An endo projection imaging apparatus and an endo projection imaging method

Abstract

This application discloses an internal projection imaging device and method. The internal projection imaging device includes a light source, a first lens group, a display device, and an imaging screen. The first lens group is disposed between the light source and the display device, and is used to adjust the light beam emitted by the light source to illuminate the display device. The imaging screen is used to receive the light beam projected by the display device and display a magnified image. The inner surface of the imaging screen facing the display device has a predetermined rough structure. This application projects display content onto the imaging screen and uses the rough inner surface for diffuse reflection imaging, resulting in no graininess, high resolution, and a small size.

Description

Technical Field

[0001] This application relates to the field of projection imaging technology, and in particular to an internal projection imaging device and an internal projection imaging method. Background Technology

[0002] Modern products use a large number of array-style RGB-LED beads, ranging from hundreds to thousands of RGB beads, presented in a matrix-style planar manner. Curved surfaces require several or dozens of pre-set fixed curved surfaces to be spliced ​​together, resulting in large pixelation of the lighting effect, low image resolution, strong pixelation, unsuitability for close-up viewing, and glare that does not protect the eyes. Fixed lighting modes or small animations of dot matrix LEDs are preset before leaving the factory. Summary of the Invention

[0003] This application proposes an internal projection imaging device and an internal projection imaging method to solve at least one technical problem in the prior art.

[0004] The first aspect disclosed in this application provides an internal projection imaging device, which includes a light source, a first lens group, a display device, and an imaging screen; the first lens group is disposed between the light source and the display device and is used to adjust the light beam emitted by the light source to illuminate the display device; the imaging screen is used to receive the light beam projected by the display device and display an image; The imaging screen has a pre-defined rough structure on its inner surface facing the display device.

[0005] In some implementations, the first lens group can control the illumination beam emitted by the light source toward the display device within the effective display range of the display device.

[0006] In some embodiments, a second lens group is provided between the display device and the imaging screen.

[0007] In some implementations, the light source adjusts the color temperature and brightness of the light in conjunction with the display content of the display device.

[0008] In some embodiments, the roughness of the inner surface is Ra0.4 to 0.7.

[0009] In some implementations, the imaging screen has a high-transmittance, high-brightness body.

[0010] In some implementations, the outer surface of the imaging screen facing away from the display device is a smooth surface.

[0011] In some implementations, the inner surface may be divided into multiple regions, each region having a different roughness; or the roughness of the inner surface may gradually change from the direction closer to the display device to the direction farther away from the display device. The roughness of the inner surface closer to the display device is less than that farther away from the display device.

[0012] In some implementations, the roughness of the inner surface varies from Ra0.4 to 1.2.

[0013] The second aspect of this application discloses an internal projection imaging method, which is applied to an internal projection imaging device, the internal projection imaging device comprising a light source, a first lens group, a display device, and an imaging screen arranged sequentially. The method includes: Configure the optical structure of the first lens group and adjust the relative positions between the first lens group, the light source, and the display device to control the illumination beam emitted by the light source toward the display device within the effective display range of the display device; The display device performs pixel modulation on the illumination beam to load display content and form a transmitted beam carrying the display content; The transmitted light beam is projected onto the inner surface of the imaging screen, and diffuse reflection imaging is performed through the rough structure provided on the inner surface, so that the outer surface of the imaging screen can reflect the display content.

[0014] In some embodiments, the internal projection imaging device further includes a second lens group disposed between the display device and the imaging screen; The internal projection imaging method further includes: configuring the optical structure of the second lens group and adjusting the relative position between the second lens group and the display device and the imaging screen, so as to control the transmitted light beam to be accurately projected onto a preset position on the inner surface.

[0015] In some implementations, the display content of the display device is pre-distorted to compensate for distortions that occur when the display content is projected onto the imaging screen.

