A spatial dynamic false color display system and method based on a spatial light modulator

Abstract

The application discloses a kind of space dynamic false color display system and method based on spatial light modulator.Halogen cold light source and optical fiber light beam connection, optical fiber light beam light outlet, pinhole diaphragm, collimating lens and spatial light modulator display screen are sequentially arranged along incident light axis, spatial light modulator display screen, Fourier lens, black paper filter, Fourier lens and receiving screen are sequentially arranged along reflected light axis, and receiving screen is used for imaging, and light shield is arranged between optical fiber light beam light outlet and receiving screen;Method includes making filling pattern, using new spectrum point to open hole on black paper filter, obtaining spatial filter, using filling pattern to divide and fill gray scale image, and finally realizing dynamic false color display on receiving screen.With the aid of the characteristics of high resolution and fast response of spatial light modulator, digital coding sheet can be quickly switched without changing the optical path, and continuous and dynamic output of false color filling pattern is realized.

Description

Technical Field

[0001] This invention relates to a spatial false-color display system and method in the field of optical spatial filtering technology, and in particular to a spatial dynamic false-color display system and method based on a spatial light modulator. Background Technology

[0002] Theta-modulation false-color coding is a classic optical spatial filtering experiment and an application of the Abbe imaging principle. By illuminating a colorless, transparent coding sheet filled with gratings of different orientations with white light, and performing appropriate spatial filtering on its spectral plane, a color image can be output. Because spatial filtering artificially selects colors from an originally colorless image to create color, the resulting colors are not the true colors of the objects; therefore, theta-modulation coding is also called spatial false-color coding. False-color coding technology is a widely used information optics technique.

[0003] Traditional theta-modulated false-color coding technology mostly uses traditional silver halide dry plate coding sheets, which require processes such as setting up the shooting optical path, development, and fixing to produce one coding sheet per shooting session. Therefore, the coding sheet preparation is relatively complex and time-consuming, and the resulting effect is somewhat limited. In addition, in the traditional dry plate coding sheet production process, the gratings corresponding to different areas in different directions need to be captured in multiple shots. Multiple exposures can easily cause displacement, which in turn affects the final stitching effect of different color block images. Summary of the Invention

[0004] To address the problems existing in the background art, the present invention aims to provide a spatial dynamic false-color display system and method based on a spatial light modulator. The method of the present invention features a simple and quick process for fabricating the coded chip, while enabling the output of dynamic false-color codes with richer and more diverse effects.

[0005] The technical solution adopted in this invention is as follows:

[0006] I. A spatial dynamic false-color display system based on a spatial light modulator:

[0007] The system includes a halogen cold light source, an optical fiber beam, an incident light module, a spatial light modulator, an optical reflection module, a receiving screen, and a light shield. The output end of the halogen cold light source is connected to the input port of the optical fiber beam. The output port of the optical fiber beam, the incident light module, and the display screen of the spatial light modulator are arranged sequentially at intervals along the propagation direction of the incident beam. The incident beam is reflected by the spatial light modulator to form a reflected beam. The spatial light modulator, the optical reflection module, and the receiving screen are arranged sequentially at intervals along the propagation direction of the reflected beam. The receiving screen receives the reflected beam and forms an image. A light shield is provided between the output port of the optical fiber beam and the receiving screen.

[0008] The light incident module includes a pinhole aperture and a collimating lens arranged coaxially. The spatial light modulator mainly consists of a spatial light modulator display screen and a spatial light modulator driving device. The spatial light modulator display screen and the spatial light modulator driving device are electrically connected. The spatial light modulator driving device is externally connected to a computer. The light reflection module includes a first Fourier lens, a black paper filter, and a second Fourier lens arranged coaxially.

[0009] The optical fiber beam output port, pinhole aperture, collimating lens, and spatial light modulator display screen are arranged coaxially at intervals along the direction of the incident light optical axis. The incident light is incident on the spatial light modulator display screen at a certain angle. The spatial light modulator display screen, the first Fourier lens, the black paper filter, the second Fourier lens, and the receiving screen are arranged at intervals along the direction of the reflected light optical axis.

[0010] The composite white light generated by the halogen cold light source is led out by the fiber optic beam. The composite white light is transformed into a parallel beam after passing through a pinhole aperture and a collimating lens and then shines on the spatial light modulator display screen. The spatial light modulator display screen reflects the incident parallel beam to the light reflection module. The first Fourier lens, the black paper filter, and the second Fourier lens in the light reflection module filter the reflected beam. The filtered beam is then incident on the receiving screen and displays a false-color coded pattern.

[0011] The light-shielding plate is located between the incident light optical axis and the reflected light optical axis, and the light-shielding plate is used to separate the receiving screen and the light outlet of the optical fiber beam.

[0012] The receiving screen includes one of a white screen, a frosted glass screen, and a camera screen.

[0013] The spatial light modulator is a reflective spatial light modulator, and the modulation mode of the spatial light modulator is amplitude modulation.

