Laser projection display system and optimization method thereof

Abstract

The present invention discloses a laser projection display system and an optimization method thereof. No convex lens is provided at the rear end of a phase light modulator, and the phase of the original convex lens acting on the light field is superimposed on the phase light modulator as an additional phase. A DMD chip is placed at the focal plane position of the original convex lens, and the additional phase is superimposed on a phase hologram of a target image and loaded on the phase light modulator, so that a light beam is modulated by the phase light modulator to form a diffraction reproduction image on the DMD chip. The DMD chip modulates the diffraction reproduction image and forms a target image through a projection lens. This avoids the influence of zero-order interference light spots on the imaging quality and simplifies the optical path design of the system. The present invention also accelerates the limit recovery algorithm by downsampling and reconverging the target image, and nearly aligns the timing with the DMD chip, thereby realizing real-time modulation of the illumination light field. The aspect ratio distortion problem of the diffraction reproduction image is solved by preprocessing the target image.

Description

Technical Field

[0001] The present invention belongs to the technical field of laser projection, and in particular relates to a dynamic range optimization method for a laser projection display system and a laser projection display system. Background Art

[0002] In the field of laser display, HDR (high dynamic range) can enrich the details of each dark area, making the dark areas darker and the bright areas brighter, enriching the colors with more details and restoring the natural details of the picture.

[0003] The core component of the DLP (digital light processing) projection system is the digital micromirror device (DMD). The PLM (phase spatial light modulator) device can efficiently modulate the distribution of the DMD's illumination light field, so that the light field illuminating the DMD is approximately the distribution of the image to be displayed. After the DMD modulates the input image, HDR image display can be achieved.

[0004] PLM imaging at the DMD is diffraction imaging. While expanding the dynamic range, it also breaks through the brightness limitations imposed by the laser light source power in the local area illuminated by the DMD, increasing the brightness to several times that of the DMD's uniform illumination. Furthermore, through light field redistribution, even lower brightness image display can be achieved. However, although the overall effective area aspect ratio of the PLM and DMD devices is the same, due to the diffraction principle, the micromirror structure of the PLM device is square, and the aspect ratio of its diffraction reproduction image is 1:1. Furthermore, when illuminated by light sources of different wavelengths, the size of the illumination light field formed at the DMD is also inconsistent. Therefore, the aspect ratio of its diffraction reproduction image is inconsistent with that of the DMD device, which cannot meet the DMD's lighting requirements. Secondly, the presence of the zero-order interference spot greatly affects the imaging quality. Thirdly, the existing phase recovery algorithm for calculating the PLM signal takes too long to align with the DMD in terms of timing, making it impossible to modulate the illumination light field in real time. Summary of the Invention

[0005] The present invention proposes a laser projection display system and an optimization method thereof. By optimizing the optical path and algorithm, the zero-order interference spot is eliminated, the imaging quality is improved, and the optical path is simpler. The phase recovery algorithm is accelerated by downsampling and reconverging the target image, and the timing is nearly aligned with the DMD chip, thereby realizing real-time modulation of the illumination light field. The aspect ratio distortion problem of the diffraction reproduction image is solved by preprocessing the target image.

[0006] The present invention is achieved by adopting the following technical solutions:

[0007] A laser projection display system optimization method is proposed, which is applied to the laser projection display system. The laser projection display system includes:

[0008] a light source for providing a light beam;

[0009] A phase light modulator, used to adjust the phase of light in the light beam provided by the light source;

[0010] A DMD chip is used to modulate the light beam after being dimmed by the phase spatial light modulator;

[0011] A projection lens, used to project the light beam modulated by the DMD chip into an image;

[0012] In the laser projection display system, no convex lens is provided between the phase light modulator and the DMD chip, and the method includes:

[0013] Calculating an additional phase; the additional phase is the phase acting on the light field when a convex lens is provided at the rear end of the phase light modulator;

[0014] Determining a phase hologram of a target image at the phase light modulator;

[0015] Superimposing the additional phase on the solved phase hologram and loading it on the phase light modulator, so that the light beam forms a diffraction reconstructed image on the DMD chip after phase modulation;

[0016] The DMD chip modulates the diffraction reproduced image and then projects it into the target image through the projection lens.