[0016] In some implementations, the pre-distortion processing includes at least one of magnification pre-processing, reduction pre-processing, and water ripple pre-processing; The amplification preprocessing includes: Obtain the output points of the original image To the distortion center distance ; and in At that time, perform distortion mapping: ; in, R represents the pixel coordinates of the pre-distorted output image; R is the distortion radius. This is the magnification factor, and ;when At that time, take directly , ; The shrinkage preprocessing includes: Obtain the output points of the original image To the distortion center distance ; and in At that time, perform distortion mapping: ; in, R represents the pixel coordinates of the pre-distorted output image; R is the distortion radius. This is a reduction factor, and ;when At that time, take directly , ; The water ripple preprocessing includes: ; in, For ripple amplitude, The wavelength is the ripple wavelength.

[0017] In some implementations, the display content of the display device is pre-compensated to reduce bright spots on the imaging screen. The pre-compensation method includes: Obtain the preprocessed area corresponding to the bright spot in the displayed content, and determine the coordinates (cx, cy) of the center point o of the preprocessed area. Calculate the Euclidean distance d between all preprocessed pixels within the preprocessed region and the center point o: Where (x, y) are the coordinates of the preprocessed pixel p; The distance d is normalized as follows: t = d / R, where R is the straight-line distance from the center point o through the preprocessed pixel point p to the boundary of the preprocessed region. Calculate the attenuation amount dim corresponding to the preprocessed pixel p: dim = K×[cos(t×π) + 1] / 2, where K is the attenuation coefficient, and 0 <K<1; The compensation value p′ of the preprocessed pixel p is calculated using the attenuation amount dim: p′=p×(1-dim).

[0018] Compared to existing LED dot-matrix display solutions, this application projects display content onto an imaging screen and utilizes a rough inner surface for diffuse reflection imaging, eliminating graininess and offering higher resolution at a smaller size. The imaging screen can be manufactured in various shapes as needed, and distortion algorithms are used to reproduce the displayed content as accurately as possible. The rough structure of the inner surface of the imaging screen is adjusted through gradients or partitions to reduce local bright spots and improve image quality. Attached Figure Description

[0019] The disclosure of this application is illustrated with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of this application. In the drawings, the same reference numerals are used to refer to the same parts: Figure 1 This is a schematic diagram of the internal projection imaging device with a spherical imaging screen according to an embodiment of this application; Figure 2 for Figure 1 AA-direction cross section; Figure 3 This is a schematic diagram of the structure and light projection direction of the internal projection imaging device for the elliptical forming screen of this application; Figure 4 This is a schematic diagram of the structure and optical path projection of the internal projection imaging device of the prism-type lens group of this application; Figure 5 This is a schematic diagram of the structure and optical path projection of the internal projection imaging device with a light guide plate according to this application; Figure 6 This is a schematic diagram of the structure and optical path projection of the internal projection imaging device with a point light source and a convex lens according to this application. Figure 7 This is an actual imaging effect diagram of Embodiment 1 of this application; Figure 8 This is an actual imaging effect diagram of Embodiment 2 of this application; Figure 9 This is an actual imaging effect diagram of Embodiment 3 of this application.

[0020] Figure 10 This is a schematic diagram of the internal projection imaging device with a planar imaging screen according to an embodiment of this application; Figure 11 for Figure 10 Another perspective illustration; Figure 12 for Figure 10 BB-direction cross-section; Figure 13 This is a schematic diagram of the light projection direction of an internal projection imaging device with a planar imaging screen according to an embodiment of this application; Figure 14This is a schematic diagram of an LCD display screen in an embodiment of this application.

[0021] Legend: 1. LED light; 2. LCD display screen; 31. First lens group; 32. Second lens group; 33. Prism; 34. Light guide plate; 4. Imaging screen; 401. Inner surface; 4011. Edge; 4012. Center; 402. Outer surface; 5. Positioning seat; 1a. Light source; 2a. Display device; 31a. First lens group; 32a. Second lens group; 4a. Imaging screen; 401a. Inner surface; 402a. Outer surface. Detailed Implementation

[0022] The present application will now be described in detail with reference to the accompanying drawings and embodiments. Various examples are provided by way of explanation and not by way of limitation. In fact, those skilled in the art will recognize that modifications and variations can be made to the present application without departing from the scope or spirit thereof. For example, a feature shown or described as part of one embodiment may be used in another embodiment to produce yet another embodiment. Therefore, it is desirable that the present application encompass such modifications and variations that fall within the scope of the appended claims and their equivalents.