[0014] The black paper filter is fixedly mounted on the filter bracket, and the light output port of the optical fiber beam is fixed on the optical bracket through the dry plate bracket. The pinhole aperture, collimating lens, spatial light modulator display screen, spatial light modulator driving device, first Fourier lens, filter bracket, second Fourier lens and receiving screen are all mounted on the external optical bracket.

[0015] II. A spatial dynamic false-color coding method based on a spatial light modulator, comprising the following steps:

[0016] Step S1: Using computer software, create n filling patterns F1, F2, ... F that match the pixel size of the spatial light modulator display screen. i ...F nWhere the subscript i represents the ordinal number of the fill pattern; in specific implementation, 5 fill patterns are created: fill pattern 1, 2, 3, 4, 5. In fill patterns 1, 2, and 3, the period of "black and white" change is two pixel units, and in fill patterns 4 and 5, the period of "black and white" change is three pixel units.

[0017] For fillable patterns 1 and 2, the formulas corresponding to the superimposed spectral surface after considering the "black grid effect" are as follows:

[0018]

[0019]

[0020] Among them, S i (ξ,η) represents the spectrum corresponding to the superimposed spectral surface of the i-th filling pattern after considering the "black grid effect", i represents the ordinal number of the filling pattern (i = 1, 2), A is the normalization constant, m,n,n',m' = 0, ±1, ±2, ..., Δx = Δy is the pixel side length of the spatial light modulator, the effective side length after considering the "black grid effect" is αΔx = βΔy, α, β are the corresponding effective fill factors, sinc is the Singer function, δ represents the Dirac delta function, and ξ and η represent the spatial frequencies in the x and y directions, respectively.

[0021] Compared to the 2D grating diffraction spectrum points without any image loaded, the locations of the newly added spectrum points are as follows:

[0022]

[0023]

[0024] For filling patterns 3, 4, and 5, the corresponding newly added spectral points can be determined according to the convolution theorem.

[0025] Step S2: According to Figure 1 The spatial dynamic false-color display system arranges the optical path; filling patterns 1, 2, 3, 4, and 5 are loaded one by one onto the spatial light modulator via a computer. Figure 4 The correspondence between the object plane and the spectral plane is shown. A window is opened at a suitable position on the black paper filter to create a filter that matches this device. Figure 5 The white dots in the diagram represent small windows, allowing light of different wavelengths to pass through new spectral points corresponding to different filling patterns. In other words, different colors correspond to different newly generated spectral points, and different newly generated spectral points correspond to different filling patterns.

[0026] Step S2 specifically involves:

[0027] Step S2.1: Using an external computer, sequentially load each fill pattern F onto the spatial light modulator display screen. i When the halogen cold light source is turned on, various filled patterns F appear on the black paper filter. i The corresponding spectral points are compared with the loaded fill pattern F. i The spectrum points displayed in the black paper filter are compared with the spectrum points displayed when no pattern is loaded, and the i-th filling pattern F will be loaded. i The additional spectral points compared to the unloaded pattern are used as the fill pattern F. i The corresponding newly added spectrum point P i ;

[0028] Step S2.2: Select n colors and match each fill pattern F1 with each color. Then, select the i-th fill pattern F1. i The corresponding color is denoted as color CO. i ;

[0029] Step S2.3: Load all the fill patterns sequentially on the spatial light modulator display screen. On the same black paper filter, load each fill pattern F one by one. i The corresponding newly added spectrum point P i The middle color is CO i A window is opened at the desired location, and the black paper filter with the window opened is used as the final spatial filter.

[0030] Step S3: Select the target grayscale animation to be dynamically false-color encoded. Using computer software, adjust each frame of the target grayscale animation to the same pixel size as the spatial light modulator. Divide each frame of the target grayscale animation into several areas to be filled based on grayscale. Use the fill pattern F... i Fill each area to be filled; in specific implementation, use the fillable pattern that matches the pixels of the spatial light modulator display screen, select the target pattern color corresponding to the fill pattern, and fill different areas using fill patterns 1, 2, 3, 4, 5 according to the correspondence between "color and fill pattern"; fill each frame of the target grayscale animation to create a set of digital coded chips.

[0031] In step S3, when filling each area to be filled using a fill pattern, the filling is based on the target color of the area to be filled: if the target color of a certain area to be filled in the grayscale image is CO... i Then fill the area with color CO. i Corresponding fill pattern F i ;

[0032] The target color of the area to be filled is specifically the actual color of the area to be filled in the target image displayed on the receiving screen.

[0033] Step S4: Using a computer, the digital coded chip group obtained in step S3 is dynamically played on the display screen of the spatial light modulator. At this time, a continuous false-color coded pattern can be obtained on the receiving screen; a camera can also be used to record the dynamic pattern.

