset total iteration number threshold, and then determining that the reconstructed image satisfies a preset condition.
  • the determining module 104 is further configured to: when the error of the reconstructed image is greater than or equal to the preset precision threshold, and the number of iterations corresponding to the reconstructed image is less than a preset total iteration number threshold, Whether the number of iterations corresponding to the reconstructed image is greater than a preset GS algorithm iteration number threshold;
  • the complex amplitude constraint module 105 is configured to: when the number of iterations corresponding to the reconstructed image is less than or equal to the preset GS algorithm iteration number threshold, perform a first type of amplitude on the reconstructed image according to a GS algorithm using a target amplitude constraint;
  • the holographic transformation module 101 is further configured to process the reconstructed image of the first type of amplitude constraint as a target image of the new round of iterative processing, and update the iteration count until the error of the obtained reconstructed image satisfies the preset precision threshold. , or the current number of iterations reaches the preset total number of iterations threshold.
  • the determining module 104 is further configured to determine whether the error of the reconstructed image converges when the number of iterations corresponding to the reconstructed image is greater than the preset GS algorithm iteration number threshold;
  • the complex amplitude constraint module 105 is further configured to: when the error of the reconstructed image converges, perform a second class on the amplitude of the reconstructed image according to a weight factor corresponding to the preset target image and the reconstructed image, and a compensation factor An amplitude constraint to accelerate error convergence of the reconstructed image;
  • the holographic transformation module 101 is further configured to process the reconstructed image of the second type of amplitude constraint as a target image of the new round of iterative processing, and update the iteration count until the error of the obtained reconstructed image satisfies the preset precision threshold. , or the current number of iterations reaches the preset total number of iterations threshold.
  • the complex amplitude constraint module 105 is further configured to perform a third type of amplitude or complex amplitude constraint on the reconstructed image when the error of the reconstructed image does not converge, so that the amplitude or complex of the reconstructed image is The amplitude jumps out of the local extremum and resets the compensation factor to the initial value;
  • the holographic conversion module 101 is further configured to process the reconstructed image that jumps out of the local extremum as a target image of the new round of iterative processing, and update the iteration count until the error of the obtained reconstructed image satisfies the preset precision threshold. Or the current number of iterations reaches the preset total number of iterations threshold.
  • the description is relatively simple, and the relevant parts can be referred to the description of the method embodiment.
  • FIG. 7 is a schematic diagram showing a specific chip structure of the signal processor 10 in the embodiment of the present invention.
  • the working principle of the holographic chip processor of the invention is that the central operating unit and the main arithmetic unit of the GPU transmit data commands to the software interface of the holographic algorithm unit to trigger the system control module, and call its time synchronization generator to control the signal and the holographic algorithm. All the way through the data interface to control the laser in the light source device, one way to control the spatial light modulator SLM, together with the output to present the holographic image.
  • the holographic image display device includes the signal processor 10, the spatial light modulator SLM20, and the light source according to any of the above embodiments.
  • the device 30, the Fourier lens 40, the spatial filter 50, and the projection objective 60, the spatial light modulator SLM20 is configured to apply the target holographic image obtained by the signal processor 10 as an image source to the light source device 30.
  • the diffraction transmission is transformed and the +1 (or -1) stage is selected to obtain a holographic reconstructed image, and the hologram is obtained by the projection objective 60. After the reconstructed image projection is enlarged, a corresponding enlarged display image is formed.
  • the light source device includes a monochromatic laser and a corresponding beam shaping module, and the monochromatic light emitted by the monochromatic laser is collimated by the beam shaping module and then incident into the space.
  • the beam shaping module specifically includes a first lens, a spatial filter, a second lens, a polarizer, and an aperture, which are sequentially disposed.
  • the diaphragm is an optical element that restricts the light beam passing through the optical system. It can be a frame of an optical component (such as a lens, a mirror, etc.) itself, or an opaque screen with a circular aperture.
  • Figure 9 is a schematic diagram of a monochrome holographic image display.
  • the light source device comprises a red laser emitter, a green laser emitter, a blue laser emitter and a corresponding beam shaping module, the light source device loading different according to the signal processor
  • the time-series sequence of the target holographic image of the color controls the laser emitter of the corresponding color to perform time-series illumination
  • the beam shaping module corresponding to the laser emitter of the corresponding color collimates the corresponding color beam, and then enters the spatial light.
  • the beam shaping module corresponding to the laser emitters of the respective colors includes a collimating lens.
  • the light source device further includes laser emission with respective colors Corresponding dichroic mirror and beam splitting prism for injecting a laser emitter of a corresponding color to the SLM, the beam splitting prism for incident on a light beam containing information of the target holographic image To the upper Fourier lens 40.
  • the implementation principle of the light source device in the display of the color hologram is mainly given. Referring to Figure 10, Figure 10 is a schematic diagram of a color holographic image display.
  • Another embodiment of the present invention further provides a holographic image display device, comprising the signal processor, the light source device, the spatial light modulator SLM loaded with digital spherical phase modulation, a spatial filter, and the like according to any of the above embodiments.
  • a projection objective lens wherein the spatial light modulator SLM loaded with digital spherical phase modulation is used to use a target holographic image obtained by the signal processor as an image source, and is applied to a light beam incident on the light source device for diffraction transmission transformation, and A holographic reconstructed image is obtained by performing a selection process by the spatial filter, and the holographic reconstructed image is projected and enlarged by the projection objective to form a corresponding enlarged display image.
  • the embodiment of the present invention can replace the function of the Fourier lens 40 by the spatial light modulator SLM loaded with digital spherical phase modulation, simplifying the overall structure of the device.
  • the device embodiments described above are merely illustrative, wherein the units described as separate components may or may not be physically separate, and the components displayed as units may or may not be physical units, ie may be located A place, or it can be distributed to multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the embodiment. Those of ordinary skill in the art can understand and implement without deliberate labor.
  • another embodiment of the present invention provides a wearable device including a wearable device and a display screen disposed on the wearable device and the holographic image display device according to any of the above embodiments, the display The screen is plated with a reflective film or a holographic optical element film to form a virtual enlarged image of the projected display image generated by the holographic image display device, and the imaging principle of the wearable device is as shown in FIG.
  • the technical solution of the present invention is described by taking smart glasses as an example.
  • the display screen of the smart glasses may be a lens of the glasses, and the lens is coated with a reflective film or a holographic optical element film.
  • the wearable device of the present invention may further include other wearable smart devices such as smart helmets.
  • an embodiment of the present invention further provides a vehicle head-up display device, including a display screen and a holographic image display device according to any of the above embodiments, wherein the display screen is plated with a reflective film or a holographic optical element film,
  • the projected display image generated by the holographic image display device forms a virtual enlarged image, and the imaging principle of the on-board head-up display device is as shown in FIG.