[0023] In the description of this application, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and do not require that this application be constructed and operated in a specific orientation, and therefore should not be construed as limiting this application. The terms "connected," "linked," and "set up" used in this application should be interpreted broadly. For example, they can refer to fixed connections or detachable connections; direct connections or indirect connections through intermediate components; wired connections, radio connections, or wireless communication signal connections. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0024] The accompanying drawings illustrate one or more examples of this application. The detailed description uses numerical and alphabetic designations to refer to features in the drawings. Similar or analogous designations in the drawings and description have been used to refer to similar or analogous parts of this application. As used herein, the terms “first,” “second,” and “third,” etc., are used interchangeably to distinguish one component from another and are not intended to indicate the location or importance of individual components.

[0025] According to the embodiments of this application, in combination Figures 1 to 9An internal projection imaging device is presented, comprising a light source, a display device, a first lens group 31, and an imaging screen 4. In this embodiment, the light source is an LED lamp 1, the display device is a high-transmittance LCD display screen 2, and the first lens group 31 is disposed between the LED lamp 1 and the LCD display screen 2, concentrating the light from the LED lamp as much as possible within the displayable range of the LCD display screen 2. The imaging screen 4 is disposed above the LCD display screen 2, and the imaging screen 4 is translucent but not completely transparent. The light beam emitted by the LED lamp 1 is adjusted by the first lens group 31 to form a controllable light beam and illuminate the LCD display screen 2, so as to project the image or light effect of the LCD display screen 2 onto the imaging screen 4. The imaging screen 4 has an inner surface 401 facing the LCD display screen 2 and an outer surface 402 facing the opposite direction. The inner surface 401 is frosted, which facilitates the diffuse reflection of the image or light effect projected from the LCD display screen 2 onto the inner surface; and the image or light effect of the inner surface can be displayed on the outer surface of the imaging screen 4. In some embodiments, the outer surface of the imaging screen 4 is glossy, which can improve the imaging effect of the imaging screen 4.

[0026] In some embodiments, the imaging screen body is made of a highly transparent material, and its outer surface is smooth to avoid multiple slow reflections of imaging light, which would cause optical interference and negatively impact image clarity. The inner surface of the imaging screen is roughened to facilitate diffuse reflection of light to form an image. For example, the imaging screen is made of highly transparent acrylic (polymethyl methacrylate) or highly transparent glass, and its inner surface is roughened by a frosting process.

[0027] For curved imaging screens, whose inner surface is curved, the projection direction of the image or light effect of the LCD display screen 2 can be controlled by adjusting the optical structure and position of the first lens group 31. However, for imaging screens with large curvature (such as spherical screens), the above method is difficult to operate. Therefore, in some embodiments, a second lens group 32 is provided between the LCD display screen 2 and the imaging screen 4, which can effectively control the light beam projected by the LCD display screen 2 to be accurately projected onto the preset position of the imaging screen 4, thereby reducing the difficulty of operation.

[0028] It should be noted that the first lens group 31 or / and the second lens group 32 includes, but is not limited to, concave lenses, convex lenses, concave lens groups, convex lens groups, Fresnel lenses, Fresnel lens groups, and prisms. Any one of the above types can be used alone, or two or more types can be selected and combined along the projection light path. No specific restrictions are imposed here.

[0029] LED 1 is used to adjust the color temperature and brightness of the projected light source in conjunction with the display content of LCD screen 2, and LED 1 shines towards LCD screen 2. In some embodiments, the size of LCD screen 2 is less than 3 inches to adapt to the miniaturized internal layout of the device; of course, LCD screens larger than 3 inches can also be used to meet different needs. LCD screen 2 supports dual-mode display of static images and dynamic animations. In addition, the frame refresh rate of LCD screen 2 is usually not less than 30fps to ensure the smoothness of dynamic imaging; however, for some processors with limited computing power, or for display requirements that are not high (such as static images), the frame refresh rate of LCD screen 2 can be appropriately reduced to improve hardware compatibility.