[0034] Due to the application of the above-mentioned technologies and solutions, the advantages of the present invention compared with the prior art are as follows:

[0035] 1. Traditional theta modulation false color coding technology generally uses traditional silver halide dry plate coding film, which requires a process of setting up the shooting optical path, developing, fixing and other procedures to produce the coding film. Therefore, the preparation of the coding film is relatively complicated and time-consuming. This invention uses a spatial light modulator as the carrier of the coding film to digitize the coding film. It does not require darkroom operation, so the coding film has great advantages in terms of production efficiency, replication speed and production cost.

[0036] 2. In the traditional dry plate coding process, the gratings corresponding to different areas in different directions need to be photographed in multiple exposures. Multiple exposures are prone to displacement, which in turn affects the final stitching effect of different color block images. However, the present invention uses digital coding sheets, which do not need to be produced in multiple stages and can be completed in one go.

[0037] 3. In traditional theta modulation false color coding technology, the coding chip is fixed and single, and the output is generally a static false color coding pattern; while the present invention uses a spatial light modulator as the carrier of the coding chip. With the help of the high resolution and fast response characteristics of the spatial light modulator, the coding chip can be quickly replaced without changing the optical path, so as to realize the continuous and dynamic output of false color patterns of different coding chips.

[0038] 4. In traditional theta modulation false color encoding technology, the size of the encoding chip is very small; however, the encoding chip in this invention is a digital encoding chip, which can be displayed simultaneously on the spatial light modulator display screen and the computer screen. Through the computer, the details of the encoding chip can be better displayed.

[0039] Therefore, this invention expands the practical application of θ modulation technology, providing a pathway for achieving dynamic output in θ-modulated false-color encoding. Furthermore, this invention can also be used as a teaching project in modern physics experiments, enriching the content of experimental teaching.

[0040] Leveraging the high resolution and fast response characteristics of spatial light modulators, this invention, building upon traditional experiments, uses a spatial light modulator as the presentation carrier for the encoded chip. Based on the correspondence between the object plane and the spectral plane under the influence of the spatial light modulator's "black grating effect," a digital encoding scheme and spatial filter matching the spatial light modulator are proposed. The correspondence between the object plane and the spectral plane under the influence of the spatial light modulator's "black grating effect" is analyzed, and appropriate spatial filtering is employed to achieve color dynamic image output. Compared to traditional experimental methods, this method eliminates complex operations such as developing, fixing, exposure, and printing. Furthermore, digitizing the encoded chip eliminates darkroom operations, resulting in significant advantages in production efficiency, replication speed, and production cost. In addition, thanks to the high resolution and fast response characteristics of the spatial light modulator, the digital encoded chip can be quickly switched without changing the optical path, achieving continuous and dynamic output of false-color filled patterns.

[0041] The beneficial effects of this invention are as follows:

[0042] 1. This invention proposes a spatial dynamic false-color display system and method based on a spatial light modulator. Using the spatial light modulator as the presentation carrier for the encoding chip, a matching encoding scheme for the spatial light modulator is proposed. The correspondence between the object plane and the spectral plane under the influence of the "black grating effect" of the spatial light modulator is analyzed. Appropriate spatial filtering is then employed to achieve the output of a color dynamic image.

[0043] 2. This invention improves upon traditional theta modulation false-color encoding technology by digitizing the production process and presentation format of the encoded image, eliminating the reliance on a darkroom in the preparation process. Furthermore, it enables dynamic image output, enriching the presentation effects and increasing engagement. This invention not only has practical application value for color encoding images using theta modulation but also enriches the teaching content of physical optics experiments related to spatial filtering. Attached Figure Description

[0044] Figure 1 A schematic diagram of the components of a spatial dynamic false-color display system based on a spatial light modulator;

[0045] Figure 2 A fillable pattern for matching the pixel size of a spatial light modulator, wherein (a) is a schematic diagram of fill pattern 1, (b) is a schematic diagram of fill pattern 2, (c) is a schematic diagram of fill pattern 3, (d) is a schematic diagram of fill pattern 4, and (e) is a schematic diagram of fill pattern 5.

[0046] Figure 3The spectrum diagrams corresponding to the filling patterns 1, 2, 3, 4 and 5 are shown, where (a) is the spectrum diagram corresponding to the filling pattern 1, (b) is the spectrum diagram corresponding to the filling pattern 2, (c) is the spectrum diagram corresponding to the filling pattern 3, (d) is the spectrum diagram corresponding to the filling pattern 4 and (e) is the spectrum diagram corresponding to the filling pattern 5.

[0047] Figure 4 A schematic diagram of the newly added spectral points corresponding to patterns 1, 2, 3, 4, and 5;

[0048] Figure 5 A flowchart of the steps involved in filter fabrication;

[0049] Figure 6 The images are frames of a digitally encoded chip animation, wherein (a) is the first frame of the digitally encoded chip animation in a specific embodiment, (b) is the third frame of the digitally encoded chip animation in a specific embodiment, (c) is the fifth frame of the digitally encoded chip animation in a specific embodiment, and (d) is the eleventh frame of the digitally encoded chip animation in a specific embodiment.