  • the display screen of the vehicle head-up display device may specifically be a windshield, and the windshield is coated with a reflective film or a holographic optical element film.
  • the holographic image generation method is applied to the wearable device and the vehicle head-up display device, and the energy efficiency is high, and the image can be realized at any position, compared with the MEMS laser scanning HUD, because the MEMS laser scanning working principle is that the laser is all Irradiation on the MEMS, and only 10% of the displayed image area will cause a lot of energy loss; and the MEMS is in a high-speed flip state, once the problem occurs, the laser will directly hit the human eye, causing human damage.
  • imaging can only be performed at a fixed position, or an additional optical system can be used to modulate the imaging position, resulting in a larger system and increased cost.
  • a liquid crystal phase spatial light modulator based system can utilize the algorithm described to arbitrarily modulate the imaging position and compensate for aberrations in the system.
  • the imaging distance can be adjusted in real time after being processed by the holographic conversion algorithm, and the image focal length is realized at a distance.
  • the holographic image generating method, the processor and the holographic image display device and the device provided by the embodiments of the present invention can realize high-contrast and low-noise real-time holographic image processing and display quickly and efficiently by determining whether the reconstructed image satisfies a preset condition. Moreover, any adjustment of the imaging distance can be achieved.

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Abstract

一种全息图像生成方法、信号处理器、全息图像显示装置、可穿戴设备以及车载抬头显示设备。该全息图像生成方法包括：基于目标图像的目标振幅相位分布进行全息变换，得到目标图像对应的全息相位图像；对全息相位图像进行相位量化，得到量化全息图像；对量化全息图像进行逆全息变换，得到目标图像对应的重建图像；若重建图像满足预设条件，则确定量化全息图像为目标全息图像；否则，对目标图像对应的重建图像的振幅相位进行约束，并基于振幅相位约束后的图像继续迭代。本全息图像生成方法能够快速、高效地实现单色及彩色高对比度、低噪声的实时全息图像生成和显示，而且，能够实现成像距离的任意调节，可广泛应用于汽车抬头显示、头戴显示等全息投影显示装备中。

Description

全息图像生成方法、处理器及全息图像显示装置、设备 技术领域
本发明涉及成像显示领域，尤其涉及一种全息图像生成方法、处理器及全息图像显示装置、设备。
背景技术
随着图像处理技术的发展，全息图和全息投影在我们的日常生活及工作生产中有着广泛的应用前景。具体的，全息图和全息投影可广泛用于图像显示，光存储加密，衍射元件设计，光通信，光刻等领域。尤其在显示领域，全息图和全息投影的能量利用率远高于传统投影，而且具有户外高亮度，体积小，结构简单，没有图像坏点，稳定性好等优势，因此，全息图可以用来实现大屏幕2D/3D投影，汽车抬头显示，头戴增强现实等。
传统的全息图像生成方法利用Gerchberg-Saxton(GS)算法，Iterative Fourier Transform Algorithm(IFTA)算法，Simulated Annealing(模拟退火)算法等，但是，其共同缺点是效果受迭代次数的影响，运算量过大，迭代几次后容易停滞，误差不继续收敛，导致重建图像质量下降，噪声多，运算时间长等问题，而且即使继续增加迭代次数也无法减小噪声，重建图像质量差，无法实现图像的实时显示。另外，虽然可以利用视觉残留效应，短时间内将全息图的快速叠加来降低噪声，但效果仍不能满足需求。
发明内容
鉴于上述问题，提出了本发明以便提供一种克服上述问题或者至少部分地解决上述问题的全息图像生成方法、处理器及全息图像显示装置、设备。
本发明的一个方面，提供了一种全息图像生成方法，包括:
基于目标图像的目标振幅相位分布进行全息变换，得到所述目标图像对应的全息相位图像；
对所述全息相位图像进行相位量化，得到量化全息图像；
对所述量化全息图像进行逆全息变换，得到所述目标图像对应的重建图像；
若所述重建图像满足预设条件，则确定所述量化全息图像为目标全息图像；