[0030] like Figure 1 In the illustrated embodiment, the imaging screen 4 is hemispherical. The outer surface 402 of the imaging screen 4 is smooth, while the inner surface 401 is rough. The roughness of the inner surface 401 gradually changes from the edge 4011 to the center 4012, and the roughness of the edge 4011 is greater than that of the center 4012. The LED light 1, LCD display 2, and first lens group 31 are all fixed to the positioning seat 5 inside the device by detachable clips. The bottom of the positioning seat 5 is provided with an anti-slip buffer pad to prevent component vibration and displacement. In this embodiment, the LED light 1, first lens group 31, and LCD display 2 are arranged coaxially along the light propagation direction to ensure the consistency of the projected light path. The LCD display 2, first lens group 31, and imaging screen 4 are arranged sequentially along the projected light path. Furthermore, a second lens group 32 is provided between the LCD display 2 and the imaging screen 4, which can effectively control the beam projected by the LCD display 2 to be accurately projected onto a preset position on the inner surface 401.

[0031] To verify the impact of inner surface roughness on the display effect of the imaging screen, this application provides the following test. For example... Figure 1 As shown, the imaging screen 4 is hemispherical and its main body is made of a highly transparent material. Its outer surface 402 is polished to form a smooth surface, while its inner surface 401 is sandblasted to form a controllable rough structure.

[0032] Example 1: Gradual Roughness Structure The roughness of the inner surface 401 gradually changes from its edge 4011 towards the center 4012, that is, the diameter of the abrasive particles gradually increases. Uniform gradient; among them, the one closest to the LCD display screen 2 , away from LCD display screen 2 .

[0033] like Figure 6 As shown, the experimental data are as follows: Example 2: Uniform rough structure The diameter of the abrasive particles on the inner surface 401 is uniformly set to [value missing]. The distribution density is consistent on both sides, and no additional bright spots are specifically adjusted to maintain a roughly uniform roughness across the entire inner surface.

[0034] like Figure 7 As shown, the experimental data are as follows: Example 3: Partitioned coarse structure The inner surface 401 is divided into a region near the LCD edge 4011 and a center region 4012. The diameter of the frosted particles in the edge region is set to [missing information]. The diameter of the abrasive particles in the central area is set to There is no gradual transition between the two areas, and the density of frosted particles in the edge area is 1.5 times that in the center area, which specifically optimizes the bright spot problem.

[0035] like Figure 8 As shown, the experimental data are as follows: As can be seen from the above embodiments, the gradient roughness structure of Embodiment 1 performs best in terms of brightness uniformity, color uniformity, image clarity, and visual comfort; the uniform roughness structure of Embodiment 2 performs the worst among the three embodiments; the partitioned roughness structure of Embodiment 3 falls between the two and can be flexibly selected according to cost budget. In other words, by adjusting the distribution of roughness, different display effects can be achieved, which can improve the overall display quality and reduce or even eliminate local bright spots on the imaging screen.

[0036] like Figures 10 to 12As shown, this application provides another internal projection imaging device, in which the imaging screen 4a is more planar than a sphere. Specifically, the internal projection imaging device includes a light source 1a, a display device 2a, a first lens group 31a, and an imaging screen 4a. The imaging screen 4a has a rough inner surface 401a and a smooth outer surface 402a, wherein the inner surface 401a faces the light source 1a. The first lens group 31a is disposed between the light source 1a and the display device 2a, and is used to adjust the light beam emitted by the light source 1a to form a controllable light beam to illuminate the display device 2a, and project the image or light effect presented by the display device 2a onto the inner surface 401a of the imaging screen 4a; the image or light effect is diffusely reflected by the inner surface 401a and then displayed on the outer surface 402a through the imaging screen 4a. In this embodiment, the rough inner surface is formed by spraying titanium dioxide; while in other embodiments, the imaging screen is made by injection molding, the injection mold has a pre-set rough structure, and the resulting imaging screen has a rough surface. Generally, the roughness of the inner surface is approximately Ra0.4–0.7 μm.

[0037] In some embodiments, to reduce local bright spots, the surface roughness of the inner surface 401a gradually increases from near the display device to far away from the display device. For example, it is uniformly varied from Ra 0.4 to 1.2 μm, wherein the roughness closer to the display device is Ra 0.4 and the roughness farther from the display device is Ra 1.2.