[0050] Figure 7 To correspond to the appendix Figure 6 The output images corresponding to the four frames of digitally encoded chips, where (a) is the output image corresponding to the first frame of the digitally encoded chip animation, (b) is the output image corresponding to the third frame of the digitally encoded chip animation, (c) is the output image corresponding to the fifth frame of the digitally encoded chip animation, and (d) is the output image corresponding to the eleventh frame of the digitally encoded chip animation.

[0051] In the diagram: 1. Halogen cold light source; 2. Fiber optic beam transmission; 3. Dry plate support; 4. Pinhole aperture; 5. Collimating lens; 6. Spatial light modulator display screen; 7. Spatial light modulator driving device; 8. First Fourier lens; 9. Filter support; 10. Black paper filter; 11. Second Fourier lens; 12. Receiving screen; 13. Light shield. Detailed Implementation

[0052] The present invention will be described in detail below with reference to specific implementation examples. These examples will help those skilled in the art to further understand the present invention, but do not limit the present invention in any way.

[0053] like Figure 1As shown, the system includes a halogen cold light source 1, an optical fiber beam 2, an incident light module, a spatial light modulator, an optical reflection module, a receiving screen 12, and a light shield 13. The output end of the halogen cold light source 1 is connected to the light inlet of the optical fiber beam 2. The output end of the optical fiber beam 2, the incident light module, and the display screen of the spatial light modulator (i.e., the spatial light modulator display screen 6) are arranged at intervals along the propagation direction of the incident beam. The incident beam is reflected by the spatial light modulator to form a reflected beam. The spatial light modulator display screen 6, the optical reflection module, and the receiving screen 12 are arranged at intervals along the propagation direction of the reflected beam. The receiving screen 12 receives the reflected beam and forms an image. A light shield 13 is provided between the output end of the optical fiber beam 2 and the receiving screen 12.

[0054] Imaging specifically involves forming dynamic false-color coded patterns.

[0055] The light incident module includes a pinhole aperture 4 and a collimating lens 5 arranged coaxially. The spatial light modulator mainly consists of a spatial light modulator display screen 6 and a spatial light modulator driving device 7. The spatial light modulator display screen 6 and the spatial light modulator driving device 7 are electrically connected. The spatial light modulator driving device 7 is externally connected to a computer. The light reflection module includes a first Fourier lens 8, a black paper filter 10, and a second Fourier lens 11 arranged coaxially.

[0056] The light outlet of the fiber optic beam 2, the pinhole aperture 4, the collimating lens 5, and the spatial light modulator display screen 6 are arranged coaxially at intervals along the direction of the incident light optical axis. The incident light is incident on the spatial light modulator display screen 6 at a certain small angle. In specific implementation, the certain incident angle is less than 10°. The spatial light modulator display screen 6, the first Fourier lens 8, the black paper filter 10, the second Fourier lens 11, and the receiving screen 12 are arranged coaxially at intervals along the direction of the reflected light optical axis.

[0057] The composite white light generated by the halogen cold light source 1 is led out through the fiber optic beam 2. The composite white light is transformed into a parallel beam after passing through the pinhole aperture 4 and the collimating lens 5 and then shines on the spatial light modulator display screen 6. The spatial light modulator display screen 6 reflects the incident parallel beam to the light reflection module. The first Fourier lens 8, the black paper filter 10, and the second Fourier lens 11 in the light reflection module filter the reflected beam. The filtered beam is incident on the receiving screen 12 and displays a false-color coded pattern on the receiving screen 12.

[0058] Halogen cold light source 1 and fiber optic beam 2 are used to generate a composite white light beam; pinhole aperture 4 is used to generate an approximate point light source; collimating lens 5 is used to adjust the diverging light emitted from pinhole aperture 4 into parallel light; Fourier lens 8, black paper filter 10, and Fourier lens 11 are used for spatial filtering; receiving screen 12 is used to display a false-color encoded image; spatial light modulator display screen 6, Fourier lens 8, black paper filter 10, Fourier lens 11, and receiving screen 12 constitute a 4f optical path to achieve spatial filtering.

[0059] The light shield 13 is located between the incident light optical axis and the reflected light optical axis. The light shield 13 is used to separate the receiving screen 12 from the light outlet of the fiber optic beam 2, so as to avoid the light from the light outlet of the fiber optic beam 2 from affecting the received image.

[0060] The receiving screen 12 includes one of a white screen, a frosted glass screen, and a camera screen, so that the false-color coded pattern can be observed directly on the receiving screen 12. For example, a white screen or a frosted glass screen can be used, or a camera can be used to record the dynamic false-color coded pattern.

[0061] The spatial light modulator is a reflective spatial light modulator, and the modulation mode of the spatial light modulator is amplitude modulation.

[0062] The spatial light modulator driver 7 is connected to a power supply, which powers the spatial light modulator. The spatial light modulator driver 7 is connected to a computer, and the spatial light modulator display screen 6 and the computer display screen are set to multi-screen replication mode.