否则，对所述目标图像对应的重建图像的振幅相位进行约束，并基于振幅相位约束后的图像继续迭代。
本发明的另一个方面，提供了一种信号处理器，包括:
全息变换模块，用于对基于目标图像的目标振幅相位分布进行全息变换，得到所述目标图像对应的全息相位图像；
相位量化模块，用于对所述全息相位图像进行相位量化，得到量化全息图像；
逆全息变换模块，用于对所述量化全息图像进行逆全息变换，得到所述目标图像对应的重建图像；
判定模块，用于判断全息相位图像是否满足预设条件，当所述重建图像满足预设条件时，确定所述量化全息图像为目标全息图像；
复振幅约束模块，用于当所述重建图像不满足预设条件时，对所述目标图像对应的重建图像的振幅相位进行约束，并返回所述全息变换模块，以供所述全息变换模块基于振幅相位约束后的图像继续进行迭代。
本发明的第三方面，提供了一种全息图像显示装置，包括如上所述的信号处理器、光源设备、空间光调制器SLM、傅里叶透镜、空间滤波器以及投影物镜，所述空间光调制器SLM用于将所述信号处理器得到的目标全息图像作为图像源，作用到所述光源设备入射的光束上，并通过所述傅里叶透镜和空间滤波器进行衍射传输变换和选择后得到全息重建图像，并通过所述投影物镜将所述全息重建图像投影放大后，形成对应的放大显示图像。
本发明的第四方面，提供了一种全息图像显示装置，包括如上所述的信号 处理器、光源设备、加载有数字球面相位调制的空间光调制器SLM、空间滤波器以及投影物镜，所述加载有数字球面相位调制的空间光调制器SLM用于将所述信号处理器得到的目标全息图像作为图像源，作用到所述光源设备入射的光束上进行衍射传输变换，并通过所述空间滤波器进行选择处理后得到全息重建图像，并通过所述投影物镜将所述全息重建图像投影放大后，形成对应的放大显示图像。
本发明还提供了一种可穿戴设备，包括可穿戴装置和设置在所述可穿戴装置上的显示屏幕和如上所述的全息图像显示装置，所述显示屏幕上镀有反射膜或全息光学元件膜，以对所述全息图像显示装置生成的投影显示图像形成虚拟放大的像。
本发明还提供了一种车载抬头显示设备，包括显示屏幕和如上所述的全息图像显示装置，所述显示屏幕上镀有反射膜或全息光学元件膜，以对所述全息图像显示装置生成的投影显示图像形成虚拟放大的像。
本发明实施例提供的全息图像生成方法、处理器及全息图像显示装置、设备，通过判定重建图像是否满足预设条件，从而快速、高效地实现高对比度、低噪声的实时全息图像处理和显示，而且，可实现成像距离的任意调节。
上述说明仅是本发明技术方案的概述，为了能够更清楚了解本发明的技术手段，而可依照说明书的内容予以实施，并且为了让本发明的上述和其它目的、特征和优点能够更明显易懂，以下特举本发明的具体实施方式。
附图说明
通过阅读下文优选实施方式的详细描述，各种其他的优点和益处对于本领域普通技术人员将变得清楚明了。附图仅用于示出优选实施方式的目的，而并不认为是对本发明的限制。而且在整个附图中，用相同的参考符号表示相同的部件。在附图中：
图1为本发明实施例的全息图像生成方法的流程图；
图2为本发明另一实施例的全息图像生成方法的流程图；
图3为本发明另一实施例的全息图像生成方法的流程图；
图4为本发明实施例的信号处理器的结构示意图；
图5为本发明另一实施例的信号处理器的结构示意图；
图6为本发明另一实施例的信号处理器的结构示意图；
图7为本发明实施例中的信号处理器的具体芯片结构原理图；
图8为本发明实施例的全息图像显示装置的结构示意图；
图9为单色全息图像显示装置的原理图；
图10为彩色全息图像显示装置的原理图；
图11为可穿戴设备的成像原理图；
图12为车载抬头显示设备的成像原理图。
具体实施方式
下面将参照附图更详细地描述本公开的示例性实施例。虽然附图中显示了本公开的示例性实施例，然而应当理解，可以以各种形式实现本公开而不应被这里阐述的实施例所限制。相反，提供这些实施例是为了能够更透彻地理解本公开，并且能够将本公开的范围完整的传达给本领域的技术人员。
本技术领域技术人员可以理解，除非另外定义，这里使用的所有术语(包括技术术语和科学术语)，具有与本发明所属领域中的普通技术人员的一般理解相同的意义。还应该理解的是，诸如通用字典中定义的那些术语，应该被理解为具有与现有技术的上下文中的意义一致的意义，并且除非被特定定义，否则不会用理想化或过于正式的含义来解释。
图1示意性示出了本发明一个实施例的全息图像生成方法的流程图。参照图1，本发明实施例的全息图像生成方法具体包括以下步骤：
步骤S11、基于目标图像的目标振幅相位分布进行全息变换，得到所述目标图像对应的全息相位图像。其中，所述全息变换可采用傅里叶变换、菲涅尔 变换、快速傅里叶变换、分数阶傅里叶变换和角谱传播空间变换等方式实现。具体的，对于不同距离的3D全息成像显示，可采用菲涅尔变换、分数阶傅里叶变换、角谱传播空间变换等方式实现。
步骤S12、对所述全息相位图像进行相位量化，得到量化全息图像。
步骤S13、对所述量化全息图像进行逆全息变换，得到所述目标图像对应的重建图像。
步骤S14、若所述重建图像满足预设条件，则确定所述量化全息图像为目标全息图像；
步骤S15、若所述重建图像不满足预设条件，则对所述目标图像对应的重建图像的振幅相位进行约束，并基于振幅相位约束后的图像继续迭代。
本实施例中，如图2所示，在所述基于目标图像的目标振幅相位分布进行全息变换之前，还包括步骤S10：
步骤S10、获取目标图像，对所述目标图像进行相位分布计算，得到所述目标图像的目标振幅相位分布。
本实施例中，如图2所示，在所述对所述全息相位图像进行相位量化之后，所述方法还包括步骤S121：
步骤S121、若相位量化后的全息相位图像存在涡旋，则对所述量化全息图像的涡旋进行邻域插值，或替换为预设值，得到修正后的量化全息图像。相应的，所述对所述量化全息图像进行逆全息变换，得到所述目标图像对应的重建图像，具体为对所述修正后的量化全息图像进行逆全息变换，得到所述目标图像对应的重建图像。
在实际应用中，在对所述目标图像进行相位分布计算之前，首先进行初始参数的设定，具体包括随机初始相位
Figure PCTCN2018073111-appb-000001
目标图像振幅
Figure PCTCN2018073111-appb-000002
其中I(p)为目标光强分布，p＝(u,v)为像空间坐标，r＝(x,y)为全息面坐标，像素尺寸M*N,信号窗口放大率Mag,权重因子ω 1、ω 2，精度ε，总迭代次数N max,GS算法迭代次数N GS,补偿因子α k，逃逸因子γ。
进一步地，在所述对所述目标图像进行相位分布计算之前，所述方法包括：根据不同颜色激光的波长，调节目标图像中相应颜色像素的尺寸。
在一个具体实施例中，采用720p的空间光调制器SLM，可令
Figure PCTCN2018073111-appb-000003
