CN112911270A - Image correction method for 100% offset three-dimensional sliced projection imaging system - Google Patents
Image correction method for 100% offset three-dimensional sliced projection imaging system Download PDFInfo
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Abstract
The invention belongs to the field of three-dimensional image display, and discloses an image correction method for a 100% offset three-dimensional sliced projection imaging system, which comprises the following steps: (1) carrying out initial correction on a 100% offset three-dimensional sliced projection imaging system; (2) establishing a three-dimensional rectangular coordinate system, and determining A, B, C, D vertex coordinates of the initial position projection image; (3) calculating the corresponding three-dimensional space coordinate A after rotating the gamma angle1、B1、C1、D1(ii) a (4) E, F, M, N four points are calculated; (5) determining an error vector, and performing secondary correction; (6) and filling the rectangular slice image into the image source after the secondary correction, namely obtaining expected projection on the target imaging screen, and realizing image correction. The invention improves the whole flow design of the correction method and the like, and utilizesThe overall cooperation among all the steps can effectively correct the three-dimensional slice image, and the negative conditions that the projected image has serious trapezoidal deformation and overflows a screen during projection are avoided.
Description
Technical Field
The invention belongs to the field of three-dimensional image display, and particularly relates to an image correction method for a 100% offset three-dimensional sliced projection imaging system.
Background
The three-dimensional slice type projection display technology is a novel naked eye three-dimensional visual display technology which is proposed in recent years. Unlike the common binocular vision-based three-dimensional display technology, the technology realizes a stereoscopic effect by forming a "three-dimensional projection volume" in a real space. The principle of the method is that three-dimensional image volume data is cut into a series of two-dimensional image slices, the series of two-dimensional slices are circularly projected onto an imaging screen which rotates concentrically at a high speed through a high-speed projection lens, the imaging screen bears a projection image corresponding to the current angle when being positioned at each position in a space, and when the image projection frequency and the rotation speed of the imaging screen reach a certain degree, human eyes can perceive a three-dimensional image with real physical depth in the space formed by the rotation of the imaging screen based on the principle of persistence of vision.
When the projection lens and the imaging screen form different included angles, the projected image can deform in the imaging screen. When the three-dimensional slice projection system operates, the imaging screen is in a high-speed rotation state, and a continuously-changing included angle exists between the projection lens and the imaging screen. Due to the projection characteristic of linear projection of 'big near and small far', projection images in the imaging screen can be deformed to different degrees when projection included angles are different. In order to keep the projected image always in the same projection area under different angles, the image needs to be corrected.
Unlike the calibration meaning and calibration purpose of a general projection device, in a three-dimensional sliced projection imaging system, the imaging screen needs to maintain high-speed rotation, so the size is small, and the projected image occupies most of the area of the imaging screen. When the projection angle is large, the projection result of the original image often overflows the screen, even a plurality of boundaries overflow the screen at the same time, and at this time, some existing methods such as using an angle sensor and a distance calculation unit, or using an additional camera to shoot the projection image and comparing the projection image with the original image cannot be implemented. In addition, three-dimensional tiled projection systems often require a series of images of the same angular spacing to be acquired. When the angle interval is different, the deformation parameter of each picture is different, the total number of the series of images will change correspondingly, and the existing method for correcting according to the projection result is not suitable from this point of view.
Disclosure of Invention
In view of the above drawbacks or needs for improvement in the prior art, an object of the present invention is to provide an image correction method for a 100% offset three-dimensional sliced projection imaging system, in which by improving the overall flow design of the correction method and the like, the three-dimensional sliced image can be effectively corrected by utilizing the overall cooperation between the steps, and the occurrence of negative situations such as the projected image overflowing the screen during projection is avoided. The method can complete the image correction process without an external measuring instrument, and does not increase additional system complexity and hardware cost; the numerical calculation process only uses the projection ratio parameter of the projection module, and does not need to know other complex optical parameters or light path structures and the like; the method is suitable for a three-dimensional slice type projection system, and has good performance when acquiring the correction parameter set of a series of two-dimensional images.