[0063] The black paper filter 10 is fixedly installed on the filter bracket 9. After performing a reasonable window opening operation on the black paper filter 10, it is used as a spatial filter. The light outlet of the fiber optic beam 2 is fixed on the optical bracket through the dry plate bracket 3. The pinhole aperture 4, collimating lens 5, spatial light modulator display screen 6, spatial light modulator driving device 7, first Fourier lens 8, filter bracket 9, second Fourier lens 11, and receiving screen 12 are all installed on the external optical bracket, which is placed on the experimental platform.

[0064] The encoded chips used are digital encoded chips.

[0065] The method of the present invention includes the following steps:

[0066] Step S1: Create the fill pattern

[0067] First, use computer software to create n different fill patterns F1, F2, ... F i ...F n ,like Figure 2 As shown, the subscript i represents the ordinal number of the fill pattern.

[0068] The filling pattern corresponds to the orientation grating in traditional false color coding, and the pixels of each filling pattern are consistent with the pixels of the spatial light modulator display screen 6.

[0069] Step S2: Fabrication of spatial filter

[0070] Spatial filters are fabricated using filling patterns;

[0071] Step S3: Prepare digital coded chip

[0072] Step S3.1: Select the target grayscale animation to be dynamically false-color encoded, and divide each frame of the grayscale image in the target grayscale animation into several regions to be filled according to the grayscale.

[0073] Step S3.2: Use fill pattern F i Fill each area to be filled. After all areas in the grayscale image have been filled, a digital coded piece is obtained. Repeat the above steps, applying the fill pattern F to each frame of the grayscale image. i Fill in the blanks to obtain a set of digital coded chips;

[0074] Step S4: Dynamic False Color Display

[0075] The digital coded chip group is dynamically played on the spatial light modulator display screen 6, and the receiving screen 12 dynamically displays the target image filled with color. The target image is specifically a grayscale image filled with color.

[0076] Step S2 is as follows:

[0077] Step S2.1: Using an external computer, sequentially load each fill pattern F onto the spatial light modulator display screen 6. i When the halogen cold light source 1 is turned on, the various filling patterns F are displayed on the black paper filter 10. i The corresponding spectral points are compared with the loaded fill pattern F. i The spectrum points displayed in the black paper filter 10, in a specific embodiment, are as follows: Figure 3 (a)- Figure 3 As shown in (e), compared to the spectrum points displayed when no pattern is loaded, the i-th filling pattern F will be loaded. i The additional spectral points compared to the unloaded pattern are used as the fill pattern F. i The corresponding newly added spectrum point P i ,like Figure 4As shown, in the specific implementation, a large circle represents a newly added spectrum point P1 and its corresponding fill pattern F1; a triangle represents a newly added spectrum point P2 and its corresponding fill pattern F2; a rhombus represents a newly added spectrum point P3 and its corresponding fill pattern F3; a small circle represents a newly added spectrum point P4 and its corresponding fill pattern F4; and a square represents a newly added spectrum point P5 and its corresponding fill pattern F5. The newly added spectrum point P corresponding to each fill pattern is... i There is no overlap between them;

[0078] Step S2.2: Select n colors and match each fill pattern F1 with each color. Then, select the i-th fill pattern F1. i The corresponding color is denoted as color CO. i ;

[0079] Step S2.3: Load each fill pattern F onto the spatial light modulator display screen 6 respectively. i On the same black paper filter 10, successively in each filling pattern F i The corresponding newly added spectrum point P i The middle color is CO i The location of the window is selectively opened, and the black paper filter 10 with the window opened is finally used as the final spatial filter, such as... Figure 5 As shown.

[0080] In step S3.2, when filling each area to be filled using a fill pattern, the filling is performed according to the target color of the area to be filled: if the target color of a certain area to be filled in the grayscale image is CO... i Then fill the area with color CO. i Corresponding fill pattern F i ;

[0081] The target color of the area to be filled is specifically the actual color of the area to be filled in the target image displayed on the receiving screen 12.

[0082] The working principle of the system of this invention is as follows:

[0083] Traditional theta-modulated false-color coding chips consist of one-dimensional gratings with different orientations. Under white light illumination, the spectral plane is formed by the superposition of diffraction from gratings in different directions, and non-zero-order spectral points of different wavelengths will undergo frequency shift. Based on this, by controlling the colors that can pass through the spectral points corresponding to gratings in different directions on the spectral plane, after the spectrum is restored by inverse Fourier transform through a lens, the regions corresponding to different gratings are assigned corresponding colors.

[0084] Compared to traditional theta-modulated false-color coding experiments, this scheme uses a digital coding chip; it utilizes the "black grating effect" of the spatial light modulator and the correspondence between the object plane and the spectral plane under the influence of the 6-pixelation of the spatial light modulator display to simulate a one-dimensional grating; however, unlike traditional dry plate coding chips, due to the limitation of the 6-pixel size of the spatial light modulator display, the orientation gratings that can be realized on the optical dry plate, except for the transverse grating and the longitudinal grating, are difficult to strictly realize on the spatial light modulator display 6.