为[-π，π)的随机分布，M＝480，N＝480,Mag＝1.5；ω 1＝2，ω 2＝1；ε＝1e-6；N max＝30，N GS＝5；α 1＝1，γ＝0.99。
对于彩色RGB全息显示，在相同的距离z处，重建图像的尺寸为：
Figure PCTCN2018073111-appb-000004
Δx为SLM的单像素尺寸，于是RGB激光分别重建的图像尺寸不同，图像不能重合，比例为L R:L G:L B＝λ R:λ G:λ B。
因此需要根据不同颜色激光的波长，调节目标图像中相应颜色像素的尺寸，以对应不同颜色激光调节目标图像的大小，满足
Figure PCTCN2018073111-appb-000005
Figure PCTCN2018073111-appb-000006
则可以实现RGB激光分别重建的图像大小重合，实现彩色全息显示。
可选地，可以蓝色图像像素尺寸为基准对红色、绿色图像像素数进行调整。
本实施例中，通过对目标图像进行相位分布计算，得到目标振幅相位分布
Figure PCTCN2018073111-appb-000007
其中，K＝2π/λ为波数。
然后，对目标振幅相位分布F k(p)通过衍射传输进行全息变换，取其相位得到全息图φ k(r)。
Figure PCTCN2018073111-appb-000008
φ k(r)＝angle{G k(r)}
所述全息变换(衍射传播函数)
Figure PCTCN2018073111-appb-000009
可以为傅里叶变换、菲涅尔变换、快速傅里叶变换、分数阶傅里叶变换、角谱空间传播等方法。
其中，angle()为取复数辐角。
具体的，快速傅里叶变换可以用FFT{},IFFT{}实现，菲涅尔变换可以用菲涅耳衍射公式实现，为：
Figure PCTCN2018073111-appb-000010
利用菲涅尔变换可以做成全息无透镜系统，从而减少系统的体积、像差等。其中，U I(x,y)为全息面光场复振幅分布，U O(u,v)为像平面光场复振幅分布,k为波数，z为全息面到像平面的传播距离，f u,f v为空间频率。
具体的，角谱空间传输公式为：
U O(u,v)＝IFFT{FFT{U I(x,y)}·H(f u,f v)}
其中，
Figure PCTCN2018073111-appb-000011
其中，U I(x,y)为全息面光场复振幅分布，U O(u,v)为像平面光场复振幅分布,H(f u,f v)为角谱传播函数，k为波数，z为全息面到像平面的传播距离，f u,f v为空间频率。
具体的，分数阶傅里叶变换可表示为：
Figure PCTCN2018073111-appb-000012
分数阶傅里叶变换可以计算的光衍射传播平面可以从透镜后表面到无限远处，比传统的傅里叶变换只能计算衍射到后焦平面上的光场分布来说，具有更广泛的适用范围和灵活性。其中，U I(x,y)为全息面光场复振幅分布，U O(u,v)为像平面光场复振幅分布,a为阶数，由于三角函数的周期性，阶数a的取值范围是0-2，当a＝1时，上式变为一个标准的傅里叶变换，k为波数，z为全息面到像平面的传播距离。然后，对全息图相位进行迭代量化，得到量化全息图＝ψ k(r)＝Q{φ k(r)}。φ k(r)在一个具体实施例中采用256阶相位量化实现对全息图相位的迭代量化。具体的，256阶相位量化有多种实现方式。
本发明实施例中，量化算符Q{}定义为:
Figure PCTCN2018073111-appb-000013
进一步地，在所述对所述全息相位图像进行相位量化之前，所述方法包括：根据不同颜色激光的波长，确定各种颜色激光的量化阶数及量化范围。具体的，对于彩色RGB全息显示全息图像，由于SLM对不同波长的gamma响应曲线不同，因此实际使用中的量化也不同。
液晶空间光调制器的相位延迟公式为：
Figure PCTCN2018073111-appb-000014
其中，
Figure PCTCN2018073111-appb-000015
表示入射光经过SLM产生的相位延迟，Δn＝n e-n o为折射率差，n o为液晶分子寻常光折射率，n e为液晶分子非寻常光折射率，h为SLM的厚度，λ为波长。
在一个具体示例中，可选择使gamma响应曲线在533nm绿光的量化高度为[0,2π]，量化台阶为[0,255]。以绿光为基准，则650nm红光的量化高度为[0,1.7π]，量化台阶为[0,255]；450nm红光的量化高度为[0,2π]，量化台阶为[0,217]。
然后，对量化全息图进行邻域插值去除零点，得到修正的量化全息图＝。ψ′ k(r)＝M{ψ k(r)}
在实际应用中，当量化的全息图中出现零点，产生涡旋效应，会使重建图像噪声加剧。因此量化后需要去除全息图中零点值。具体的，去除零点有多种实现方式，如赋予零点一个极小值，或进行邻域插值。
本发明实施例中，邻域插值算符M{}定义为:
Figure PCTCN2018073111-appb-000016
当I(x,y)＝0时
在实际应用中，可选择9邻域插值，具体的可取R＝3，C＝3。
其中，去零值可在上一步量化过程中执行，在量化过程中避免量化为0。
对修正的量化全息图进行逆全息变换，通过衍射传输得到重建图像f′ k(p)。
Figure PCTCN2018073111-appb-000017
Figure PCTCN2018073111-appb-000018
所述逆全息变换(衍射传播函数)
Figure PCTCN2018073111-appb-000019
可以为傅里叶逆变换、菲涅尔逆变换、快速傅里叶逆变换、分数阶傅里叶逆变换、角谱空间逆传播变换等方法。
其中，abs()为取复数的模。
图3示意性示出了本发明另一个实施例的全息图像生成方法的流程图。参照图3，本发明实施例的全息图像生成方法具体包括以下步骤：
步骤S30、获取目标图像，对所述目标图像进行相位分布计算，得到所述目标图像的目标振幅相位分布。
步骤S31、基于目标图像的目标振幅相位分布进行全息变换，得到所述目标图像对应的全息相位图像。其中，所述全息变换包括傅里叶变换、菲涅尔变换、快速傅里叶变换、分数阶傅里叶变换和/或角谱空间传播变换等方式实现。
步骤S32、对所述全息相位图像进行相位量化，得到量化全息图像。
步骤S321、若相位量化后的全息相位图像存在涡旋，则对所述量化全息图像的涡旋进行邻域插值，或替换为预设值，得到修正后的量化全息图像；
步骤S33、对所述修正的量化全息图像进行逆全息变换，得到所述目标图像对应的重建图像。
步骤S34、判断所述重建图像的误差是否小于预设精度阈值，或所述重建图像对应的迭代次数是否等于预设总迭代次数阈值；若是，则执行步骤S35， 否则，执行步骤S36；
步骤S35、确定所述修正的量化全息图像为目标全息图像。