[0038] An internal projection imaging method includes the following steps: S11. Configure the optical structure of the first lens group and adjust the relative position between the first lens group, the light source, and the display device to control the illumination beam emitted by the light source toward the display device within the effective display range of the display device.

[0039] The light source can be a single ultra-fine (1mm×1mm) high-power pure white wafer light-emitting LED planar light-emitting lamp bead. This light source can control the beam direction well and avoid generating messy diffuse reflection beams.

[0040] The types of lenses include, but are not limited to, concave lenses, convex lenses, concave lens groups, convex lens groups, Fresnel lenses, Fresnel lens groups, and prisms. The optical configuration of the first lens group can use any one of the above lens types alone, or it can select two or more lens types and combine them along the projection light path.

[0041] The first lens group can control the light beam emitted by the light source towards the display device within the effective display range of the display device, thereby improving light utilization efficiency. Furthermore, the first lens group can control the light beam into a parallel or conical beam, so that the beam illuminates the display device and projects its content onto the imaging screen.

[0042] S12. The illumination beam is pixel-modulated by the display device to load display content and form a transmission beam carrying the display content.

[0043] The display device includes a backlight-free LCD, a liquid crystal light valve, or a projection LCD panel. The embodiments of this application use a high-transmittance LCD with an aperture ratio of 85% and a high-density pixel (e.g., a pixel density of 332 PPI).

[0044] S13. Project the transmitted light beam onto the inner surface of the imaging screen, and perform diffuse reflection imaging through the rough structure set on the inner surface, so that the display content is presented on its outer surface through the imaging screen.

[0045] It should be noted that the content displayed on the display device is prone to distortion after being magnified and projected. Pre-distortion processing of the display content at the system level, combined with a fixed distance between the display device and the imaging screen, and with imaging screens of various shapes such as arc, hemispherical, and racetrack, can offset the imaging distortion after projection.

[0046] The core of pre-distortion is inverse pixel mapping: for each pixel in the output image Calculate its corresponding sampling coordinates in the original image. That is, complete The mapping avoids the pixel hole problem caused by forward mapping.

[0047] definition: The pixel coordinates of the pre-distorted output image; The pixel coordinates of the original input image. R is the distortion center, and R is the distortion radius.

[0048] I. Convex Lens Predistortion Formula: Calculate output points To the distortion center Distance: ; when At that time, perform distortion mapping: ; when At that time, take directly , .

[0049] Parameter description: This is the magnification factor. .

[0050] II. Concave Lens Predistortion Formula: Calculate output points To the distortion center Distance: ; when hour: ; Parameter description: To reduce the factor, .

[0051] III. Predistortion formula for waves or water ripples: Pre-distortion used to generate dynamic water ripple effects, adapting to the dynamic imaging needs of ambient lighting: ; Parameter description: For ripple amplitude, The wavelength is the ripple wavelength.

[0052] Due to the limited resources of embedded processors, distortion algorithms can be optimized. For example, to adapt to the characteristics of the BK7258, such as low clock speed, lack of a dedicated GPU, and small memory, the following optimization scheme can be adopted: The sin / cos / square root operation uses a lookup table method, which can pre-calculate a mapping table of integer values ​​within a range, replacing floating-point operations.

[0053] Floating-point to fixed-point integer conversion: For example, magnify all coordinate values ​​by 256 times, and then reduce the result by 256 times; Regional Restriction: The distortion formula is applied only to the core region; other regions are directly taken. This reduces the amount of computation.

[0054] To address the issue of localized bright spots that easily appear on the imaging screen near the display device, optimization can be achieved by adjusting the roughness of the inner surface. For example, the surface roughness of the inner surface 401a gradually increases from near the display device to far away from the display device; please refer to the above for details.