To achieve the above object, according to the present invention, there is provided an image correction method for a 100% offset three-dimensional sliced projection imaging system, comprising the steps of:
(1) based on an initial image source in a rectangular shape, performing initial correction on a 100% offset three-dimensional sliced projection imaging system to enable the spatial position of a projection module and an imaging screen to meet 100% offset projection display, and simultaneously enabling the spatial position and the posture of the imaging screen to meet the requirement that an image obtained by projection is displayed as a rectangle on the imaging screen, wherein the central line of the rectangle is completely overlapped with a rotating shaft of the imaging screen; after initial correction, fixing the spatial position of the projection module, and simultaneously recording the imaging screen at the moment as an initial imaging screen, wherein a rectangular image on the initial imaging screen is an initial rectangle;
(2) establishing a three-dimensional rectangular coordinate system to obtain a three-dimensional space coordinate L of the projection module and a three-dimensional space coordinate of four vertexes A, B, C, D of the rectangular image on the initial imaging screen, wherein a rectangular area surrounded by A, B, C, D is a projection area;
(3) rotating the initial imaging screen by a preset gamma angle around a rotating shaft to obtain a target imaging screen; the four vertices A, B, C, D on the initial imaging screen will arrive at new spatial positions along with the rotation, denoted as A respectively1、B1、C1、D1While recording A1、B1、C1、D1Three-dimensional space coordinates of (a);
(4) calculating LA1、LB1、LC1、LD1The four intersection points of the four straight lines and the plane where the initial imaging screen is located are respectively marked as E, F, M, N; E. f, M, N, the correspondingly formed quadrangle EFMN is in a right trapezoid shape, and the three-dimensional coordinates of the four points E, F, M, N are the initial target corrected image coordinate set;
(5) adjusting the initial image source in proportion according to the proportional relation of the corresponding side length between the quadrilateral EFMN and the initial rectangle ABCD, and recording the adjusted image source as an image source for secondary correction; then, projecting the image source for secondary correction to the target imaging screen to obtain a projection graph for secondary correction, wherein the projection graph for secondary correction also has four vertexes; then, based on the four vertices of the projected graph for secondary correction and the A1、B1、C1、D1Determining an error vector by the position deviation between the four points, wherein if the value of the error vector does not exceed a preset threshold value, the three-dimensional coordinates of the E, F, M, N four points are the final target corrected image coordinate set under the gamma angle; if the magnitude of the error vector exceeds a preset threshold value, the E, F, M, N four points are adjusted in a stepping mode until the four vertexes of the projected graph for secondary correction and the A1、B1、C1、D1The position deviation between the four points meets the preset requirement, and the finally obtained adjusted E, F, M,The three-dimensional coordinates of the N four points are the final target correction image coordinate set under the gamma angle;
(6) updating the gamma angle to another preset angle value, and repeating the steps (3) to (5) to obtain a final target correction image coordinate set under each required angle; and respectively deforming a group of rectangular slice images to be projected according to a final target correction image coordinate set under a corresponding angle to obtain a corrected slice image group, wherein the slice image group can obtain an expected projection rectangle on a target imaging screen at the corresponding angle to realize image correction.
As a further preferred embodiment of the present invention, in the step (2), the XOZ plane of the three-dimensional rectangular coordinate system is a plane where the initial imaging screen is located, and the projection module is located on the Y-axis of the three-dimensional rectangular coordinate system.
As a further preferred embodiment of the present invention, in the step (2), the three-dimensional space coordinate L of the projection module is (0, mT, 0), where m is the image width corresponding to the initial rectangle, and T is the projection ratio of the projection imaging system.
As a further preferred embodiment of the present invention, in the step (2), the coordinate system graduation of the three-dimensional rectangular coordinate system is equal to an image pixel.
As a further preferred aspect of the present invention, a mesh paper having an accuracy meeting a predetermined requirement is laid on the imaging screen in advance, so that the error vector can be determined directly by observation in step (5).
As a further preferable aspect of the present invention, the accuracy of the mesh paper is equal to or better than the preset threshold in the step (5).
As a further preferred aspect of the present invention, in the step (6), the deformation is performed by performing pixel completion based on a bilinear interpolation algorithm.
Through the technical scheme, compared with the prior art, the three-dimensional slice image can be effectively corrected by utilizing the overall cooperation among the steps of the correction method, the negative conditions that the projected image is seriously deformed in a trapezoid way and overflows a screen during projection are avoided, and the method is particularly suitable for a 100% offset linear projection three-dimensional slice type projection imaging system.
In a three-dimensional slice type projection system, when an imaging screen is required to be at different angles, projected images are all located in the same area of the imaging screen; the image correction method can calculate the image correction result of the imaging screen and the projection lens under any included angle excluding the vertical direction (the vertical direction corresponds to the situation that the rotating angle is 90 degrees, 270 degrees and the like, at this time, the projected image is necessarily a straight line), and ensures that the projected images are all positioned in the same area of the imaging screen when the imaging screen is at different rotating positions.