步骤S36、判断所述重建图像对应的迭代次数是否大于预设GS算法迭代次数阈值；若所述重建图像对应的迭代次数小于或等于所述预设GS算法迭代次数阈值，则执行步骤S37，否则执行步骤S38；
步骤37、根据GS算法采用目标振幅对所述重建图像进行第一类振幅约束；并返回步骤S31，将第一类振幅约束后的重建图像作为新一轮迭代处理的目标图像进行处理，并更新迭代次数计数，直到得到的重建图像的误差满足预设精度阈值，或当前迭代次数等于预设总迭代次数阈值。
步骤38、若所述重建图像对应的迭代次数大于所述预设GS算法迭代次数阈值，判断所述重建图像的误差是否收敛；若所述重建图像的误差收敛，则执行步骤S39，否则执行步骤S311；
步骤S39、根据预设的目标图像和重建图像对应的权重因子，以及补偿因子，对所述重建图像的振幅进行第二类振幅约束，以加速所述重建图像的误差收敛。其中，所述第二类振幅约束包括振幅补偿约束及能量守恒约束。
步骤S310、并根据所述补偿因子进行补偿约束；并返回步骤S31，将第二类振幅约束后的重建图像作为新一轮迭代处理的目标图像进行处理，并更新迭代次数计数，直到得到的重建图像的误差满足预设精度阈值，或当前迭代次数等于预设总迭代次数阈值。
步骤S311、对所述重建图像进行第三类振幅或复振幅约束，以使所述重建图像的振幅或复振幅跳出局部极值；
步骤S312、将补偿因子重置为初始值；并返回步骤S31，将跳出局部极值后的重建图像作为新一轮迭代处理的目标图像进行处理，并更新迭代次数计数，直到得到的重建图像的误差满足预设精度阈值，或当前迭代次数等于预设总迭代次数阈值。
在一个具体实施例中，判断重建图像误差Error k是否满足预设精度ε或重 建图像对应的迭代次数k超过总迭代次数N max。
其中，
Figure PCTCN2018073111-appb-000020
Figure PCTCN2018073111-appb-000021
其中，μ k的作用是保证计算过程中能量守恒。
若重建图像误差Error k小于精度ε或达到总迭代次数N max，即k≥N max||Error k≤ε时，则得到最终全息图＝；ψ final＝ψ′ k(r)；结束循环。
若不满足重建图像误差Error k小于精度ε或k小于总迭代次数N max，即k≤N max||Error k≥ε时，则继续执行循环。并判断k是否超过GS算法迭代次数N GS，即是否满足k≤N GS。
若k超过GS算法迭代次数N GS，即k≥N GS时，判断误差是否收敛，即是否满足。Error k-1-Error k-2＜0
若k不超过GS算法迭代次数N GS，即k≤N GS时采用GS算法对重建图像振幅进行第一类振幅约束，使振幅为目标振幅，相位不变，即：
f k+1(p)＝C 1{f′ k(p)}＝f(p)
若k超过GS算法迭代次数N GS且误差收敛，即k＞N GS&&Error k-1-Error k-2＜0时，则对重建图像信号窗口的振幅进行第二类振幅约束，加速收敛约束，保留噪声窗口的振幅，相位不变，即：
Figure PCTCN2018073111-appb-000023
Figure PCTCN2018073111-appb-000024
其中，ω 1,ω 2分别为目标图像和重建图像的权重因子，作用是分别控制目标图像和重建图像的能量大小。
α k为补偿因子，作用是根据重建图像相对目标图像的能量分布对重建图像进行强度补偿。
μ k的作用是保证计算过程中能量守恒。
W signal,W noise分别为信号窗口和噪声窗口。
Figure PCTCN2018073111-appb-000025
Figure PCTCN2018073111-appb-000026
然后，调节补偿因子α k进行反馈约束。
Figure PCTCN2018073111-appb-000027
其中，α k为补偿因子，初始为1，作用是根据重建图像相对目标图像的能量分布对重建图像进行反馈能量补偿。
若超过GS算法迭代次数且误差不收敛时，即k＞N GS&&Error k-1-Error k-2≥0时，则进行第三类振幅或复振幅约束，以对重建图像减少约束，使迭代跳出局部极值，回归收敛。
在本实施例中，具体可采用以下三种方法实现第三类振幅或复振幅约束：
方法1：对重建图像信号窗口的振幅进行约束，使其为目标振幅，保留噪声窗口的振幅，相位不变。即：
Figure PCTCN2018073111-appb-000028
Figure PCTCN2018073111-appb-000029
方法2：对重建图像信号窗口的振幅进行约束，使其为能量相对降低的目标振幅，保留噪声窗口的振幅，则噪声窗口能量相对提高，相位不变，即：
Figure PCTCN2018073111-appb-000030
Figure PCTCN2018073111-appb-000031
γ为逃逸因子，γ＜1,作用为降低信号窗口能量的权重，减少对目标的约束，使迭代回归收敛。
方法3：对重建图像振幅约束同第二类振幅约束,然后对相位加一个随机微扰，使迭代跳出局部极值。
Figure PCTCN2018073111-appb-000032
Figure PCTCN2018073111-appb-000033
迭代跳出局部极值后，调节补偿因子，将其重置为1。
α k+1＝1
本发明实施例提供的全息图像生成方法、处理器及全息图像显示装置、设备，通过初始参数设定；衍射传输生成全息图；对全息图相位进行迭代量化；逆衍射传输得到重建图像；判断是否满足精度或总迭代次数；是否超过GS迭代次数；超过GS迭代次数时，误差是否收敛；GS迭代次数内的振幅约束；超过GS迭代次数，且误差收敛时的振幅约束；补偿因子约束；超过GS迭代次 数，且误差不收敛时，跳出局部极值的振幅或复振幅约束；补偿因子约束等一系列处理流程。有效地实现了加速迭代收敛，跳出局部最小值，进而实现高对比度，低噪声的实时快速动态全息图生成。而且，可实现成像距离的任意调节。
对于方法实施例，为了简单描述，故将其都表述为一系列的动作组合，但是本领域技术人员应该知悉，本发明实施例并不受所描述的动作顺序的限制，因为依据本发明实施例，某些步骤可以采用其他顺序或者同时进行。其次，本领域技术人员也应该知悉，说明书中所描述的实施例均属于优选实施例，所涉及的动作并不一定是本发明实施例所必须的。
图4示意性示出了本发明一个实施例的信号处理器10的结构示意图。参照图4，本发明实施例的信号处理器具体包括全息变换模块101、相位量化模块102、逆全息变换模块103、判定模块104以及复振幅约束模块105，其中：
所述的全息变换模块101，用于对目标图像的目标振幅相位分布进行全息变换，得到所述目标图像对应的全息相位图像；