[0085] Therefore, this invention proposes fillable patterns 1, 2, 3, 4, and 5 for spatial light modulator display screen 6, which match the pixel size of the spatial light modulator and are unaffected by the "black grid effect," and are suitable for subsequent spatial filtering. The pixels of the patterns are consistent with the pixels of the spatial light modulator display screen 6, such as... Figure 2 (a)- Figure 2 As shown in (e). To clarify the details, Figure 2 A 24×24 pixel interval is given. In fillable patterns 1, 2, and 3, the period of "black and white" variation is two pixel units. In fillable patterns 4 and 5, the period of "black and white" variation is three pixel units. Fillable patterns 1 and 2 are similar to those in conventional experiments, consisting of a horizontal grating and a vertical grating, respectively, with a grating constant of 2μx, where μx = μy is the pixel side length of the spatial light modulator.

[0086] After loading fillable patterns 1, 2, 3, 4 and 5 respectively, new spectral points will appear at different positions on the spectral plane compared with the 2D grating diffraction spectral points when no image is loaded.

[0087] Let F(ξ, η) represent the spectrum of the image f(x, y) itself, and T(ξ, η) represent the spectrum of the "black grate effect". According to the convolution theorem, the spectrum of the superimposed spectrum is:

[0088] s(ξ, η)=F(ξ, η)*T(ξ, η)

[0089] Therefore, the effect of the "black grating effect" is that the spectrum after superimposing the black grating is the convolution of the spectrum corresponding to the spatial light modulator black grating and the spectrum of the image itself.

[0090] For fillable patterns 1 and 2, the formula corresponding to the superimposed spectral surface after considering the "black grid effect" is:

[0091]

[0092]

[0093] Among them, s i(ξ, η) represents the spectrum corresponding to the superimposed spectral surface of the i-th fillable pattern after considering the "black grid effect", i represents the ordinal number of the fillable pattern (i = 1, 2), A is the normalization constant, m, n = 0, ±1, ±2, ..., Δx = Δy is the pixel side length of the spatial light modulator, the effective side length after considering the "black grid effect" is αΔx = βμy, α, β are the corresponding effective fill factors, sinc is the Singer function, δ is the δ function, and ξ and η represent the spatial frequencies in the x and y directions, respectively.

[0094] Compared to the 2D grating diffraction spectrum points without any image loaded, the locations of the newly added spectrum points are as follows:

[0095]

[0096]

[0097] The newly added spectral points corresponding to patterns 3, 4, and 5 can be determined according to the convolution theorem.

[0098] After loading fillable patterns 1, 2, 3, 4, and 5 respectively, compared with the two-dimensional grating diffraction spectrum points without any images loaded, new spectrum points appear at different positions on the spectrum plane, such as... Figure 4 As shown, there is no overlap between the newly added spectral points corresponding to different filling patterns. Figure 4 In the diagram, large circles represent newly added spectrum points corresponding to fill pattern 1, triangles represent newly added spectrum points corresponding to fill pattern 2, rhombuses represent newly added spectrum points corresponding to fill pattern 3, small circles represent newly added spectrum points corresponding to fill pattern 4, and squares represent newly added spectrum points corresponding to fill pattern 5.

[0099] Under white light illumination, except for the zero-order spectral point, each spectral point undergoes dispersion from the inside out. By selectively allowing light of different wavelengths to pass through the newly added spectral points corresponding to different fillable patterns, and corresponding openings are made in the black paper filter 10, a spatial filter matching the current experimental setup can be fabricated, obtaining the correspondence between "color" and "fillable pattern". For example: dark blue—fillable pattern 1, light blue—fillable pattern 2, yellow—fillable pattern 3, green—fillable pattern 4, red—fillable pattern 5, and so on. Figure 5 As shown.

[0100] By loading digital encoding chips matching its pixels onto the spatial light modulator display screen 6, and keeping the instrument and spectral plane fixed, the digital encoding chips on the spatial light modulator display screen 6 can be quickly switched by computer control, thereby achieving the output of dynamic false-color encoded images.

[0101] Therefore, based on the spatial light modulator, by reasonably selecting the coded chip to fill the pattern, and utilizing the additional spectral points compared to when no image is loaded, spatial dynamic false color coding can be performed very well.

[0102] The embodiments and implementation process of the present invention are as follows:

[0103] Example: Using this system, a grayscale animation containing 60 frames is encoded in false color to achieve false color encoded animation output.

[0104] Implementation process: includes three steps: filter preparation, digital encoder chip fabrication, and optical path implementation.

[0105] (1) Step 1: Filter preparation

[0106] (1.1) Using computer software, create five fillable patterns to match the 6-pixel size of the spatial light modulator display screen: fill patterns 1, 2, 3, 4, and 5, as shown below. Figure 2 As shown in (a)-2(e). In a specific embodiment, the spatial light modulator display screen has a pixel resolution of 1920×1080, and the pixels of the fabricated fillable patterns 1, 2, 3, 4, and 5 are also 1920×1080. In fillable patterns 1, 2, and 3, the stripe variation period is two pixel units; in fillable patterns 4 and 5, the stripe variation period is three pixel units.