[0017] In some embodiments of the present invention, solving the phase hologram of the target image at the phase light modulator specifically includes:

[0018] Downsampling the target image to 1 / n of the original resolution;

[0019] Compute the phase hologram of the downsampled image;

[0020] The phase hologram of the downsampled image is replicated n times in n areas on the phase light modulator;

[0021] The n images are converged into one image by superimposing the blazed grating phase factors.

[0022] In some embodiments of the present invention, when superimposing the blazed grating phase factor, the method includes:

[0023] A blazed grating with a period of 2a is superimposed in both the horizontal and vertical directions; wherein a is the size of the micromirror of the phase light modulator;

[0024] The blazed grating phase factors of na and -na are superimposed on the phase holograms in different regions.

[0025] In some embodiments of the present invention, before solving the phase hologram of the target image at the phase light modulator, the method further includes:

[0026] Compress the width of the target image to M / N, and fill the grayscale values ​​of the remaining pixels with 0; where M and N are the aspect ratios of the target image; or,

[0027] The N*N micromirrors of the phase light modulator are set to place an M:N target image in an N*N black background image.

[0028] In some embodiments of the present invention, before solving the phase hologram of the target image at the phase light modulator, the method further includes:

[0029] Scale the target image, where the R channel sub-image is scaled according to the ratio a1, and the G channel sub-image is scaled according to the ratio a2; a1 = λ B / λ R , a2=λ B / λ G ,λ B ,λ R and λ G They are blue laser wavelength, red laser wavelength and green laser wavelength respectively.

[0030] A laser projection display system is proposed, comprising:

[0031] a light source for providing a light beam;

[0032] A phase light modulator, used to adjust the phase of light in the light beam provided by the light source;

[0033] A DMD chip is used to modulate the light beam after being dimmed by the phase spatial light modulator;

[0034] A projection lens, used to project the light beam modulated by the DMD chip into an image;

[0035] No convex lens is provided between the phase light modulator and the DMD chip, and the system further comprises:

[0036] An optical path adjustment unit, configured to calculate an additional phase; the additional phase is the phase acting on the light field assuming that a convex lens is provided at the rear end of the phase light modulator;

[0037] A phase calculation unit, configured to calculate a phase hologram of a target image at the phase light modulator;

[0038] A diffraction control unit, configured to superimpose an additional phase on the solved phase hologram and load it onto the phase light modulator, so that a diffraction reconstructed image is formed on the DMD chip after the light beam is phase modulated;

[0039] The DMD chip modulates the diffraction reproduced image and then projects it into the target image through the projection lens.

[0040] In some embodiments of the present invention, the phase calculation unit solves the phase hologram of the target image at the phase light modulator, specifically including:

[0041] Downsampling the target image to 1 / n of the original resolution;

[0042] Compute the phase hologram of the downsampled image;

[0043] The phase hologram of the downsampled image is replicated n times in n areas on the phase light modulator;

[0044] The n images are converged into one image by superimposing the blazed grating phase factors.

[0045] In some embodiments of the present invention, the phase calculation unit, when superimposing the blazed grating phase factor, includes:

[0046] A blazed grating with a period of 2a is superimposed in both the horizontal and vertical directions; wherein a is the size of the micromirror of the phase light modulator;

[0047] The blazed grating phase factors of na and -na are superimposed on the phase holograms in different regions.

[0048] In some embodiments of the present invention, the system further includes a first image preprocessing unit, which is used to compress the width of the target image to M / N and fill the grayscale values ​​of the idle pixels with 0 before solving the phase hologram of the target image at the phase light modulator; wherein M and N are the aspect ratio of the target image; or, set N*N micromirrors of the phase light modulator to place the M:N target image in an N*N black background image.

[0049] In some embodiments of the present invention, the system further includes a second image pre-processing unit for scaling the target image before solving the phase hologram of the target image at the phase light modulator, wherein the R channel sub-image is scaled according to a1 ratio, and the G channel sub-image is scaled according to a2 ratio; a1=λ B / λ R , a2=λ B / λ G ,λ B ,λ R and λ G It is divided into blue laser wavelength, red laser wavelength and green laser wavelength.

[0050] Compared with the prior art, the advantages and positive effects of the present invention are as follows: in the laser projection display system and optimization method thereof proposed in the present invention, no convex lens is provided at the rear end of the phase light modulator, the phase of the original convex lens acting on the light field is superimposed on the phase light modulator as an additional phase, the DMD chip is placed at the focal plane position of the original convex lens, the additional phase and the phase hologram of the target image are superimposed and loaded on the phase light modulator, so that the light beam forms a diffraction reproduction image on the DMD chip after being modulated by the phase light modulator, and the DMD chip forms a target image after modulating the diffraction reproduction image through the projection lens, which avoids the influence of the zero-order interference spot on the imaging quality while simplifying the optical path design of the system.