Specifically, the present invention can achieve the following advantageous effects:
(1) according to the method, image deformation parameters at different projection angles are obtained without using an angle sensor, a distance calculation unit or adding a camera and the like, and a three-dimensional rectangular coordinate system is established to carry out numerical calculation according to linear projection characteristics. For the three-dimensional slice type projection system, any hardware equipment cannot be added for image correction, and the complexity of the system and the hardware cost are reduced.
(2) For convenience of numerical calculation, the graduation of the coordinate system can be preferably equal to the image pixels, the coordinates of the key points can be obtained according to the spatial resolution of the image, the coordinate values cannot be influenced when the projection distance and the size of the projected image are changed, and errors caused by manual or automatic calibration are avoided; meanwhile, because the four vertexes of the final calculation result and the four vertexes of the initial position projection image are positioned on the same plane, the conversion from an image space to an object space is avoided, the original image is directly deformed and filled into the corrected quadrangle according to the same proportion, the final image can be obtained, the calculation process is simplified, and the flow is clear.
(3) The method is suitable for a three-dimensional slice type projection system, and the performance is good when the correction parameter group of the series of two-dimensional images is obtained. Especially, when the projection angle is large and the original projection image may overflow or even overflow the screen in multiple sides, the approximate image deformation parameter when the projection angle is gamma can be calculated in advance through the linear projection characteristic, and then the error between the human eye observation and the ideal projection effect of the projection image is projected, so as to obtain the final correction result. The semi-automatic method is simple to operate, ensures that the projection image of each projection position has a better result in human eyes, and has stronger robustness.
Drawings
Fig. 1 is a schematic diagram of two linear projection modes, 100% offset and 0% offset.
Fig. 2 is a flow chart of a calibration method implemented by the present invention for a 100% offset linear projection three-dimensional sliced projection imaging system.
FIG. 3 is a schematic diagram of ideal projection effect (six spatial degrees of freedom are labeled in the figure, namely, 3 translational degrees of freedom x, y, z and 3 rotational degrees of freedom tα、tβ、tθ)。
FIG. 4 is a schematic diagram of an image correction process; wherein (a) in fig. 4 is a schematic diagram of coordinates of four points of ABCD on the imaging screen obtained by projecting the initial image without initial rotation, and (b) in fig. 4 is a coordinate a of four points corresponding to ABCD when rotating γ1B1C1D1Schematic view, fig. 4 (c) is according to A1B1C1D1The process schematic diagram of four-point space coordinates of the target correction image coordinate set EFMN is calculated by four-point coordinates, and (d) in fig. 4 is a schematic diagram of a ratio of ABCD to γ -angle target correction coordinate set EFMN.
FIG. 5 is a diagram showing a modification process of an actual system; wherein (a-1) in fig. 5 is an initial image source; FIG. 5 (a-2) shows a projected image corresponding to the initial image source shown in FIG. 5 (a-1) when the imaging screen is in the initial position; FIG. 5 (b-1) shows the source of the target correction image when the imaging screen is rotated 30 °; FIG. 5 (b-2) is a projected image corresponding to the target correction image source shown in FIG. 5 (b-1) when the imaging screen is rotated by 30 °; FIG. 5 (c-1) shows the source of the target correction image when the imaging screen is rotated 45 °; fig. 5 (c-2) shows a projection image corresponding to the target correction image source shown in fig. 5 (c-1) when the imaging screen is rotated by 45 °.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
First, in order to make the description of the present invention more concise and understandable, the abbreviations and terms appearing in the present invention are explained (these explanations satisfy the conventional definitions in the field of projection displays):
(i) and the projection angle is the included angle between the plane of the projection lens and the plane of the imaging screen, which is called the projection angle for short.
(ii) The projection ratio is calculated by the ratio of the projection distance to the projection screen width.
(iii) Offset in the field of projection display, the offset is used to describe the path of the projection light after leaving the projection lens. The 0% offset optical module represents the sending light which is uniform up and down after the projection light leaves the projection lens. And a 100% offset optical module indicates that the projected light is shifted upward so that the bottom of the image coincides with the projection lens axis. Two projection diagrams are shown in fig. 1.
In summary, the processing flow of the image correction method for a 100% offset three-dimensional sliced projection system according to the present invention is shown in fig. 2; for any projection angle, the method can automatically calculate geometric correction parameters and obtain corrected images to realize the correction process.