所述的相位量化模块102，用于对所述全息相位图像进行相位量化，得到量化全息图像；
所述的逆全息变换模块103，用于对所述量化全息图像进行逆全息变换，得到所述目标图像对应的重建图像；
所述的判定模块104，用于判断全息相位图像是否满足预设条件，当所述重建图像满足预设条件时，确定所述量化全息图像为目标全息图像；
所述的复振幅约束模块105，用于当所述重建图像不满足预设条件时，对所述目标图像对应的重建图像的振幅相位进行约束，并返回所述全息变换模块，以供所述全息变换模块基于振幅相位约束后的图像继续进行迭代。
本发明另一实施例中，如图5所示，所述信号处理器还包括相位计算模块100，所述的相位计算模块100，用于在所述基于目标图像的目标振幅相位分布进行全息变换之前，获取目标图像，对所述目标图像进行相位分布计算，得到所述目标图像的目标振幅相位分布。
进一步地，所述信号处理器还包括附图中未示出的像素调节模块，所述的像素调节模块，用于在所述基于目标图像的目标振幅相位分布进行全息变换之前，根据不同颜色激光的波长，调节目标图像中相应颜色像素的尺寸。
进一步地，所述的相位量化模块102，还用于在对所述全息相位图像进行相位量化之前，根据不同颜色激光的波长，确定各种颜色激光的量化阶数及量化范围。
本实施例中，如图6所示，所述信号处理器还包括修正模块106，所述的修正模块，用于在所述对所述全息相位图像进行相位量化之后，当相位量化后的全息相位图像存在涡旋时，对所述量化全息图像的涡旋进行邻域插值，或替换为预设值，得到修正后的量化全息图像。
本发明另一实施例中，所述判定模块104，具体用于判断所述重建图像的误差是否满足预设精度阈值，或所述重建图像对应的迭代次数是否达到预设总迭代次数阈值；若所述重建图像的误差小于预设精度阈值，或所述重建图像对应的迭代次数等于预设总迭代次数阈值，则确定所述重建图像满足预设条件。
相应的，所述判定模块104，具体还用于当所述重建图像的误差大于或等于所述预设精度阈值，且所述重建图像对应的迭代次数小于预设总迭代次数阈值时，判断所述重建图像对应的迭代次数是否大于预设GS算法迭代次数阈值；
所述复振幅约束模块105，具体用于当所述重建图像对应的迭代次数小于或等于所述预设GS算法迭代次数阈值时，根据GS算法采用目标振幅对所述重建图像进行第一类振幅约束；
所述全息变换模块101，还用于将第一类振幅约束后的重建图像作为新一轮迭代处理的目标图像进行处理，并更新迭代次数计数，直到得到的重建图像的误差满足预设精度阈值，或当前迭代次数达到预设总迭代次数阈值。
本实施例中，所述判定模块104，还用于当所述重建图像对应的迭代次数大于所述预设GS算法迭代次数阈值时，判断所述重建图像的误差是否收敛；
所述复振幅约束模块105，还用于当所述重建图像的误差收敛时，根据预 设的目标图像和重建图像对应的权重因子，以及补偿因子，对所述重建图像的振幅进行第二类振幅约束，以加速所述重建图像的误差收敛；
所述全息变换模块101，还用于将第二类振幅约束后的重建图像作为新一轮迭代处理的目标图像进行处理，并更新迭代次数计数，直到得到的重建图像的误差满足预设精度阈值，或当前迭代次数达到预设总迭代次数阈值。
进一步地，所述复振幅约束模块105，还用于当所述重建图像的误差不收敛时，对所述重建图像进行第三类振幅或复振幅约束，以使所述重建图像的振幅或复振幅跳出局部极值，并将补偿因子重置为初始值；
所述全息变换模块101，还用于将跳出局部极值后的重建图像作为新一轮迭代处理的目标图像进行处理，并更新迭代次数计数，直到得到的重建图像的误差满足预设精度阈值，或当前迭代次数达到预设总迭代次数阈值。
对于装置实施例而言，由于其与方法实施例基本相似，所以描述的比较简单，相关之处参见方法实施例的部分说明即可。
图7给出了本发明实施例中的信号处理器10的具体芯片结构原理图。本发明全息芯片处理器的工作原理是，主要通过中央CPU以及GPU的主运算单元给全息算法单元的软件接口传输数据指令，来触发系统控制模块，调用其时间同步发生器来控制信号和全息算法，一路通过数据接口来控制光源设备中的激光器，一路控制空间光调制器SLM，共同结合输出来呈现全息图像。
本发明的另一实施例还提供了一种全息图像显示装置，如图8所示，所述全息图像显示装置包括如上任一实施例所述的信号处理器10、空间光调制器SLM20、光源设备30、傅里叶透镜40、空间滤波器50以及投影物镜60，所述空间光调制器SLM20用于将所述信号处理器10得到的目标全息图像作为图像源，作用到所述光源设备30入射的光束上，并通过所述傅里叶透镜40和空间滤波器50进行衍射传输变换和选择+1(或-1)级后得到全息重建图像，并通过所述投影物镜60将所述全息重建图像投影放大后，形成对应的放大显示图像。
在本发明的一个可选实施例中，所述光源设备包括单色激光器和对应的光束整形模块，所述单色激光器发射的单色光通过所述光束整形模块准直后入射到所述空间光调制器。其中，所述光束整形模块具体包括依次设置的第一透镜、空间滤波器、第二透镜、偏振器以及光阑。其中，光阑是对通过光学系统的光束起限制作用的光学元件。它可以是光学元件(如透镜、反射镜等)本身的边框，也可以是另外设置的带圆孔的不透光屏。本实施例中主要给出了单色全息图片显示时的光源设备的实现原理。参见图9，图9为单色全息图像显示的原理图。
在本发明的一个可选实施例中，所述光源设备包括红色激光发射器、绿色激光发射器、蓝色激光发射器和对应的光束整形模块，所述光源设备根据所述信号处理器加载不同颜色的目标全息图像的分时序列控制相应颜色的激光发射器进行分时序列的发光，与相应颜色的激光发射器对应的光束整形模块对相应颜色光束进行准直后，入射到所述空间光调制器。本实施例中，与各个颜色的激光发射器对应的光束整形模块包括准直透镜。进一步地，为了使得空间光调制器SLM20能够将所述信号处理器10得到的目标全息图像作为衍射信息作用到所述光源设备30入射的光束上，所述光源设备还包括与各个颜色的激光发射器对应的二向色镜和分束棱镜，所述二向色镜用于将相应颜色的激光发射器入射向所述SLM，所述分束棱镜用于将包含有目标全息图像信息的光束入射到上傅里叶透镜40。本实施例中主要给出了彩色全息图片显示时的光源设备的实现原理。参见图10，图10为彩色全息图像显示的原理图。
本发明的另一实施例还提供了一种全息图像显示装置，包括如上任一实施例所述的信号处理器、光源设备、加载有数字球面相位调制的空间光调制器SLM、空间滤波器以及投影物镜，所述加载有数字球面相位调制的空间光调制器SLM用于将所述信号处理器得到的目标全息图像作为图像源，作用到所述光源设备入射的光束上进行衍射传输变换，并通过所述空间滤波器进行选择处理后得到全息重建图像，并通过所述投影物镜将所述全息重建图像投影放大后， 形成对应的放大显示图像。本发明实施例通过加载有数字球面相位调制的空间光调制器SLM可以替代傅里叶透镜40的功能，简化装置的整体结构。