[0051] Furthermore, the present invention shortens the execution time of the phase recovery algorithm by calculating the phase hologram after downsampling the target image. Then, on the phase modulation device, the phase hologram obtained after downsampling is reconverged by partitioning the phase hologram and superimposing the blazed grating phase factor to obtain the target image before downsampling, so that the signal adjusted by the phase light modulator is almost aligned with the DMD chip in terms of timing, thereby realizing real-time modulation of the illumination light field.

[0052] Furthermore, the present invention makes the aspect ratio of the diffraction reproduction image consistent with the target image by preprocessing the target image, so that the phase light modulator can meet the lighting requirements of the DMD chip.

[0053] Other features and advantages of the present invention will become more apparent after reading the detailed description of the embodiments of the present invention in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0055] Figure 1 This is a schematic diagram of the system architecture of the laser projection display system proposed in the present invention;

[0056] Figure 2 Schematic diagram of the steps of the laser projection display system optimization method proposed by the present invention;

[0057] Figure 3 Schematic diagram of the steps of the laser projection display system optimization method proposed by the present invention;

[0058] Figure 4 A phase hologram calculated from a downsampled target image processed by the optimization method of the present invention;

[0059] Figure 5 This is a schematic diagram of a dislocated and overlapping phase image obtained by dividing n regions and replicating n times in the optimization method of the present invention;

[0060] Figure 6 Schematic diagram of the distribution of diffracted reproduced images in an existing lens-containing laser projection display system;

[0061] Figure 7 Schematic diagram of the reproduced image of the superimposed blazed grating processed by the optimization method of the present invention;

[0062] Figure 8 This is a schematic diagram of the final effect of the reproduced image of the superimposed blazed grating processed by the optimization method of the present invention;

[0063] Figure 9 This is a schematic diagram of the target image preprocessing in the optimization method of the present invention;

[0064] Figure 10 This is a schematic diagram of the target image preprocessing in the optimization method of the present invention;

[0065] Figure 11 Schematic diagram of the steps of implementing scale correction on a target image in the optimization method of the present invention;

[0066] Figure 12 This is a schematic diagram of the system composition of the laser projection display system proposed in the present invention. DETAILED DESCRIPTION

[0067] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0068] The present invention proposes a laser projection display system and an optimization algorithm used therein, such as Figure 1 As shown, the laser projection display system includes:

[0069] Light source 1 is used to provide a light beam; in this embodiment, it is a laser light source. The laser light source emits a shaped light beam toward phase light modulator 2. The laser light source includes a red light source, a blue light source, and a green light source, which emit parallel light. These three light sources can emit light simultaneously or in a set time sequence.

[0070] The phase light modulator 2 is used to modulate the phase of the light in the light beam provided by the light source 1 .

[0071] The DMD chip 3, also known as the spatial light modulator, is used to modulate the light beam modulated by the phase light modulator 2. Specifically, the projected image is divided into R, G, and B component sub-images according to the three primary colors R, G, and B. The control circuit of the laser projection display system converts the signal of each color component sub-image into a corresponding drive signal, causing the DMD chip 3 to modulate the light beam incident on it. In the present invention, however, the light beam modulated by the phase light modulator 2 is modulated.

[0072] The projection lens 4 is used to project the light beam modulated by the DMD chip 3 onto the projection screen 5 to form an image.

[0073] In the laser projection display system of the present invention, in order to eliminate the problem of zero-order interference spot, the rear end of the phase light modulator 2 is not provided with a convex lens, that is, the convex lens behind the phase light modulator of the existing system is eliminated. Combined with this simplified optical path structure, as shown in FIG. Figure 2 As shown, the present invention proposes an optimization method for the laser projection display system, comprising the following steps:

[0074] S1: Calculate additional phase.

[0075] The additional phase is the phase acting on the light field when a convex lens is provided at the rear end of the phase light modulator 2. That is, the phase of the convex lens acting on the light field in the existing system is superimposed on the phase light modulator 2 in the form of an additional phase, and the phase light modulator 2 is used to modulate the light beam to replace the role of the convex lens.