Specifically, the method comprises the following steps:
(1) equipment calibration was performed manually. Embodied as fixing the spatial position of the projection lens by six degrees of freedom (three translational degrees of freedom (T)) in three-dimensional space for the imaging screenx,Ty,Tz) And three rotational degrees of freedom (T)θ,Tα,Tβ) Adjusting (three translational degrees of freedom correspond to the spatial position of the imaging screen, and three rotational degrees of freedom correspond to the spatial attitude of the imaging screen) until the effect of the projected image at the initial position satisfies the following conditions:
1. according to the general requirement of projection, the image is positioned in the center of the imaging screen, and the projected image is paved in most of the area of the imaging screen;
2. the central line of the projected image is completely coincided with the rotating shaft of the imaging screen;
3. the area of the left image is completely equal to that of the right image by taking the rotating shaft of the imaging screen as a boundary, the left image and the right image are completely the same in shape, and the left image and the right image are in a standard rectangular shape without deformation.
The schematic diagram of ideal projection effect and spatial degree of freedom is shown in fig. 3, and the imaging screen is fully covered with high-precision mesh paper (the precision requirement can be preset) for auxiliary correction.
(2) And (3) projecting an image at the initial position of the imaging screen, and establishing a three-dimensional rectangular coordinate system by taking the middle point of the lower boundary of the projected image as the origin of coordinates, wherein the division value of the coordinate system is equal to the pixels of the image. For a projection image with a spatial resolution of m × n, namely the width of the projection image is m, the height of the projection image is n, and r is m/2, the coordinates of four points are A (-r,0, n), B (r,0, n), c (r,0,0), D (-r,0,0), and the positions of the four points are marked on the imaging screen; when the projection module is processed as a point, the projection module coordinate L (0, m × T,0) can be calculated according to the projection ratio T, as shown in fig. 4 (a).
(3) The imaging screen is arranged along T from the initial positionβWhen the direction overlook angle rotates anticlockwise gamma, the current space coordinate A of four points of the imaging screen A, B, C, D is calculated1(-rcosγ,rsinγ,n),B1(rcosγ,-rsinγ,n),C1(rcosγ,-rsinγ,0),D1(rcosγ, rsin γ,0), as shown in (b) of FIG. 4.
(4) Finding the line LA1、LB1、LC1、LD1The intersection E, F, M, N of the four straight lines with the XZ plane (i.e., the plane of the initial position of the imaging screen), i.e., the initial target correction image coordinate set. According to the linear projection law, when the initial position image is the quadrangle EFMN, the projection area of the image is exactly equal to the quadrangle A after the imaging screen rotates the angle gamma1B1C1D1Complete coincidence, E, F, M, N calculated to obtain
As shown in fig. 4 (c).
(5) The obtained E, F, M, N was subjected to error analysis. The projection module is treated as a point in the algorithm,therefore, a certain error may exist in the actual projection process of the calculated four points, the computer generates a pure white image with the same shape as the quadrilateral EFMN, the image size is in the same proportion with the original image, the pure white image is projected when the projection angle is gamma, the human eye positions and observes the projection result by means of the high-precision grid, and records the projection result and the A1、B1、C1、D1The position offset of the four points is corrected according to the E, F, M, N four points until the position offset is equal to A1、B1、C1、D1And (4) recording and adjusting E, F, M, N four-point final target correction image coordinate sets after the horizontal and vertical coordinates of the four-point positions are all smaller than a set threshold value.
(6) A, B, C, D and E, F, M, N are located in the same plane and have the same projection distance and projection ratio as shown in fig. 4 (d), so that the content of the quadrilateral ABCD image can be directly deformed and filled into the quadrilateral EFMN in the same proportion to directly obtain the corrected image. Let S, T be the intersection point of the upper and lower boundaries of the projected image and the rotation center axis of the imaging screen, and know that the imaging screen is along TβWhen the direction is rotated, the image content on the ST line segment is always kept completely the same, and then the deformation filling process is divided into two parts: filling the quadrilateral ASTD image content deformation into a quadrilateral ESTN; and (3) filling the quadrilateral SBCT image content deformation into a quadrilateral SFMT, and completing the pixel value by adopting a bilinear interpolation method in the deformation filling process to obtain a corrected image when the projection angle is gamma.