以上所描述的装置实施例仅仅是示意性的，其中所述作为分离部件说明的单元可以是或者也可以不是物理上分开的，作为单元显示的部件可以是或者也可以不是物理单元，即可以位于一个地方，或者也可以分布到多个网络单元上。可以根据实际的需要选择其中的部分或者全部模块来实现本实施例方案的目的。本领域普通技术人员在不付出创造性的劳动的情况下，即可以理解并实施。
此外，本发明另一实施例还提供了一种可穿戴设备，包括可穿戴装置和设置在所述可穿戴装置上的显示屏幕和如上任一实施例所述的全息图像显示装置，所述显示屏幕上镀有反射膜或全息光学元件膜，以对所述全息图像显示装置生成的投影显示图像形成虚拟放大的像，所述可穿戴设备的成像原理如图11所示。本实施例中以智能眼镜为例对本发明技术方案进行说明，智能眼镜的显示屏幕可以为眼镜的镜片，在镜片上镀有反射膜或全息光学元件膜。可理解的，除了智能眼镜以外，本发明所述的可穿戴设备还可以包括智能头盔等其他可穿戴智能设备。
此外，本发明实施例还提供了一种车载抬头显示设备，包括显示屏幕和如上任一实施例所述的全息图像显示装置，所述显示屏幕上镀有反射膜或全息光学元件膜，以对所述全息图像显示装置生成的投影显示图像形成虚拟放大的像，车载抬头显示设备的成像原理如图12所示。其中，车载抬头显示设备的显示屏幕具体可以为挡风玻璃，在挡风玻璃上镀有反射膜或全息光学元件膜。
全息光学元件膜，其中全息光学元件的英文简称HOE，全息光学元件膜是由HOE制作的膜。
本发明实施例中，将全息图像生成方法应用于可穿戴设备和车载抬头显示设备，能量效率高，可实现任意位置成像，与MEMS激光扫描HUD相比，因为MEMS激光扫描工作原理是激光是全部照射在MEMS上，而显示的图像区域只有10％的时候会造成大量的能量损耗；并且MEMS是处于高速的翻转 状态，一旦出现问题会使得激光直射人眼，造成人体损害。一般的只能在固定位置成像，或者利用额外的光学系统来对成像位置进行调制，导致系统的体积较大，成本增加。而基于液晶相位空间光调制器的系统可以利用所述的算法对成像位置进行任意调制，并且补偿系统的像差。成像距离可以用过全息转换算法处理后实现实时可调，实现图像焦距在远处。
本发明实施例提供的全息图像生成方法、处理器及全息图像显示装置、设备，通过判定重建图像是否满足预设条件，从而快速、高效地实现高对比度、低噪声的实时全息图像处理和显示，而且，可实现成像距离的任意调节。
通过以上的实施方式的描述，本领域的技术人员可以清楚地了解到各实施方式可借助软件加必需的通用硬件平台的方式来实现，当然也可以通过硬件。基于这样的理解，上述技术方案本质上或者说对现有技术做出贡献的部分可以以软件产品的形式体现出来，该计算机软件产品可以存储在计算机可读存储介质中，如ROM/RAM、磁碟、光盘等，包括若干指令用以使得一台计算机设备(可以是个人计算机，服务器，或者网络设备等)执行各个实施例或者实施例的某些部分所述的方法。
此外，本领域的技术人员能够理解，尽管在此的一些实施例包括其它实施例中所包括的某些特征而不是其它特征，但是不同实施例的特征的组合意味着处于本发明的范围之内并且形成不同的实施例。例如，在下面的权利要求书中，所要求保护的实施例的任意之一都可以以任意的组合方式来使用。
最后应说明的是：以上实施例仅用以说明本发明的技术方案，而非对其限制；尽管参照前述实施例对本发明进行了详细的说明，本领域的普通技术人员应当理解：其依然可以对前述各实施例所记载的技术方案进行修改，或者对其中部分技术特征进行等同替换；而这些修改或者替换，并不使相应技术方案的本质脱离本发明各实施例技术方案的精神和范围。

Claims (24)

  1. 一种全息图像生成方法，其特征在于，包括:
    基于目标图像的目标振幅相位分布进行全息变换，得到所述目标图像对应的全息相位图像；
    对所述全息相位图像进行相位量化，得到量化全息图像；
    对所述量化全息图像进行逆全息变换，得到所述目标图像对应的重建图像；
    若所述重建图像满足预设条件，则确定所述量化全息图像为目标全息图像；
    否则，对所述目标图像对应的重建图像的振幅相位进行约束，并基于振幅相位约束后的图像继续迭代。
  2. 根据权利要求1所述的方法，其特征在于，所述全息变换包括傅里叶变换、菲涅尔变换、快速傅里叶变换、分数阶傅里叶变换和角谱传播空间变换。
  3. 根据权利要求1所述的方法，其特征在于，在所述对所述全息相位图像进行相位量化之后，所述方法还包括：
    若相位量化后的全息相位图像存在涡旋，则对所述量化全息图像的涡旋进行邻域插值，或替换为预设值，得到修正后的量化全息图像。
  4. 根据权利要求1所述的方法，其特征在于，所述方法还包括：
    判断所述重建图像的误差是否满足预设精度阈值，或所述重建图像对应的迭代次数是否达到预设总迭代次数阈值；
    若所述重建图像的误差小于预设精度阈值，或所述重建图像对应的迭代次数等于预设总迭代次数阈值，则确定所述重建图像满足预设条件。
  5. 根据权利要求4所述的方法，其特征在于，所述方法还包括：
    若所述重建图像的误差大于或等于所述预设精度阈值，且所述重建图像对应的迭代次数小于预设总迭代次数阈值，则执行所述对所述目标图像对应的重 建图像的振幅相位进行约束的操作。
  6. 根据权利要求5所述的方法，其特征在于，所述对所述目标图像对应的重建图像的振幅相位进行约束的操作，包括：
    判断所述重建图像对应的迭代次数是否大于预设GS算法迭代次数阈值；
    若所述重建图像对应的迭代次数小于或等于所述预设GS算法迭代次数阈值，则根据GS算法采用目标振幅对所述重建图像进行第一类振幅约束；
    将第一类振幅约束后的重建图像作为新一轮迭代处理的目标图像进行处理，并更新迭代次数计数，直到得到的重建图像的误差满足预设精度阈值，或当前迭代次数等于预设总迭代次数阈值。
  7. 根据权利要求6所述的方法，其特征在于，所述方法还包括：
    若所述重建图像对应的迭代次数大于所述预设GS算法迭代次数阈值，判断所述重建图像的误差是否收敛；
    若所述重建图像的误差收敛，则根据预设的目标图像和重建图像对应的权重因子，以及补偿因子，对所述重建图像的振幅进行第二类振幅约束，以加速所述重建图像的误差收敛；并根据所述补偿因子进行补偿约束；
    将第二类振幅约束后的重建图像作为新一轮迭代处理的目标图像进行处理，并更新迭代次数计数，直到得到的重建图像的误差满足预设精度阈值，或当前迭代次数达到预设总迭代次数阈值。
  8. 根据权利要求7所述的方法，其特征在于，所述方法还包括：
    若所述重建图像的误差不收敛，则对所述重建图像进行第三类振幅或复振幅约束，以使所述重建图像的振幅或复振幅跳出局部极值，并将补偿因子重置为初始值；