[0076] The length and width of the diffraction image are both fλ / a, where f is the focal length of the convex lens, λ is the wavelength of the light source, and a is the size of the micromirror of the phase light modulator. In the embodiment of the present invention, the additional phase of the convex lens on the light field is directly obtained by taking the phase angle in the complex amplitude conversion coefficient of the convex lens; the complex amplitude conversion coefficient is expressed as:

[0077] x and y are the coordinates of the image pixel respectively.

[0078] S2: Adjust the DMD chip to the focal plane position of the convex lens.

[0079] The diffraction image is at the same depth as the focal plane of the convex lens. In the existing system, a convex lens is placed behind the phase light modulator 2 to focus the light beam at the DMD chip, and the image is displayed at the DMD chip. The present invention uses a phase light modulator to modulate the additional phase to replace the function of the convex lens, and the DMD chip is placed according to the focal length when the convex lens is assumed to exist.

[0080] S3: Determine the phase hologram of the target image at the phase light modulator.

[0081] The GS algorithm can be used to reversely solve the phase distribution at the phase light modulator from the amplitude distribution of the target image at the DMD chip, and ultimately the target image can be reproduced at the DMD chip using only the phase information.

[0082] like Figure 3 As shown in the figure, the solution process includes: first, setting the amplitude A1 at the phase light modulator to 1 and randomly selecting the phase φ1 to random; based on the diffraction formula, the phase distribution φ2 and amplitude distribution A2 at the DMD chip are obtained, the phase distribution φ2 is retained, and the amplitude is set to the amplitude At of the target image; according to the inverse diffraction formula, the amplitude A1 and phase φ1 transmitted back to the phase light modulator are obtained, and A1 is set to 1 to retain the phase information. The diffraction and inverse diffraction processes are repeated until the amplitude A2 of the diffracted image meets the amplitude At of the target image, or the maximum number of iterations is reached.

[0083] In some embodiments of the present invention, the target image and high-quality phase holograms generated by other algorithms are prepared as training sets and test sets, and the existing deep learning network is used to solve the phase hologram of the target image at the phase light modulator, the loss function is optimized, and the trained weights are pre-stored in the FPGA. The weights can be used in the FPGA to predict the phase hologram of the target image in real time, thereby realizing the real-time dimming function of the phase light modulator.

[0084] S4: The additional phase is superimposed on the solved phase hologram and loaded onto the phase light modulator.

[0085] The phase light modulator 2, as a micro-mirror matrix, controls the light beam by moving up and down to change the light field distribution according to the superimposed phase, and forms a diffraction reproduction image on the image plane of the DMD chip.

[0086] S5: The DMD chip modulates the diffraction reproduction image and projects the target image through the projection lens.

[0087] As described above, the present invention eliminates the convex lens at the rear end of the phase light modulator in the existing laser projection display system, and superimposes the phase of the original convex lens on the light field as an additional phase on the phase light modulator. The DMD chip is placed on the focal plane of the convex lens, and the additional phase mode is superimposed on the phase hologram of the target image and loaded on the phase light modulator, so that the light beam is modulated by the phase light modulator to form a diffraction reproduction image on the DMD chip. The DMD chip modulates the diffraction reproduction image and forms the target image through the projection lens. While avoiding the influence of the zero-order interference spot on the imaging quality, it also simplifies the optical path design of the system.

[0088] In order to improve the running speed of the phase reversal recovery algorithm and align it with the laser and DMD chip in terms of timing, the present invention uses a method of quickly generating phase holograms to improve the speed. The fast generation method is as follows: Figure 3 As shown, including:

[0089] S31: downsample the target image to 1 / n of the original resolution, and calculate the phase hologram of the downsampled image.

[0090] Here n is a positive integer greater than or equal to 2. Calculating small-sized phase holograms can significantly shorten the algorithm's running time. For example, when the target image resolution is reduced to 1 / 4 of the original, n = 4, the algorithm's running time will be shortened by 75%. Figure 4 The embodiment shown is a phase hologram calculated when the resolution is reduced to 1 / 4 of the original resolution.

[0091] S32: The phase hologram of the downsampled image is replicated n times in n areas on the phase light modulator.

[0092] like Figure 5 As shown, the phase plane of the phase light modulator is divided into four areas, and the downsampled phase hologram is replicated four times in these four areas, and four offset and overlapping images can be obtained on the image plane of the DMD chip.