Example 1
The embodiment comprises the following steps:
(1) in the embodiment, a three-dimensional projection system is constructed by adopting a high-speed projection chip DLP6500 based on a DMD (digital micromirror device) produced by TI company and matching with a projection lens optical module adapted to the high-speed projection chip DLP 6500. The module supports projection of 1920 x 1080 resolution images and is a 100% offset linear projection image. The three-dimensional imaging screen is designed and processed independently, an angle scale is engraved on the surface of the base, and the index value is 1 degree and is used for marking the initial position and the rotation angle of the imaging screen; and the four corners of the bottom of the base are provided with height adjusting components which can be used for actions such as plane leveling and the like. The imaging screen is rectangular, the size is 15cm x 15cm, and imaging can be realized by the driving of the servo motorIs shielded at TβThe direction completes 1500r/min high-speed concentric rotation movement. And (3) spreading high-precision grid paper on the imaging screen, wherein the precision is 1mm x 1 mm. The grid paper is completely attached to the imaging screen, the surface is smooth and has no folds, and the whole imaging screen is divided into 150 × 150 small grids.
(2) A square image with 800 × 800 resolution is projected, for correction, the center line in the vertical direction is taken as a dividing line, the left side is a white pure color image (pixel value 255), and the right side is a gray pure color image (pixel value 128), and according to the representation of the projected image in the imaging screen, the six spatial degrees of freedom of the imaging screen are adjusted until the ideal imaging effect in the initial position of the imaging screen is achieved (of course, other colors or specific patterns can be adopted for distinguishing besides white and gray).
(3) Correcting a projection image when the offset angle of the imaging screen is gamma, illustrating a numerical calculation process when the overlooking angle of the imaging screen rotates 10 degrees anticlockwise from an initial position, completing coordinate calculation and image correction by writing a C + + program, and setting a development platform to be Qt 5.14.2.
And (3-1) establishing a three-dimensional rectangular coordinate system by taking the center point of the lower boundary of the projection image as the origin of coordinates, setting the division value of the coordinate axes to be 1mm and matching with the grid, and then setting the four-vertex space coordinates of the projection image at the initial position to be A (-400,0,800), B (400,0,800), C (400,0,0) and D (-400,0, 0). For the DLP6500 projection chip, the projection image resolution is 1920 × 1080, the projection ratio T is 1.66, and the spatial position coordinates of the projection source are calculated to be (0,3187, 0).
(3-2) after the imaging screen rotates 10 degrees counterclockwise (the specific angle of rotation can be flexibly adjusted, for example, the frequency can be selected according to the rotation speed of high-speed rotation motion and the principle of persistence of vision, so as to select the rotation angles at a plurality of moments in a period or select the rotation angles at a plurality of moments in a period for calculation), the new coordinate obtained by moving the spatial position of the four points A, B, C, D in the imaging screen is A1(-394,70,800),B1(394,-70,800),C1(394,-70,0),D1(-394,70,0)；
(3-3) connection of LA1、LB1、LC1、LD1Solving the intersection point E between the four straight lines and the plane y which is 0,F. M, N, and E (-403,0,818), F (386,0,783), M (386,0,0), N (-403,0, 0);
(3-4) E, F, M, N four points form a right trapezoid, the right trapezoid is filled into a pure white image and is projected, and by means of high-precision grid paper, the error vector of the actual projected image and the vertex of the ideal imaging area under the projection angle is estimated and recorded by human eyes. Step adjustment is carried out on each vertex until the four-point error estimation results are all smaller than a set threshold value by 1mm, and the coordinates of the four points at the moment are recorded as a coordinate set for correction under the final angle;
(3-5) dividing the original image content into a left side and a right side by taking the rotation of the imaging screen as a center, and respectively carrying out deformation according to the coordinate sets for correction to obtain corrected images at the angle; in the deformation process, a bilinear interpolation algorithm can be adopted for pixel completion.
The above-described embodiments are merely examples, and the present invention is applicable to all three-dimensional sliced projection systems that project images at 100% offset, and is not limited to the above-described specific types of projection lenses, three-dimensional imaging screens, and the like. In addition, the bilinear interpolation algorithm can be directly carried out by referring to the related prior art, and the invention is not repeated; of course, other interpolation methods known in the art may be used in addition to the bilinear interpolation algorithm. The rectangle in the invention meets the conventional mathematical definition; for example, after the initial correction, the center line of the initial rectangle completely coincides with the rotation axis of the imaging screen, and at this time, the left and right images are completely equal in area and shape, taking the rotation axis of the imaging screen as a boundary, and thus, a standard rectangular shape is formed without deformation.