[0107] (1.2) According to Figure 1 The spatial dynamic false color display system arranges the optical path and loads the filling patterns 1, 2, 3, 4, and 5 one by one onto the spatial light modulator via a computer.

[0108] (1.3) According to the correspondence between the object plane and the spectral plane, such as Figure 4 As shown, windows are successively opened at appropriate positions on the same black paper filter 10 to create a filter that matches this device, as follows. Figure 5 As shown, Figure 5 The white dots in the diagram represent small windows, allowing light of different wavelengths to pass through new spectral points corresponding to different fill patterns. In other words, different colors correspond to different newly generated spectral points, and different newly generated spectral points correspond to different fill patterns. In a specific embodiment: dark blue—fill pattern 1, light blue—fill pattern 2, yellow—fill pattern 3, green—fill pattern 4, and red—fill pattern 5.

[0109] (2) Second step: Digital encoding chip production

[0110] Using computer software, the pixels and pattern fill of each frame in the target grayscale animation are adjusted. During filling, according to the desired color and the correspondence between "color and fill pattern", fill patterns 1, 2, 3, 4, and 5 are used to fill different areas.

[0111] In a specific embodiment, the target animation is the Zhejiang University emblem, which radiates outwards to four regions. The eagle in the emblem rotates clockwise, while the four radiating regions rotate counterclockwise. Each frame rotates 6 degrees compared to the previous frame, for a total of 60 frames. Figure 6 (a)- Figure 6 (d) The digital coded slices corresponding to frames 1, 3, 5, and 11 are given respectively, such as frame 1 ( Figure 6 The correspondence of (a) is as follows: upper left area - fill pattern 5 - red, lower left area - fill pattern 1 - dark blue, upper right area - fill pattern 3 - yellow, lower right area - fill pattern 4 - green, and Qiushi Eagle - fill pattern 2 - light blue.

[0112] (3) Third step: optical path implementation

[0113] Using a computer, a digitally encoded chip set is dynamically played on the spatial light modulator display screen 6, and a continuous false-color encoded pattern can be obtained on the receiving screen 12, such as... Figure 7 (a)- Figure 7 As shown in (d), a camera can be used to record dynamic patterns.

[0114] In summary, the spatial dynamic false-color encoding display system and method based on a spatial light modulator proposed in this invention can effectively conduct spatial dynamic false-color encoding experiments by rationally selecting the fillable pattern of the digital encoding chip and utilizing the additional spectral points added during loading. This invention can simply and quickly complete the preparation of the encoding chip, and the output effect is richer.

[0115] This invention improves upon traditional theta-modulation false-color encoding technology by digitizing the production process and presentation of the encoded image. The production process no longer relies on darkroom operations, and dynamic image output is possible, enriching the presentation effects and increasing engagement. It offers significant advantages in terms of encoding efficiency, replication speed, and production cost. Leveraging the high resolution and fast response characteristics of spatial light modulators, dynamic image output can be achieved without altering the optical path, further enhancing the image presentation. It expands the practical applications of theta modulation technology, providing a pathway for dynamic output in theta-modulation false-color encoding. Furthermore, this invention can also be used as a teaching project in modern physics experiments, enriching the content of experimental teaching.

Claims

1. A spatial dynamic false-color encoding method for a spatial dynamic false-color display system based on a spatial light modulator, characterized in that, The spatial dynamic false-color display system based on a spatial light modulator includes a halogen cold light source (1), an optical fiber beam (2), a light incident module, a spatial light modulator, a light reflection module, a receiving screen (12), and a light shield (13). The output end of the halogen cold light source (1) is connected to the light inlet of the optical fiber beam (2). The light outlet of the optical fiber beam (2), the light incident module, and the display screen of the spatial light modulator are arranged at intervals along the propagation direction of the incident beam. The incident beam is reflected by the spatial light modulator to form a reflected beam. The spatial light modulator, the light reflection module, and the receiving screen (12) are arranged at intervals along the propagation direction of the reflected beam. The receiving screen (12) receives the reflected beam and forms an image. A light shield (13) is arranged between the light outlet of the optical fiber beam (2) and the receiving screen (12). The spatial dynamic false-color encoding method includes the following steps: Step S1: Create the fill pattern First, create n fill patterns F1, F2, ... F i ... F n , where subscript i Indicates the ordinal number of the fill pattern; Step S2: Fabrication of spatial filter Spatial filters are fabricated using filling patterns; Step S3: Prepare digital coded chip Step S3.1: Select the target grayscale animation to be dynamically false-color encoded, and divide each frame of the grayscale image in the target grayscale animation into several regions to be filled according to the grayscale. Step S3.2: Use fill pattern F i Fill each area to be filled. After all areas in the grayscale image have been filled, a digital coded piece is obtained. Repeat the above steps, applying the fill pattern F to each frame of the grayscale image. i Fill in the blanks to obtain a set of digital coded chips; Step S4: Dynamic False Color Display The digital coded chip set is dynamically played on the spatial light modulator display screen (6), and the target image filled with color is dynamically displayed on the receiving screen (12).