[0093] S33: Converging n images into one image by superimposing the blazed grating phase factor.

[0094] Converging n images into one image is achieved by superimposing a blazed grating phase factor on the phase hologram. The function of the blazed grating is to move light energy.

[0095] In a phase light modulator optical system containing a lens, after the phase light modulator is loaded with the phase hologram calculated by the GS algorithm or obtained by deep learning, the distribution of the diffraction reconstructed image is as follows: Figure 6 As shown, from the interference fringe conditions a sin = kλ, k = ±1, 2, 3..., we can see that, in units of sin / λ, the first-order interference maximum is located at ±1 / a, and the first-order reconstructed image is located at 1 / 2a, where a is the micromirror size (equal length and width). The blaze condition for a blazed grating is 2dsinγ = λ, where d is the blazed grating period and γ is the blaze angle. Its physical meaning is that when the blaze condition is met, the blazed grating acts as if it shifts the image by 1 / d.

[0096] It can be seen that the diffraction image can be moved from 1 / 2a to the zero order by simply setting the period d of the superimposed blazed grating to 2a. In the down-sampling GS algorithm of the present invention, taking n=4 as an example, after superimposing blazed gratings with a period of 2a in the horizontal and vertical directions, the effect is as follows: Figure 7 shown.

[0097] According to the analysis, the centers of these images are located at (-1 / 4a, 1 / 4a), (-1 / 4a, -1 / 4a), (1 / 4a, -1 / 4a), and (1 / 4a, 1 / 4a). Therefore, it is necessary to superimpose blazed grating phase factors with periods of 4a and -4a (a negative period indicates that the arrangement direction of the blazed grating from low to high is opposite) on the holograms in different areas to achieve the re-convergence of the four diffraction images. The final effect is as follows: Figure 8 shown.

[0098] The above-mentioned present invention shortens the execution time of the phase recovery algorithm by calculating the phase hologram after downsampling the target image. Then, on the phase modulation device, the phase hologram obtained after downsampling is reconverged by partitioning and replicating the phase hologram and superimposing the blazed grating phase factor to obtain the target image before downsampling, so that the signal adjusted by the phase light modulator is almost aligned with the DMD chip in terms of timing, thereby realizing real-time modulation of the illumination light field.

[0099] Due to the diffraction principle, the micromirror structure of the phase light modulator is square, resulting in an aspect ratio of 1:1 for the reproduced image after diffraction, which is inconsistent with the aspect ratio of the DMD chip. To solve this problem, in some embodiments of the present invention, the aspect ratio of the diffracted reproduced image is made consistent with that of the target image by preprocessing the target image, thereby solving the problem of aspect ratio distortion of the diffracted reproduced image and ensuring that the light beam modulated by the phase light modulator can meet the lighting requirements of the DMD chip. The preprocessing method includes:

[0100] 1. Compress the width of the target image to M / N and fill the grayscale values ​​of the remaining pixels with 0.

[0101] Here, M and N are the aspect ratios of the target image, such as 16:10, 16:9, 4:3, etc.; that is, the width of the target image is stretched to M / N, such as Figure 9 As shown, after the target image with stretched width is acted upon by the phase light modulator, the target image with normal aspect ratio can be reproduced on the image plane of the DMD chip.

[0102] 2. Set up N*N micromirrors using a phase light modulator and place the M:N target image in an N*N black background image.

[0103] For example, for a 1280*800 resolution phase light modulator, only 800*800 micromirrors are used to scale the M:N target image and then place it in an 800*800 black background image, as shown in the figure. Figure 10 As shown in the figure, a black background image with an aspect ratio of 1:1 can also reproduce a target image with a normal aspect ratio on the image plane of the DMD chip after being acted upon by a phase light modulator.

[0104] The size of the diffraction reproduction image under different wavelength light sources is fλ / a. The longer the wavelength, the larger the size of the reproduction image. Therefore, in order to obtain the target image with the correct proportion, in some embodiments of the present invention, the target image is scaled. The overall image preprocessing process is as follows: Figure 11 As shown, the R channel sub-image is scaled according to the ratio a1, and the G channel sub-image is scaled according to the ratio a2; a1 = λ B / λ R , a2=λ B / λ G ,λ B ,λ R and λ G are blue laser wavelength, red laser wavelength and green laser wavelength respectively; taking the combination of 450nm, 532nm and 640nm lasers as an example, the calculation formula is:

[0105]

[0106]

[0107] The scaled target image is further decomposed into R channel hologram, G channel hologram and B channel hologram by using GS algorithm to calculate the phase hologram at the phase light modulation device.