It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (7)
1. An image correction method for a 100% offset three-dimensional sliced projection imaging system, comprising the steps of:
(1) based on an initial image source in a rectangular shape, performing initial correction on a 100% offset three-dimensional sliced projection imaging system to enable the spatial position of a projection module and an imaging screen to meet 100% offset projection display, and simultaneously enabling the spatial position and the posture of the imaging screen to meet the requirement that an image obtained by projection is displayed as a rectangle on the imaging screen, wherein the central line of the rectangle is completely overlapped with a rotating shaft of the imaging screen; after initial correction, fixing the spatial position of the projection module, and simultaneously recording the imaging screen at the moment as an initial imaging screen, wherein a rectangular image on the initial imaging screen is an initial rectangle;
(2) establishing a three-dimensional rectangular coordinate system to obtain a three-dimensional space coordinate L of the projection module and a three-dimensional space coordinate of four vertexes A, B, C, D of the rectangular image on the initial imaging screen, wherein a rectangular area surrounded by A, B, C, D is a projection area;
(3) rotating the initial imaging screen by a preset gamma angle around a rotating shaft to obtain a target imaging screen; the four vertices A, B, C, D on the initial imaging screen will arrive at new spatial positions along with the rotation, denoted as A respectively1、B1、C1、D1While recording A1、B1、C1、D1Three-dimensional space coordinates of (a);
(4) calculating LA1、LB1、LC1、LD1The four intersection points of the four straight lines and the plane where the initial imaging screen is located are respectively marked as E, F, M, N; E. f, M, N, the correspondingly formed quadrangle EFMN is in a right trapezoid shape, and the three-dimensional coordinates of the four points E, F, M, N are the initial target corrected image coordinate set;
(5) adjusting the initial image source in proportion according to the proportional relation of the corresponding side length between the quadrilateral EFMN and the initial rectangle ABCD, and recording the adjusted image source as an image source for secondary correction; then, projecting the image source for secondary correction to the target imaging screen to obtain a projection graph for secondary correction, wherein the projection graph for secondary correction also has four vertexes; then, based on the four vertices of the projected graph for secondary correction and the A1、B1、C1、D1Determining an error vector if the value of the error vector is determined by the position offset between four pointsIf the size of the E, F, M, N is not more than a preset threshold value, the three-dimensional coordinates of the E, F, M, N four points are the final target correction image coordinate set under the gamma angle; if the magnitude of the error vector exceeds a preset threshold value, the E, F, M, N four points are adjusted in a stepping mode until the four vertexes of the projected graph for secondary correction and the A1、B1、C1、D1The position deviation between the four points meets the preset requirement, and the finally obtained three-dimensional coordinates of the E, F, M, N four points after adjustment are the final target correction image coordinate set under the gamma angle;
(6) updating the gamma angle to another preset angle value, and repeating the steps (3) to (5) to obtain a final target correction image coordinate set under each required angle; and respectively deforming a group of rectangular slice images to be projected according to a final target correction image coordinate set under a corresponding angle to obtain a corrected slice image group, wherein the slice image group can obtain an expected projection rectangle on a target imaging screen at the corresponding angle to realize image correction.
2. The image correction method for a 100% offset three-dimensional sliced projection imaging system of claim 1, wherein in step (2), the XOZ plane of the three-dimensional rectangular coordinate system is the plane of the initial imaging screen, and the projection module is located on the Y-axis of the three-dimensional rectangular coordinate system.
3. The image correction method for a 100% offset three-dimensional sliced projection imaging system as claimed in claim 1, wherein in the step (2), the three-dimensional space coordinate L of the projection module is (0, mT, 0), where m is the image width corresponding to the initial rectangle and T is the projection ratio of the projection imaging system.
4. The image correction method for a 100% offset three-dimensional sliced projection imaging system of claim 1, wherein in step (2), the three-dimensional rectangular coordinate system has a coordinate system index equal to the image pixels.
5. The image correction method for a 100% offset three-dimensional sliced projection imaging system as claimed in claim 1, wherein the imaging screen is pre-laid with a mesh paper having an accuracy meeting a predetermined requirement so that the error vector can be directly determined by observation in the step (5).
6. The image correction method for a 100% offset three-dimensional sliced projection imaging system according to any of claims 1-5, wherein the accuracy of the mesh paper is equal to or better than the predetermined threshold in the step (5).
7. The image correction method for a 100% offset three-dimensional sliced projection imaging system according to any of claims 1-6, wherein in the step (6), the deformation is pixel-complementing based on a bilinear interpolation algorithm.
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