[0055] The light source forms an illumination beam through the first lens group. The brightness of this illumination beam is usually not uniform, which is related to the type and structure of the light source, the optical structure of the first lens group, and their positional relationship. For example... Figure 10 and Figure 13 As shown, in some embodiments, unevenly bright illumination beams can cause bright spot areas C to form on the imaging screen, reducing display quality. Therefore, this application provides a pre-compensation method that preprocesses the display content of the display device to reduce bright spots on the imaging screen. Specifically, as... Figure 13 , Figure 14As shown, the bright spot area C of the imaging screen can be measured or calculated to obtain the corresponding bright spot area D on the LCD display screen 2a, and the approximate center point o (i.e., the position with the highest brightness) of the bright spot area D can be determined. The coordinates of the center point o are defined as (cx, cy). Then, the preprocessing area is determined based on testing or calculation. For ease of explanation, this application sets the preprocessing area D as a circular area with (cx, cy) as the center point o and a radius of R. Of course, in other embodiments, the preprocessing area can also present other shapes, such as ellipse, square, triangle or polygon, and can be regular or irregular shapes. No specific limitation is made here. It can be understood that the preprocessing area D on the LCD display screen can be directly mapped to the preprocessing area E of the display content I. The pre-compensation method of this application is used to process the display content I, mainly targeting each pixel in the preprocessing area E, and includes the following steps: S21. Calculate the distance d between all pixels p and the center point o within the preprocessing region E: Wherein, the preprocessing region E is a circular region centered at (cx, cy) with a radius of R; (x, y) are the coordinates of the preprocessing pixel p.

[0056] S22. Normalization: t = d / R, where d ≤ R, t ∈ [0, 1].

[0057] like Figure 14 As shown, it should be noted that the preprocessing region E in this embodiment is a circular region; in other embodiments, the preprocessing region can be of other shapes. Here, R can be understood as the straight-line distance from the center point o through the preprocessed pixel point p to the boundary of the preprocessing region.

[0058] S23. Calculate the attenuation amount dim, dim ∈ [0, K], where K is the attenuation coefficient.

[0059] Dim=K×[cos(t×π) + 1] / 2; Where dim = K at the center (t = 0) and dim = 0 at the edge (t = 1).

[0060] The function of K×[cos(t×π) + 1] / 2 is to map the range of the cosine function from [−1, 1] to [0, 1], so that the decay is maximum at the center and zero at the edge, and its derivative is 0 at t = 0 and t = 1, thus achieving a smooth transition and avoiding visual abrupt changes.

[0061] K is used to control the maximum attenuation intensity; for example, K = 0.45 means that the brightness of the center pixel is retained by approximately 1 − 0.45 = 0.55 (i.e., attenuation of 45%). In this embodiment, the value of K ranges from 0.40 to 0.60.

[0062] S24. Calculate the gain mapping value gain: gain = 1 − dim.

[0063] For embedded processors, which have limited computing resources, the gain value corresponding to each pixel can be pre-calculated and stored in a lookup table. When preprocessing the display content, the gain value corresponding to each pixel can be directly obtained by looking up the table.

[0064] S25. Calculate the compensation value for each pixel.

[0065] Obtain the original R, G, and B values ​​for each pixel, and calculate the corresponding compensation value: R′= R × gain, G′= G × gain, B′= B × gain.

[0066] Then, based on R′, G′, and B′, the compensated display value for each pixel (x, y) is obtained.

[0067] Similarly, to reduce the processor load and avoid floating-point operations, gain can be magnified by 256 times, and then the result can be right-shifted by 8 bits. For example, in S24, gain_int = round[(1 − dim) × 256] is pre-stored; in S25, R′ = (R × gain_int) >> 8 (that is, right-shifting by 8 bits to achieve division by 256), and G′ and B′ are calculated similarly.

[0068] In some embodiments, a second lens group disposed between the LCD display 2 and the imaging screen 4 controls the light beam projected by the LCD display 2 to be accurately projected onto a preset position of the imaging screen 4. The internal projection method of this application further includes configuring the optical structure of the second lens group and adjusting the relative position between the second lens group and the display device and the imaging screen to control the transmitted light beam to be accurately projected onto a preset position on the inner surface of the imaging screen.

[0069] The technical scope of this application is not limited to the content described above. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this application, and all such modifications and variations should fall within the protection scope of this application.