[0108] In combination with the above, the present invention can achieve the following optimization of the laser projection display system in one embodiment: first, the target image is preprocessed and scaled to solve the problem of diffraction reproduction image distortion; further, by simplifying the optical path and loading the phase of the convex lens acting on the light field into the phase light modulator in the form of an additional phase, the problem of eliminating zero-order interference fringes is achieved; finally, the calculation speed of the phase recovery algorithm is improved by downsampling and reconverging the target image.

[0109] Based on the above, the laser projection display system proposed by the present invention is as follows: Figure 12 As shown, it also includes an optical path adjustment unit 6, a phase calculation unit 7 and a diffraction control unit 8; the optical path adjustment unit 6 is used to calculate the additional phase and adjust the focal plane position of the DMD chip at the convex lens; the phase calculation unit 7 is used to solve the phase hologram of the target image at the phase light modulator; the diffraction control unit 8 is used to superimpose the additional phase on the solved phase hologram and load it on the phase light modulator, so that the light beam forms a diffraction reproduction image on the DMD chip after phase modulation; the DMD chip modulates the diffraction reproduction image and projects it into the target image through the projection lens.

[0110] In some embodiments of the present invention, the phase calculation unit 7 solves the phase hologram of the target image at the phase light modulator, specifically including: downsampling the target image to 1 / n of the original resolution; calculating the phase hologram of the downsampled image; replicating the phase hologram of the downsampled image n times in n areas on the phase light modulator; and converging the n images into one image by superimposing the blazed grating phase factor.

[0111] In some embodiments of the present invention, when superimposing a blazed grating, the phase calculation unit includes: superimposing a blazed grating with a period of 2a in the horizontal and vertical directions; where a is the effective size of the micromirror of the phase light modulator; and superimposing blazed grating phase factors of na and -na on the phase hologram in different regions, respectively.

[0112] In some embodiments of the present invention, the system further includes a first image preprocessing unit 9, which is used to compress the width of the target image to M / N and fill the grayscale values ​​of the idle pixels with 0 before solving the phase hologram of the target image at the phase light modulator; wherein M and N are the aspect ratio of the target image; or, set N*N micromirrors of the phase light modulator to place the M:N target image in an N*N black background image.

[0113] In some embodiments of the present invention, the system further includes a second image pre-processing unit 10 for scaling the target image before solving the phase hologram of the target image at the phase light modulator, wherein the R channel sub-image is scaled according to a1 ratio and the G channel sub-image is scaled according to a2 ratio; a1=λ B / λ R , a2=λ B / λ G ,λ B ,λ R and λ G It is divided into blue laser wavelength, red laser wavelength and green laser wavelength.

[0114] The specific optimization method has been described in detail and will not be repeated here.

[0115] It should be noted that, in the specific implementation process, part of the above-mentioned method can be implemented by a hardware processor executing computer execution instructions in software form stored in the memory, which will not be elaborated here, and the programs corresponding to the executed actions can be stored in the system's computer-readable storage medium in software form, so that the processor can call and execute the operations corresponding to the above modules.

[0116] The computer-readable storage medium mentioned above may include volatile memory, such as random access memory; may also include non-volatile memory, such as read-only memory, flash memory, hard disk or solid-state drive; may also include a combination of the above types of memory.

[0117] The processor mentioned above can also be a collective term for multiple processing elements. For example, the processor can be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs) or other programmable logic devices (PLDs), discrete gate or transistor logic devices (LDDs), discrete hardware components, etc. A general-purpose processor can be a microprocessor or any conventional processor, etc., and can also be a special-purpose processor.

[0118] It should be pointed out that the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by ordinary technicians in this technical field within the essential scope of the present invention should also fall within the scope of protection of the present invention.