    将跳出局部极值后的重建图像作为新一轮迭代处理的目标图像进行处理，并更新迭代次数计数，直到得到的重建图像的误差满足预设精度阈值，或当前迭代次数等于预设总迭代次数阈值。
  9. 根据权利要求2所述的方法，其特征在于，在所述对所述目标图像进 行相位分布计算之前，所述方法包括：
    根据不同颜色激光的波长，调节目标图像中相应颜色像素的尺寸。
  10. 根据权利要求9所述的方法，其特征在于，在所述对所述全息相位图像进行相位量化之前，所述方法包括：
    根据不同颜色激光的波长，确定各种颜色激光的量化阶数及量化范围。
  11. 一种信号处理器，其特征在于，包括:
    全息变换模块，用于对目标图像的目标振幅相位分布进行全息变换，得到所述目标图像对应的全息相位图像；
    相位量化模块，用于对所述全息相位图像进行相位量化，得到量化全息图像；
    逆全息变换模块，用于对所述量化全息图像进行逆全息变换，得到所述目标图像对应的重建图像；
    判定模块，用于判断全息相位图像是否满足预设条件，当所述重建图像满足预设条件时，确定所述量化全息图像为目标全息图像；
    复振幅约束模块，用于当所述重建图像不满足预设条件时，对所述目标图像对应的重建图像的振幅相位进行约束，并返回所述全息变换模块，以供所述全息变换模块基于振幅相位约束后的图像继续进行迭代。
  12. 根据权利要求11所述的信号处理器，其特征在于，所述信号处理器还包括：
    像素调节模块，用于在所述对所述目标图像进行相位分布计算之前，根据不同颜色激光的波长，调节目标图像中相应颜色像素的尺寸。
  13. 根据权利要求12所述的信号处理器，其特征在于，所述相位量化模块，还用于在对所述全息相位图像进行相位量化之前，根据不同颜色激光的波长，确定各种颜色激光的量化阶数及量化范围。
  14. 根据权利要求11所述的信号处理器，其特征在于，所述信号处理器还包括：
    修正模块，用于在所述对所述全息相位图像进行相位量化之后，当相位量化后的全息相位图像存在涡旋时，对所述量化全息图像的涡旋进行邻域插值，或替换为预设值，得到修正后的量化全息图像。
  15. 根据权利要求11所述的信号处理器，其特征在于，所述判定模块，具体用于判断所述重建图像的误差是否满足预设精度阈值，或所述重建图像对应的迭代次数是否达到预设总迭代次数阈值；若所述重建图像的误差小于预设精度阈值，或所述重建图像对应的迭代次数等于预设总迭代次数阈值，则确定所述重建图像满足预设条件。
  16. 根据权利要求15所述的信号处理器，其特征在于，所述判定模块，具体还用于当所述重建图像的误差大于或等于所述预设精度阈值，且所述重建图像对应的迭代次数小于预设总迭代次数阈值时，判断所述重建图像对应的迭代次数是否大于预设GS算法迭代次数阈值；
    所述复振幅约束模块，具体用于当所述重建图像对应的迭代次数小于或等于所述预设GS算法迭代次数阈值时，根据GS算法采用目标振幅对所述重建图像进行第一类振幅约束；
    所述全息变换模块，还用于将第一类振幅约束后的重建图像作为新一轮迭代处理的目标图像进行处理，并更新迭代次数计数，直到得到的重建图像的误差满足预设精度阈值，或当前迭代次数达到预设总迭代次数阈值。
  17. 根据权利要求16所述的信号处理器，其特征在于，所述判定模块，还用于当所述重建图像对应的迭代次数大于所述预设GS算法迭代次数阈值时，判断所述重建图像的误差是否收敛；
    所述复振幅约束模块，还用于当所述重建图像的误差收敛时，根据预设的目标图像和重建图像对应的权重因子，以及补偿因子，对所述重建图像的振幅进行第二类振幅约束，以加速所述重建图像的误差收敛；
    所述全息变换模块，还用于将第二类振幅约束后的重建图像作为新一轮迭代处理的目标图像进行处理，并更新迭代次数计数，直到得到的重建图像的误 差满足预设精度阈值，或当前迭代次数达到预设总迭代次数阈值。
  18. 根据权利要求17所述的信号处理器，其特征在于，所述复振幅约束模块，还用于当所述重建图像的误差不收敛时，对所述重建图像进行第三类振幅或复振幅约束，以使所述重建图像的振幅或复振幅跳出局部极值，并将补偿因子重置为初始值；
    所述全息变换模块，还用于将跳出局部极值后的重建图像作为新一轮迭代处理的目标图像进行处理，并更新迭代次数计数，直到得到的重建图像的误差满足预设精度阈值，或当前迭代次数达到预设总迭代次数阈值。
  19. 一种全息图像显示装置，其特征在于，包括如权利要求11-18任一项所述的信号处理器、光源设备、空间光调制器SLM、傅里叶透镜、空间滤波器以及投影物镜，所述空间光调制器SLM用于将所述信号处理器得到的目标全息图像作为图像源，作用到所述光源设备入射的光束上，并通过所述傅里叶透镜和空间滤波器进行衍射传输变换和选择后得到全息重建图像，并通过所述投影物镜将所述全息重建图像投影放大后，形成对应的放大显示图像。
  20. 根据权利要求19所述的装置，其特征在于，所述光源设备包括单色激光器和对应的光束整形模块，所述单色激光器发射的单色光通过所述光束整形模块准直后入射到所述空间光调制器。
  21. 根据权利要求19所述的装置，其特征在于，所述光源设备包括红色激光发射器、绿色激光发射器、蓝色激光发射器和对应的光束整形模块，所述光源设备根据所述信号处理器分时序列地加载不同颜色的目标全息图像，控制相应颜色的激光发射器进行分时序列的发光，与相应颜色的激光发射器对应的光束整形模块对相应颜色光束进行准直后，入射到所述空间光调制器。
  22. 一种全息图像显示装置，其特征在于，包括如权利要求11-18任一项所述的信号处理器、光源设备、加载有数字球面相位调制的空间光调制器SLM、空间滤波器以及投影物镜，所述加载有数字球面相位调制的空间光调制器SLM用于将所述信号处理器得到的目标全息图像作为图像源，作用到所述光源设备 入射的光束上进行衍射传输变换，并通过所述空间滤波器进行选择处理后得到全息重建图像，并通过所述投影物镜将所述全息重建图像投影放大后，形成对应的放大显示图像。
  23. 一种可穿戴设备，其特征在于，包括可穿戴装置和设置在所述可穿戴装置上的显示屏幕和如权利要求19-22任一项所述的全息图像显示装置，所述显示屏幕上镀有反射膜或全息光学元件膜，以对所述全息图像显示装置生成的投影显示图像形成虚拟放大的像。
  24. 一种车载抬头显示设备，其特征在于，包括显示屏幕和如权利要求19-22任一项所述的全息图像显示装置，所述显示屏幕上镀有反射膜或全息光学元件膜，以对所述全息图像显示装置生成的投影显示图像形成虚拟放大的像。
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