2. The spatial dynamic false-color encoding method for a spatial dynamic false-color display system based on a spatial light modulator according to claim 1, characterized in that: The light incident module includes a small aperture stop (4) and a collimating lens (5) arranged coaxially. The spatial light modulator consists of a spatial light modulator display screen (6) and a spatial light modulator driving device (7). The spatial light modulator display screen (6) and the spatial light modulator driving device (7) are electrically connected. The spatial light modulator driving device (7) is connected to an external computer. The light reflection module includes a first Fourier lens (8), a black paper filter (10), and a second Fourier lens (11) arranged coaxially. The light outlet of the fiber optic beam (2), the pinhole aperture (4), the collimating lens (5), and the spatial light modulator display screen (6) are arranged sequentially at intervals along the direction of the incident light optical axis. The incident light is incident on the spatial light modulator display screen (6) at a certain angle. The spatial light modulator display screen (6), the first Fourier lens (8), the black paper filter (10), the second Fourier lens (11), and the receiving screen (12) are arranged sequentially at intervals along the direction of the reflected light optical axis.

3. The spatial dynamic false-color encoding method for a spatial dynamic false-color display system based on a spatial light modulator according to claim 2, characterized in that: The composite white light generated by the halogen cold light source (1) is exported by the fiber optic beam (2). After the composite white light passes through the pinhole aperture (4) and collimating lens (5) and becomes a parallel beam, it illuminates the spatial light modulator display screen (6). The spatial light modulator display screen (6) reflects the incident parallel beam to the light reflection module. The first Fourier lens (8), the black paper filter (10), and the second Fourier lens (11) in the light reflection module filter the reflected beam. The filtered beam is then incident on the receiving screen (12) and displays a false color coded pattern on the receiving screen (12).

4. The spatial dynamic false-color encoding method for a spatial dynamic false-color display system based on a spatial light modulator according to claim 1, characterized in that: The light shield (13) is located between the incident light optical axis and the reflected light optical axis, and the light shield (13) is used to separate the receiving screen (12) and the light outlet of the fiber optic beam (2).

5. The spatial dynamic false-color encoding method for a spatial dynamic false-color display system based on a spatial light modulator according to claim 1, characterized in that: The receiving screen (12) includes one of a white screen, a frosted glass screen, and a camera screen.

6. The spatial dynamic false-color encoding method for a spatial dynamic false-color display system based on a spatial light modulator according to claim 1, characterized in that: The spatial light modulator is a reflective spatial light modulator, and the modulation mode of the spatial light modulator is amplitude modulation.

7. The spatial dynamic false-color encoding method for a spatial dynamic false-color display system based on a spatial light modulator according to claim 2, characterized in that: The black paper filter (10) is fixedly installed on the filter bracket (9). The light outlet of the fiber optic beam (2) is fixed on the optical bracket through the dry plate bracket (3). The pinhole aperture (4), collimating lens (5), spatial light modulator display screen (6), spatial light modulator driving device (7), first Fourier lens (8), filter bracket (9), second Fourier lens (11) and receiving screen (12) are all installed on the external optical bracket.

8. The spatial dynamic false-color encoding method for a spatial dynamic false-color display system based on a spatial light modulator according to claim 1, characterized in that: Step S2 specifically includes the following steps: Step S2.1: Using an external computer, load each filling pattern Fi sequentially on the spatial light modulator display screen (6), turn on the halogen cold light source (1), and display the spectrum points corresponding to each filling pattern Fi on the black paper filter (10). Compare the spectrum points displayed in the black paper filter (10) when loading the filling pattern Fi with the spectrum points displayed when no pattern is loaded. Take the extra spectrum points when loading the i-th filling pattern Fi compared to when no pattern is loaded as the new spectrum point Pi corresponding to the filling pattern Fi. Step S2.2: Select n colors and match each fill pattern Fi with each color. Record the color corresponding to the i-th fill pattern Fi as color COi. Step S2.3: Load all the fill patterns sequentially on the spatial light modulator display screen (6). On the same black paper filter (10), open windows at the positions of the newly added spectral points Pi corresponding to each fill pattern Fi, where the color is COi. Finally, use the black paper filter (10) with the windows opened as the final spatial filter.

9. The spatial dynamic false-color encoding method for a spatial dynamic false-color display system based on a spatial light modulator according to claim 1, characterized in that: In step S3.2, when filling each area to be filled using a fill pattern, the filling is performed according to the target color of the area to be filled: if the target color of a certain area to be filled in the grayscale image is CO... i Then fill the area with color CO. i Corresponding fill pattern F i ; The target color of the area to be filled is specifically the actual color of the area to be filled in the target image displayed on the receiving screen (12).

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