Claims

1. A laser projection display system optimization method, applied to a laser projection display system, wherein the laser projection display system comprises: a light source for providing a light beam; A phase light modulator, used to adjust the phase of light in the light beam provided by the light source; A DMD chip is used to modulate the light beam after being dimmed by the phase spatial light modulator; A projection lens, used to project the light beam modulated by the DMD chip into an image; It is characterized in that, in the laser projection display system, no convex lens is provided between the phase light modulator and the DMD chip, and the method comprises: Calculating an additional phase; the additional phase is the phase acting on the light field when a convex lens is provided at the rear end of the phase light modulator; Determining a phase hologram of a target image at the phase light modulator; Superimposing the additional phase on the solved phase hologram and loading it on the phase light modulator, so that the light beam forms a diffraction reconstructed image on the DMD chip after phase modulation; The DMD chip modulates the diffracted reproduced image and projects the modulated image into the target image through the projection lens; Solving the phase hologram of the target image at the phase light modulator specifically includes: Downsampling the target image to 1 / n of the original resolution; Compute the phase hologram of the downsampled image; The phase hologram of the downsampled image is replicated n times in n areas on the phase light modulator; The n images are converged into one image by superimposing the blazed grating phase factors.

2. The laser projection display system optimization method according to claim 1, characterized in that: When superimposing the blazed grating phase factor, it includes: A blazed grating with a period of 2a is superimposed in both the horizontal and vertical directions; wherein a is the size of the micromirror of the phase light modulator; The blazed grating phase factors of na and -na are superimposed on the phase holograms in different regions.

3. The laser projection display system optimization method according to claim 1, characterized in that: Before solving the phase hologram of the target image at the phase light modulator, the method further includes: Compress the width of the target image to M / N, and fill the grayscale values ​​of the remaining pixels with 0; where M and N are the aspect ratios of the target image; or, The N*N micromirrors of the phase light modulator are set to place an M:N target image in an N*N black background image.

4. The laser projection display system optimization method according to claim 1, characterized in that: Before solving the phase hologram of the target image at the phase light modulator, the method further includes: The target image is scaled, wherein the R channel sub-image is scaled according to the ratio a1, and the G channel sub-image is scaled according to the ratio a2; a1= / ,a2= / , 、 and They are blue laser wavelength, red laser wavelength and green laser wavelength respectively.

5. A laser projection display system comprising: a light source for providing a light beam; A phase light modulator, used to adjust the phase of light in the light beam provided by the light source; A DMD chip is used to modulate the light beam after being dimmed by the phase spatial light modulator; A projection lens, used to project the light beam modulated by the DMD chip into an image; It is characterized in that no convex lens is provided between the phase light modulator and the DMD chip, and the system further comprises: An optical path adjustment unit, configured to calculate an additional phase; the additional phase is the phase acting on the light field assuming that a convex lens is provided at the rear end of the phase light modulator; A phase calculation unit, configured to calculate a phase hologram of a target image at the phase light modulator; A diffraction control unit, configured to superimpose an additional phase on the solved phase hologram and load it onto the phase light modulator, so that a diffraction reconstructed image is formed on the DMD chip after the light beam is phase modulated; The DMD chip modulates the diffracted reproduced image and projects the modulated image into the target image through the projection lens; The phase calculation unit solves the phase hologram of the target image at the phase light modulator, specifically including: Downsampling the target image to 1 / n of the original resolution; Compute the phase hologram of the downsampled image; The phase hologram of the downsampled image is replicated n times in n areas on the phase light modulator; The n images are converged into one image by superimposing the blazed grating phase factors.

6. The laser projection display system according to claim 5, characterized in that: When the blazed grating phase factor is superimposed, the phase calculation unit includes: A blazed grating with a period of 2a is superimposed in both the horizontal and vertical directions; wherein a is the size of the micromirror of the phase light modulator; The blazed grating phase factors of na and -na are superimposed on the phase holograms in different regions.

7. The laser projection display system according to claim 5, characterized in that: The system also includes a first image preprocessing unit, which is used to compress the width of the target image to M / N before solving the phase hologram of the target image at the phase light modulator, and fill the grayscale values ​​of the idle pixels with 0; wherein M and N are the aspect ratio of the target image; or, set the N*N micromirrors of the phase light modulator to place the M:N target image in an N*N black background image.

8. The laser projection display system according to claim 5, characterized in that: The system further includes a second image pre-processing unit for scaling the target image before solving the phase hologram of the target image at the phase light modulator, wherein the R channel sub-image is scaled according to a1 ratio, and the G channel sub-image is scaled according to a2 ratio; a1= / ,a2= / , 、 and It is divided into blue laser wavelength, red laser wavelength and green laser wavelength.

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