Claims

1. An internal projection imaging device, characterized in that, It includes a light source, a first lens group, a display device, and an imaging screen; the first lens group is disposed between the light source and the display device, and is used to adjust the illumination beam emitted by the light source to shine on the display device; the imaging screen is used to receive the beam of light projected by the display device and display an image; The imaging screen has a pre-defined rough structure on its inner surface facing the display device.

2. The internal projection imaging device according to claim 1, characterized in that: The first lens group can control the illumination beam emitted by the light source toward the display device within the effective display range of the display device; or / and A second lens group is provided between the display device and the imaging screen.

3. The internal projection imaging device according to claim 1 or 2, characterized in that: The light source adjusts the color temperature and brightness of the light in conjunction with the display content of the display device; or / and The roughness of the inner surface is Ra0.4 to 0.7; or / and The imaging screen has a high-transmittance, high-brightness main body; and / or... The outer surface of the imaging screen facing away from the display device is a smooth surface.

4. The internal projection imaging device according to claim 1, characterized in that: The inner surface is divided into multiple regions, each region having a different roughness; or the roughness of the inner surface gradually changes from the direction closer to the display device to the direction farther away from the display device. The roughness of the inner surface closer to the display device is less than that farther away from the display device.

5. The internal projection imaging device according to claim 4, characterized in that: The roughness of the inner surface varies from Ra0.4 to 1.

2.

6. An internal projection imaging method, applied to an internal projection imaging device, characterized in that, The internal projection imaging device includes a light source, a first lens group, a display device, and an imaging screen arranged sequentially. The method includes: Configure the optical structure of the first lens group and adjust the relative positions between the first lens group, the light source, and the display device to control the illumination beam emitted by the light source toward the display device within the effective display range of the display device; The display device performs pixel modulation on the illumination beam to load display content and form a transmitted beam carrying the display content; The transmitted light beam is projected onto the inner surface of the imaging screen, and diffuse reflection imaging is performed through the rough structure provided on the inner surface, so that the outer surface of the imaging screen can reflect the display content.

7. The internal projection imaging method according to claim 6, characterized in that: The internal projection imaging device further includes a second lens group disposed between the display device and the imaging screen; The internal projection imaging method further includes: configuring the optical structure of the second lens group and adjusting the relative position between the second lens group and the display device and the imaging screen, so as to control the transmitted light beam to be accurately projected onto a preset position on the inner surface.

8. The internal projection imaging method according to claim 6, characterized in that: The display content of the display device is pre-distorted to compensate for the distortion that occurs when the display content is projected onto the imaging screen.

9. The internal projection imaging method according to claim 8, characterized in that: The pre-distortion processing includes at least one of magnification pre-processing, reduction pre-processing, and water ripple pre-processing; The amplification preprocessing includes: Obtain the output points of the original image To the distortion center distance ; and in At that time, perform distortion mapping: ; in, R represents the pixel coordinates of the pre-distorted output image; R is the distortion radius. This is the magnification factor, and ;when At that time, take directly , ; The shrinkage preprocessing includes: Obtain the output points of the original image To the distortion center distance ; and in At that time, perform distortion mapping: ; in, R represents the pixel coordinates of the pre-distorted output image; R is the distortion radius. This is a reduction factor, and ;when At that time, take directly , ; The water ripple preprocessing includes: ； in, For ripple amplitude, The wavelength is the ripple wavelength.

10. The internal projection imaging method according to claim 6, characterized in that: The display content of the display device is pre-compensated to reduce bright spots on the imaging screen. The pre-compensation method includes: Obtain the preprocessed area corresponding to the bright spot in the displayed content, and determine the coordinates (cx, cy) of the center point o of the preprocessed area. Calculate the Euclidean distance d between all preprocessed pixels within the preprocessed region and the center point o: Where (x, y) are the coordinates of the preprocessed pixel p; The distance d is normalized as follows: t = d / R, where R is the straight-line distance from the center point o through the preprocessed pixel point p to the boundary of the preprocessed region. Calculate the attenuation amount dim corresponding to the preprocessed pixel p: dim = K×[cos(t×π) + 1] / 2, where K is the attenuation coefficient, and 0 < K < 1; The compensation value p′ of the preprocessed pixel p is calculated using the attenuation amount dim: p′=p×(1-dim).

Images